Sample records for reactor based epithermal

  1. An accelerator-based epithermal photoneutron source for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Nigg, D.W.; Mitchell, H.E.; Harker, Y.D.; Yoon, W.Y. [and others


    Therapeutically-useful epithermal-neutron beams for BNCT are currently generated by nuclear reactors. Various accelerator-based neutron sources for BNCT have been proposed and some low intensity prototypes of such sources, generally featuring the use of proton beams and beryllium or lithium targets have been constructed. This paper describes an alternate approach to the realization of a clinically useful accelerator-based source of epithermal neutrons for BNCT that reconciles the often conflicting objectives of target cooling, neutron beam intensity, and neutron beam spectral purity via a two stage photoneutron production process.

  2. Performance verification of an epithermal neutron flux monitor using accelerator-based BNCT neutron sources (United States)

    Guan, X.; Murata, I.; Wang, T.


    The performance of an epithermal neutron flux monitor developed for boron neutron capture therapy (BNCT) is verified by Monte Carlo simulations using accelerator-based neutron sources (ABNSs). The results indicate that the developed epithermal neutron flux monitor works well and it can be efficiently used in practical applications to measure the epithermal neutron fluxes of ABNSs in a high accuracy.

  3. Multipurpose epithermal neutron beam on new research station at MARIA research reactor in Swierk-Poland

    Energy Technology Data Exchange (ETDEWEB)

    Gryzinski, M.A.; Maciak, M. [National Centre for Nuclear Research, Andrzeja Soltana 7, 05-400 Otwock-Swierk (Poland)


    MARIA reactor is an open-pool research reactor what gives the chance to install uranium fission converter on the periphery of the core. It could be installed far enough not to induce reactivity of the core but close enough to produce high flux of fast neutrons. Special design of the converter is now under construction. It is planned to set the research stand based on such uranium converter in the near future: in 2015 MARIA reactor infrastructure should be ready (preparation started in 2013), in 2016 the neutron beam starts and in 2017 opening the stand for material and biological research or for medical training concerning BNCT. Unused for many years, horizontal channel number H2 at MARIA research rector in Poland, is going to be prepared as a part of unique stand. The characteristics of the neutron beam will be significant advantage of the facility. High flux of neutrons at the level of 2x10{sup 9} cm{sup -2}s{sup -1} will be obtainable by uranium neutron converter located 90 cm far from the reactor core fuel elements (still inside reactor core basket between so called core reflectors). Due to reaction of core neutrons with converter U{sub 3}Si{sub 2} material it will produce high flux of fast neutrons. After conversion neutrons will be collimated and moderated in the channel by special set of filters and moderators. At the end of H2 channel i.e. at the entrance to the research room neutron energy will be in the epithermal energy range with neutron intensity at least at the level required for BNCT (2x10{sup 9} cm{sup -2}s{sup -1}). For other purposes density of the neutron flux could be smaller. The possibility to change type and amount of installed filters/moderators which enables getting different properties of the beam (neutron energy spectrum, neutron-gamma ratio and beam profile and shape) is taken into account. H2 channel is located in separate room which is adjacent to two other empty rooms under the preparation for research laboratories (200 m2). It is

  4. An accelerator-based epithermal photoneutron source for boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Hannah E. [Georgia Inst. of Technology, Atlanta, GA (United States)


    Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. Current usable beams are reactor-based but a viable alternative is the production of an epithermal neutron beam from an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of 107 neutrons per second per milliampere of electron current is shown to be obtainable. Additionally, the neutron beam is modified and characterized for BNCT applications by employing two unique moderating materials (an Al/AlF3 composite and a stacked Al/Teflon design) at various incident electron energies.

  5. Optimization study for an epithermal neutron beam for boron neutron capture therapy at the University of Virginia Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Jr., Thomas Dean [Univ. of Virginia, Charlottesville, VA (United States)


    The non-surgical brain cancer treatment modality, Boron Neutron Capture Therapy (BNCT), requires the use of an epithermal neutron beam. This purpose of this thesis was to design an epithermal neutron beam at the University of Virginia Research Reactor (UVAR) suitable for BNCT applications. A suitable epithermal neutron beam for BNCT must have minimal fast neutron and gamma radiation contamination, and yet retain an appreciable intensity. The low power of the UVAR core makes reaching a balance between beam quality and intensity a very challenging design endeavor. The MCNP monte carlo neutron transport code was used to develop an equivalent core radiation source, and to perform the subsequent neutron transport calculations necessary for beam model analysis and development. The code accuracy was validated by benchmarking output against experimental criticality measurements. An epithermal beam was designed for the UVAR, with performance characteristics comparable to beams at facilities with cores of higher power. The epithermal neutron intensity of this beam is 2.2 x 108 n/cm2 • s. The fast neutron and gamma radiation KERMA factors are 10 x 10-11cGy•cm2/nepi and 20 x 10-11 cGy•cm2/nepi , respectively, and the current-to-flux ratio is 0.85. This thesis has shown that the UVAR has the capability to provide BNCT treatments, however the performance characteristics of the final beam of this study were limited by the low core power.

  6. Dose measurements and calculations in the epithermal neutron beam at the Brookhaven Medical Research Reactor (BMRR)

    Energy Technology Data Exchange (ETDEWEB)

    Fairchild, R.G.; Greenberg, D.; Kamen, Y.; Fiarman, S. (Brookhaven National Lab., Upton, NY (USA). Medical Dept.); Benary, V. (Brookhaven National Lab., Upton, NY (USA). Medical Dept. Tel Aviv Univ. (Israel)); Kalef-Ezra, J. (Brookhaven National Lab., Upton, NY (USA). Medical Dept. Ioannina Univ. (Greece)); Wielopolski, L. (Brookhaven National Lab., Upton, NY (USA). Medical Dept. State Univ. of New


    The characteristics of the epithermal neutron beam at BMRR were measured, calculated, and reported. This beam has already been used for animal irradiations. We anticipate that it will be used for clinical trials. Thermal and epithermal neutron flux densities distributions, and dose rate distributions, as a function of depth were measured in a lucite dog-head phantom. Monte Carlo calculations were performed and compared with the measured values. 2 refs., 4 figs., 1 tab.

  7. Single-crystal filters for attenuating epithermal neutrons and gamma rays in reactor beams

    DEFF Research Database (Denmark)

    Rustad, B.M.; Als-Nielsen, Jens Aage; Bahnsen, A.


    Cross section of representative samples of bismuth and quartz were measured at room and liquid nitrogen temperatures over neutron energy range of 0.0007 to 2.0 ev to obtain data for design of single-crystal 32-cm bismuth filters for attenuating fast neutrons and γ-rays in reactor beams; filters may...... be constructed to optimize beam characteristics for low energy neutron experiments....


    Directory of Open Access Journals (Sweden)

    Michaela Rabochová


    Full Text Available In this study, a measurements of neutron field using a special positioning device with a 6Li + Si detector and image plate is described. The measurements were provided for Boron Neutron Capture Therapy (BNCT channel of the LVR-15 reactor in the Research Centre Rez Ltd., Czech Republic. Mapping of neutron field represents an essential and crucial part of planning BNCT treatment (especially for patients suffering from brain tumor Glioblastoma Multiforme.

  9. Boron neutron capture therapy (BNCT) for glioblastoma multiforme using the epithermal neutron beam at the Brookhaven Medical Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Capala, J. [Brookhaven National Lab., Upton, NY (United States); Diaz, A.Z.; Chadha, M. [Univ. Hospital, State Univ. of New York, NY (United States)] [and others


    The abstract describes evaluation of boron neutron capture therapy (BNCT) for two groups of glioblastoma multiforme patients. From September 1994 to February 1996 15 patients have been treated. In September 1997 another 34 patients were examined. Authors determined a safe starting dose for BNCT using epithermal neutrons and BPA-F. They have also evaluated adverse effects of BNCT at this starting dose. Therapeutic effectiveness of this starting dose has been evaluated. No significant side effects from BPA-F infusion or BNCT treatment were observed in normal brains.

  10. Experimental demonstration of a compact epithermal neutron source based on a high power laser (United States)

    Mirfayzi, S. R.; Alejo, A.; Ahmed, H.; Raspino, D.; Ansell, S.; Wilson, L. A.; Armstrong, C.; Butler, N. M. H.; Clarke, R. J.; Higginson, A.; Kelleher, J.; Murphy, C. D.; Notley, M.; Rusby, D. R.; Schooneveld, E.; Borghesi, M.; McKenna, P.; Rhodes, N. J.; Neely, D.; Brenner, C. M.; Kar, S.


    Epithermal neutrons from pulsed-spallation sources have revolutionised neutron science allowing scientists to acquire new insight into the structure and properties of matter. Here, we demonstrate that laser driven fast (˜MeV) neutrons can be efficiently moderated to epithermal energies with intrinsically short burst durations. In a proof-of-principle experiment using a 100 TW laser, a significant epithermal neutron flux of the order of 105 n/sr/pulse in the energy range of 0.5-300 eV was measured, produced by a compact moderator deployed downstream of the laser-driven fast neutron source. The moderator used in the campaign was specifically designed, by the help of MCNPX simulations, for an efficient and directional moderation of the fast neutron spectrum produced by a laser driven source.

  11. Geologic and tectonic setting of Deseado Massif epithermal deposits, Argentina, based on El Dorado-Monserrat (United States)

    Echavarría, Leandro E.; Schalamuk, Isidoro B.; Etcheverry, Ricardo O.


    Middle-Late Jurassic bimodal volcanism, typical of a retroarc setting, developed during widespread extensional tectonism within the Deseado Massif, southern Argentina. This geologic environment led to the formation of numerous low-sulfidation epithermal deposits that are spatially and temporally related to the volcanic activity. The lack of significant high-sulfidation epithermal deposits may be because the tectonic and volcanic settings do not favor the formation of these types of deposits. El Dorado-Monserrat is a low-sulfidation epithermal prospect located near the southern boundary of the Deseado Massif. Mineralization is genetically linked to the Late Jurassic Chon Aike Formation and hosted by volcanic rocks of the middle Late Jurassic Bajo Pobre Formation. Two different mineralization areas have been identified. The Monserrat area is the most important, with veins hosted in a north-striking, left-lateral shear zone. The average thickness is 0.85 m, and the average metal content is 6.2 ppm gold and 153 ppm silver. The El Dorado area has discontinuous echelon veins within a right-lateral shear zone with low gold and silver grades. Hydrothermal alteration of the host rocks includes an inner zone of quartz-adularia and illite alteration and an outer zone of propylitic alteration. The main gangue mineral is quartz, which formed in successive pulses, plus adularia, pyrite, hematite, magnetite, and barite. Precious metals occur as zoned electrum. Ore mineral precipitation took place between 200 and 280 °C from low salinity fluids due to boiling.

  12. Accelerator based fusion reactor (United States)

    Liu, Keh-Fei; Chao, Alexander Wu


    A feasibility study of fusion reactors based on accelerators is carried out. We consider a novel scheme where a beam from the accelerator hits the target plasma on the resonance of the fusion reaction and establish characteristic criteria for a workable reactor. We consider the reactions d+t\\to n+α,d+{{}3}{{H}\\text{e}}\\to p+α , and p+{{}11}B\\to 3α in this study. The critical temperature of the plasma is determined from overcoming the stopping power of the beam with the fusion energy gain. The needed plasma lifetime is determined from the width of the resonance, the beam velocity and the plasma density. We estimate the critical beam flux by balancing the energy of fusion production against the plasma thermo-energy and the loss due to stopping power for the case of an inert plasma. The product of critical flux and plasma lifetime is independent of plasma density and has a weak dependence on temperature. Even though the critical temperatures for these reactions are lower than those for the thermonuclear reactors, the critical flux is in the range of {{10}22}-{{10}24}~\\text{c}{{\\text{m}}-2}~{{\\text{s}}-1} for the plasma density {ρt}={{10}15}~\\text{c}{{\\text{m}}-3} in the case of an inert plasma. Several approaches to control the growth of the two-stream instability are discussed. We have also considered several scenarios for practical implementation which will require further studies. Finally, we consider the case where the injected beam at the resonance energy maintains the plasma temperature and prolongs its lifetime to reach a steady state. The equations for power balance and particle number conservation are given for this case.

  13. Production of epithermal neutron beams for BNCT

    CERN Document Server

    Bisceglie, E; Colonna, N; Paticchio, V; Santorelli, P; Variale, V


    The use of boron neutron capture therapy (BNCT) for the treatment of deep-seated tumors requires neutron beams of suitable energy and intensity. Simulations indicate the optimal energy to reside in the epithermal region, in particular between 1 and 10 keV. Therapeutic neutron beams with high spectral purity in this energy range could be produced with accelerator-based neutron sources through a suitable neutron-producing reaction. Herein, we report on different solutions that have been investigated as possible sources of epithermal neutron beams for BNCT. The potential use of such sources for a hospital-based therapeutic facility is discussed.

  14. A (13)C(d,n)-based epithermal neutron source for Boron Neutron Capture Therapy. (United States)

    Capoulat, M E; Kreiner, A J


    Boron Neutron Capture Therapy (BNCT) requires neutron sources suitable for in-hospital siting. Low-energy particle accelerators working in conjunction with a neutron producing reaction are the most appropriate choice for this purpose. One of the possible nuclear reactions is (13)C(d,n)(14)N. The aim of this work is to evaluate the therapeutic capabilities of the neutron beam produced by this reaction, through a 30mA beam of deuterons of 1.45MeV. A Beam Shaping Assembly design was computationally optimized. Depth dose profiles in a Snyder head phantom were simulated with the MCNP code for a number of BSA configurations. In order to optimize the treatment capabilities, the BSA configuration was determined as the one that allows maximizing both the tumor dose and the penetration depth while keeping doses to healthy tissues under the tolerance limits. Significant doses to tumor tissues were achieved up to ∼6cm in depth. Peak doses up to 57Gy-Eq can be delivered in a fractionated scheme of 2 irradiations of approximately 1h each. In a single 1h irradiation, lower but still acceptable doses to tumor are also feasible. Treatment capabilities obtained here are comparable to those achieved with other accelerator-based neutron sources, making of the (13)C(d,n)(14)N reaction a realistic option for producing therapeutic neutron beams through a low-energy particle accelerator. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  15. MANTA. An Integral Reactor Physics Experiment to Infer the Neutron Capture Cross Sections of Actinides and Fission Products in Fast and Epithermal Spectra

    Energy Technology Data Exchange (ETDEWEB)

    Youinou, Gilles Jean-Michel [Idaho National Lab. (INL), Idaho Falls, ID (United States)


    Neutron cross-sections characterize the way neutrons interact with matter. They are essential to most nuclear engineering projects and, even though theoretical progress has been made as far as the predictability of neutron cross-section models, measurements are still indispensable to meet tight design requirements for reduced uncertainties. Within the field of fission reactor technology, one can identify the following specializations that rely on the availability of accurate neutron cross-sections: (1) fission reactor design, (2) nuclear fuel cycles, (3) nuclear safety, (4) nuclear safeguards, (5) reactor monitoring and neutron fluence determination and (6) waste disposal and transmutation. In particular, the assessment of advanced fuel cycles requires an extensive knowledge of transuranics cross sections. Plutonium isotopes, but also americium, curium and up to californium isotope data are required with a small uncertainty in order to optimize significant features of the fuel cycle that have an impact on feasibility studies (e.g. neutron doses at fuel fabrication, decay heat in a repository, etc.). Different techniques are available to determine neutron cross sections experimentally, with the common denominator that a source of neutrons is necessary. It can either come from an accelerator that produces neutrons as a result of interactions between charged particles and a target, or it can come from a nuclear reactor. When the measurements are performed with an accelerator, they are referred to as differential since the analysis of the data provides the cross-sections for different discrete energies, i.e. σ(Ei), and for the diffusion cross sections for different discrete angles. Another approach is to irradiate a very pure sample in a test reactor such as the Advanced Test Reactor (ATR) at INL and, after a given time, determine the amount of the different transmutation products. The precise characterization of the nuclide densities before and after

  16. Physics of epi-thermal boron neutron capture therapy (epi-thermal BNCT). (United States)

    Seki, Ryoichi; Wakisaka, Yushi; Morimoto, Nami; Takashina, Masaaki; Koizumi, Masahiko; Toki, Hiroshi; Fukuda, Mitsuhiro


    The physics of epi-thermal neutrons in the human body is discussed in the effort to clarify the nature of the unique radiologic properties of boron neutron capture therapy (BNCT). This discussion leads to the computational method of Monte Carlo simulation in BNCT. The method is discussed through two examples based on model phantoms. The physics is kept at an introductory level in the discussion in this tutorial review.

  17. A new indicator mineral methodology based on a generic Bi-Pb-Te-S mineral inclusion signature in detrital gold from porphyry and low/intermediate sulfidation epithermal environments in Yukon Territory, Canada (United States)

    Chapman, R. J.; Allan, M. M.; Mortensen, J. K.; Wrighton, T. M.; Grimshaw, M. R.


    Porphyry-epithermal and orogenic gold are two of the most important styles of gold-bearing mineralization within orogenic belts. Populations of detrital gold resulting from bulk erosion of such regions may exhibit a compositional continuum wherein Ag, Cu, and Hg in the gold alloy may vary across the full range exhibited by natural gold. This paper describes a new methodology whereby orogenic and porphyry-epithermal gold may be distinguished according to the mineralogy of microscopic inclusions observed within detrital gold particles. A total of 1459 gold grains from hypogene, eluvial, and placer environments around calc-alkaline porphyry deposits in Yukon (Nucleus-Revenue, Casino, Sonora Gulch, and Cyprus-Klaza) have been characterized in terms of their alloy compositions (Au, Ag, Cu, and Hg) and their inclusion mineralogy. Despite differences in the evolution of the different magmatic hydrothermal systems, the gold exhibits a clear Bi-Pb-Te-S mineralogy in the inclusion suite, a signature which is either extremely weak or (most commonly) absent in both Yukon orogenic gold and gold from orogenic settings worldwide. Generic systematic compositional changes in ore mineralogy previously identified across the porphyry-epithermal transition have been identified in the corresponding inclusion suites observed in samples from Yukon. However, the Bi-Te association repeatedly observed in gold from the porphyry mineralization persists into the epithermal environment. Ranges of P-T-X conditions are replicated in the geological environments which define generic styles of mineralization. These parameters influence both gold alloy composition and ore mineralogy, of which inclusion suites are a manifestation. Consequently, we propose that this methodology approach can underpin a widely applicable indicator methodology based on detrital gold.

  18. In vitro biological effectiveness of JRR-4 epithermal neutron beam. Experiment under free air beam and in water phantom. Cooperative research

    CERN Document Server

    Yamamoto, T; Horiguchi, Y; Kishi, T; Kumada, H; Matsumura, A; Nose, T; Torii, Y; Yamamoto, K


    The surviving curve and the biological effectiveness factor of dose components generated in boron neutron capture therapy (BNCT) were separately determined in neutron beams at Japan Research Reactor No.4. Surviving fraction of V79 Chinese hamster cell with or without sup 1 sup 0 B was obtained using an epithermal neutron beam (ENB), a mixed thermal-epithermal neutron beam (TNB-1), and a thermal neutron beam (TNB-2), which were used or planned to use for BNCT clinical trial. The cell killing effect of these neutron beams with or without the presence of sup 1 sup 0 B depended highly on the neutron beam used, according to the epithermal and fast neutron content in the beam. The biological effectiveness factor values of the boron capture reaction for ENB, TNB-1 and TNB-2 were 3.99+-0.24, 3.04+-0.19 and 1.43+-0.08, respectively. The biological effectiveness factor values of the high-LET dose components based on the hydrogen recoils and the nitrogen capture reaction were 2.50+-0.32, 2.34+-0.30 and 2.17+-0.28 for EN...

  19. Intermediate sulfidation epithermal mineralization of No. 4 anomaly of Golojeh deposit (N. Zanjan based on mineralography, alteration and ore fluid geochemistry features

    Directory of Open Access Journals (Sweden)

    Behzad Mehrab


    contents of galena, sphalerite and minor chalcopyrite and tennantite, low to moderate temperature and salinity of ore-bearing fluid, low depth of mineralization and Fe–bearing sphalerite features at the No. 4 anomaly of Golojeh deposit, are similar to those of intermediate sulfidation (IS epithermal base and precious metals vein–type deposit that probably might be related to Cu–Au porphyry system in depth.

  20. Imaging of gamma and neutron dose distributions at LVR-15 epithermal beam by means of FGLDs

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G., E-mail: [Department of Physics, Universita degli Studi, Milan (Italy)] [INFN, Istituto Nazionale di Fisica Nucleare, Section of Milan, Milan (Italy); Bartesaghi, G. [Department of Physics, Universita degli Studi, Milan (Italy)] [INFN, Istituto Nazionale di Fisica Nucleare, Section of Milan, Milan (Italy); Carrara, M. [The Fondazione IRCCS ' Istituto Nazionale Tumori' , Milan (Italy); Negri, A. [INFN, Istituto Nazionale di Fisica Nucleare, Section of Milan, Milan (Italy); Paganini, L. [Department of Physics, Universita degli Studi, Milan (Italy); Vanossi, E. [INFN, Istituto Nazionale di Fisica Nucleare, Section of Milan, Milan (Italy); Burian, J.; Marek, M.; Viererbl, L.; Klupak, V.; Rejchrt, J. [Department of Reactor Physics, NRI Rez, plc (Czech Republic)


    Gamma and fast neutron dose spatial distributions have been measured at the collimator exit of the epithermal neutron beam of LVR-15 reactor (Rez). Measurements were performed by means of optically analyzed Fricke-gel-layer detectors. The separation of the two dose contributions has been achieved by suitable pixel-to-pixel elaboration of the light transmittance images of Fricke-gel-layer detectors prepared with water and heavy water.

  1. DNA-Based Enzyme Reactors and Systems

    Directory of Open Access Journals (Sweden)

    Veikko Linko


    Full Text Available During recent years, the possibility to create custom biocompatible nanoshapes using DNA as a building material has rapidly emerged. Further, these rationally designed DNA structures could be exploited in positioning pivotal molecules, such as enzymes, with nanometer-level precision. This feature could be used in the fabrication of artificial biochemical machinery that is able to mimic the complex reactions found in living cells. Currently, DNA-enzyme hybrids can be used to control (multi-enzyme cascade reactions and to regulate the enzyme functions and the reaction pathways. Moreover, sophisticated DNA structures can be utilized in encapsulating active enzymes and delivering the molecular cargo into cells. In this review, we focus on the latest enzyme systems based on novel DNA nanostructures: enzyme reactors, regulatory devices and carriers that can find uses in various biotechnological and nanomedical applications.

  2. Critical elements in Carlin, epithermal, and orogenic gold deposits (United States)

    Goldfarb, Richard J.; Hofstra, Albert H.; Simmons, Stuart F.


    Carlin, epithermal, and orogenic gold deposits, today mined almost exclusively for their gold content, have similar suites of anomalous trace elements that reflect similar low-salinity ore fluids and thermal conditions of metal transport and deposition. Many of these trace elements are commonly referred to as critical or near-critical elements or metals and have been locally recovered, although typically in small amounts, by historic mining activities. These elements include As, Bi, Hg, In, Sb, Se, Te, Tl, and W. Most of these elements are now solely recovered as by-products from the milling of large-tonnage, base metal-rich ore deposits, such as porphyry and volcanogenic massive sulfide deposits.A combination of dominance of the world market by a single country for a single commodity and a growing demand for many of the critical to near-critical elements could lead to future recovery of such elements from select epithermal, orogenic, or Carlin-type gold deposits. Antimony continues to be recovered from some orogenic gold deposits and tellurium could potentially be a primary commodity from some such deposits. Tellurium and indium in sphalerite-rich ores have been recovered in the past and could be future commodities recovered from epithermal ores. Carlin-type gold deposits in Nevada are enriched in and may be a future source for As, Hg, Sb, and/or Tl. Some of the Devonian carbonaceous host rocks in the Carlin districts are sufficiently enriched in many trace elements, including Hg, Se, and V, such that they also could become resources. Thallium may be locally enriched to economic levels in Carlin-type deposits and it has been produced from Carlin-like deposits elsewhere in the world (e.g., Alsar, southern Macedonia; Lanmuchang, Guizhou province, China). Mercury continues to be recovered from shallow-level epithermal deposits, as well as a by-product of many Carlin-type deposits where refractory ore is roasted to oxidize carbon and pyrite, and mercury is then

  3. TR-EDB: Test Reactor Embrittlement Data Base, Version 1

    Energy Technology Data Exchange (ETDEWEB)

    Stallmann, F.W.; Wang, J.A.; Kam, F.B.K. [Oak Ridge National Lab., TN (United States)


    The Test Reactor Embrittlement Data Base (TR-EDB) is a collection of results from irradiation in materials test reactors. It complements the Power Reactor Embrittlement Data Base (PR-EDB), whose data are restricted to the results from the analysis of surveillance capsules in commercial power reactors. The rationale behind their restriction was the assumption that the results of test reactor experiments may not be applicable to power reactors and could, therefore, be challenged if such data were included. For this very reason the embrittlement predictions in the Reg. Guide 1.99, Rev. 2, were based exclusively on power reactor data. However, test reactor experiments are able to cover a much wider range of materials and irradiation conditions that are needed to explore more fully a variety of models for the prediction of irradiation embrittlement. These data are also needed for the study of effects of annealing for life extension of reactor pressure vessels that are difficult to obtain from surveillance capsule results.

  4. In vitro biological effectiveness of JRR-4 epithermal neutron beam. Experiment under free air beam and in water phantom. Cooperative research

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Tetsuya; Matsumura, Akira; Nose, Tadao [Tsukuba Univ., Tsukuba, Ibaraki (Japan); Yamamoto, Kazuyoshi; Kumada, Hiroaki; Kishi, Toshiaki; Hori, Naohiko; Torii, Yoshiya; Horiguchi, Yoji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment


    The surviving curve and the biological effectiveness factor of dose components generated in boron neutron capture therapy (BNCT) were separately determined in neutron beams at Japan Research Reactor No.4. Surviving fraction of V79 Chinese hamster cell with or without {sup 10}B was obtained using an epithermal neutron beam (ENB), a mixed thermal-epithermal neutron beam (TNB-1), and a thermal neutron beam (TNB-2), which were used or planned to use for BNCT clinical trial. The cell killing effect of these neutron beams with or without the presence of {sup 10}B depended highly on the neutron beam used, according to the epithermal and fast neutron content in the beam. The biological effectiveness factor values of the boron capture reaction for ENB, TNB-1 and TNB-2 were 3.99{+-}0.24, 3.04{+-}0.19 and 1.43{+-}0.08, respectively. The biological effectiveness factor values of the high-LET dose components based on the hydrogen recoils and the nitrogen capture reaction were 2.50{+-}0.32, 2.34{+-}0.30 and 2.17{+-}0.28 for ENB, TNB-1 and TNB-2, respectively. The biological effectiveness factor values of the neutron and photon components were 1.22{+-}0.16, 1.23{+-}0.16 and 1.21{+-}0.16, respectively. The depth function of biological effectiveness factor in water phantom and the difference in biological effectiveness factor among boron compounds were also determined. The experimental determination of biological effectiveness factor outlined in this paper is applicable to the dose calculation for each dose component of the neutron beams and contribute to an accurate biological effectiveness factor as comparison with a neutron beam at a different facility employed in ongoing and planned BNCT clinical trials. (author)

  5. Tokamak reactor cost model based on STARFIRE/WILDCAT costing

    Energy Technology Data Exchange (ETDEWEB)

    Evans, K. Jr.


    A cost model is presented which is useful for survey and comparative studies of tokamak reactors. The model is heavily based on STARFIRE and WILDCAT costing guidelines, philosophies, and procedures and reproduces the costing for these devices quite accurately.

  6. Epithermal gold occurrences in the lakes district of the Main ...

    African Journals Online (AJOL)

    The overall characteristics of the known ore occurrences and the evolution of the Quaternary central volcanoes within the MER, and related epithermal processes seem to delineate an individual, homogeneous metallogenic province. A new field of investigation on epithermal ore occurrences which are unusual for the ...

  7. Permeability enhancement during gold mineralization: Evidences from Kestanelik epithermal vein system, NW Turkey (United States)

    Gulyuz, Nilay; Shipton, Zoe; Kuscu, Ilkay; Lord, Richard A.; Gladwell, David R.; Kaymakci, Nuretdin


    The most favourable and principal mineral deposition mechanism in low sulphidation epithermal systems is boiling. Mineralization in these systems occurs dominantly as veins and stockworks; therefore, structures play major role in the localization of epithermal fluid flow. Epithermal fluids rise from depth along structural conduits at high temperatures under enough pressure to prevent boiling. When the pressure drops suddenly (for instance, through faulting or any fracturing), boiling occurs, and CO2 and H2S are released to the vapour phase. Change in fluid chemistry due to the boiling causes first the base metals, and then the ore and gangue minerals to deposit in a well-recognized temporal and vertical sequence until all open spaces are filled. Vein infill in epithermal deposits indicate that mineralization is multiphase and associated with repeated and episodic fluid flow rather than a steady-state process. How can permeability enhancement be achieved after deposition of minerals in fractures and faults chokes permeable pathways and restrict fluid flow? Although geochemical aspects of LS epithermal systems are well known, limited studies exist on the permeability enhancement mechanisms in LS epithermal veins. The main aim of the study is to understand the permeability enhancement mechanisms in epithermal gold deposits by focussing on the structures and quartz textures of a well-preserved low sulphidation epithermal quartz vein/breccia system in Lapseki, NW Turkey. We revealed the kinematics of the structure-vein network by mapping the geometries of epithermal quartz veins and associated structures and collecting detailed structural data from them. In addition, we determined the different phases of fluid flow and mineralization with the cross-cutting and structural relationships among them by examining the quartz textures and breccias and mapping their spatial distribution on vein outcrops and in drill cores with the help of thin section analyses. On-going work

  8. Introduction to Chemical Engineering Reactor Analysis: A Web-Based Reactor Design Game (United States)

    Orbey, Nese; Clay, Molly; Russell, T.W. Fraser


    An approach to explain chemical engineering through a Web-based interactive game design was developed and used with college freshman and junior/senior high school students. The goal of this approach was to demonstrate how to model a lab-scale experiment, and use the results to design and operate a chemical reactor. The game incorporates both…

  9. Vanadium-base alloys for fusion reactor applications

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.L.; Loomis, B.A.; Diercks, D.R.


    Vanadium-base alloys offer potentially significant advantages over other candidate alloys as a structural material for fusion reactor first wall/blanket applications. Although the data base is more limited than that for the other leading candidate structural materials, viz., austenitic and ferritic steels, vanadium-base alloys exhibit several properties that make them particularly attractive for the fusion reactor environment. This paper presents a review of the structural material requirements, a summary of the materials data base for selected vanadium-base alloys, and a comparison of projected performance characteristics compared to other candidate alloys. Also, critical research and development (R and D) needs are defined.

  10. Micro-reactors for characterization of nanostructure-based sensors (United States)

    Savu, R.; Silveira, J. V.; Flacker, A.; Vaz, A. R.; Joanni, E.; Pinto, A. C.; Gobbi, A. L.; Santos, T. E. A.; Rotondaro, A. L. P.; Moshkalev, S. A.


    Fabrication and testing of micro-reactors for the characterization of nanosensors is presented in this work. The reactors have a small volume (100 μl) and are equipped with gas input/output channels. They were machined from a single piece of kovar in order to avoid leaks in the system due to additional welding. The contact pins were electrically insulated from the body of the reactor using a borosilicate sealing glass and the reactor was hermetically sealed using a lid and an elastomeric o-ring. One of the advantages of the reactor lies in its simple assembly and ease of use with any vacuum/gas system, allowing the connection of more than one device. Moreover, the lid can be modified in order to fit a window for in situ optical characterization. In order to prove its versatility, carbon nanotube-based sensors were tested using this micro-reactor. The devices were fabricated by depositing carbon nanotubes over 1 μm thick gold electrodes patterned onto Si/SiO2 substrates. The sensors were tested using oxygen and nitrogen atmospheres, in the pressure range between 10-5 and 10-1 mbar. The small chamber volume allowed the measurement of fast sensor characteristic times, with the sensors showing good sensitivity towards gas and pressure as well as high reproducibility.

  11. Formation and Aggregation of Gold (Electrum) Nanoparticles in Epithermal Ores


    James A. Saunders; Michelle Burke


    Here, we review the concept that nanoparticles and colloids may have played a significant role in forming some types of hydrothermal ores deposits, particularly epithermal. This concept was first proposed almost a century ago but the development of new analytical technologies, lab experiments, and the discovery of new epithermal deposits where nanoparticles are evident have added credence to the “gold colloid theory”. Nanoparticles are defined to have at least one dimension <10−7 m, and ma...

  12. Enhanced plastic neutron shielding for thermal and epithermal neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Palomino, L A RodrIguez; Blostein, J J; Dawidowski, J [Consejo Nacional de Investigaciones CientIficas y Tecnicas, Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de EnergIa Atomica, Universidad Nacional de Cuyo, (8400) Bariloche, Av. Bustillo 9500, S. C. de Bariloche, RIo Negro (Argentina); Cuello, G J [Institut Laue Langevin, 6, rue Jules Horowitz, F-38042 Grenoble Cedex 9 (France)], E-mail:


    We describe a compound made of paraffin and boron carbide (boraffin) deviced to enhance epithermal neutron shielding. The compound is easily prepared and is specially suited to be adapted to particular surfaces. Transmission experiments show a favourable comparison with a commercial rubber-boron carbide compound in the epithermal range. A detector shielding built with this material is described and the achieved background reduction experimentally determined is shown.

  13. CANDU in-reactor quantitative visual-based inspection techniques (United States)

    Rochefort, P. A.


    This paper describes two separate visual-based inspection procedures used at CANDU nuclear power generating stations. The techniques are quantitative in nature and are delivered and operated in highly radioactive environments with access that is restrictive, and in one case is submerged. Visual-based inspections at stations are typically qualitative in nature. For example a video system will be used to search for a missing component, inspect for a broken fixture, or locate areas of excessive corrosion in a pipe. In contrast, the methods described here are used to measure characteristic component dimensions that in one case ensure ongoing safe operation of the reactor and in the other support reactor refurbishment. CANDU reactors are Pressurized Heavy Water Reactors (PHWR). The reactor vessel is a horizontal cylindrical low-pressure calandria tank approximately 6 m in diameter and length, containing heavy water as a neutron moderator. Inside the calandria, 380 horizontal fuel channels (FC) are supported at each end by integral end-shields. Each FC holds 12 fuel bundles. The heavy water primary heat transport water flows through the FC pressure tube, removing the heat from the fuel bundles and delivering it to the steam generator. The general design of the reactor governs both the type of measurements that are required and the methods to perform the measurements. The first inspection procedure is a method to remotely measure the gap between FC and other in-core horizontal components. The technique involves delivering vertically a module with a high-radiation-resistant camera and lighting into the core of a shutdown but fuelled reactor. The measurement is done using a line-of-sight technique between the components. Compensation for image perspective and viewing elevation to the measurement is required. The second inspection procedure measures flaws within the reactor's end shield FC calandria tube rolled joint area. The FC calandria tube (the outer shell of the FC) is

  14. Small reactor power systems for manned planetary surface bases (United States)

    Bloomfield, Harvey S.


    A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a variety of human-rated modular reactor power system configurations selected for a range of power levels from 25 kWe to hundreds of kilowatts is described. Trade-off analyses for reactor power systems utilizing both man-made and indigenous shielding materials are provided to examine performance, installation and operational safety feasibility issues. The results of this study have confirmed the preliminary feasibility of a wide variety of small reactor power plant configurations for growth oriented manned planetary surface exploration missions. The capability for power level growth with increasing manned presence, while maintaining safe radiation levels, was favorably assessed for nominal 25 to 100 kWe modular configurations. No feasibility limitations or technical barriers were identified and the use of both distance and indigenous planetary soil material for human rated radiation shielding were shown to be viable and attractive options.

  15. System and method for temperature control in an oxygen transport membrane based reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Sean M.


    A system and method for temperature control in an oxygen transport membrane based reactor is provided. The system and method involves introducing a specific quantity of cooling air or trim air in between stages in a multistage oxygen transport membrane based reactor or furnace to maintain generally consistent surface temperatures of the oxygen transport membrane elements and associated reactors. The associated reactors may include reforming reactors, boilers or process gas heaters.

  16. Epithermal Neutron Activation Analysis of the Asian Herbal Plants (United States)

    Baljinnyam, N.; Jugder, B.; Norov, N.; Frontasyeva, M. V.; Ostrovnaya, T. M.; Pavlov, S. S.


    Asian medicinal herbs Chrysanthemum (Spiraea aquilegifolia Pall.) and Red Sandalwood (Pterocarpus Santalinus) are widely used in folk and Ayurvedic medicine for healing and preventing some diseases. The modern medical science has proved that the Chrysanthemum (Spiraea aquilegifolia Pall.) possesses the following functions: reducing blood press, dispelling cancer cell, coronary artery's expanding and bacteriostating and Red Sandalwood (Pterocarpus Santalinus) is recommended against headache, toothache, skin diseases, vomiting and sometimes it is taken for treatment of diabetes. Species of Chrysanthemums were collected in the north-eastern and central Mongolia, and the Red Sandalwood powder was imported from India. Samples of Chrysanthemums (branches, flowers and leaves) (0.5 g) and red sandalwood powder (0.5 g) were subjected to the multi-element instrumental neutron activation analysis using epithermal neutrons (ENAA) at the IBR-2 reactor, Frank Laboratory of Neutron Physics (FLNP) JINR, Dubna. A total of 41 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Cd, Cs, Ba, La, Hf, Ta, W, Sb, Au, Hg, Ce, Nd, Sm, Eu, Tb, Dy, Yb, Th, U, Lu) were determined. For the first time such a large group of elements was determined in the herbal plants used in Mongolia. The quality control of the analytical results was provided by using certified reference material Bowen Cabbage. The results obtained are compared to the "Reference plant» data (B. Markert, 1992) and interpreted in terms of excess of such elements as Se, Cr, Ca, Fe, Ni, Mo, and rare earth elements.

  17. Conceptual design of a clinical BNCT beam in an adjacent dry cell of the Jozef Stefan Institute TRIGA reactor

    NARCIS (Netherlands)

    Maucec, M


    The MCNP4B Monte Carlo transport code is used in a feasibility study of the epithermal neutron boron neutron capture therapy facility in the thermalizing column of the 250-kW TRIGA Mark II reactor at the Jozef Stefan Institute (JSI). To boost the epithermal neutron flux at the reference irradiation

  18. Recent Advances in Pd-Based Membranes for Membrane Reactors. (United States)

    Arratibel Plazaola, Alba; Pacheco Tanaka, David Alfredo; Van Sint Annaland, Martin; Gallucci, Fausto


    Palladium-based membranes for hydrogen separation have been studied by several research groups during the last 40 years. Much effort has been dedicated to improving the hydrogen flux of these membranes employing different alloys, supports, deposition/production techniques, etc. High flux and cheap membranes, yet stable at different operating conditions are required for their exploitation at industrial scale. The integration of membranes in multifunctional reactors (membrane reactors) poses additional demands on the membranes as interactions at different levels between the catalyst and the membrane surface can occur. Particularly, when employing the membranes in fluidized bed reactors, the selective layer should be resistant to or protected against erosion. In this review we will also describe a novel kind of membranes, the pore-filled type membranes prepared by Pacheco Tanaka and coworkers that represent a possible solution to integrate thin selective membranes into membrane reactors while protecting the selective layer. This work is focused on recent advances on metallic supports, materials used as an intermetallic diffusion layer when metallic supports are used and the most recent advances on Pd-based composite membranes. Particular attention is paid to improvements on sulfur resistance of Pd based membranes, resistance to hydrogen embrittlement and stability at high temperature.


    Energy Technology Data Exchange (ETDEWEB)

    E. Blanford; E. Keldrauk; M. Laufer; M. Mieler; J. Wei; B. Stojadinovic; P.F. Peterson


    Advanced technologies for structural design and construction have the potential for major impact not only on nuclear power plant construction time and cost, but also on the design process and on the safety, security and reliability of next generation of nuclear power plants. In future Generation IV (Gen IV) reactors, structural and seismic design should be much more closely integrated with the design of nuclear and industrial safety systems, physical security systems, and international safeguards systems. Overall reliability will be increased, through the use of replaceable and modular equipment, and through design to facilitate on-line monitoring, in-service inspection, maintenance, replacement, and decommissioning. Economics will also receive high design priority, through integrated engineering efforts to optimize building arrangements to minimize building heights and footprints. Finally, the licensing approach will be transformed by becoming increasingly performance based and technology neutral, using best-estimate simulation methods with uncertainty and margin quantification. In this context, two structural engineering technologies, seismic base isolation and modular steel-plate/concrete composite structural walls, are investigated. These technologies have major potential to (1) enable standardized reactor designs to be deployed across a wider range of sites, (2) reduce the impact of uncertainties related to site-specific seismic conditions, and (3) alleviate reactor equipment qualification requirements. For Gen IV reactors the potential for deliberate crashes of large aircraft must also be considered in design. This report concludes that base-isolated structures should be decoupled from the reactor external event exclusion system. As an example, a scoping analysis is performed for a rectangular, decoupled external event shell designed as a grillage. This report also reviews modular construction technology, particularly steel-plate/concrete construction using

  20. Implementation of k0-INAA standardisation at ITU TRIGA Mark II research reactor, Turkey based on k0-IAEA software (United States)

    Esen, Ayse Nur; Haciyakupoglu, Sevilay


    The purpose of this study is to test the applicability of k0-INAA method at the Istanbul Technical University TRIGA Mark II research reactor. The neutron spectrum parameters such as epithermal neutron flux distribution parameter (α), thermal to epithermal neutron flux ratio (f) and thermal neutron flux (φth) were determined at the central irradiation channel of the ITU TRIGA Mark II research reactor using bare triple-monitor method. HPGe detector calibrations and calculations were carried out by k0-IAEA software. The α, f and φth values were calculated to be -0.009, 15.4 and 7.92·1012 cm-2 s-1, respectively. NIST SRM 1633b coal fly ash and intercomparison samples consisting of clay and sandy soil samples were used to evaluate the validity of the method. For selected elements, the statistical evaluation of the analysis results was carried out by z-score test. A good agreement between certified/reported and experimental values was obtained.

  1. Formation and Aggregation of Gold (Electrum Nanoparticles in Epithermal Ores

    Directory of Open Access Journals (Sweden)

    James A. Saunders


    Full Text Available Here, we review the concept that nanoparticles and colloids may have played a significant role in forming some types of hydrothermal ores deposits, particularly epithermal. This concept was first proposed almost a century ago but the development of new analytical technologies, lab experiments, and the discovery of new epithermal deposits where nanoparticles are evident have added credence to the “gold colloid theory”. Nanoparticles are defined to have at least one dimension <10−7 m, and may have different chemical and physical properties than the bulk solids. Colloids are typically <10−6 m in diameter and have the added characteristic that they are dispersed in another medium. In epithermal ore-forming solutions, gold or electrum nanoparticles nucleate from supersaturated hydrothermal solutions, and thus this is a “far-from-equilibrium” process. In some cases, gold nanoparticles may simply play a transitory role of aggregating to form much coarser-grained crystals, where all of the evidence of nanoparticles precursor phases is not preserved. However, in some epithermal ores, silica nanoparticles also formed, and their co-deposition with gold (electrum nanoparticles preserved the gold aggregation features as self-organized “fractal” dendrites. Here, we review existing the data on gold and electrum nanoparticles in epithermal ores, present images of electrum nanoparticles and their aggregates, and discuss the significance of gold nanoparticles formation and aggregation in helping to produce some of the highest-grade gold ores in the world.

  2. Robust observer based control for axial offset in pressurized-water nuclear reactors based on the multipoint reactor model using Lyapunov approach

    Energy Technology Data Exchange (ETDEWEB)

    Zaidabadinejad, Majid; Ansarifar, Gholam Reza [Isfahan Univ. (Iran, Islamic Republic of). Dept. of Nuclear Engineering


    In nuclear reactor imbalance of axial power distribution induces xenon oscillations. These fluctuations must be maintained bounded within allowable limits. Otherwise, the nuclear power plant could become unstable. Therefore, bounded these oscillations is considered to be a restriction for the load following operation. Also, in order to design the nuclear reactor control systems, poisons concentrations, especially xenon must be accessible. But, physical measurement of these parameters is impossible. In this paper, for the first time, in order to estimate the axial xenon oscillations and ensures these oscillations are kept bounded within allowable limits during load-following operation, a robust observer based nonlinear control based on multipoint kinetics reactor model for pressurized-water nuclear reactors is presented. The reactor core is simulated based on the multi-point nuclear reactor model (neutronic and thermal-hydraulic). Simulation results are presented to demonstrate the effectiveness of the proposed observer based controller for the load-following operation.

  3. Impact of Fission Neutron Energies on Reactor Antineutrino Spectra (United States)

    Hermanek, Keith; Littlejohn, Bryce; Gustafson, Ian


    Recent measurements of the reactor antineutrino spectra (Double Chooz, Reno, and Daya Bay) have shown a discrepancy in the 5-7 MeV region when compared to current theoretical models (Vogel and Huber-Mueller). There are numerous theories pertaining to this antineutrino anomaly, including theories that point to new physics beyond the standard model. In the paper ``Possible Origins and Implications of the Shoulder in Reactor Neutrino Spectra'' by A. Hayes et al., explanations for this anomaly are suggested. One theory is that there are interactions from fast and epithermal incident neutrons which are significant enough to create more events in the 5-7 MeV by a noticeable amount. In our research, we used the Oklo software network created by Dan Dwyer. This generates ab initio antineutrino and beta decay spectra based on standard fission yield databases ENDF, JENDL, JEFF, and the beta decay transition database ENSDF-6. Utilizing these databases as inputs, we show with reasonable assumptions one can prove contributions of fast and epithermal neutrons is less than 3% in the 5-7 MeV region. We also discovered rare isotopes are present in beta decay chains but not well measured and have no corresponding database information, and studied its effect onto the spectrum.

  4. Measurement of epithermal neutrons by a coherent demodulation technique

    CERN Document Server

    Horiuchi, N; Takahashi, H; Kobayashi, H; Harasawa, S


    Epithermal neutrons have been measured using a neutron dosimeter via a coherent demodulation technique. This dosimeter consists of CsI(Tl)-photodiode scintillation detectors, four of which are coupled to neutron-gamma converting foils of various sizes. Neutron-gamma converting foils of In, Au and Co materials were used, each of which has a large capture cross section which peaks in the epithermal neutron energy region. The type of foil was selected according to the material properties that best correspond to the energy of the epithermal neutrons to be measured. In addition, the proposed technique was applied using Au-foils in order to measure the Cd ratio. The validity of the proposed technique was examined using an sup 2 sup 4 sup 1 Am-Be source placed in a testing stack of polyethylene blocks, and the results were compared with the theoretical values calculated by the Monte Carlo calculation. Finally, the dosimeter was applied for measuring epithermal neutrons and the Cd ratio in an experimental beam-tube o...

  5. Spent fuel data base: commercial light water reactors. [PWR; BWR

    Energy Technology Data Exchange (ETDEWEB)

    Hauf, M.J.; Kniazewycz, B.G.


    As a consequence of this country's non-proliferation policy, the reprocessing of spent nuclear fuel has been delayed indefinitely. This has resulted in spent light water reactor (LWR) fuel being considered as a potential waste form for disposal. Since the Nuclear Regulatory Commission (NRC) is currently developing methodologies for use in the regulation of the management and disposal of high-level and transuranic wastes, a comprehensive data base describing LWR fuel technology must be compiled. This document provides that technology baseline and, as such, will support the development of those evaluation standards and criteria applicable to spent nuclear fuel.

  6. MHTGR: New production reactor summary of experience base

    Energy Technology Data Exchange (ETDEWEB)


    Worldwide interest in the Modular High-Temperature Gas-Cooled Reactor (MHTGR) stems from the capability of the system to retain the advanced fuel and thermal performance while providing unparalleled levels of safety. The small power level of the MHTGR and its passive systems give it a margin of safety not attained by other concepts being developed for power generation. This report covers the experience base for the key nuclear system, components, and processes related to the MHTGR-NPR. 9 refs., 39 figs., 9 tabs.

  7. Corrosion of structural materials by lead-based reactor coolants.

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, D. P.; Leibowitz, L.; Maroni, V. A.; McDeavitt, S. M.; Raraz, A. G.


    Advanced nuclear reactor design has, in recent years, focused increasingly on the use of heavy-liquid-metal coolants, such as lead and lead-bismuth eutectic. Similarly, programs on accelerator-based transmutation systems have also considered the use of such coolants. Russian experience with heavy-metal coolants for nuclear reactors has lent credence to the validity of this approach. Of significant concern is the compatibility of structural materials with these coolants. We have used a thermal convection-based test method to allow exposure of candidate materials to molten lead and lead-bismuth flowing under a temperature gradient. The gradient was deemed essential in evaluating the behavior of the test materials in that should preferential dissolution of components of the test material occur we would expect dissolution in the hotter regions and deposition in the colder regions, thus promoting material transport. Results from the interactions of a Si-rich mild steel alloy, AISI S5, and a ferritic-martensitic stainless steel, HT-9, with the molten lead-bismuth are presented.

  8. Boron neutron capture therapy (BNCT). Recent aspect, a change from thermal neutron to epithermal neutron beam and a new protocol

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Yoshinobu [Dept. of Neurosurgery National Kagawa Children' s Hospital, Zentsuji, Kagawa (Japan)


    Since 1968, One-hundred seventy three patients with glioblastoma (n=81), anaplastic astrocytoma (n=44), low grade astrocytoma (n=16) or other types of tumor (n=32) were treated by boron-neutron capture therapy (BNCT) using a combination of thermal neutron and BSH in 5 reactors (HTR n=13, JRR-3 n=1, MuITR n=98, KUR n=28, JRR-2 n=33). Out of 101 patients with glioma treated by BNCT under the recent protocol, 33 (10 glioblastoma, 14 anaplastic astrocytoma, 9 low grade astrocytoma) patients lived or have lived longer than 3 years. Nine of these 33 lived or have lived longer than 10 years. According to the retrospective analysis, the important factors related to the clinical results were tumor dose radiation dose and maximum radiation dose in thermal brain cortex. The result was not satisfied as it was expected. Then, we decided to introduce mixed beams which contain thermal neutron and epithermal neutron beams. KUR was reconstructed in 1996 and developed to be available to use mixed beams. Following the shutdown of the JRR-2, JRR-4 was renewed for medical use in 1998. Both reactors have capacity to yield thermal neutron beam, epithermal neutron beam and mixed beams. The development of the neutron source lead us to make a new protocol. (author)

  9. Reactor-Based Plutonium Disposition: Opportunities, Options, and Issues

    Energy Technology Data Exchange (ETDEWEB)

    Greene, S.R.


    The end of the Cold War has created a legacy of surplus fissile materials (plutonium and highly enriched uranium) in the United States (U.S.) and the former Soviet Union. These materials pose a danger to national and international security. During the past few years, the U.S. and Russia have engaged in an ongoing dialog concerning the safe storage and disposition of surplus fissile material stockpiles. In January 1997, the Department of Energy (DOE) announced the U. S. would pursue a dual track approach to rendering approximately 50 metric tons of plutonium inaccessible for use in nuclear weapons. One track involves immobilizing the plutonium by combining it with high-level radioactive waste in glass or ceramic ''logs''. The other method, referred to as reactor-based disposition, converts plutonium into mixed oxide (MOX) fuel for nuclear reactors. The U.S. and Russia are moving ahead rapidly to develop and demonstrate the technology required to implement the MOX option in their respective countries. U.S. MOX fuel research and development activities were started in the 1950s, with irradiation of MOX fuel rods in commercial light water reactors (LWR) from the 1960s--1980s. In all, a few thousand MOX fuel rods were successfully irradiated. Though much of this work was performed with weapons-grade or ''near'' weapons-grade plutonium--and favorable fuel performance was observed--the applicability of this data for licensing and use of weapons-grade MOX fuel manufactured with modern fuel fabrication processes is somewhat limited. The U.S. and Russia are currently engaged in an intensive research, development, and demonstration program to support implementation of the MOX option in our two countries. This paper focuses on work performed in the U.S. and provides a brief summary of joint U.S./Russian work currently underway.

  10. A simulator-based nuclear reactor emergency response training exercise. (United States)

    Waller, Edward; Bereznai, George; Shaw, John; Chaput, Joseph; Lafortune, Jean-Francois

    Training offsite emergency response personnel basic awareness of onsite control room operations during nuclear power plant emergency conditions was the primary objective of a week-long workshop conducted on a CANDU® virtual nuclear reactor simulator available at the University of Ontario Institute of Technology, Oshawa, Canada. The workshop was designed to examine both normal and abnormal reactor operating conditions, and to observe the conditions in the control room that may have impact on the subsequent offsite emergency response. The workshop was attended by participants from a number of countries encompassing diverse job functions related to nuclear emergency response. Objectives of the workshop were to provide opportunities for participants to act in the roles of control room personnel under different reactor operating scenarios, providing a unique experience for participants to interact with the simulator in real-time, and providing increased awareness of control room operations during accident conditions. The ability to "pause" the simulator during exercises allowed the instructors to evaluate and critique the performance of participants, and to provide context with respect to potential offsite emergency actions. Feedback from the participants highlighted (i) advantages of observing and participating "hands-on" with operational exercises, (ii) their general unfamiliarity with control room operational procedures and arrangements prior to the workshop, (iii) awareness of the vast quantity of detailed control room procedures for both normal and transient conditions, and (iv) appreciation of the increased workload for the operators in the control room during a transient from normal operations. Based upon participant feedback, it was determined that the objectives of the training had been met, and that future workshops should be conducted.

  11. Conceptual design of BNCT facility based on the TRR medical room (United States)

    Golshanian, M.; Rajabi, A. A.; Kasesaz, Y.


    This paper presents a conceptual design of the Boron Neutron Capture Therapy (BNCT) facility based on the medical room of Tehran Research Reactor (TRR). The medical room is located behind the east wall of the reactor pool. The designed beam line is an in-pool Beam Shaping Assembly (BSA) which is considered between the reactor core and the medical room wall. The final designed BSA can provide 2.96× 109 n/cm2ṡs epithermal neutron flux at the irradiation position with acceptable beam contamination to use as a clinical BNCT.

  12. Reactor vibration reduction based on giant magnetostrictive materials

    Directory of Open Access Journals (Sweden)

    Yan Rongge


    Full Text Available The vibration of reactors not only produces noise pollution, but also affects the safe operation of reactors. Giant magnetostrictive materials can generate huge expansion and shrinkage deformation in a magnetic field. With the principle of mutual offset between the giant magnetostrictive force produced by the giant magnetostrictive material and the original vibration force of the reactor, the vibration of the reactor can be reduced. In this paper, magnetization and magnetostriction characteristics in silicon steel and the giant magnetostrictive material are measured, respectively. According to the presented magneto-mechanical coupling model including the electromagnetic force and the magnetostrictive force, reactor vibration is calculated. By comparing the vibration of the reactor with different inserted materials in the air gaps between the reactor cores, the vibration reduction effectiveness of the giant magnetostrictive material is validated.

  13. Reactor vibration reduction based on giant magnetostrictive materials (United States)

    Rongge, Yan; Weiying, Liu; Yuechao, Wu; Menghua, Duan; Xiaohong, Zhang; Lihua, Zhu; Ling, Weng; Ying, Sun


    The vibration of reactors not only produces noise pollution, but also affects the safe operation of reactors. Giant magnetostrictive materials can generate huge expansion and shrinkage deformation in a magnetic field. With the principle of mutual offset between the giant magnetostrictive force produced by the giant magnetostrictive material and the original vibration force of the reactor, the vibration of the reactor can be reduced. In this paper, magnetization and magnetostriction characteristics in silicon steel and the giant magnetostrictive material are measured, respectively. According to the presented magneto-mechanical coupling model including the electromagnetic force and the magnetostrictive force, reactor vibration is calculated. By comparing the vibration of the reactor with different inserted materials in the air gaps between the reactor cores, the vibration reduction effectiveness of the giant magnetostrictive material is validated.

  14. Reliability of digital reactor protection system based on extenics. (United States)

    Zhao, Jing; He, Ya-Nan; Gu, Peng-Fei; Chen, Wei-Hua; Gao, Feng


    After the Fukushima nuclear accident, safety of nuclear power plants (NPPs) is widespread concerned. The reliability of reactor protection system (RPS) is directly related to the safety of NPPs, however, it is difficult to accurately evaluate the reliability of digital RPS. The method is based on estimating probability has some uncertainties, which can not reflect the reliability status of RPS dynamically and support the maintenance and troubleshooting. In this paper, the reliability quantitative analysis method based on extenics is proposed for the digital RPS (safety-critical), by which the relationship between the reliability and response time of RPS is constructed. The reliability of the RPS for CPR1000 NPP is modeled and analyzed by the proposed method as an example. The results show that the proposed method is capable to estimate the RPS reliability effectively and provide support to maintenance and troubleshooting of digital RPS system.

  15. The alanine detector in BNCT dosimetry: Dose response in thermal and epithermal neutron fields

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, T., E-mail: [Institute for nuclear chemistry, Johannes Gutenberg-University, Mainz D-55128 (Germany); Bassler, N. [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus C, Aarhus 8000 (Denmark); Blaickner, M. [AIT Austrian Institute of Technology GmbH, Vienna A-1220 (Austria); Ziegner, M. [AIT Austrian Institute of Technology GmbH, Vienna A-1220, Austria and TU Wien, Vienna University of Technology, Vienna A-1020 (Austria); Hsiao, M. C. [Insitute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Liu, Y. H. [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Koivunoro, H. [Department of Physics, University of Helsinki, POB 64, FI-00014, Finland and HUS Medical Imaging Center, Helsinki University Central Hospital, FI-00029 HUS (Finland); Auterinen, I.; Serén, T.; Kotiluoto, P. [VTT Technical Research Centre of Finland, Espoo (Finland); Palmans, H. [National Physical Laboratory, Acoustics and Ionising Radiation Division, Teddington TW11 0LW, United Kingdom and Medical Physics Group, EBG MedAustron GmbH, Wiener Neustadt A-2700 (Austria); Sharpe, P. [National Physical Laboratory, Acoustics and Ionising Radiation Division, Teddington TW11 0LW (United Kingdom); Langguth, P. [Department of Pharmacy and Toxicology, University of Mainz, Mainz D-55128 (Germany); Hampel, G. [Institut für Kernchemie, Johannes Gutenberg-Universität, Mainz D-55128 (Germany)


    Purpose: The response of alanine solid state dosimeters to ionizing radiation strongly depends on particle type and energy. Due to nuclear interactions, neutron fields usually also consist of secondary particles such as photons and protons of diverse energies. Various experiments have been carried out in three different neutron beams to explore the alanine dose response behavior and to validate model predictions. Additionally, application in medical neutron fields for boron neutron capture therapy is discussed. Methods: Alanine detectors have been irradiated in the thermal neutron field of the research reactor TRIGA Mainz, Germany, in five experimental conditions, generating different secondary particle spectra. Further irradiations have been made in the epithermal neutron beams at the research reactors FiR 1 in Helsinki, Finland, and Tsing Hua open pool reactor in HsinChu, Taiwan ROC. Readout has been performed with electron spin resonance spectrometry with reference to an absorbed dose standard in a {sup 60}Co gamma ray beam. Absorbed doses and dose components have been calculated using the Monte Carlo codes FLUKA and MCNP. The relative effectiveness (RE), linking absorbed dose and detector response, has been calculated using the Hansen and Olsen alanine response model. Results: The measured dose response of the alanine detector in the different experiments has been evaluated and compared to model predictions. Therefore, a relative effectiveness has been calculated for each dose component, accounting for its dependence on particle type and energy. Agreement within 5% between model and measurement has been achieved for most irradiated detectors. Significant differences have been observed in response behavior between thermal and epithermal neutron fields, especially regarding dose composition and depth dose curves. The calculated dose components could be verified with the experimental results in the different primary and secondary particle fields. Conclusions: The

  16. The optimal windows for seismically-enhanced gold precipitation in the epithermal environment


    Sanchez-Alfaro, Pablo; Reich, Martin; Driesner, Thomas; Cembrano, José; Arancibia,Gloria; Pérez-Flores, Pamela; Heinrich, Christoph A.; Rowland, Julie; Tardani, Daniele; Lange, Dietrich; Campos,Eduardo


    Highlights • A geothermal system was studied as a modern analogue of epithermal Au deposits • Fluid data were combined with thermodynamic modeling and numerical simulations • Small-magnitude (Mw < 2) earthquakes can produce large drops in Au solubility • Earthquake-driven flash vaporization is more efficient than cooling and boiling • Protracted seismicity enhances Au precipitation rates in the epithermal environment Abstract Epithermal gold (Au) deposit...

  17. Compton suppression method and epithermal NAA in the determination of nutrients and heavy metals in Nigerian food and beverages

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Y.A., E-mail: [Reactor Engineering Section, Centre for Energy Research and Training, Ahmadu Bello University, Zaria (Nigeria); Nuclear Engineering Teaching Laboratory, University of Texas at Austin, Austin, TX 78758 (United States); Landsberger, S.; O' Kelly, D.J.; Braisted, J. [Nuclear Engineering Teaching Laboratory, University of Texas at Austin, Austin, TX 78758 (United States); Gabdo, H. [Physics Department, Federal College of Education, Yola (Nigeria); Ewa, I.O.B.; Umar, I.M.; Funtua, I.I. [Reactor Engineering Section, Centre for Energy Research and Training, Ahmadu Bello University, Zaria (Nigeria)


    We used in this study Compton suppression method and epithermal neutron activation analysis to determine the concentration of nutrients and heavy metals in Nigerian food and beverages. The work was performed at the University of Texas TRIGA Reactor by short, medium, and long irradiation protocols, using thermal flux of 1.4x10{sup 12} n cm{sup -2} s{sup -1} and epithermal flux of 1.4x10{sup 11} n cm{sup -2} s{sup -1}. Application of Compton suppression method has reduced interferences from Compton scattered photons thereby allowing easy evaluation of Na, Cl, Ca, Cu, Mn, Mg, Co, Cr, Rb, Fe, and Se. The epithermal NAA method has enabled determination of Cd, As, Ba, Sr, Br, I, and V with little turn-around time. Quality Control and Quality Assurance of the method was tested by analyzing four Standard Reference Materials (non-fat powdered milk, apple leaves, citrus leaves, and peach leaves) obtained from National Institute for Standards and Technology. Our results show that sorghum, millet, and maize have high values of Zn, Mn, Fe, low values of Cd, As, and Se. Powdered milks, rice, beans, and soybeans were found to have moderate amounts of all the elements. Tobacco recorded high content of Cd, Mn, and As, whereas tea, tsobo leaves, Baobab leaves, and okro seed have more As values than others. However, biscuits, macaroni, spaghetti, and noodles show lower concentrations of all the elements. The distribution of these nutrients and heavy metals in these food and beverages shows the need to fortify biscuits and pastas with micro and macro-nutrients and reduce the use of tobacco, tea, tsobo leaves, Baobab leaves, and Okro seed to avoid intake of heavy elements.

  18. Compton suppression method and epithermal NAA in the determination of nutrients and heavy metals in Nigerian food and beverages. (United States)

    Ahmed, Y A; Landsberger, S; O'Kelly, D J; Braisted, J; Gabdo, H; Ewa, I O B; Umar, I M; Funtua, I I


    We used in this study Compton suppression method and epithermal neutron activation analysis to determine the concentration of nutrients and heavy metals in Nigerian food and beverages. The work was performed at the University of Texas TRIGA Reactor by short, medium, and long irradiation protocols, using thermal flux of 1.4x10(12)n cm(-2)s(-1) and epithermal flux of 1.4x10(11)n cm(-2)s(-1). Application of Compton suppression method has reduced interferences from Compton scattered photons thereby allowing easy evaluation of Na, Cl, Ca, Cu, Mn, Mg, Co, Cr, Rb, Fe, and Se. The epithermal NAA method has enabled determination of Cd, As, Ba, Sr, Br, I, and V with little turn-around time. Quality Control and Quality Assurance of the method was tested by analyzing four Standard Reference Materials (non-fat powdered milk, apple leaves, citrus leaves, and peach leaves) obtained from National Institute for Standards and Technology. Our results show that sorghum, millet, and maize have high values of Zn, Mn, Fe, low values of Cd, As, and Se. Powdered milks, rice, beans, and soybeans were found to have moderate amounts of all the elements. Tobacco recorded high content of Cd, Mn, and As, whereas tea, tsobo leaves, Baobab leaves, and okro seed have more As values than others. However, biscuits, macaroni, spaghetti, and noodles show lower concentrations of all the elements. The distribution of these nutrients and heavy metals in these food and beverages shows the need to fortify biscuits and pastas with micro and macro-nutrients and reduce the use of tobacco, tea, tsobo leaves, Baobab leaves, and Okro seed to avoid intake of heavy elements. Copyright 2010 Elsevier Ltd. All rights reserved.

  19. Non-linear model based control of a propylene polymerization reactor

    NARCIS (Netherlands)

    Al-Haj Ali, M.; Betlem, B.; Weickert, G.; Roffel, B.


    A modified generic model controller is developed and tested through a simulation study. The application involves model-based control of a propylene polymerization reactor in which the monomer conversion and melt index of the produced polymer are controlled by manipulating the reactor cooling water

  20. Study of Plastic Scintillator based Reactor Neutrino Detector


    Ono, Hiroaki; Takahashi, Katsuyuki; Miyata, Hitoshi; Ishida, Kyouhei; Katsumata, Masaaki; Watanabe, Minori


    Recently nuclear power plant becomes one of the important electric power sources to reduce the greenhouse gasses emission. Nuclear reactor fuel consists of the uranium-235 (^U) enriched uranium and produces the thermal energy via nuclear fission process. Through the reactor operation, uranium-238 (^U) fission also produces the plutonium- 239 (^Pu), which should be strictly under controlled to avoid the diversion to the nuclear weapon for a nonproliferation and safeguard. At this point, monito...

  1. Effect of epithermal neutrons on viability of glioblastoma tumor cells in vitro. (United States)

    Mostovich, L A; Gubanova, N V; Kutsenko, O S; Aleinik, V I; Kuznetsov, A S; Makarov, A N; Sorokin, I N; Taskaev, S Yu; Nepomnyashchikh, G I; Grigor'eva, E V


    We studied in vitro effect of epithermal neutrons in various doses on viability of glioblastoma U87 tumor cells. Increasing the dose from 1.9 to 4.1 Sv promoted cell death. Cytofluorimetric analysis revealed no activation of apoptosis in the irradiated cells, which attested to necrotic death of the tumor cells exposed to epithermal neutron radiation.

  2. Geochemical characteristics of igneous rocks associated with epithermal mineral deposits—A review (United States)

    du Bray, Edward A.


    Newly synthesized data indicate that the geochemistry of igneous rocks associated with epithermal mineral deposits varies extensively and continuously from subalkaline basaltic to rhyolitic compositions. Trace element and isotopic data for these rocks are consistent with subduction-related magmatism and suggest that the primary source magmas were generated by partial melting of the mantle-wedge above subducting oceanic slabs. Broad geochemical and petrographic diversity of individual igneous rock units associated with epithermal deposits indicate that the associated magmas evolved by open-system processes. Following migration to shallow crustal reservoirs, these magmas evolved by assimilation, recharge, and partial homogenization; these processes contribute to arc magmatism worldwide.Although epithermal deposits with the largest Au and Ag production are associated with felsic to intermediate composition igneous rocks, demonstrable relationships between magmas having any particular composition and epithermal deposit genesis are completely absent because the composition of igneous rock units associated with epithermal deposits ranges from basalt to rhyolite. Consequently, igneous rock compositions do not constitute effective exploration criteria with respect to identification of terranes prospective for epithermal deposit formation. However, the close spatial and temporal association of igneous rocks and epithermal deposits does suggest a mutual genetic relationship. Igneous systems likely contribute heat and some of the fluids and metals involved in epithermal deposit formation. Accordingly, deposit formation requires optimization of source metal contents, appropriate fluid compositions and characteristics, structural features conducive to hydrothermal fluid flow and confinement, and receptive host rocks, but not magmas with special compositional characteristics.

  3. Correlated Observations of Epithermal Neutrons and Polar Illumination for Orbital Neutron Detectors (United States)

    McClanahan, T. P.; Mitrofanov, I. G.; Boynton, W. V.; Chin, G.; Droege, G.; Evans, L. G.; Garvin, J.; Harshman, K.; Malakhov, A.; Livengood, T.; hide


    We correlate Lunar Reconnaisance Orbiter's (LRO) Lunar Exploration Neutron Detector (LEND) and the Lunar Prospector Neutron Spectrometer's (LPNS) orbital epithermal neutron maps of the Lunar high-latitudes with co-registered illumination maps derived from the Lunar Orbiter Laser Altimeter (LOLA) topography. Epithermal neutron count rate maps were derived from the LEND: 1) Collimated Sensor for Epithermal Neutrons, CSETNI-4 2) Uncollimated Sensor for Epithermal Neutrons, SETN and the Uncollimated Lunar Prospector: 3) Low-altitude and 4) High-altitude mapping phases. In this abstract we illustrate 1) and 3) and include 2) and 4) in our presentation. The correlative study provides unique perspectives on the regional epithermal neutron fluences from the Lunar polar regions under different detector and altitude configurations.

  4. Design and R&D Progress of China Lead-Based Reactor for ADS Research Facility

    Directory of Open Access Journals (Sweden)

    Yican Wu


    Full Text Available In 2011, the Chinese Academy of Sciences launched an engineering project to develop an accelerator-driven subcritical system (ADS for nuclear waste transmutation. The China Lead-based Reactor (CLEAR, proposed by the Institute of Nuclear Energy Safety Technology, was selected as the reference reactor for ADS development, as well as for the technology development of the Generation IV lead-cooled fast reactor. The conceptual design of CLEAR-I with 10 MW thermal power has been completed. KYLIN series lead-bismuth eutectic experimental loops have been constructed to investigate the technologies of the coolant, key components, structural materials, fuel assembly, operation, and control. In order to validate and test the key components and integrated operating technology of the lead-based reactor, the lead alloy-cooled non-nuclear reactor CLEAR-S, the lead-based zero-power nuclear reactor CLEAR-0, and the lead-based virtual reactor CLEAR-V are under realization.

  5. Fast and epithermal neutron radiography using neutron irradiator

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Karol A.M. de; Crispim, Verginia R., E-mail:, E-mail: [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil).Programa de Engenharia Nuclear; Ferreira, Francisco J.O., E-mail: [Instituto de Energia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Divisao de Reatores


    The neutron radiography technique (NR) with neutrons in the energy range fast to epithermal is a powerful tool used in no-destructive inspection of bulky objects of diverse materials, including those rich in hydrogen, oxygen, nitrogen ad carbon. Thus, it can be used to identify, inclusions, voids and thickness differences in materials such as explosive artifacts and narcotics. Aiming at using NR with fast and epithermal neutrons, an Irradiator was constructed by: a {sup 241}Am-Be source, with 5 Ci activity, a collimator with adjustable collimation rate, L/D; and a shield device composed by plates of borated paraffin and iron. The test specimens chosen were a Beam Purity Indicator (BPI) and an Indicator of Visual Resolution (IVR). The neutron radiography images obtained had a resolution of 444.4 μm and 363.6 μm respectively when registered in: 1) the sheet of the nuclear track solid detector, CR-39 type, through X (n,p) Y nuclear reaction; and 2) Kodak Industrex M radiographic film plate in close contact with a boron converter screen, both stored in a Kodak radiographic cassette. (author)

  6. Determination of uranium in tree bark samples by epithermal neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Nicole Pereira de; Saiki, Mitiko, E-mail: [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)


    In this study uranium (U) concentrations were determined in certified reference materials (CRMs) and in tree bark samples collected in 'Cidade Universitaria Armando de Salles Oliveira' (CUASO) USP, Sao Paulo, SP, Brazil). The barks were collected from different species namely Poincianella pluviosa and Tipuana tipu. These bark samples were cleaned, dried, grated and milled for the analyses by epithermal neutron activation analysis method (ENAA). This method consists on irradiating samples and U standard in IEAR1 nuclear reactor with thermal neutron flux of 1:9 x 10{sup 12} n cm{sup -2} s{sup -1} during 40 to 60 seconds depending on the samples matrices. The samples and standard were measured by gamma ray spectroscopy. U was identified by the peak of 74.66 keV of {sup 239}U with half life of 23.47 minutes. Concentration of U was calculated by comparative method. For analytical quality control of U results, certified reference materials were analysed. Results obtained for CRMs presented good precision and accuracy, with |Z score| <= 0.39. Uranium concentrations in tree barks varied from 83.1 to 627.6 ng g{sup -} {sup 1} and the relative standard deviations of these results ranged from 1.8 to 10%. (author)

  7. A preliminary analysis of the reactor-based plutonium disposition alternative deployment schedules

    Energy Technology Data Exchange (ETDEWEB)

    Zurn, R.M.


    This paper discusses the preliminary analysis of the implementation schedules of the reactor-based plutonium disposition alternatives. These schedule analyses are a part of a larger process to examine the nine decision criteria used to determine the most appropriate method of disposing of U.S. surplus weapons plutonium. The preliminary analysis indicates that the mission durations for the reactor-based alternatives range from eleven years to eighteen years and the initial mission fuel assemblies containing surplus weapons-usable plutonium could be loaded into the reactors between nine and fourteen years after the Record of Decision.

  8. Geochemistry and statistical analyses of porphyry system and epithermal veins at Hizehjan in northwestern Iran (United States)

    Radmard, Kaikhosrov; Zamanian, Hassan; Hosseinzadeh, Mohamad Reza; Khalaji, Ahmad Ahmadi


    Situated about 130 km northeast of Tabriz (northwest Iran), the Mazra'eh Shadi deposit is in the Arasbaran metallogenic belt (AAB). Intrusion of subvolcanic rocks, such as quartz monzodiorite-diorite porphyry, into Eocene volcanic and volcano-sedimentary units led to mineralisation and alteration. Mineralisation can be subdivided into a porphyry system and Au-bearing quartz veins within andesite and trachyandesite which is controlled by fault distribution. Rock samples from quartz veins show maximum values of Au (17100 ppb), Pb (21100 ppm), Ag (9.43ppm), Cu (611ppm) and Zn (333 ppm). Au is strongly correlated with Ag, Zn and Pb. In the Au-bearing quartz veins, factor group 1 indicates a strong correlation between Au, Pb, Ag, Zn and W. Factor group 2 indicates a correlation between Cu, Te, Sb and Zn, while factor group 3 comprises Mo and As. Based on Spearman correlation coefficients, Sb and Te can be very good indicator minerals for Au, Ag and Pb epithermal mineralisation in the study area. The zoning pattern shows clearly that base metals, such as Cu, Pb, Zn and Mo, occur at the deepest levels, whereas Au and Ag are found at higher elevations than base metals in boreholes in northern Mazra'eh Shadi. This observation contrasts with the typical zoning pattern caused by boiling in epithermal veins. At Mazra'eh Shadi, quartz veins containing co-existing liquid-rich and vapour-rich inclusions, as strong evidence of boiling during hydrothermal evolution, have relatively high Au grades (up to 813 ppb). In the quartz veins, Au is strongly correlated with Ag, and these elements are in the same group with Fe and S. Mineralisation of Au and Ag is a result of pyrite precipitation, boiling of hydrothermal fluids and a pH decrease.

  9. Distribution of 35 Elements in Peat Cores from Ombrotrophic Bogs Studied by Epithermal Neutron Activation Analysis

    CERN Document Server

    Frontasyeva, M V


    In ombrotrophic bogs the surface peat layer is supplied with chemical substances only from the atmosphere. Peat cores from these bogs therefore can be used to study temporal trends in atmospheric deposition of pollutants. In this work epithermal neutron activation analysis was applied for the first time to study the distribution of 35 elements in peat profiles from ombrotrophic bogs. The selected examples were from Finnmark county in northern Norway: one pristine site far from any local pollution source, and another strongly affected by long-term operation of Russian copper-nickel smelters located close to the border. The elements are classified with respect to their behavior in the uppermost 40 cm of the peat, and similarities and differences between the two profiles are discussed. As compared with other more commonly used analytical techniques based on acid decomposition of the sample ENAA has the advantage of providing the total concentrations of the elements.

  10. Zoning in the Carboniferous-Lower Permian Cracow epithermal vein system, central Queensland, Australia (United States)

    Dong, G. Y.; Zhou, T.


    Four epithermal vein deposits (i.e. Dawn, Central Extended, Rose’s Pride and Klondyke) in the Cracow gold field, central Queensland were investigated in terms of paragenesis, mineralogy, vein textures, fluid inclusions and stable isotopes. The Cracow epithermal field is confined to an area approximately 6 by 5 kilometers. All the deposits are hosted by the massive Camboon Andesite of Upper Carboniferous to Lower Permian age, occur as open-space vein fillings, and have similar paragenesis. However, significant variations in mineralogy, textures of quartz and adularia, and fluid geochemistry were found for a main mineralisation stage (Stage II) of each individual deposits. At Rose’s Pride and Klondyke, base-metal sulphides are virtually absent, but significant amounts of calcite and quartz with minor adularia are widely distributed. Replacement textures are distinct, and mineralisation temperature is less than 220 °C and salinity less than 0.2 wt%. The δ18O values of quartz and calcite range from -2.65 to -2.06‰ and from -6.66 to -6.34‰ respectively, and calculated δ18OH2O value is about -17‰ which represents a nearly unshifted palaeo-meteoric water. Gold mineralisation is best developed at Central Extended among the studied deposits, where patches rich in electrum are often observed in polished thin sections and where gold grades exceeding 10 g/t are frequently indicated by assays. Base-metal sulphides are only present locally and rarely exceed 5 volume percent of the vein samples. Quartz is the dominant gangue mineral, but significant amounts of rhombic adularia and chlorite are widely distributed. Various primary and recrystallisation textures possibly inherited from silica gel are well developed and widespread. At individual sites where crustiform bands developed from both walls of a fissure, temperatures could drop sharply from 275 °C to less than 220 °C. The ore-forming fluid at Central Extended, compared with that at Rose’s Pride and Klondyke

  11. Determination of the thermal and epithermal neutron sensitivities of an LBO chamber

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Satoru; Kotani, Kei; Kajimoto, Tsuyoshi; Tanaka, Kenichi [Hiroshima University, Quantum Energy Applications, Graduate School of Engineering, Higashi-Hiroshima (Japan); Sato, Hitoshi; Nakajima, Erika [Ibaraki Prefectural University of Health Science, Radiological Sciences, Ibaraki (Japan); Shimazaki, Takuto [Hiroshima University, Quantum Energy Applications, Graduate School of Engineering, Higashi-Hiroshima (Japan); Delta Kogyo Co., Ltd., Hiroshima (Japan); Suda, Mitsuru; Hamano, Tsuyoshi [National Institute of Radiological Sciences, Chiba-Shi, Chiba (Japan); Hoshi, Masaharu [Hiroshima University, Institute for Peace Science, Hiroshima (Japan)


    An LBO (Li{sub 2}B{sub 4}O{sub 7}) walled ionization chamber was designed to monitor the epithermal neutron fluence in boron neutron capture therapy clinical irradiation. The thermal and epithermal neutron sensitivities of the device were evaluated using accelerator neutrons from the {sup 9}Be(d, n) reaction at a deuteron energy of 4 MeV (4 MeV d-Be neutrons). The response of the chamber in terms of the electric charge induced in the LBO chamber was compared with the thermal and epithermal neutron fluences measured using the gold-foil activation method. The thermal and epithermal neutron sensitivities obtained were expressed in units of pC cm{sup 2}, i.e., from the chamber response divided by neutron fluence (cm{sup -2}). The measured LBO chamber sensitivities were 2.23 x 10{sup -7} ± 0.34 x 10{sup -7} (pC cm{sup 2}) for thermal neutrons and 2.00 x 10{sup -5} ± 0.12 x 10{sup -5} (pC cm{sup 2}) for epithermal neutrons. This shows that the LBO chamber is sufficiently sensitive to epithermal neutrons to be useful for epithermal neutron monitoring in BNCT irradiation. (orig.)

  12. Determination of the thermal and epithermal neutron sensitivities of an LBO chamber. (United States)

    Endo, Satoru; Sato, Hitoshi; Shimazaki, Takuto; Nakajima, Erika; Kotani, Kei; Suda, Mitsuru; Hamano, Tsuyoshi; Kajimoto, Tsuyoshi; Tanaka, Kenichi; Hoshi, Masaharu


    An LBO (Li2B4O7) walled ionization chamber was designed to monitor the epithermal neutron fluence in boron neutron capture therapy clinical irradiation. The thermal and epithermal neutron sensitivities of the device were evaluated using accelerator neutrons from the (9)Be(d, n) reaction at a deuteron energy of 4 MeV (4 MeV d-Be neutrons). The response of the chamber in terms of the electric charge induced in the LBO chamber was compared with the thermal and epithermal neutron fluences measured using the gold-foil activation method. The thermal and epithermal neutron sensitivities obtained were expressed in units of pC cm(2), i.e., from the chamber response divided by neutron fluence (cm(-2)). The measured LBO chamber sensitivities were 2.23 × 10(-7) ± 0.34 × 10(-7) (pC cm(2)) for thermal neutrons and 2.00 × 10(-5) ± 0.12 × 10(-5) (pC cm(2)) for epithermal neutrons. This shows that the LBO chamber is sufficiently sensitive to epithermal neutrons to be useful for epithermal neutron monitoring in BNCT irradiation.

  13. K-capture by Al-Si based Additives in an Entrained Flow Reactor

    DEFF Research Database (Denmark)

    Wang, Guoliang; Jensen, Peter Arendt; Wu, Hao


    A water slurry, consisting of KCl and Al-Si based additives (kaolin and coal fly ash) was fed into an entrained flow reactor (EFR) to study the K-capturing reaction of the additives at suspension-fired conditions. Solid products collected from the reactor were analysed with respect to total...... of KCl to K-aluminosilicate decreased. When reaction temperature increased from 1100 °C to 1450 °C, the conversion of KCl does not change significantly, which differs from the trend observed in fixed-bed reactor....

  14. IAEA designated international centre based on research reactors (ICERR)

    Energy Technology Data Exchange (ETDEWEB)

    Di Tigliole, Andrea Borio; Bradley, Edward; Khoroshev, Mikhail; Marshall, Frances; Morris, Charles; Tozser, Sandor [International Atomic Energy Agency, Vienna (Austria). Dept. of Nuclear Energy


    International activities in the back end of the research reactor (RR) fuel cycle have so far been dominated by the programmes of acceptance of highly-enriched uranium (HEU) spent nuclear fuel (SNF) by the country where it was originally enriched. These programmes will soon have achieved their goals. However, the needs of the nuclear community dictate that the majority of the research reactors continues to operate using low enriched uranium (LEU) fuel in order to meet the varied mission objectives. As a result, inventories of LEU SNF will continue to be created and the back end solution of RR SNF remains a critical issue. In view of this fact, the IAEA drew up a report presenting available reprocessing and recycling services for RR SNF.

  15. Epithermal Neutron Activation Analysis of Spirulina platensis Biomass, of the C-Phycocianin and of DNA Extracted from It

    CERN Document Server

    Mosulishvili, L M; Belokobylsky, A I; Kirkesali, E I; Khizanishvili, A I; Pomyakushina, E V


    The epithermal neutron activation analysis (ENAA) was used for study of the biomass of Spirulina platensis. The background levels of concentration 27 macro-, micro- and trace elements ranging from 10^{-3} up to 10^{4} ppm were determined. It was found that the biomass of spirulina does not contain toxic elements above the tolerance levels and can be utilized as a matrix of pharmaceuticals based on it. The concentrations of basic elements in C-phycocianin and DNA extracted from Spirulina platensis were determined by ENAA. A comparison of the element content of a whole spirulina biomass with that of a refined C-phycocianin preparation was made.

  16. Very high flux research reactors based on particle fuels

    Energy Technology Data Exchange (ETDEWEB)

    Powell, J.R.; Takahashi, H.


    A new approach to high flux research reactors is described, the VHFR (Very High Flux Reactor). The VHFR fuel region(s) are packed beds of HTGR-type fuel particles through which coolant (e.g., D/sub 2/O) flows directly. The small particle diameter (typically on the order of 500 microns) results in very large surface areas for heat transfer (approx. 100 cm/sup 2//cm/sup 3/ of bed), high power densities (approx. 10 megawatts per liter), and minimal between fuel and coolant (approx. 10 K) VHFR designs are presented which achieve steady-state fluxes of approx. 2x10/sup 16/ n/cm/sup 2/sec. Deuterium/beryllium combinations give the highest flux levels. Critical mass is low, approx. 2 kg /sup 235/U for 20% enriched fuel. Refueling can be carried out continuously on-line, or in a batch process with a short daily shutdown. Fission product inventory is very low, approx. 100 to 300 grams, depending on design.

  17. Geochemical patterns of epithermal ore formation in the Okhotsk-Chukotka volcanoplutonic belt (Northeast Russia) (United States)

    Volkov, A. V.; Murashov, K. Yu.; Sidorov, A. A.


    Ores of epithermal Au-Ag deposits of the Okhotsk-Chukotka volcanoplutonic belt are characterized by enrichment in a wide spectrum of elements in relation to the average upper crustal values. The data obtained show that the host volcanic rocks are the most likely sources of minor elements and REEs for the fluids that formed epithermal Au-Ag deposits of the Okhotsk-Chukotka volcanoplutonic belt.

  18. Studies on the liquid fluoride thorium reactor: Comparative neutronics analysis of MCNP6 code with SRAC95 reactor analysis code based on FUJI-U3-(0)

    Energy Technology Data Exchange (ETDEWEB)

    Jaradat, S.Q., E-mail:; Alajo, A.B., E-mail:


    Highlights: • The verification for FUJI-U3-(0)—a molten salt reactor—was performed. • The MCNP6 was used to study the reactor physics characteristics for FUJI-U3 type. • The results from the MCNP6 were comparable with the ones obtained from literature. - Abstract: The verification for FUJI-U3-(0)—a molten salt reactor—was performed. The reactor used LiF-BeF2-ThF4-UF4 as the mixed liquid fuel salt, and the core was graphite moderated. The MCNP6 code was used to study the reactor physics characteristics for the FUJI-U3-(0) reactor. Results for reactor physics characteristic of the FUJI-U3-(0) exist in literature, which were used as reference. The reference results were obtained using SRAC95 (a reactor analysis code) coupled with ORIGEN2 (a depletion code). Some modifications were made in the reconstruction of the FUJI-U3-(0) reactor in MCNP due to unavailability of more detailed description of the reactor core. The assumptions resulted in two representative models of the reactor. The results from the MCNP6 models were compared with the reference results obtained from literature. The results were comparable with each other, but with some notable differences. The differences are because of the approximations that were done on the SRAC95 model of the FUJI-U3 to simplify the simulation. Based on the results, it is concluded that MCNP6 code predicts well the overall simulation of neutronics analysis to the previous simulation works using SRAC95 code.

  19. Model based design of biochemical micro-reactors

    Directory of Open Access Journals (Sweden)

    Tobias eElbinger


    Full Text Available Mathematical modelling of biochemical pathways is an important resource in Synthetic Biology, as the predictive power of simulating synthetic pathways represents an important step in the design of synthetic metabolons. In this paper, we are concerned with the mathematical modeling, simulation and optimization of metabolic processes in biochemical micro-reactors able to carry out enzymatic reactions and to exchange metabolites with their surrounding medium. The results of the reported modeling approach are incorporated in the design of the first micro-reactor prototypes that are under construction. These microreactors consist of compartments separated by membranes carrying specific transporters for the input of substrates and export of products. Inside the compartments multi-enzyme complexes assembled on nano-beads by peptide adapters are used to carry out metabolic reactions.The spatially resolved mathematical model describing the ongoing processes consists of a system of diffusion equations together with boundary and initial conditions. The boundary conditions model the exchange of metabolites with the neighboring compartments and the reactions at the surface of the nano-beads carrying the multi-enzyme complexes. Efficient and accurate approaches for numerical simulation of the mathematical model and for optimal design of the micro-reactor are developed. As a proof-of-concept scenario, a synthetic pathway for the conversion of sucrose to glucose-6-phosphate (G6P was chosen. In this context, the mathematical model is employed to compute the spatio-temporal distributions of the metabolite concentrations, as well as application relevant quantities like the outflow rate of G6P. These computations are performed for different scenarios, where the number of beads as well as their loading capacity are varied. The computed metabolite distributions show spatial patterns which differ for different experimental arrangements. Furthermore, the total output

  20. Development of An Epi-thermal Neutron Field for Fundamental Researches for BNCT with A DT Neutron Source (United States)

    Osawa, Yuta; Imoto, Shoichi; Kusaka, Sachie; Sato, Fuminobu; Tanoshita, Masahiro; Murata, Isao


    Boron Neutron Capture Therapy (BNCT) is known to be a new promising cancer therapy suppressing influence against normal cells. In Japan, Accelerator Based Neutron Sources (ABNS) are being developed for BNCT. For the spread of ABNS based BNCT, we should characterize the neutron field beforehand. For this purpose, we have been developing a low-energy neutron spectrometer based on 3He position sensitive proportional counter. In this study, a new intense epi-thermal neutron field was developed with a DT neutron source for verification of validity of the spectrometer. After the development, the neutron field characteristics were experimentally evaluated by using activation foils. As a result, we confirmed that an epi-thermal neutron field was successfully developed suppressing fast neutrons substantially. Thereafter, the neutron spectrometer was verified experimentally. In the verification, although a measured detection depth distribution agreed well with the calculated distribution by MCNP, the unfolded spectrum was significantly different from the calculated neutron spectrum due to contribution of the side neutron incidence. Therefore, we designed a new neutron collimator consisting of a polyethylene pre-collimator and boron carbide neutron absorber and confirmed numerically that it could suppress the side incident neutrons and shape the neutron flux to be like a pencil beam.

  1. Development of An Epi-thermal Neutron Field for Fundamental Researches for BNCT with A DT Neutron Source

    Directory of Open Access Journals (Sweden)

    Osawa Yuta


    Full Text Available Boron Neutron Capture Therapy (BNCT is known to be a new promising cancer therapy suppressing influence against normal cells. In Japan, Accelerator Based Neutron Sources (ABNS are being developed for BNCT. For the spread of ABNS based BNCT, we should characterize the neutron field beforehand. For this purpose, we have been developing a low-energy neutron spectrometer based on 3He position sensitive proportional counter. In this study, a new intense epi-thermal neutron field was developed with a DT neutron source for verification of validity of the spectrometer. After the development, the neutron field characteristics were experimentally evaluated by using activation foils. As a result, we confirmed that an epi-thermal neutron field was successfully developed suppressing fast neutrons substantially. Thereafter, the neutron spectrometer was verified experimentally. In the verification, although a measured detection depth distribution agreed well with the calculated distribution by MCNP, the unfolded spectrum was significantly different from the calculated neutron spectrum due to contribution of the side neutron incidence. Therefore, we designed a new neutron collimator consisting of a polyethylene pre-collimator and boron carbide neutron absorber and confirmed numerically that it could suppress the side incident neutrons and shape the neutron flux to be like a pencil beam.

  2. ESR-dosimetry in thermal and epithermal neutron fields for application in boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Tobias


    Dosimetry is essential for every form of radiotherapy. In Boron Neutron Capture Therapy (BNCT) mixed neutron and gamma fields have to be considered. Dose is deposited in different neutron interactions with elements in the penetrated tissue and by gamma particles, which are always part of a neutron field. The therapeutic dose in BNCT is deposited by densely ionising particles, originating from the fragmentation of the isotope boron-10 after capture of a thermal neutron. Despite being investigated for decades, dosimetry in neutron beams or fields for BNCT remains complex, due to the variety in type and energy of the secondary particles. Today usually ionisation chambers combined with metal foils are used. The applied techniques require extensive effort and are time consuming, while the resulting uncertainties remain high. Consequently, the investigation of more effective techniques or alternative dosimeters is an important field of research. In this work the possibilities of ESR-dosimeters in those fields have been investigated. Certain materials, such as alanine, generate stable radicals upon irradiation. Using Electron Spin Resonance (ESR) spectrometry the amount of radicals, which is proportional to absorbed dose, can be quantified. Different ESR detector materials have been irradiated in the thermal neutron field of the research reactor TRIGA research reactor in Mainz, Germany, with five setups, generating different secondary particle spectra. Further irradiations have been conducted in two epithermal neutron beams. The detector response, however, strongly depends on the dose depositing particle type and energy. It is hence necessary to accompany measurements by computational modelling and simulation. In this work the Monte Carlo code FLUKA was used to calculate absorbed doses and dose components. The relative effectiveness (RE), linking absorbed dose and detector response, has been calculated using amorphous track models. For the simulation, detailed models of

  3. Implementation of the k{sub 0} technique using multi-detectors on diverse irradiation facilities of TRIGA Reactor; Implementacion de la tecnica k{sub 0} usando multidetectores en diferentes instalaciones de irradiacion del Reactor TRIGA

    Energy Technology Data Exchange (ETDEWEB)

    Caldera C, M. de G.


    The k{sub 0} method with the technique of neutron activation analysis allows obtaining important characteristics parameters that describe a nuclear reactor. Among these parameters are the form factor of epithermal neutron flux, α and the ratio of thermal neutron flux with respect to the epithermal neutron flux, f. These parameters were obtained by irradiation of two different monitors, one of Au-Zr and the other of Au-Mo-Cr, where the last one was made and implemented for the first time. Both monitors were irradiated in different positions in the TRIGA Mark III Reactor at the National Institute of Nuclear Research. (Author)


    Directory of Open Access Journals (Sweden)

    Nina Fauziah


    Full Text Available Studies were carried out to design a collimator which results in epithermal neutron beam for IN VITRO and IN VIVO of Boron Neutron Capture Therapy (BNCT at the Kartini research reactor by means of Monte Carlo N-Particle (MCNP codes. Reactor within 100 kW of thermal power was used as the neutron source. The design criteria were based on recommendation from the International Atomic Energy Agency (IAEA. All materials used were varied in size, according to the value of mean free path for each material. MCNP simulations indicated that by using 5 cm thick of Ni as collimator wall, 60 cm thick of Al as moderator, 15 cm thick of 60Ni as filter, 2 cm thick of Bi as γ-ray shielding, 3 cm thick of 6Li2CO3-polyethylene as beam delimiter, with 1 to 5 cm varied aperture size, epithermal neutron beam with maximum flux of 7.65 x 108 could be produced. The beam has minimum fast neutron and γ-ray components of, respectively, 1.76 x 10-13 Gy.cm2.n-1 and 1.32 x 10-13 Gy.cm2.n-1, minimum thermal neutron per epithermal neutron ratio of 0.008, and maximum directionality of 0.73. It did not fully pass the IAEA’s criteria, since the epithermal neutron flux was below the recommended value, 1.0 x 109 Nonetheless, it was still usable with epithermal neutron flux exceeding 5.0 x 108 When it was assumed that the graphite inside the thermal column was not discharged but only the part which was going to be replaced by the collimator, the performance of the collimator became better within the positive effect from the surrounding graphite that the beam resulted passed all criteria with epithermal neutron flux up to 1.68 x 109 Keywords: design, collimator, epithermal neutron beam, BNCT, MCNP, criteria   Telah dilakukan penelitian tentang desain kolimator yang menghasilkan radiasi netron epitermal untuk uji in vitro dan in vivo pada Boron Neutron Capture Therapy (BNCT di Reaktor Riset Kartini dengan menggunakan program Monte

  5. Graphic-object information system {open_quotes}research base for reactor materials science{close_quotes}

    Energy Technology Data Exchange (ETDEWEB)

    Markina, N.V.; Lebedeva, E.E.; Arkhangel`skii, N.V.; Semenov, S.B.; Moiseev, A.L.


    An information system developed for reactor materials research is described. The information system incorporates an expert system, MATREKS, and a heirarchial data base. The data base contains information from 20 Russian research reactors. The information system structure, data base structure, search methods, system output modes, and technical facilities and software required are briefly discussed. 6 refs., 2 figs.

  6. A two-stage ethanol-based biodiesel production in a packed bed reactor

    DEFF Research Database (Denmark)

    Xu, Yuan; Nordblad, Mathias; Woodley, John


    -spec’ levels according to the European biodiesel specifications for methanol-based biodiesel. The highest overall productivity achieved in the first stage was 2.52 kg FAEE(kg catalyst)−1 h−1 at a superficial velocity of 7.6 cm min−1, close to the efficiency of a stirred tank reactor under similar conditions...... were conducted in a simulated series of reactors by repeatedly passing the reaction mixture through a single reactor, with separation of the by-product glycerol and water between passes in the first and second stages, respectively. The second stage brought the major components of biodiesel to ‘in....... The overall productivity of the proposed two-stage process was 1.56 kg FAEE(kg catalyst)−1 h−1. Based on this process model, the challenges of scale-up have been addressed and potential continuous process options have been proposed....

  7. Optimization of lamp arrangement in a closed-conduit UV reactor based on a genetic algorithm. (United States)

    Sultan, Tipu; Ahmad, Zeshan; Cho, Jinsoo


    The choice for the arrangement of the UV lamps in a closed-conduit ultraviolet (CCUV) reactor significantly affects the performance. However, a systematic methodology for the optimal lamp arrangement within the chamber of the CCUV reactor is not well established in the literature. In this research work, we propose a viable systematic methodology for the lamp arrangement based on a genetic algorithm (GA). In addition, we analyze the impacts of the diameter, angle, and symmetry of the lamp arrangement on the reduction equivalent dose (RED). The results are compared based on the simulated RED values and evaluated using the computational fluid dynamics simulations software ANSYS FLUENT. The fluence rate was calculated using commercial software UVCalc3D, and the GA-based lamp arrangement optimization was achieved using MATLAB. The simulation results provide detailed information about the GA-based methodology for the lamp arrangement, the pathogen transport, and the simulated RED values. A significant increase in the RED values was achieved by using the GA-based lamp arrangement methodology. This increase in RED value was highest for the asymmetric lamp arrangement within the chamber of the CCUV reactor. These results demonstrate that the proposed GA-based methodology for symmetric and asymmetric lamp arrangement provides a viable technical solution to the design and optimization of the CCUV reactor.

  8. A spin reversal system for polarized epithermal neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, J.D. [Los Alamos Nat. Lab., NM (United States); Penttilae, S.I. [Los Alamos Nat. Lab., NM (United States); Tippens, W.B. [University of Virginia, Charlottesville, VA 22903 (United States)


    The design and construction of a spin-reversal system for longitudinally polarized epithermal neutrons are presented. The design uses a static magnetic field parallel to the momentum of the neutron. The longitudinal field changes the direction at its midpoint. A transverse magnetic field is turned off to control the spin direction at the end of the spin flipper. The neutron spin is reversed with respect to both the neutron momentum and the static longitudinal field at the exit of the spin flipper. In the transverse field-on state the spin adiabatically follows the field direction and the spin direction is reversed. In the transverse field-off state the spin passes rapidly through the region where the solenoidal field reverses the sign and the spin direction is not reversed. With this design, the spins of an 8-cm-diameter beam of longitudinally polarized neutrons can be reversed with an efficiency greater than 88% over a range of neutron energies of more than four orders of magnitude. (orig.).

  9. Evidence for rapid epithermal mineralization and coeval bimodal volcanism, Bruner Au-Ag property, NV USA (United States)

    Baldwin, Dylan

    -ore hydrothermal system is overprinted by Au-Ag stage alteration consisting of proximal quartz + Fe-sericite + pyrite +/- adularia and distal illite-montmorillonite-chlorite (after biotite). The distribution of steam-heated alteration zones and vitrophyre units, along with prominent chemical and textural zonation of veins, suggest that a 400 m vertical section of the epithermal system is now exposed at surface. 40Ar/39Ar geochronology of 3 adularia and 4 volcanic samples identified a rhyolite unit that slightly predates ~16.34 Ma Au-Ag mineralization and mafic magmatism. The proposed timeline for deposit formation is: 21-20 Ma, eruption of locally derived rhyolitic flows; 16.62 Ma, development of new rhyolite flow-dome complex and meteoric-dominated geothermal circulation along N-S structural fabric driven by heat from rhyolite domes; ~16.34 Ma, emplacement of NW trending basalt dikes, followed by violent hydrothermal eruptions, eruption of tuffisite breccia dikes, and Au-Ag mineralization; <16.34 Ma, post-mineral rhyolitic volcanism and normal faulting; and <16 Ma to present, continued faulting and dismemberment of the mineral system. The close spatial and temporal association of veining with coeval volcanic units suggests that Au-Ag-S traveled along similar structure and may have been supplied from the same magma chamber. Deposition of Au and Ag from HS- complexes by boiling appears to have occurred rapidly following closely spaced violent magmatic/hydrothermal eruption events. On a deposit scale, a complex interplay of depth, proximity to dikes, and structural dilatency during Au-Ag stage fluid pulses controlled localization of economic mineralization, which can be highly variable over meter-scale distances. Bruner appears to belong to a small subset of mid-Miocene epithermal deposits in Nevada with low base metal contents and low to no Se, related to calc- alkaline rhyolite flow-dome complexes. Multiple lines of evidence document decoupled sourcing of Al-Si-K-O from Au

  10. Study of carbon dioxide gas treatment based on equations of kinetics in plasma discharge reactor (United States)

    Abedi-Varaki, Mehdi


    Carbon dioxide (CO2) as the primary greenhouse gas, is the main pollutant that is warming earth. CO2 is widely emitted through the cars, planes, power plants and other human activities that involve the burning of fossil fuels (coal, natural gas and oil). Thus, there is a need to develop some method to reduce CO2 emission. To this end, this study investigates the behavior of CO2 in dielectric barrier discharge (DBD) plasma reactor. The behavior of different species and their reaction rates are studied using a zero-dimensional model based on equations of kinetics inside plasma reactor. The results show that the plasma reactor has an effective reduction on the CO2 density inside the reactor. As a result of reduction in the temporal variations of reaction rate, the speed of chemical reactions for CO2 decreases and very low concentration of CO2 molecules inside the plasma reactor is generated. The obtained results are compared with the existing experimental and simulation findings in the literature.

  11. Design studies of innovatively small fusion reactor based on biomass-fusion hybrid concept: GNOME

    Energy Technology Data Exchange (ETDEWEB)

    Ibano, K., E-mail: [Institute of Advanced Energy, Kyoto University, Uji-shi, Kyoto 611-0011 (Japan); Utoh, H.; Tobita, K. [Japan Atomic Energy Agency, Naka-shi, Ibaraki 311-0193 (Japan); Yamamoto, Y.; Konishi, S. [Institute of Advanced Energy, Kyoto University, Uji-shi, Kyoto 611-0011 (Japan)


    Conceptual design of an innovatively small tokamak reactor 'GNOME' based on a non-fission biomass-fusion hybrid concept is proposed. This fusion plant concept intends to use high-temperature heat from the blanket to generate hydrogen or synthetic fuels out of waste biomass. Since energy multiplication is expected by utilizing chemical energy of biomass, the requirement for the fusion plasma for net plant energy output is reduced to Q {>=} 5. As a result, the GNOME reactor has been designed to produce 320 MW fusion power with a 5.2 m major radius, 3.1 normalized beta and 11 T maximum field. This relatively small maximum field can be achieved by using Nb{sub 3}Sn superconducting magnets. Besides, this reactor allows 3.0 m diameter space for its center solenoid coil and requires 60 MW of the input power. These features require minimal technical extensions from ITER.

  12. A new MC-based method to evaluate the fission fraction uncertainty at reactor neutrino experiment

    CERN Document Server

    Ma, X B; Chen, Y X


    Uncertainties of fission fraction is an important uncertainty source for the antineutrino flux prediction in a reactor antineutrino experiment. A new MC-based method of evaluating the covariance coefficients between isotopes was proposed. It was found that the covariance coefficients will varying with reactor burnup and which may change from positive to negative because of fissioning balance effect, for example, the covariance coefficient between $^{235}$U and $^{239}$Pu changes from 0.15 to -0.13. Using the equation between fission fraction and atomic density, the consistent of uncertainty of fission fraction and the covariance matrix were obtained. The antineutrino flux uncertainty is 0.55\\% which does not vary with reactor burnup, and the new value is about 8.3\\% smaller.

  13. Design of a heterogeneous subcritical nuclear reactor with molten salts based on thorium; Diseno de un reactor nuclear subcritico heterogeneo con sales fundidas a base de torio

    Energy Technology Data Exchange (ETDEWEB)

    Medina C, D.; Hernandez A, P.; Letechipia de L, C.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Sajo B, L., E-mail: [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Apdo. Postal 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of)


    This paper presents the design of a heterogeneous subcritical nuclear reactor with molten salts based on thorium, with graphite moderator and a {sup 252}Cf source, whose dose levels at the periphery allows its use in teaching and research activities. The design was realized by the Monte Carlo method, where the geometry, dimensions and the fuel was varied in order to obtain the best design. The result was a cubic reactor of 110 cm of side, with graphite moderator and reflector. In the central part having 9 ducts of 3 cm in diameter, eight of them are 110 cm long, which were placed on the Y axis; the separation between each duct is 10 cm. The central duct has 60 cm in length and this contains the {sup 252}Cf source, also there are two irradiation channels and the other six contain a molten salt ({sup 7}LiF - BeF{sub 2} - ThF{sub 4} - UF{sub 4}) as fuel. For the design the k{sub eff} was calculated, neutron spectra and ambient dose equivalent. In the first instance the above was calculated for a virgin fuel, was called case 1; then a percentage of {sup 233}U was used and the percentage of Th was decreased and was called case 2. This with the purpose of comparing two different fuels operating within the reactor. For the two irradiation ducts three positions are used: center, back and front, in each duct in order to have different flows. (Author)

  14. Nuclear reactor power as applied to a space-based radar mission (United States)

    Jaffe, L.; Beatty, R.; Bhandari, P.; Chow, E.; Deininger, W.; Ewell, R.; Fujita, T.; Grossman, M.; Bloomfield, H.; Heller, J.


    A space-based radar mission and spacecraft are examined to determine system requirements for a 300 kWe space nuclear reactor power system. The spacecraft configuration and its orbit, launch vehicle, and propulsion are described. Mission profiles are addressed, and storage in assembly orbit is considered. Dynamics and attitude control and the problems of nuclear and thermal radiation are examined.

  15. A fuzzy-logic based diagnosis and control of a reactor performing complete autotrophic nitrogen removal

    DEFF Research Database (Denmark)

    Mauricio Iglesias, Miguel; Vangsgaard, Anna Katrine; Gernaey, Krist

    Diagnosis and control modules based on fuzzy set theory were tested for novel bioreactor monitoring and control. Two independent modules were used jointly to carry out first the diagnosis of the state of the system and then use transfer this information to control the reactor. The separation...

  16. Gas phase photocatalytic water splitting in silicon based µ-reactors

    DEFF Research Database (Denmark)

    Dionigi, Fabio; Vesborg, Peter Christian Kjærgaard

    is discussed in the beginning of this thesis followed by an introduction to the basics of photocatalysis. The experimental setup used in this study and the silicon based μ-reactor technology is described afterwards. Almost the entire work presented in the thesis has been done loading the catalysts in these μ...

  17. Assessment method for epithermal gold deposits in Northeast Washington State using weights-of-evidence GIS modeling (United States)

    Boleneus, D.E.; Raines, G.L.; Causey, J.D.; Bookstrom, A.A.; Frost, T.P.; Hyndman, P.C.


    The weights-of-evidence analysis, a quantitative mineral resource mapping tool, is used to delineate favorable areas for epithermal gold deposits and to predict future exploration activity of the mineral industry for similar deposits in a four-county area (222 x 277 km), including the Okanogan and Colville National Forests of northeastern Washington. Modeling is applied in six steps: (1) building a spatial digital database, (2) extracting predictive evidence for a particular deposit, based on an exploration model, (3) calculating relative weights for each predictive map, (4) combining the geologic evidence maps to predict the location of undiscovered mineral resources and (5) measuring the intensity of recent exploration activity by use of mining claims on federal lands, and (6) combining mineral resource and exploration activity into an assessment model of future mining activity. The analysis is accomplished on a personal computer using ArcView GIS platform with Spatial Analyst and Weights-of-Evidence software. In accord with the descriptive model for epithermal gold deposits, digital geologic evidential themes assembled include lithologic map units, thrust faults, normal faults, and igneous dikes. Similarly, geochemical evidential themes include placer gold deposits and gold and silver analyses from stream sediment (silt) samples from National Forest lands. Fifty mines, prospects, or occurrences of epithermal gold deposits, the training set, define the appropriate a really-associated terrane. The areal (or spatial) correlation of each evidential theme with the training set yield predictor theme maps for lithology, placer sites and normal faults. The weights-of-evidence analysis disqualified the thrust fault, dike, and gold and silver silt analyses evidential themes because they lacked spatial correlation with the training set. The decision to accept or reject evidential themes as predictors is assisted by considering probabilistic data consisting of weights and

  18. Mineralogy of telluride-bearing epithermal ores in the Kassiteres-Sappes area, western Thrace, Greece (United States)

    Voudouris, P.; Tarkian, M.; Arikas, K.


    The Kassiteres-Sappes district represents a multi-centered, porphyry-epithermal system developed during the Oligocene to Miocene at a composite calc-alkaline to high-K calc-alkaline volcanic edifice. Precious and base metal mineralization postdates the emplacement of dacite and rhyolite porphyries and is partly superimposed on earlier microdiorite-related porphyry-style mineralization exposed at the Koryfes Hill prospect. A second mineralized porphyry-type system genetically related to a dacite porphyry body developed near the St Demetrios deposit. Tellurides occur mainly at the St Barbara prospect and the St Demetrios deposit. Based on petrographic, electron microprobe, and scanning electron microscope analyses, hessite, petzite, sylvanite, altaite, stützite and native tellurium occur in the St Barbara prospect. These tellurium-bearing minerals are hosted in intermediate-sulfidation type veins and accompanied by pyrite, chalcopyrite, tetrahedrite-group minerals, galena and native gold/electrum. The St Demetrios mineralization includes hessite, altaite, stützite, and tetradymite in close spatial relation to a high-sulfidation assemblage composed of enargite, chalcopyrite, goldfieldite, and native gold. Tellurides were deposited at logfTe2 values of -8.5 to -7.1 and logfS2 values of -10.7 to -7.9 (275 °C). The ore systems are characterized by Au, Ag, Te, Bi, and Mo, which suggests a magmatic contribution to the mineralizing fluids. Ore-forming components were likely derived from both the dacite and rhyolite porphyries.

  19. Ore mineralogy and textural zonation in the world-class epithermal Waihi Vein System, Hauraki Goldfield (United States)

    Mauk, Jeffrey L.; Skinner, Erin G; Fyfe, Sarah J; Menzies, Andrew H; Lowers, Heather A.; Koenig, Alan E.


    The Waihi district in the Hauraki Goldfield of New Zealand contains adularia-sericite epithermal gold-silver veins that have produced more than 7.7 Moz gold. The outermost veins of the district (Martha, Favona, Moonlight, and Cowshed) contain abundant colloform, cherty, and black quartz fill textures, with minor crustiform and massive quartz. The central veins (Amaranth, Trio, and Union) contain predominantly massive and crustiform textures, and these veins are also commonly coarser grained than outermost veins. Pyrite, sphalerite, galena, chalcopyrite, electrum, and acanthite occur in both outermost and central veins; base metal sulfide minerals typically increase in abundance in deeper samples. Antimony-, arsenic-, and selenium-bearing minerals are most abundant in the Favona and Moonlight veins, whereas base metal sulfide minerals are more abundant in the central veins at Correnso. Throughout the Waihi vein system, electrum is by far the most widespread, abundant, and significant gold-bearing mineral, but LA-ICP-MS analyses show that arsenian pyrite also contains some gold. Mineralogical and textural data are consistent with the central veins forming at a deeper structural level, or from hydrothermal fluids with different chemistry, or both.

  20. Advances in boron neutron capture therapy (BNCT) at kyoto university - From reactor-based BNCT to accelerator-based BNCT (United States)

    Sakurai, Yoshinori; Tanaka, Hiroki; Takata, Takushi; Fujimoto, Nozomi; Suzuki, Minoru; Masunaga, Shinichiro; Kinashi, Yuko; Kondo, Natsuko; Narabayashi, Masaru; Nakagawa, Yosuke; Watanabe, Tsubasa; Ono, Koji; Maruhashi, Akira


    At the Kyoto University Research Reactor Institute (KURRI), a clinical study of boron neutron capture therapy (BNCT) using a neutron irradiation facility installed at the research nuclear reactor has been regularly performed since February 1990. As of November 2014, 510 clinical irradiations were carried out using the reactor-based system. The world's first accelerator-based neutron irradiation system for BNCT clinical irradiation was completed at this institute in early 2009, and the clinical trial using this system was started in 2012. A shift of BCNT from special particle therapy to a general one is now in progress. To promote and support this shift, improvements to the irradiation system, as well as its preparation, and improvements in the physical engineering and the medical physics processes, such as dosimetry systems and quality assurance programs, must be considered. The recent advances in BNCT at KURRI are reported here with a focus on physical engineering and medical physics topics.

  1. Artificial photosynthesis of oxalate and oxalate-based polymer by a photovoltaic reactor. (United States)

    Nong, Guangzai; Chen, Shan; Xu, Yuanjin; Huang, Lijie; Zou, Qingsong; Li, Shiqiang; Mo, Haitao; Zhu, Pingchuan; Cen, Weijian; Wang, Shuangfei


    A photovoltaic reactor was designed for artificial photosynthesis, based on the reactions involved in high energy hydrogen atoms, which were produced from water electrolysis. Water and CO2, under the conditions studied, were converted to oxalate (H2C2O4) and a polymer. This was the first time that the oxalates and oxalate-based polymer were produced from the artificial photosynthesis process.

  2. Spectrum shaping of accelerator-based neutron beams for BNCT

    CERN Document Server

    Montagnini, B; Esposito, J; Giusti, V; Mattioda, F; Varone, R


    We describe Monte Carlo simulations of three facilities for the production of epithermal neutrons for Boron Neutron Capture Therapy (BNCT) and examine general aspects and problems of designing the spectrum-shaping assemblies to be used with these neutron sources. The first facility is based on an accelerator-driven low-power subcritical reactor, operating as a neutron amplifier. The other two facilities have no amplifier and rely entirely on their primary sources, a D-T fusion reaction device and a conventional 2.5 MeV proton accelerator with a Li target, respectively.

  3. PR-EDB: Power Reactor Embrittlement Data Base, Version 2. Revision 2, Program description

    Energy Technology Data Exchange (ETDEWEB)

    Stallmann, F.W.; Wang, J.A.; Kam, F.B.K.; Taylor, B.J. [Oak Ridge National Lab., TN (United States)


    Investigations of regulatory issues such as vessel integrity over plant life, vessel failure, and sufficiency of current codes Standard Review Plans (SRP`s) and Guides for license renewal can be greatly expedited by the use of a well-designed computerized data base. Also, such a data base is essential for the validation of embrittlement prediction models by researchers. The Power Reactor Embrittlement Data Base (PR-EDB) is such a comprehensive collection of data for US commercial nuclear reactors. The current version of the PR-EDB contains the Charpy test data that were irradiated in 252 capsules of 96 reactors and consists of 207 data points for heat-affected-zone (HAZ) materials (98 different HAZ), 227 data points for weld materials (105 different welds), 524 data points for base materials (136 different base materials), including 297 plate data points (85 different plates), 119 forging data points (31) different forging), and 108 correlation monitor materials data points (3 different plates). The data files are given in dBASE format and can be accessed with any computer using the DOS operating system. ``User-friendly`` utility programs are used to retrieve and select specific data, manipulate data, display data to the screen or printer, and to fit and plot Charpy impact data. The results of several studies investigated are presented in Appendix D.

  4. Determination flux in the Reactor JEN-1; Medida de flujos de neutrones en el nucleo del Reactor JEN-1

    Energy Technology Data Exchange (ETDEWEB)

    Manas Diaz, L.; Montes Ponce de leon, J.


    This report summarized several irradiations that have been made to determine the neutron flux distributions in the core of the JEN-1 reactor. Gold foils of 380 {mu} gr and Mn-Ni (12% de Ni) of 30 mg have been employed. the epithermal flux has been determined by mean of the Cd radio. The resonance integral values given by Macklin and Pomerance have been used. (Author) 9 refs.

  5. Behavior of nitrogen removal in an aerobic sponge based moving bed biofilm reactor. (United States)

    Zhang, Xinbo; Song, Zi; Guo, Wenshan; Lu, Yanmin; Qi, Li; Wen, Haitao; Ngo, Huu Hao


    This study aims to investigate the behavior of nitrogen removal in an aerobic sponge based moving bed biofilm reactor by evaluating nitrification and denitrification rates of sponge biocarriers from three aerobic moving bed biofilm reactors (MBBRs) with filling ratios of 10% (R-10), 20% (R-20) and 30% (R-30). Results showed that the highest removal efficiencies of total nitrogen in three reactors were 84.5% (R-10), 93.6% (R-20) and 95.3% (R-30). Correspondingly, simultaneous nitrification and denitrification rate (SND) was 90.9%, 97.6% and 100%, respectively. Although R-20 had the highest attached-growth biomass (AGB) per gram of sponge compared to the other two reactors, R-30 showed the maximum ammonium oxidation rate (AOR) (2.1826±0.0717mgNH4(+)-N/gAGB/h) and denitrification rate (DNR) (5.0852±0.0891mgNO3(-)-N/gAGB/h), followed by R-20 and R-10. These results indicated AOR, DNR and AGB were affected by the filling ratio under the same operation mode. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Oxygen transport membrane reactor based method and system for generating electric power (United States)

    Kelly, Sean M.; Chakravarti, Shrikar; Li, Juan


    A carbon capture enabled system and method for generating electric power and/or fuel from methane containing sources using oxygen transport membranes by first converting the methane containing feed gas into a high pressure synthesis gas. Then, in one configuration the synthesis gas is combusted in oxy-combustion mode in oxygen transport membranes based boiler reactor operating at a pressure at least twice that of ambient pressure and the heat generated heats steam in thermally coupled steam generation tubes within the boiler reactor; the steam is expanded in steam turbine to generate power; and the carbon dioxide rich effluent leaving the boiler reactor is processed to isolate carbon. In another configuration the synthesis gas is further treated in a gas conditioning system configured for carbon capture in a pre-combustion mode using water gas shift reactors and acid gas removal units to produce hydrogen or hydrogen-rich fuel gas that fuels an integrated gas turbine and steam turbine system to generate power. The disclosed method and system can also be adapted to integrate with coal gasification systems to produce power from both coal and methane containing sources with greater than 90% carbon isolation.

  7. Accelerator Based Neutron Beams for Neutron Capture Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yanch, Jacquelyn C.


    The DOE-funded accelerator BNCT program at the Massachusetts Institute of Technology has resulted in the only operating accelerator-based epithermal neutron beam facility capable of generating significant dose rates in the world. With five separate beamlines and two different epithermal neutron beam assemblies installed, we are currently capable of treating patients with rheumatoid arthritis in less than 15 minutes (knee joints) or 4 minutes (finger joints) or irradiating patients with shallow brain tumors to a healthy tissue dose of 12.6 Gy in 3.6 hours. The accelerator, designed by Newton scientific Incorporated, is located in dedicated laboratory space that MIT renovated specifically for this project. The Laboratory for Accelerator Beam Applications consists of an accelerator room, a control room, a shielded radiation vault, and additional laboratory space nearby. In addition to the design, construction and characterization of the tandem electrostatic accelerator, this program also resulted in other significant accomplishments. Assemblies for generating epithermal neutron beams were designed, constructed and experimentally evaluated using mixed-field dosimetry techniques. Strategies for target construction and target cooling were implemented and tested. We demonstrated that the method of submerged jet impingement using water as the coolant is capable of handling power densities of up to 6 x 10(sup 7) W/m(sup 2) with heat transfer coefficients of 10(sup 6)W/m(sup 2)-K. Experiments with the liquid metal gallium demonstrated its superiority compared with water with little effect on the neutronic properties of the epithermal beam. Monoenergetic proton beams generated using the accelerator were used to evaluate proton RBE as a function of LET and demonstrated a maximum RBE at approximately 30-40 keV/um, a finding consistent with results published by other researchers. We also developed an experimental approach to biological intercomparison of epithermal beams and

  8. Different Activation Techniques for the Study of Epithermal Spectra, Applied to Heavy Water Lattices of Varying Fuel-To-Moderator Ratio

    Energy Technology Data Exchange (ETDEWEB)

    Sokolowski, E.K.


    Spectral indices at the cell boundary have been studied as functions of lattice pitch in the reference core of the Swedish R0 reactor. Epithermal indices were determined by activation of In{sup 115}, employing three different techniques: the two-foil, the cadmium ratio and the sandwich foil methods. The latter of these has the advantage of being independent of assumptions about foil cross sections or spectral functions, and it gives a spectrum index that lends itself readily to comparisons with theoretical multigroup calculations. Alternatively the results can be expressed in terms of the Westcott parameters r and T{sub n} when this is justified by the spectral conditions. The agreement between the three methods investigated is generally good. Good agreement is also found with multigroup collision.

  9. Construction of elements data base of JRR-3, 4 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Akira; Iwata, Yoshihiro [Akita Univ. (Japan); Sawahata, Hiroyuki


    Two kinds of the basic data base were constructed. One of them contains stable isotope information (atomic number, mass number, atomic weight and isotope ratio) and other consists of radionuclide information (atomic number, mass number, half-life, {gamma}-ray average energy, {beta}-ray average energy and {beta}+ray release rate). We tried to add the spectrum data determined by experiments, but many kinds of radionuclide in the sample could not separated. (S.Y.)

  10. Investigation of bi-enzymatic reactor based on hybrid monolith with nanoparticles embedded and its proteolytic characteristics. (United States)

    Shangguan, Lulu; Zhang, Lingyi; Xiong, Zhichao; Ren, Jun; Zhang, Runsheng; Gao, Fangyuan; Zhang, Weibing


    The bottom-up strategy of proteomic profiling study based on mass spectrometer (MS) has drawn high attention. However, conventional solution-based digestion could not satisfy the demands of highly efficient and complete high throughput proteolysis of complex samples. We proposed a novel bi-enzymatic reactor by immobilizing two different enzymes (trypsin/chymotrypsin) onto a mixed support of hybrid organic-inorganic monolith with SBA-15 nanoparticles embedded. Typsin and chymotrypsin were crossly immobilized onto the mixed support by covalent bonding onto the monolith with glutaraldehyde as bridge reagent and chelation via copper ion onto the nanoparticles, respectively. Compared with single enzymatic reactors, the bi-enzymatic reactor improved the overall functional analysis of membrane proteins of rat liver by doubling the number of identified peptides (from 1184/1010 with trypsin/chymotrypsin enzymatic reactors to 2891 with bi-enzymatic reactor), which led to more proteins identified with deep coverage (from 452/336 to 620); the efficiency of the bi-enzymatic reactor is also better than that of solution-based tandem digestion, greatly shorting the digestion time from 24h to 50s. Moreover, more transmembrane proteins were identified by bi-enzymatic reactor (106) compared with solution-based tandem digestion (95) with the same two enzymes and enzymatic reactors with single enzyme immobilized (75 with trypsin and 66 with chymotrypsin). The proteolytic characteristics of the bi-enzymatic reactors were evaluated by applying them to digestion of rat liver proteins. The reactors showed good digestion capability for proteins with different hydrophobicity and molecular weight. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. IER-297 CED-2: Final Design for Thermal/Epithermal eXperiments with Jemima Plates with Polyethylene and Hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, A. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Percher, C. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zywiec, W. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Heinrichs, D. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    This report presents the final design (CED-2) for IER-297, and focuses on 15 critical configurations using highly enriched uranium (HEU) Jemima plates moderated by polyethylene with and without hafnium diluent. The goal of the U.S. Nuclear Criticality Safety Program’s Thermal/Epithermal eXperiments (TEX) is to design and conduct new critical experiments to address high priority nuclear data needs from the nuclear criticality safety and nuclear data communities, with special emphasis on intermediate energy (0.625 eV – 100 keV) assemblies that can be easily modified to include various high priority diluent materials. The TEX (IER 184) CED-1 Report [1], completed in 2012, demonstrated the feasibility of meeting the TEX goals with two existing NCSP fissile assets, plutonium Zero Power Physics Reactor (ZPPR) plates and highly enriched uranium (HEU) Jemima plates. The first set of TEX experiments will focus on using the plutonium ZPPR plates with polyethylene moderator and tantalum diluents.

  12. A modular gas-cooled cermet reactor system for planetary base power (United States)

    Jahshan, Salim N.; Borkowski, Jeffrey A.


    Fission nuclear power is foreseen as the source for electricity in planetary colonization and exploration. A six module gas-cooled, cermet-fueled reactor is proposed that can meet the design objectives. The highly enriched core is compact and can operate at high temperature for a long life. The helium coolant powers six modular Brayton cycles that compare favorably with the SP-100-based Brayton cycle.

  13. Emotional learning based intelligent controller for a PWR nuclear reactor core during load following operation

    Energy Technology Data Exchange (ETDEWEB)

    Khorramabadi, Sima Seidi [Department of Mechanical Engineering, Sharif University of Technology, P.O. Box 11365-9567, Tehran (Iran, Islamic Republic of)], E-mail:; Boroushaki, Mehrdad [Department of Mechanical Engineering, Sharif University of Technology, P.O. Box 11365-9567, Tehran (Iran, Islamic Republic of); Lucas, Caro [Center of Excellence for Control and Intelligent Processing, Department of Electrical and Computer Engineering, University of Tehran, and School of Intelligent Systems, IPM, P.O. Box 14395-515, Tehran (Iran, Islamic Republic of)


    The design and evaluation of a novel approach to reactor core power control based on emotional learning is described. The controller includes a neuro-fuzzy system with power error and its derivative as inputs. A fuzzy critic evaluates the present situation, and provides the emotional signal (stress). The controller modifies its characteristics so that the critic's stress is reduced. Simulation results show that the controller has good convergence and performance robustness characteristics over a wide range of operational parameters.

  14. Global radioxenon emission inventory based on nuclear power reactor reports. (United States)

    Kalinowski, Martin B; Tuma, Matthias P


    Atmospheric radioactivity is monitored for the verification of the Comprehensive Nuclear-Test-Ban Treaty, with xenon isotopes 131mXe, 133Xe, 133mXe and 135Xe serving as important indicators of nuclear explosions. The treaty-relevant interpretation of atmospheric concentrations of radioxenon is enhanced by quantifying radioxenon emissions released from civilian facilities. This paper presents the first global radioxenon emission inventory for nuclear power plants, based on North American and European emission reports for the years 1995-2005. Estimations were made for all power plant sites for which emission data were unavailable. According to this inventory, a total of 1.3PBq of radioxenon isotopes are released by nuclear power plants as continuous or pulsed emissions in a generic year.

  15. Gold grade of epithermal gold ore at Lamuntet, Brang Rea, West Sumbawa District, West Nusa Tenggara Province, Indonesia (United States)

    Ernawati, Rika; Idrus, Arifudin; TBMP, Himawan


    Lamuntet is one of gold ore mining area carried out by the Artisanal Small scale Gold Mining (ASGM) located in West Sumbawa, Indonesia. Most of the miners at this area are not the local miners but also those from other regions. Mineralization of this area is strong identified as low sulfidation epithermal system. There are two blocks of this mining location, namely, Ngelampar block with an area of 0.164 km2 and Song block with an area of 0.067 km2. This study was focused on Ngelampar block. The characteristic of epithermal system is the existence of quartz vein with comb, vuggy, and sugary texture. The aim of this research was to analyze the gold grade and other metals, such as Cu, Ag, Pb, As, Zn, and Hg. The research methods included literature study from previous researches, field work, laboratory work, and interpretation. The literature study was performed on previous researches with similar study area. The field work comprised of direct observation and sampling. Fieldwork was done for a week to obtain gold ore/vein. Sixteen samples were analyzed to obtain the grade of ore/metal. The Hg laboratory analysis was then performed on the six samples with the highest gold grade. Laboratory works were conducted at Intertek Jakarta by using Fire Assay (FA) for gold grade and Atomic Absorption Spectrophotometry (AAS) for Cu, Ag, Pb, As, Zn, and Hg. Results of the analysis showed the range of Au was grade (0.1 ppm - 27.8 ppm), Cu was 26 ppm -1740 ppm, Pb was 101 ppm- >4000 ppm, Zn of 73 ppm- >10,000 ppm, Ag of 3 ppm -185 ppm, As was 150 ppm-6530 ppm, and Hg of 0.08 ppm - 1.89 ppm. L1 and L15 had high grade for all values (Au, Ag, Zn, Cu, As, and Hg). Gold mineralization was formed as electrum because of Ag content is higher than 20%. Associated minerals of the samples in the study area were galena, sphalerite, arsenopyrite, and chalcopyrite which showed the characteristic of rich base metal of Pb, Zn, and Cu at LS epithermal.

  16. Photoneutron effects on pulse reactor kinetics for the Annular Core Research Reactor (ACRR).

    Energy Technology Data Exchange (ETDEWEB)

    Parma, Edward J., Jr.


    The Annular Core Research Reactor (ACRR) is a swimming-pool type pulsed reactor that maintains an epithermal neutron flux and a nine-inch diameter central dry cavity. One of its uses is neutron and gamma-ray irradiation damage studies on electronic components under transient reactor power conditions. In analyzing the experimental results, careful attention must be paid to the kinetics associated with the reactor to ensure that the transient behavior of the electronic device is understood. Since the ACRR fuel maintains a substantial amount of beryllium, copious quantities of photoneutrons are produced that can significantly alter the expected behavior of the reactor power, especially following a reactor pulse. In order to understand these photoneutron effects on the reactor kinetics, the KIFLE transient reactor-analysis code was modified to include the photoneutron groups associated with the beryllium. The time-dependent behavior of the reactor power was analyzed for small and large pulses, assuming several initial conditions including following several pulses during the day, and following a long steady-state power run. The results indicate that, for these types of initial conditions, the photoneutron contribution to the reactor pulse energy can have a few to tens of percent effect.

  17. Enhancement of a 252Cf-based neutron beam via subcritical multiplication for neutron capture therapy. (United States)

    Wang, C K; Zino, J F; Kessler, G


    Previous studies indicated that an epithermal-neutron beam based on bare 252Cf is not feasible for neutron capture therapy (NCT). It was reported that a clinically useful epithermal-neutron beam requires a minimum of 1.0 g of 252Cf, which is more than twice the US current annual supply. However, it was reasoned that the required quantity of 252Cf could be dramatically reduced when used with a subcritical multiplying assembly (SMA). This reasoning is based on the assumption that the epithermal-neutron beam intensity for NCT is directly proportional to the fission neutron population, and that the neutron multiplying factor of the SMA can be estimated by 1/(1 - k(eff)). We have performed detailed Monte Carlo calculations to investigate the validity of the above reasoning. Our results show that 1/(1 - k(eff)) grossly overestimates the beam enhancement factor for NCT. For example, Monte Carlo calculations predict a beam enhancement factor of 6.0 for an optimized SMA geometry with k(eff) = 0.968. This factor is much less than 31 predicted by 1/(1 - k(eff)). The overestimation is due to the fact that most of the neutrons produced in the SMA are self-shielded, whereas self-shielding is negligible in a bare 252Cf source. Since the beam intensity of a 0.1 g 252Cf with the optimized SMA enhancement is still more than an order of magnitude too low compared to the existing reactor beams, we conclude that the enhancement via an SMA for a 252Cf-based epithermal-neutron beam is inadequate for NCT.

  18. Proposed design for the PGAA facility at the TRIGA IPR-R1 research reactor. (United States)

    Guerra, Bruno T; Jacimovic, Radojko; Menezes, Maria Angela Bc; Leal, Alexandre S


    This work presents an initial proposed design of a Prompt Gamma Activation Analysis (PGAA) facility to be installed at the TRIGA IPR-R1, a 60 years old research reactor of the Centre of Development of Nuclear Technology (CDTN) in Brazil. The basic characteristics of the facility and the results of the neutron flux are presented and discussed. The proposed design is based on a quasi vertical tube as a neutron guide from the reactor core, inside the reactor pool, 6 m below the room's level where shall be located the rack containing the set sample/detector/shielding. The evaluation of the thermal and epithermal neutron flux in the sample position was done considering the experimental data obtained from a vertical neutron guide, already existent in the reactor, and the simulated model for the facility. The experimental determination of the neutron flux was obtained through the standard procedure of using Au monitors in different positions of the vertical tube. In order to validate both, this experiment and calculations of the simulated model, the flux was also determined in different positions in the core used for sample irradiation. The model of the system was developed using the Monte Carlo code MCNP5. The preliminary results suggest the possibility of obtaining a beam with minimum thermal flux of magnitude 10(6) cm(-2) s(-1), which confirm the technical feasibility of the installation of PGAA at the TRIGA IPR-R1 reactor. This beam would open new possibilities for enhancing the applications using the reactor.

  19. Studies on the properties of an epithermal-neutron hydrogen analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Papp, A., E-mail: papppa@atomki.h [Institute of Nuclear Research of the Hungarian Academy of Sciences, Pf. 51, 4001 Debrecen (Hungary); Csikai, J. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Pf. 51, 4001 Debrecen (Hungary); Institute of Experimental Physics, University of Debrecen, Pf. 105, 4010 Debrecen-10 (Hungary)


    Systematic investigations have proved the advantages of the Epithermal Neutron Analyzer (ETNA) for bulk hydrogen analysis as compared to the thermal neutron techniques. Results can contribute, for example, to the design and construction of instruments needed for the detection and identification of plastic anti-personnel landmines, explosives hidden in airline baggage and cargo containers via hydrogen contents as an indicator of their presence.

  20. Epithermal Neutron Evidence for a Diurnal Surface Hydration Process in the Moon's High Latitudes (United States)

    McClanahan, T. P.; Mitrofanov, I. G.; Boynton, W. V.; Chin, G.; Parsons, A.; Starr, R. D.; Evans, L. G.; Sanin, A.; Litvak, M.; Livengood, T.


    We report evidence from epithermal neutron flux observations that show that the Moon's high latitude surfaces are being actively hydrated, dehydrated and rehydrated in a diurnal cycle. The near-surface hydration is indicated by an enhanced suppression of the lunar epithermal neutron leakage flux on the dayside of the dawn terminator on poleward-facing slopes (PFS). At 0600 to 0800 local-time, hydrogen concentrations within the upper 1 meter of PFS are observed to be maximized relative to equivalent equator-facing slopes (EFS). During the lunar day surface hydrogen concentrations diminish towards dusk and then rebuild overnight. Surface hydration is determined by differential comparison of the averaged EFS to PFS epithermal neutron count rates above +/- 75 deg latitude. At dawn the contrast bias towards PFS is consistent with at least 15 to 25 parts-per-million (ppm) hydrogen that dissipates by dusk. We review several lines of evidence derived from temperature and epithermal neutron data by a correlated analysis of observations from the Lunar Reconnaissance Orbiter's (LRO) Lunar Exploration Neutron Detector (LEND) that were mapped as a function of lunar local-time, Lunar Observing Laser Altimeter (LOLA) topography and Diviner (DLRE) surface temperature.

  1. Possibilities of the short-term thermal and epithermal neutron activation for analysis of macromycetes (mushrooms)

    Czech Academy of Sciences Publication Activity Database

    Řanda, Zdeněk; Soukal, Ladislav; Mizera, Jiří


    Roč. 264, č. 1 (2005), s. 67-76 ISSN 0236-5731 R&D Projects: GA AV ČR IAA3048201 Institutional research plan: CEZ:AV0Z10480505 Keywords : neutron activation analysis * epithermal NAA * mushrooms * macromycetes Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.460, year: 2005

  2. Fine Structure Discussion of Parity-Nonconserving Neutron Scattering at Epithermal Energies


    Hussein, M. S.; Kerman, A. K.; Lin, C-Y


    The large magnitude and the sign correlation effect in the parity non-conserving resonant scattering of epithermal neutrons from $^{232}$Th is discussed in terms of a non-collective $2p-1h$ local doorway model. General conclusions are drawn as to the probability of finding large parity violation effects in other regions of the periodic table.

  3. Cost-based optimization of a nuclear reactor core design: a preliminary model

    Energy Technology Data Exchange (ETDEWEB)

    Sacco, Wagner F.; Alves Filho, Hermes [Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Inst. Politecnico. Dept. de Modelagem Computacional]. E-mails:;; Pereira, Claudio M.N.A. [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil). Div. de Reatores]. E-mail:


    A new formulation of a nuclear core design optimization problem is introduced in this article. Originally, the optimization problem consisted in adjusting several reactor cell parameters, such as dimensions, enrichment and materials, in order to minimize the radial power peaking factor in a three-enrichment zone reactor, considering restrictions on the average thermal flux, criticality and sub-moderation. Here, we address the same problem using the minimization of the fuel and cladding materials costs as the objective function, and the radial power peaking factor as an operational constraint. This cost-based optimization problem is attacked by two metaheuristics, the standard genetic algorithm (SGA), and a recently introduced Metropolis algorithm called the Particle Collision Algorithm (PCA). The two algorithms are submitted to the same computational effort and their results are compared. As the formulation presented is preliminary, more elaborate models are also discussed (author)

  4. A modular diagnosis system based on fuzzy logic for UASB reactors treating sewage. (United States)

    Borges, R M; Mattedi, A; Munaro, C J; Franci Gonçalves, R

    A modular diagnosis system (MDS), based on the framework of fuzzy logic, is proposed for upflow anaerobic sludge blanket (UASB) reactors treating sewage. In module 1, turbidity and rainfall information are used to estimate the influent organic content. In module 2, a dynamic fuzzy model is used to estimate the current biogas production from on-line measured variables, such as daily average temperature and the previous biogas flow rate, as well as the organic load. Finally, in module 3, all the information above and the residual value between the measured and estimated biogas production are used to provide diagnostic information about the operation status of the plant. The MDS was validated through its application to two pilot UASB reactors and the results showed that the tool can provide useful diagnoses to avoid plant failures.

  5. A fuzzy-logic-based controller for methane production in anaerobic fixed-film reactors. (United States)

    Robles, A; Latrille, E; Ruano, M V; Steyer, J P


    The main objective of this work was to develop a controller for biogas production in continuous anaerobic fixed-bed reactors, which used effluent total volatile fatty acids (VFA) concentration as control input in order to prevent process acidification at closed loop. To this aim, a fuzzy-logic-based control system was developed, tuned and validated in an anaerobic fixed-bed reactor at pilot scale that treated industrial winery wastewater. The proposed controller varied the flow rate of wastewater entering the system as a function of the gaseous outflow rate of methane and VFA concentration. Simulation results show that the proposed controller is capable to achieve great process stability even when operating at high VFA concentrations. Pilot results showed the potential of this control approach to maintain the process working properly under similar conditions to the ones expected at full-scale plants.

  6. A Microwave Thermostatic Reactor for Processing Liquid Materials Based on a Heat-Exchanger. (United States)

    Zhou, Yongqiang; Zhang, Chun; Xie, Tian; Hong, Tao; Zhu, Huacheng; Yang, Yang; Liu, Changjun; Huang, Kama


    Microwaves have been widely used in the treatment of different materials. However, the existing adjustable power thermostatic reactors cannot be used to analyze materials characteristics under microwave effects. In this paper, a microwave thermostatic chemical reactor for processing liquid materials is proposed, by controlling the velocity of coolant based on PLC (programmable logic controller) in different liquid under different constant electric field intensity. A nonpolar coolant (Polydimethylsiloxane), which is completely microwave transparent, is employed to cool the liquid materials. Experiments are performed to measure the liquid temperature using optical fibers, the results show that the precision of temperature control is at the range of ±0.5 °C. Compared with the adjustable power thermostatic control system, the effect of electric field changes on material properties are avoided and it also can be used to detect the properties of liquid materials and special microwave effects.

  7. Anaerobic digestion model no. 1-based distributed parameter model of an anaerobic reactor: I. Model development. (United States)

    Mu, S J; Zeng, Y; Wu, P; Lou, S J; Tartakovsky, B


    This work presents a distributed parameter model of the anaerobic digestion process. The model is based on the Anaerobic digestion model no. 1 (ADM1) and was developed to simulate anaerobic digestion process in high-rate reactors with significant axial dispersion, such as in upflow anaerobic sludge bed (UASB) reactors. The model, which was named ADM1d, combines ADM1's kinetics of biomass growth and substrate transformation with axial dispersion material balances. ADM1d uses a hyperbolic tangent function to describe biomass distribution within a one compartment model. A comparison of this approach with a two-compartment, sludge bed - liquid above the bed, model showed similar simulation results while the one-compartment model had less equations. A comparison of orthogonal collocation and finite difference algorithms for numerical solution of ADM1d showed better stability of the finite difference algorithm.

  8. A Predictive Neural Network-Based Cascade Control for pH Reactors

    Directory of Open Access Journals (Sweden)

    Mujahed AlDhaifallah


    Full Text Available This paper is concerned with the development of predictive neural network-based cascade control for pH reactors. The cascade structure consists of a master control loop (fuzzy proportional-integral and a slave one (predictive neural network. The master loop is chosen to be more accurate but slower than the slave one. The strong features found in cascade structure have been added to the inherent features in model predictive neural network. The neural network is used to alleviate modeling difficulties found with pH reactor and to predict its behavior. The parameters of predictive algorithm are determined using an optimization algorithm. The effectiveness and feasibility of the proposed design have been demonstrated using MatLab.

  9. Influences of iron and calcium carbonate on wastewater treatment performances of algae based reactors. (United States)

    Zhao, Zhimiao; Song, Xinshan; Wang, Wei; Xiao, Yanping; Gong, Zhijie; Wang, Yuhui; Zhao, Yufeng; Chen, Yu; Mei, Mengyuan


    The influences of iron and calcium carbonate (CaCO3) addition in wastewater treatments reactors performance were investigated. Adding different concentrations of Fe(3+) (5, 10, 30 and 50mmol/m(3)), iron and CaCO3 powder led to changes in algal characteristics and physico-chemical and microbiological properties. According to the investigation results, nutrient removal efficiency in algae based reactors was obviously increased by the addition of 10mmol/m(3) Fe(3+), iron (5mmol/m(3)) and CaCO3 powder (0.2gm(-3)) and the removal efficiencies of BOD5, TN, and TP in Stage 2 were respectively increased by 28%, 8.9%, and 22%. The improvements in physico-chemical performances were verified by microbial community tests (bacteria quantity, activity and community measured in most probable number, extracellular enzymes activity, and Biolog Eco Plates). Microbial variations indicated the coexistence of Fe ions and carbonate-bicarbonate, which triggered the synergistic effect of physico-chemical action and microbial factors in algae based reactors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Assessment of start-up mechanisms for anaerobic fluidized bed reactor in series based on mathematical simulation (United States)

    Sudibyo, Hanifrahmawan; Guntama, Dody; Budhijanto, Wiratni


    Anaerobic digestion is associated with long hydraulic residence time and hence leads to huge reactor volume, especially for high rate input to the reactor. To overcome this major drawback, one of the possibilities is optimizing the schemes of reactor configuration and start-up mechanisms. This study aimed to determine the most promising start-up mechanism for anaerobic digestion reactors in series, with respect to the shortest hydraulic residence time to reach the highest biogas production rate. The reactor to be studied is anaerobic fluidized bed reactor (AFBR) which is known as the most efficient reactor for high organic loading rate. Case to be studied is landfill leachate digestion. Although reactor optimization can be conducted experimentally, it could be expensive and time consuming. This study proposed the utilization of mathematical modeling to screen the possibilities towards the best options to be verified experimentally. Kinetic study of landfill leachate anaerobic digestion was first conducted to depict the rate of microbial growth and the rate of substrate consumption. Kinetics constants obtained from this batch experiment were then used in the mathematical model representing AFBR. Several mechanisms were simulated in this study. In the first mechanism, all digesters were started simultaneously. In the second mechanism, each digester was started until it achieved steady-state condition before the next digester was started. The third mechanism was start-up scenario for single reactor as opposed to the previous two mechanisms. These all three mechanisms were simulated for either one-through stream and recycling a portion of the reactor effluent. The mathematical simulation result was used to evaluate each mechanism based on hydraulic residence time required for all digesters in series to reach the steady-state condition, the extent of pollutant removal, and the rate of biogas production. In the need of high sCOD removal, the second mechanism emerged as

  11. Anaerobic treatment of a chemical synthesis-based pharmaceutical wastewater in a hybrid upflow anaerobic sludge blanket reactor. (United States)

    Oktem, Yalcin Askin; Ince, Orhan; Sallis, Paul; Donnelly, Tom; Ince, Bahar Kasapgil


    In this study, performance of a lab-scale hybrid up-flow anaerobic sludge blanket (UASB) reactor, treating a chemical synthesis-based pharmaceutical wastewater, was evaluated under different operating conditions. This study consisted of two experimental stages: first, acclimation to the pharmaceutical wastewater and second, determination of maximum loading capacity of the hybrid UASB reactor. Initially, the carbon source in the reactor feed came entirely from glucose, applied at an organic loading rate (OLR) 1 kg COD/m(3) d. The OLR was gradually step increased to 3 kg COD/m(3) d at which point the feed to the hybrid UASB reactor was progressively modified by introducing the pharmaceutical wastewater in blends with glucose, so that the wastewater contributed approximately 10%, 30%, 70%, and ultimately, 100% of the carbon (COD) to be treated. At the acclimation OLR of 3 kg COD/m(3) d the hydraulic retention time (HRT) was 2 days. During this period of feed modification, the COD removal efficiencies of the anaerobic reactor were 99%, 96%, 91% and 85%, and specific methanogenic activities (SMA) were measured as 240, 230, 205 and 231 ml CH(4)/g TVS d, respectively. Following the acclimation period, the hybrid UASB reactor was fed with 100% (w/v) pharmaceutical wastewater up to an OLR of 9 kg COD/m(3) d in order to determine the maximum loading capacity achievable before reactor failure. At this OLR, the COD removal efficiency was 28%, and the SMA was measured as 170 ml CH(4)/g TVS d. The hybrid UASB reactor was found to be far more effective at an OLR of 8 kg COD/m(3) d with a COD removal efficiency of 72%. At this point, SMA value was 200 ml CH(4)/g TVS d. It was concluded that the hybrid UASB reactor could be a suitable alternative for the treatment of chemical synthesis-based pharmaceutical wastewater.

  12. Characterization and quantification of an in-core neutron irradiation facility at a TRIGA II research reactor (United States)

    Aghara, Sukesh; Charlton, William


    Experiments have been performed to characterize the neutron environment at an in-core TRIGA type nuclear research reactor. Steady-state thermal and epithermal neutron environment testing is important for many applications including, materials, electronics and biological cells. A well characterized neutron environment at a research reactor, including energy spectrum and spatial distribution, can be useful to many research communities and for educational research. This paper describes the characterization process and an application of exposing electronics to high neutron fluence.

  13. High Spatial Resolution Studies of Epithermal Neutron Emission from the Lunar Poles: Constraints on Hydrogen Mobility (United States)

    Boynton, W. V.; Droege, G. F.; Mitrofanov, I. G.; McClanahan, T. P.; Sanin, A. B.; Litvak, M. L.; Schaffner, M.; Chin, G.; Evans, L. G.; Garvin, J. B.; hide


    The data from the collimated sensors of the LEND instrument are shown to be of exceptionally high quality. Counting uncertainties are about 0.3% relative and are shown to be the only significant source of random error, thus conclusions based on small differences in count rates are valid. By comparison with the topography of Shoemaker crater, the spatial resolution of the instrument is shown to be consistent with the design value of 5 km for the radius of the circle over which half the counts from the lunar surface would be determined. The observed epithermal-neutron suppression factor due to the hydrogen deposit in Shoemaker crater of 0.25 plus or minus 0.04 cps is consistent with the collimated field-of-view rate of 1.7 cps estimated by Mitrofanov et al. (2010a). The statistical significance of the neutron suppressed regions (NSRs) relative to the larger surrounding polar region is demonstrated, and it is shown that they are not closely related to the permanently shadowed regions. There is a significant increase in H content in the polar regions independent of the H content of the NSRs. The non-NSR H content increases directly with latitude, and the rate of increase is virtually identical at both poles. There is little or no increase with latitude outside the polar region. Various mechanisms to explain this steep increase in the non-NSR polar H with latitude are investigated, and it is suggested that thermal volatilization is responsible for the increase because it is minimized at the low surface temperatures close to the poles.

  14. Origin of epithermal Ag-Au-Cu-Pb-Zn mineralization in Guanajuato, Mexico (United States)

    Mango, Helen; Arehart, Greg; Oreskes, Naomi; Zantop, Half


    The Guanajuato epithermal district is one of the largest silver producers in Mexico. Mineralization occurs along three main vein systems trending dominantly northwest-southeast: the central Veta Madre, the La Luz system to the northwest, and the Sierra system to the east. Mineralization consists dominantly of silver sulfides and sulfosalts, base metal sulfides (mostly chalcopyrite, galena, sphalerite, and pyrite), and electrum. There is a broad zonation of metal distribution, with up to 10 % Cu+Pb+Zn in the deeper mines along the northern and central portions of the Veta Madre. Ore occurs in banded veins and breccias and as stockworks, with gangue composed dominantly of quartz and calcite. Host rocks are Mesozoic sedimentary and intrusive igneous rocks and Tertiary volcanic rocks. Most fluid inclusion homogenization temperatures are between 200 and 300 °C, with salinities below 4 wt.% NaCl equivalent. Fluid temperature and salinity decreased with time, from 290 to 240 °C and from 2.5 to 1.1 wt.% NaCl equivalent. Relatively constant fluid inclusion liquid-to-vapor ratios and a trend of decreasing salinity with decreasing temperature and with increasing time suggest dilution of the hydrothermal solutions. However, evidence of boiling (such as quartz and calcite textures and the presence of adularia) is noted along the Veta Madre, particularly at higher elevations. Fluid inclusion and mineralogical evidence for boiling of metal-bearing solutions is found in gold-rich portions of the eastern Sierra system; this part of the system is interpreted as the least eroded part of the district. Oxygen, carbon, and sulfur isotope analysis of host rocks, ore, and gangue minerals and fluid inclusion contents indicate a hydrothermal fluid, with an initial magmatic component that mixed over time with infiltrating meteoric water and underwent exchange with host rocks. Mineral deposition was a result of decreasing activities of sulfur and oxygen, decreasing temperature, increasing p

  15. Thermal-hydraulics verification of a coarse-mesh OpenFOAM-based solver for a Sodium Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bonet López, M.


    Recently, in the Institute Swiss Paul Scherrer Institut, is has developed a platform Multiphysics, based in OpenFOAM, that is capable of performing an analysis multidimensional of a reactor nuclear. One of the main objectives of this project is to verify the part of the code responsible for the Thermo-hydraulic analysis of the reactor. To carry out simulations this part of the code uses the approximation of thick mesh based on the equations of a porous medium. Therefore, the other objective is demonstrate that this method is applicable to the analysis of a reactor nuclear fast of sodium, focusing is in his capacity of predict the transfer of heat between a subset and the space vacuum between subsets of the core of the reactor. (Author)

  16. Development and evaluation of a novel low power, high frequency piezoelectric-based ultrasonic reactor for intensifying the transesterification reaction

    Directory of Open Access Journals (Sweden)

    Mortaza Aghbashlo


    Full Text Available In this study, a novel low power, high frequency piezoelectric-based ultrasonic reactor was developed and evaluated for intensifying the transesterification process. The reactor was equipped with an automatic temperature control system, a heating element, a precise temperature sensor, and a piezoelectric-based ultrasonic module. The conversion efficiency and specific energy consumption of the reactor were examined under different operational conditions, i.e., reactor temperature (40‒60 °C, ultrasonication time (6‒10 min, and alcohol/oil molar ratio (4:1‒8:1. Transesterification of waste cooking oil (WCO was performed in the presence of a base-catalyst (potassium hydroxide using methanol. According to the obtained results, alcohol/oil molar ratio of 6:1, ultrasonication time of 10 min, and reactor temperature of 60 °C were found as the best operational conditions. Under these conditions, the reactor converted WCO to biodiesel with a conversion efficiency of 97.12%, meeting the ASTM standard satisfactorily, while the lowest specific energy consumption of 378 kJ/kg was also recorded. It should be noted that the highest conversion efficiency of 99.3 %, achieved at reactor temperature of 60 °C, ultrasonication time of 10 min, and alcohol/oil molar ratio of 8:1, was not favorable as the associated specific energy consumption was higher at 395 kJ/kg. Overall, the low power, high frequency piezoelectric-based ultrasonic module could be regarded as an efficient and reliable technology for intensifying the transesterification process in terms of energy consumption, conversion efficiency, and processing time, in comparison with high power, low frequency ultrasonic system reported previously. Finally, this technology could also be considered for designing, developing, and retrofitting chemical reactors being employed for non-biofuel applications as well.

  17. Aircraft and Bases Powered by Compact Nuclear Reactors: Solutions to Projecting Power in Highly Contested Environments and Fossil Fuel Dependence (United States)


    deuterium, and lithium are plentiful on the earth and in the solar system. As far as fuel for existing and future fission reactors, uranium and...number of operating centrifuges and its stockpile of low- enriched uranium. In return, the United States promised fewer economic sanctions. President...vessels, and bases. Like fission, fusion reactors have options for fuel. These options include hydrogen, deuterium, lithium , and helium-3. The first

  18. Design issues on using FPGA-based I and C systems in nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Farias, Marcos S.; Carvalho, Paulo Victor R. de; Santos, Isaac Jose A.L. dos; Lacerda, Fabio de, E-mail:, E-mail:, E-mail:, E-mail: [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Div. de Engenharia Nuclear


    The FPGA (field programmable gate array) is widely used in various fields of industry. FPGAs can be used to perform functions that are safety critical and require high reliability, like in automobiles, aircraft control and assistance and mission-critical applications in the aerospace industry. With these merits, FPGAs are receiving increased attention worldwide for application in nuclear plant instrumentation and control (I and C) systems, mainly for Reactor Protection System (RPS). Reasons for this include the fact that conventional analog electronics technologies are become obsolete. I and C systems of new Reactors have been designed to adopt the digital equipment such as PLC (Programmable Logic Controller) and DCS (Distributed Control System). But microprocessors-based systems may not be simply qualified because of its complex characteristics. For example, microprocessor cores execute one instruction at a time, and an operating system is needed to manage the execution of programs. In turn, FPGAs can run without an operating system and the design architecture is inherently parallel. In this paper we aim to assess these and other advantages, and the limitations, on FPGA-based solutions, considering the design guidelines and regulations on the use of FPGAs in Nuclear Plant I and C Systems. We will also examine some circuit design techniques in FPGA to help mitigate failures and provide redundancy. The objective is to show how FPGA-based systems can provide cost-effective options for I and C systems in modernization projects and to the RMB (Brazilian Multipurpose Reactor), ensuring safe and reliable operation, meeting licensing requirements, such as separation, redundancy and diversity. (author)

  19. Relative fission product yield determination in the USGS TRIGA Mark I reactor (United States)

    Koehl, Michael A.

    Fission product yield data sets are one of the most important and fundamental compilations of basic information in the nuclear industry. This data has a wide range of applications which include nuclear fuel burnup and nonproliferation safeguards. Relative fission yields constitute a major fraction of the reported yield data and reduce the number of required absolute measurements. Radiochemical separations of fission products reduce interferences, facilitate the measurement of low level radionuclides, and are instrumental in the analysis of low-yielding symmetrical fission products. It is especially useful in the measurement of the valley nuclides and those on the extreme wings of the mass yield curve, including lanthanides, where absolute yields have high errors. This overall project was conducted in three stages: characterization of the neutron flux in irradiation positions within the U.S. Geological Survey TRIGA Mark I Reactor (GSTR), determining the mass attenuation coefficients of precipitates used in radiochemical separations, and measuring the relative fission products in the GSTR. Using the Westcott convention, the Westcott flux, modified spectral index, neutron temperature, and gold-based cadmium ratios were determined for various sampling positions in the USGS TRIGA Mark I reactor. The differential neutron energy spectrum measurement was obtained using the computer iterative code SAND-II-SNL. The mass attenuation coefficients for molecular precipitates were determined through experiment and compared to results using the EGS5 Monte Carlo computer code. Difficulties associated with sufficient production of fission product isotopes in research reactors limits the ability to complete a direct, experimental assessment of mass attenuation coefficients for these isotopes. Experimental attenuation coefficients of radioisotopes produced through neutron activation agree well with the EGS5 calculated results. This suggests mass attenuation coefficients of molecular

  20. First Test of Lorentz Violation with a Reactor-based Antineutrino Experiment

    CERN Document Server

    Abe, Y; Anjos, J C dos; Bergevin, M; Bernstein, A; Bezerra, T J C; Bezrukhov, L; Blucher, E; Bowden, N S; Buck, C; Busenitz, J; Cabrera, A; Caden, E; Camilleri, L; Carr, R; Cerrada, M; Chang, P -J; Chimenti, P; Classen, T; Collin, A P; Conover, E; Conrad, J M; Crespo-Anadón, J I; Crum, K; Cucoanes, A; D'Agostino, M V; Damon, E; Dawson, J V; Dazeley, S; Dietrich, D; Djurcic, Z; Dracos, M; Durand, V; Ebert, J; Efremenko, Y; Elnimr, M; Erickson, A; Fallot, M; Fechner, M; von Feilitzsch, F; Felde, J; Fischer, V; Franco, D; Franke, A J; Franke, M; Furuta, H; Gama, R; Gil-Botella, I; Giot, L; Göger-Neff, M; Gonzalez, L F G; Goodman, M C; Goon, J TM; Greiner, D; Haag, N; Habib, S; Hagner, C; Hara, T; Hartmann, F X; Haser, J; Hatzikoutelis, A; Hayakawa, T; Hofmann, M; Horton-Smith, G A; Ishitsuka, M; Jochum, J; Jollet, C; Jones, C L; Kaether, F; Kalousis, L N; Kamyshkov, Y; Kaplan, D M; Katori, T; Kawasaki, T; Keefer, G; Kemp, E; de Kerret, H; Konno, T; Kryn, D; Kuze, M; Lachenmaier, T; Lane, C E; Lasserre, T; Letourneau, A; Lhuillier, D; Lima, H P; Lindner, M; López-Castanõ, J M; LoSecco, J M; Lubsandorzhiev, B K; Lucht, S; McKee, D; Maeda, J; Maesano, C N; Mariani, C; Maricic, J; Martino, J; Matsubara, T; Mention, G; Meregaglia, A; Meyer, M; Miletic, T; Milincic, R; Miyata, H; Mueller, Th A; Nagasaka, Y; Nakajima, K; Novella, P; Obolensky, M; Oberauer, L; Onillon, A; Osborn, A; Ostrovskiy, I; Palomares, C; Pepe, I M; Perasso, S; Perrin, P; Pfahler, P; Porta, A; Potzel, W; Pronost, G; Reichenbacher, J; Reinhold, B; Remoto, A; Röhling, M; Roncin, R; Roth, S; Rybolt, B; Sakamoto, Y; Santorelli, R; Sato, F; Schönert, S; Schoppmann, S; Schwetz, T; Shaevitz, M H; Shrestha, D; Sida, J -L; Sinev, V; Skorokhvatov, M; Smith, E; Spitz, J; Stahl, A; Stancu, I; Stokes, L F F; Strait, M; Stüken, A; Suekane, F; Sukhotin, S; Sumiyoshi, T; Sun, Y; Terao, K; Tonazzo, A; Toups, M; Thi, H H Trinh; Valdiviesso, G; Veyssiere, C; Wagner, S; Watanabe, H; White, B; Wiebusch, C; Winslow, L; Worcester, M; Wurm, M; Yanovitch, E; Yermia, F; Zimmer, V


    We present a search for Lorentz violation with 8249 candidate electron antineutrino events taken by the Double Chooz experiment in 227.9 live days of running. This analysis, featuring a search for a sidereal time dependence of the events, is the first test of Lorentz invariance using a reactor-based antineutrino source. No sidereal variation is present in the data and the disappearance results are consistent with sidereal time independent oscillations. Under the Standard-Model Extension (SME), we set the first limits on fourteen Lorentz violating coefficients associated with transitions between electron and tau flavor, and set two competitive limits associated with transitions between electron and muon flavor.

  1. Epithermal mercury-antimony and gold-bearing vein lodes of southwestern Alaska (United States)

    Gray, John E.; Gent, Carol A.; Snee, Lawrence W.; Wilson, Frederic H.; Goldfarb, Richard J.; Miller, Lance D.


    Epithermal mineral deposits and occurrences of southwestern Alaska consist of Hg-Sb and gold- and sulfide-bearing vein lodes. Numerous Hg-Sb lodes are located throughout a region measuring several tens of thousands of square kilometers in and surrounding the Kuskokwim River basin in southwestern Alaska. The Hg-Sb lodes are hosted in sedimentary rocks of the Cretaceous Kuskokwim Group, the Triassic to Cretaceous Gemuk Group, and the Paleozoic Holitna Group, as well as in Late Cretaceous and early Tertiary mafic to felsic intrusive rocks. Mineralized Hg-Sb vein and vein breccia lodes are found in the sedimentary or igneous rocks or at their contacts. The minerology of the Hg-Sb lodes is dominated by cinnabar and stibnite, with subordinate realgar, orpiment, and native mercury, pyrite, gold, and hematite, as well as solid and liquid hydrocarbons; quartz, carbonate, limonite, dickite, and sercite are alteration gangue minerals. The largest mercury mine in Alaska, Red Devil, produced about 36,000 flasks of mercury, but the Hg-Sb lodes of southwestern Alaska generally consist of small, discontinuous veins that rarely exceed a few meters in width and a few tens of meters in strike length. The Hg-Sb lodes generally contain about 1 to 5 percent Hg and less than 1 percent Sb and As but are generally poor in base emtals and precious metals. Anomalous concentrations of gold in some lodes, however, suggest that gold deposits may be present in higher temperature environments below some of the Hg-Sb lodes.The formation of the Hg-Sb lodes is closely correlated with igneous activity of a Late Cretaceous and early tertiary magmatic arc in southwestern Alaska. Geologic and geochemical characteristics of the Hg-Sb lodes suggest that ore fluids were generated in local sedimentary rocks as they were intruded by magmas. These intrusions provided the heat to initiate dehydration reactions and expel fluids from hydrous minerals and formational waters in the sedimentary rocks, causing

  2. A Neural-Network-Based Nonlinear Adaptive State-Observer for Pressurized Water Reactors

    Directory of Open Access Journals (Sweden)

    Zhe Dong


    Full Text Available Although there have been some severe nuclear accidents such as Three Mile Island (USA, Chernobyl (Ukraine and Fukushima (Japan, nuclear fission energy is still a source of clean energy that can substitute for fossil fuels in a centralized way and in a great amount with commercial availability and economic competitiveness. Since the pressurized water reactor (PWR is the most widely used nuclear fission reactor, its safe, stable and efficient operation is meaningful to the current rebirth of the nuclear fission energy industry. Power-level regulation is an important technique which can deeply affect the operation stability and efficiency of PWRs. Compared with the classical power-level controllers, the advanced power-level regulators could strengthen both the closed-loop stability and control performance by feeding back the internal state-variables. However, not all of the internal state variables of a PWR can be obtained directly by measurements. To implement advanced PWR power-level control law, it is necessary to develop a state-observer to reconstruct the unmeasurable state-variables. Since a PWR is naturally a complex nonlinear system with parameters varying with power-level, fuel burnup, xenon isotope production, control rod worth and etc., it is meaningful to design a nonlinear observer for the PWR with adaptability to system uncertainties. Due to this and the strong learning capability of the multi-layer perceptron (MLP neural network, an MLP-based nonlinear adaptive observer is given for PWRs. Based upon Lyapunov stability theory, it is proved theoretically that this newly-built observer can provide bounded and convergent state-observation. This observer is then applied to the state-observation of a special PWR, i.e., the nuclear heating reactor (NHR, and numerical simulation results not only verify its feasibility but also give the relationship between the observation performance and observer parameters.

  3. Determination of rare earths and thorium in apatites by thermal and epithermal neutron-activation analysis. (United States)

    Brunfelt, A O; Roelandts, I


    A procedure is described for the non-destructive determination of Na, Mn, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu and Th in apatites by thermal and epithermal neutron-activation of independent portions of the material. The method was applied to three apatites with different contents. The precision obtained was better than +/-5% for La, Ce, Sm, Eu, Gd, Tb and Dy and +/-20% for Yb, Nd, Ho, Er and Lu for an apatite with a total rare-earth oxide content of the order of 1%. Determination of Ce, Tb and Yb could only be carried out with thermal neutron-activation analysis, while Gd, Ho and Er could only be determined after irradiation with epithermal neutrons.

  4. Characteristics-based model predictive control of a catalytic flow reversal reactor

    Energy Technology Data Exchange (ETDEWEB)

    Fuxman, A.M.; Forbes, J.F.; Hayes, R.E. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering


    A model-based controller for a catalytic flow reversal reactor (CFRR) was presented. The characteristics-based model predictive control (CBMPC) was used to provide greater accuracy in the prediction of process output variables as well as to ensure the maintenance of safe operating temperatures. Performance of the CBMPC was simulated in order to evaluate combustion of lean methane streams for the reduction of greenhouse gas (GHG) emissions. Dynamics of the CFRR were described using partial differential equations (PDEs) derived from mass and energy balances. The PDEs were then transformed into an equivalent lumped parameter model, which was in turn used to design the non-linear predictive controller. The prediction horizon was divided into Hp intervals during each half cycle. A constrained quadratic program was then solved to obtain an optimal input sequence. The strategy was then evaluated by applying it to a simple CFRR plant, as well as a more complex plant modelled by a dynamical-dimensional heterogenous model that incorporated the effect of a large insulation layer needed to reduce heat loss from the reactor. Results of the simulations suggested that mass extraction in a CBMPC scheme can be used to maintain safe operating conditions. It was concluded that the strategy provided good control performance for regulation and set point tracking in the presence of inlet disturbances and other changes in operating conditions. 18 refs., 1 tab., 10 figs.

  5. Catalytic pyrolysis of wood biomass in an auger reactor using calcium-based catalysts. (United States)

    Veses, A; Aznar, M; Martínez, I; Martínez, J D; López, J M; Navarro, M V; Callén, M S; Murillo, R; García, T


    Wood catalytic pyrolysis using calcium-based materials was studied in an auger reactor at 450°C. Two different catalysts, CaO and CaO·MgO were evaluated and upgraded bio-oils were obtained in both cases. Whilst acidity and oxygen content remarkable decrease, both pH and calorific value increase with respect to the non-catalytic test. Upgrading process was linked to the fact that calcium-based materials could not only fix the CO2-like compounds but also promoted the dehydration reactions. In addition, process simulation demonstrated that the addition of these catalysts, especially CaO, could favour the energetic integration since a lowest circulation of heat carrier between combustor and auger reactor should be needed. An energy self-sustained system was obtained where thermal energy required for biomass drying and for pyrolysis reaction was supplied by non-condensable gas and char combustion, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Optical modeling of nickel-base alloys oxidized in pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Clair, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France); Foucault, M.; Calonne, O. [Areva ANP, Centre Technique Departement Corrosion-Chimie, 30 Bd de l' industrie, BP 181, 71205 Le Creusot (France); Finot, E., E-mail: [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France)


    The knowledge of the aging process involved in the primary water of pressurized water reactor entails investigating a mixed growth mechanism in the corrosion of nickel-base alloys. A mixed growth induces an anionic inner oxide and a cationic diffusion parallel to a dissolution-precipitation process forms the outer zone. The in situ monitoring of the oxidation kinetics requires the modeling of the oxide layer stratification with the full knowledge of the optical constants related to each component. Here, we report the dielectric constants of the alloys 600 and 690 measured by spectroscopic ellipsometry and fitted to a Drude-Lorentz model. A robust optical stratification model was determined using focused ion beam cross-section of thin foils examined by transmission electron microscopy. Dielectric constants of the inner oxide layer depleted in chromium were assimilated to those of the nickel thin film. The optical constants of both the spinels and extern layer were determined. - Highlights: Black-Right-Pointing-Pointer Spectroscopic ellipsometry of Ni-base alloy oxidation in pressurized water reactor Black-Right-Pointing-Pointer Measurements of the dielectric constants of the alloys Black-Right-Pointing-Pointer Optical simulation of the mixed oxidation process using a three stack model Black-Right-Pointing-Pointer Scattered crystallites cationic outer layer; linear Ni-gradient bottom layer Black-Right-Pointing-Pointer Determination of the refractive index of the spinel and the Cr{sub 2}O{sub 3} layers.

  7. The effects of actinide based fuels on incremental cross sections in a Candu reactor

    Energy Technology Data Exchange (ETDEWEB)

    Morreale, A.C.; Ball, M.R.; Novog, D.R.; Luxat, J.C., E-mail:, E-mail:, E-mail:, E-mail: [Department of Engineering Physics, McMaster University, Ontario (Canada)


    The reprocessing of spent fuel such as the extraction of actinide materials for use in mixed oxide fuels is a key component of reducing the end waste from nuclear power plant operations. Using recycled spent fuels in current reactors is becoming a popular option to help close the fuel cycle. In order to ensure safe and consistent operations in existing facilities, the properties of these fuels must be compatible with current reactor designs. This paper examines the features of actinide mixed oxide fuel, TRUMOX, in a CANDU reactor. Specifically, the effect of this fuel design on the incremental cross sections related to the use of adjuster rods is investigated. The actinide concentrations studied in this work were based on extraction from thirty year cooled spent fuel and mixed with natural uranium to yield a MOX fuel of 4.75% actinide by weight. The incremental cross sections were calculated using the DRAGON neutron transport code. The results for the actinide fuel were compared to those for standard natural uranium fuel and for a slightly enriched (1% U-235) fuel designed to reduce void reactivity. Adjuster reactivity effect calculations and void reactivity simulations were also performed. The impact of the adjuster on reactivity decreased by as much as 56% with TRUMOX fuel while the CVR was reduced by 71% due to the addition of central burnable poison. The incremental cross sections were largely affected by the use of the TRUMOX fuel primarily due to its increased level of fissile material (five times that of NU). The largest effects are in the thermal neutron group where the Σ{sub T} value is increased by 46.7%, the Σ{sub ny)} values increased by 13.0% and 9.9%. The value associated with thermal fission, υΣ{sub f}, increased by 496.6% over regular natural uranium which is expected due to the much higher reactivity of the fuel. (author)

  8. Geology of epithermal silver-gold bulk-mining targets, bodie district, Mono County, California (United States)

    Hollister, V.F.; Silberman, M.L.


    The Bodie mining district in Mono County, California, is zoned with a core polymetallic-quartz vein system and silver- and gold-bearing quartz-adularia veins north and south of the core. The veins formed as a result of repeated normal faulting during doming shortly after extrusion of felsic flows and tuffs, and the magmatic-hydrothermal event seems to span at least 2 Ma. Epithermal mineralization accompanied repeated movement of the normal faults, resulting in vein development in the planes of the faults. The veins occur in a very large area of argillic alteration. Individual mineralized structures commonly formed new fracture planes during separate fault movements, with resulting broad zones of veinlets growing in the walls of the major vein-faults. The veinlet swarms have been found to constitute a target estimated at 75,000,000 tons, averaging 0.037 ounce gold per ton. The target is amenable to bulkmining exploitation. The epithermal mineralogy is simple, with electrum being the most important precious metal mineral. The host veins are typical low-sulfide banded epithermal quartz and adularia structures that filled voids created by the faulting. Historical data show that beneficiation of the simple vein mineralogy is very efficient. ?? 1995 Oxford University Press.

  9. Textural Evidence of Episodic Introduction of Metallic Nanoparticles into Bonanza Epithermal Ores

    Directory of Open Access Journals (Sweden)

    James A. Saunders


    Full Text Available Tertiary low sulfidation (LS epithermal deposits in the western USA often show evidence of the former presence of nanoparticle-sized precious-metal and silica phases in the highest grade (bonanza ores. Here, nanoparticles are defined to have a size less than ~10−7 m. The ore-mineral textures that formed from aggregation of nanoparticles (or colloids observed to date in these ores include electrum and naumannite (Ag2Se. Here it is proposed that chalcopyrite also forms nanoparticles in these ores, but sulfide nanoparticles apparently have significantly different physical (surface properties than the precious-metal phases, and thus exhibit different mineral textures (e.g., no textural evidence of previous chalcopyrite nanoparticles. Textures described here show that nanoparticles of precious-metal phases and silica were episodically and often repeatedly deposited to form the banded bonanza veins typical of many western USA epithermal deposits. Chalcopyrite is the most abundant metal-sulfide mineral in these bonanza ores, and it was also deposited episodically as well, and it appears to replace earlier formed naumannite dendrites. However, this apparent “replacement” texture may just be the result of naumannite dendrite limbs trapping chalcopyrite nanoparticles that later recrystallized to the apparent replacement texture. The episodic and repetitive nature of the metal-depositing events may record periodic “degassing” of magma chambers at depth, where metals are repeatedly delivered to the shallow epithermal environment by “vapor-phase” metal (loid transport.

  10. On the {sup 252}Cf primary and secondary gamma rays and epithermal neutron flux for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Ghassoun, J. [LPTN, Departement de Physique, Faculte des Sciences Semlalia, BP 2390, 40000 Marrakech (Morocco)], E-mail:; Merzouki, A. [LPTN, Departement de Physique, Faculte des Sciences Semlalia, BP 2390, 40000 Marrakech (Morocco); Remote Sensing and Geomatics of the Environnement Laboratory, Ottawa-Carleton Geoscience Centre, Marion Hall-140Louis Pasteur Ottawa, ON, KIN 6N5 (Canada); El Morabiti, A.; Jehouani, A. [LPTN, Departement de Physique, Faculte des Sciences Semlalia, BP 2390, 40000 Marrakech (Morocco)


    Monte Carlo simulation has been used to calculate the different components of neutrons and secondary gamma rays originated by {sup 252}Cf fission and also the primary gamma rays emitted directly by the {sup 252}Cf source at the exit face of a compact system designed for the BNCT. The system consists of a {sup 252}Cf source and a moderator/reflector/filter assembly. To study the material properties and configuration possibilities, the MCNP code has been used. The moderator/reflector/filter arrangement is optimised to moderate neutrons to epithermal energy and, as far as possible, to get rid of fast and thermal neutrons and photons from the therapeutic beam. To reduce the total gamma contamination and to have a sufficiently high epithermal neutron flux we have used different photon filters of different thickness. Our analysis showed that the use of an appropriate filter leads to a gamma ray flux reduction without affecting the epithermal neutron beam quality at the exit face of the system.

  11. Nuclear reactor power for a space-based radar. SP-100 project (United States)

    Bloomfield, Harvey; Heller, Jack; Jaffe, Leonard; Beatty, Richard; Bhandari, Pradeep; Chow, Edwin; Deininger, William; Ewell, Richard; Fujita, Toshio; Grossman, Merlin


    A space-based radar mission and spacecraft, using a 300 kWe nuclear reactor power system, has been examined, with emphasis on aspects affecting the power system. The radar antenna is a horizontal planar array, 32 X 64 m. The orbit is at 61 deg, 1088 km. The mass of the antenna with support structure is 42,000 kg; of the nuclear reactor power system, 8,300 kg; of the whole spacecraft about 51,000 kg, necessitating multiple launches and orbital assembly. The assembly orbit is at 57 deg, 400 km, high enough to provide the orbital lifetime needed for orbital assembly. The selected scenario uses six Shuttle launches to bring the spacecraft and a Centaur G upper-stage vehicle to assembly orbit. After assembly, the Centaur places the spacecraft in operational orbit, where it is deployed on radio command, the power system started, and the spacecraft becomes operational. Electric propulsion is an alternative and allows deployment in assembly orbit, but introduces a question of nuclear safety.

  12. Nuclear reactor power for a space-based radar. SP-100 project (United States)

    Bloomfield, Harvey; Heller, Jack; Jaffe, Leonard; Beatty, Richard; Bhandari, Pradeep; Chow, Edwin; Deininger, William; Ewell, Richard; Fujita, Toshio; Grossman, Merlin


    A space-based radar mission and spacecraft, using a 300 kWe nuclear reactor power system, has been examined, with emphasis on aspects affecting the power system. The radar antenna is a horizontal planar array, 32 X 64 m. The orbit is at 61 deg, 1088 km. The mass of the antenna with support structure is 42,000 kg; of the nuclear reactor power system, 8,300 kg; of the whole spacecraft about 51,000 kg, necessitating multiple launches and orbital assembly. The assembly orbit is at 57 deg, 400 km, high enough to provide the orbital lifetime needed for orbital assembly. The selected scenario uses six Shuttle launches to bring the spacecraft and a Centaur G upper-stage vehicle to assembly orbit. After assembly, the Centaur places the spacecraft in operational orbit, where it is deployed on radio command, the power system started, and the spacecraft becomes operational. Electric propulsion is an alternative and allows deployment in assembly orbit, but introduces a question of nuclear safety.

  13. Enhanced anaerobic digestion performance via combined solids- and leachate-based hydrolysis reactor inoculation. (United States)

    Wilson, L Paige; Sharvelle, Sybil E; De Long, Susan K


    Suboptimal conditions in anaerobic digesters (e.g., presence of common inhibitors ammonia and salinity) limit waste hydrolysis and lead to unstable performance and process failures. Application of inhibitor-tolerant inocula improves hydrolysis, but approaches are needed to establish and maintain these desired waste-hydrolyzing bacteria in high-solids reactors. Herein, performance was compared for leach bed reactors (LBRs) seeded with unacclimated or acclimated inoculum (0-60% by mass) at start-up and over long-term operation. High quantities of inoculum (∼60%) increase waste hydrolysis and are beneficial at start-up or when inhibitors are increasing. After start-up (∼112days) with high inoculum quantities, leachate recirculation leads to accumulation of inhibitor-tolerant hydrolyzing bacteria in leachate. During long-term operation, low inoculum quantities (∼10%) effectively increase waste hydrolysis relative to without solids-derived inoculum. Molecular analyses indicated that combining digested solids with leachate-based inoculum doubles quantities of Bacteria contacting waste over a batch and supplies additional desirable phylotypes Bacteriodes and Clostridia. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Atomistic simulations of deuterium irradiation on iron-based alloys in future fusion reactors

    Directory of Open Access Journals (Sweden)

    E. Safi


    Full Text Available Iron-based alloys are now being considered as plasma-facing materials for the first wall of future fusion reactors. Therefore, the iron (Fe and carbon (C erosion will play a key role in predicting the life-time and viability of reactors with steel walls. In this work, the surface erosion and morphology changes due to deuterium (D irradiation in pure Fe, Fe with 1% C impurity and the cementite, are studied using molecular dynamics (MD simulations, varying surface temperature and impact energy. The sputtering yields for both Fe and C were found to increase with incoming energy. In iron carbide, C sputtering was preferential to Fe and the deuterium was mainly trapped as D2 in bubbles, while mostly atomic D was present in Fe and Fe–1%C. The sputtering yields obtained from MD were compared to SDTrimSP yields. At lower impact energies, the sputtering mechanism was of both physical and chemical origin, while at higher energies (>100eV the physical sputtering dominated.

  15. Beam transient analyses of Accelerator Driven Subcritical Reactors based on neutron transport method

    Energy Technology Data Exchange (ETDEWEB)

    He, Mingtao; Wu, Hongchun [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Zheng, Youqi, E-mail: [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Wang, Kunpeng [Nuclear and Radiation Safety Center, PO Box 8088, Beijing 100082 (China); Li, Xunzhao; Zhou, Shengcheng [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China)


    Highlights: • A transport-based kinetics code for Accelerator Driven Subcritical Reactors is developed. • The performance of different kinetics methods adapted to the ADSR is investigated. • The impacts of neutronic parameters deteriorating with fuel depletion are investigated. - Abstract: The Accelerator Driven Subcritical Reactor (ADSR) is almost external source dominated since there is no additional reactivity control mechanism in most designs. This paper focuses on beam-induced transients with an in-house developed dynamic analysis code. The performance of different kinetics methods adapted to the ADSR is investigated, including the point kinetics approximation and space–time kinetics methods. Then, the transient responds of beam trip and beam overpower are calculated and analyzed for an ADSR design dedicated for minor actinides transmutation. The impacts of some safety-related neutronics parameters deteriorating with fuel depletion are also investigated. The results show that the power distribution varying with burnup leads to large differences in temperature responds during transients, while the impacts of kinetic parameters and feedback coefficients are not very obvious. Classification: Core physic.

  16. Microcomputer-based equipment-control and data-acquisition system for fission-reactor reactivity-worth measurements

    Energy Technology Data Exchange (ETDEWEB)

    McDowell, W.P.; Bucher, R.G.


    Material reactivity-worth measurements are one of the major classes of experiments conducted on the Zero Power research reactors (ZPR) at Argonne National Laboratory. These measurements require the monitoring of the position of a servo control element as a sample material is positioned at various locations in a critical reactor configuration. In order to guarantee operational reliability and increase experimental flexibility for these measurements, the obsolete hardware-based control unit has been replaced with a microcomputer based equipment control and data acquisition system. This system is based on an S-100 bus, dual floppy disk computer with custom built cards to interface with the experimental system. To measure reactivity worths, the system accurately positions samples in the reactor core and acquires data on the position of the servo control element. The data are then analyzed to determine statistical adequacy. The paper covers both the hardware and software aspects of the design.

  17. Genetic Algorithm Based PID Controller Tuning Approach for Continuous Stirred Tank Reactor

    Directory of Open Access Journals (Sweden)

    A. Jayachitra


    Full Text Available Genetic algorithm (GA based PID (proportional integral derivative controller has been proposed for tuning optimized PID parameters in a continuous stirred tank reactor (CSTR process using a weighted combination of objective functions, namely, integral square error (ISE, integral absolute error (IAE, and integrated time absolute error (ITAE. Optimization of PID controller parameters is the key goal in chemical and biochemical industries. PID controllers have narrowed down the operating range of processes with dynamic nonlinearity. In our proposed work, globally optimized PID parameters tend to operate the CSTR process in its entire operating range to overcome the limitations of the linear PID controller. The simulation study reveals that the GA based PID controller tuned with fixed PID parameters provides satisfactory performance in terms of set point tracking and disturbance rejection.

  18. H Reactor (United States)

    Federal Laboratory Consortium — The H Reactor was the first reactor to be built at Hanford after World War II.It became operational in October of 1949, and represented the fourth nuclear reactor on...

  19. Foam suppression in overloaded manure-based biogas reactors using antifoaming agents

    DEFF Research Database (Denmark)

    Kougias, Panagiotis; Boe, Kanokwan; Tsapekos, Panagiotis


    Foam control is an imperative need in biogas plants, as foaming is a major operational problem. In the present study, the effect of oils (rapeseed oil, oleic acid, and octanoic acid) and tributylphosphate on foam reduction and process performance in batch and continuous manure-based biogas reactors...... was investigated. The compounds were tested in dosages of 0.05%, 0.1% and 0.5% v/vfeed. The results showed that rapeseed oil was most efficient to suppress foam at the dosage of 0.05% and 0.1% v/vfeed, while octanoic acid was most efficient to suppress foam at dosage of 0.5% v/vfeed. Moreover, the addition...

  20. Evaluation of Nb-base alloys for the divertor structure in fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Purdy, I.M. [Argonne National Laboratory, Upton, IL (United States)


    Niobium-base alloys are candidate materials for the divertor structure in fusion reactors. For this application, an alloy should resist aqueous corrosion, hydrogen embrittlement, and radiation damage and should have high thermal conductivity and low thermal expansion. Results of corrosion and embrittlement screening tests of several binary and ternary Nb alloys in high-temperature water indicated the Mb-1Zr, Nb-5MO-1Zr, and Nb-5V-1Z4 (wt %) showed sufficient promise for further investigation. These alloys, together with pure Nb and Zircaloy-4 have been exposed to high purity water containing a low concentration of dissolved oxygen (<12 ppb) at 170, 230, and 300{degrees}C for up to {approx}3200 h. Weight-change data, microstructural observations, and qualitative mechanical-property evaluation reveal that Nb-5V-1Zr is the most promising alloy at higher temperatures. Below {approx}200{degrees}C, the alloys exhibit similiar corrosion behavior.

  1. Analysis of Nickel Based Hardfacing Materials Manufactured by Laser Cladding for Sodium Fast Reactor (United States)

    Aubry, P.; Blanc, C.; Demirci, I.; Dal, M.; Malot, T.; Maskrot, H.

    For improving the operational capacity, the maintenance and the decommissioning of the future French Sodium Fast Reactor ASTRID which is under study, it is asked to find or develop a cobalt free hardfacing alloy and the associated manufacturing process that will give satisfying wear performances. This article presents recent results obtained on some selected nickel-based hardfacing alloys manufactured by laser cladding, particularly on Tribaloy 700 alloy. A process parameter search is made and associated the microstructural analysis of the resulting clads. A particular attention is made on the solidification of the main precipitates (chromium carbides, boron carbides, Laves phases,…) that will mainly contribute to the wear properties of the material. Finally, the wear resistance of some samples is evaluated in simple wear conditions evidencing promising results on tribology behavior of Tribaloy 700.

  2. Neutron-based measurements for nondestructive assay of minor actinides produced in nuclear power reactors

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, J.E.; Eccleston, G.W.; Ensslin, N.; Cremers, T.L.; Foster, L.A.; Menlove, H.O.; Rinard, P.M.


    Because of their impacts on long-term storage of high-level radioactive waste and their value as nuclear fuels, measurement and accounting of the minor actinides produced in nuclear power reactors are becoming significant issues. This paper briefly reviews the commercial nuclear fuel cycle with emphasis on reprocessing plants and key measurement points therein. Neutron signatures and characteristics are compared and contrasted for special nuclear materials (SNMs) and minor actinides (MAs). The paper focuses on application of neutron-based nondestructive analysis (NDA) methods that can be extended for verification of MAs. We describe current IAEA methods for NDA of SNMs and extension of these methods to satisfy accounting requirements for MAs in reprocessing plant dissolver solutions, separated products, and high-level waste. Recommendations for further systems studies and development of measurement methods are also included.

  3. Software development methodology for computer based I&C systems of prototype fast breeder reactor

    Energy Technology Data Exchange (ETDEWEB)

    Manimaran, M., E-mail:; Shanmugam, A.; Parimalam, P.; Murali, N.; Satya Murty, S.A.V.


    Highlights: • Software development methodology adopted for computer based I&C systems of PFBR is detailed. • Constraints imposed as part of software requirements and coding phase are elaborated. • Compliance to safety and security requirements are described. • Usage of CASE (Computer Aided Software Engineering) tools during software design, analysis and testing phase are explained. - Abstract: Prototype Fast Breeder Reactor (PFBR) is sodium cooled reactor which is in the advanced stage of construction in Kalpakkam, India. Versa Module Europa bus based Real Time Computer (RTC) systems are deployed for Instrumentation & Control of PFBR. RTC systems have to perform safety functions within the stipulated time which calls for highly dependable software. Hence, well defined software development methodology is adopted for RTC systems starting from the requirement capture phase till the final validation of the software product. V-model is used for software development. IEC 60880 standard and AERB SG D-25 guideline are followed at each phase of software development. Requirements documents and design documents are prepared as per IEEE standards. Defensive programming strategies are followed for software development using C language. Verification and validation (V&V) of documents and software are carried out at each phase by independent V&V committee. Computer aided software engineering tools are used for software modelling, checking for MISRA C compliance and to carry out static and dynamic analysis. Various software metrics such as cyclomatic complexity, nesting depth and comment to code are checked. Test cases are generated using equivalence class partitioning, boundary value analysis and cause and effect graphing techniques. System integration testing is carried out wherein functional and performance requirements of the system are monitored.

  4. CO2 Reduction Assembly Prototype Using Microlith-Based Sabatier Reactor for Ground Demonstration (United States)

    Junaedi, Christian; Hawley, Kyle; Walsh, Dennis; Roychoudhury, Subir; Abney, Morgan B.; Perry, Jay L.


    The utilization of CO2 to produce life support consumables, such as O2 and H2O, via the Sabatier reaction is an important aspect of NASA's cabin Atmosphere Revitalization System (ARS) and In-Situ Resource Utilization (ISRU) architectures for both low-earth orbit and long-term manned space missions. Carbon dioxide can be reacted with H2, obtained from the electrolysis of water, via Sabatier reaction to produce methane and H2O. Methane can be stored and utilized as propellant while H2O can be either stored or electrolyzed to produce oxygen and regain the hydrogen atoms. Depending on the application, O2 can be used to replenish the atmosphere in human-crewed missions or as an oxidant for robotic and return missions. Precision Combustion, Inc. (PCI), with support from NASA, has previously developed an efficient and compact Sabatier reactor based on its Microlith® catalytic technology and demonstrated the capability to achieve high CO2 conversion and CH4 selectivity (i.e., =90% of the thermodynamic equilibrium values) at high space velocities and low operating temperatures. This was made possible through the use of high-heat-transfer and high-surface-area Microlith catalytic substrates. Using this Sabatier reactor, PCI designed, developed, and demonstrated a stand-alone CO2 Reduction Assembly (CRA) test system for ground demonstration and performance validation. The Sabatier reactor was integrated with the necessary balance-of-plant components and controls system, allowing an automated, single "push-button" start-up and shutdown. Additionally, the versatility of the test system prototype was demonstrated by operating it under H2-rich (H2/CO2 of >4), stoichiometric (ratio of 4), and CO2-rich conditions (ratio of <4) without affecting its performance and meeting the equilibrium-predicted water recovery rates. In this paper, the development of the CRA test system for ground demonstration will be discussed. Additionally, the performance results from testing the system at

  5. Phosphorus recovery from anaerobic digester supernatant by struvite crystallization: model-based evaluation of a fluidized bed reactor. (United States)

    Rahaman, M S; Mavinic, D S; Ellis, N


    This paper is an attempt to model the UBC (University of British Columbia) MAP (Magnesium Ammonium Phosphate) fluidized bed crystallizer. A mathematical model is developed based on the assumption of perfect size classification of struvitre crystals in the reactor and considering the movement of liquid phase as a plug flow pattern. The model predicts variation of species concentration of struvite along the crystal bed height. The species concentrations at two extreme ends (inlet and outlet) are then used to evaluate the reactor performance. The model predictions provide a reasonable good fit with the experimental results for both PO4-P and NH4-N removals. Another important aspect of this model is its capability of predicting the crystals size and the bed voidage at different height of the reactor. Those predictions also match fairly well with the experimental observations. Therefore, this model can be used as a tool for performance evaluation of the reactor and can also be extended to optimize the struvite crystallization process in the UBC MAP reactor. IWA Publishing 2008.

  6. Metrology and quality of radiation therapy dosimetry of electron, photon and epithermal neutron beams (United States)

    Kosunen, Antti

    In radiation therapy using electron and photon beams the dosimetry chain consists of several sequential phases starting by the realization of the dose quantity in the Primary Standard Dosimetry Laboratory and ending to the calculation of the dose to a patient. A similar procedure can be described for the dosimetry of epithermal neutron beams in boron neutron capture therapy (BNCT). This work is focused on two items in the dosimetry chains: the determination of the dose in the reference conditions and the evaluation of the accuracy of dose calculation methods. The issues investigated and discussed in detail are: (a)the calibration methods of plane parallel ionization chambers used in electron beam dosimetry, (b)the specification of the critical dosimetric parameter i.e. the ratio of stopping powers for water to air, (S/r) waterair , in photon beams, (c)the feasibility of the twin ionization chamber technique for dosimetry in epithermal neutron beams applied to BNCT and (d)the determination accuracy of the calculated dose distributions in phantoms in electron, photon, and epithermal neutron beams. The results demonstrate that UP to a 3% improvement in the consistency of dose determinations in electron beams is achieved by the calibration of plane parallel ionization chambers in high energy electron beams instead of calibrations in 60Co gamma beams. In photon beam dosimetry (S/r) waterair can be determined with an accuracy of 0.2% using the percentage dose at the 10 cm depth, %dd(10), as a beam specifier. By a twin ionization chamber technique accuracy the gamma dose can be determined with uncertainty of 6% (1 standard deviation) and the total neutron dose with an uncertainty of 15 to 20% (1 standard deviation). The general accuracy achieved by treatment planning systems is approximately 4% for photons and 5 to 7% for electrons. Large (>10%) deviations in calculated doses are possible even when relatively modern calculation approaches are used.

  7. Correlation of Lunar South Polar Epithermal Neutron Maps: Lunar Exploration Neutron Detector and Lunar Prospector Neutron Detector (United States)

    McClanahan, Timothy P.; Mitrofanov, I. G.; Boynton, W. V.; Sagdeev, R.; Trombka, J. I.; Starr, R. D.; Evans, L. G.; Litvak, M. L.; Chin, G.; Garvin, J.; hide


    The Lunar Reconnaissance Orbiter's (LRO), Lunar Exploration Neutron Detector (LEND) was developed to refine the lunar surface hydrogen (H) measurements generated by the Lunar Prospector Neutron Spectrometer. LPNS measurements indicated a approx.4,6% decrease in polar epithermal fluxes equivalent to (1.5+/-0,8)% H concentration and are direct geochemical evidence indicating water /high H at the poles. Given the similar operational and instrumental objectives of the LEND and LPNS systems, an important science analysis step for LEND is to test correlation with existing research including LPNS measurements. In this analysis, we compare corrected low altitude epithermal rate data from LPNS available via NASA's Planetary Data System (PDS) with calibrated LEND epithermal maps using a cross-correlation technique

  8. Physically-Based Power-Level Control for Modular High Temperature Gas-Cooled Reactors (United States)

    Dong, Zhe


    Because of its strong inherent safety, the modular high temperature gas-cooled nuclear reactor (MHTGR) has been regarded as the central part of the next generation nuclear plants (NGNPs). Power-level control is one of the key techniques which provide safe, stable and efficient operation for the MHTGRs. The physically-based regulation theory is definitely a promising trend of modern control theory and provides a control design method that can suppress the unstable part of the system dynamics and remain the stable part. Usually, the control law designed by the physically-based control theory has a simple form and high performance. Stimulated by this, a novel nonlinear dynamic output feedback power-level control is established in this paper for the MHTGR based upon its own dynamic features. This newly-built control strategy guarantees the globally asymptotic stability and provides a satisfactory transient performance through properly adjusting the feedback gains. Simulation results not only verify the correctness of the theoretical results but also illustrate the high control performance.

  9. Web-based, Interactive, Nuclear Reactor Transient Analyzer using LabVIEW and RELAP5 (ATHENA)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K. D.; Chung, B. D. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Rizwan-uddin [University of Illinois at Urbana-Champaign, Urbana (United States)


    In nuclear engineering, large system analysis codes such as RELAP5, TRAC-M, etc. play an important role in evaluating a reactor system behavior during a wide range of transient conditions. One limitation that restricts their use on a wider scale is that these codes often have a complicated I/O structure. This has motivated the development of GUI tools for best estimate codes, such as SNAP and ViSA, etc. In addition to a user interface, a greater degree of freedom in simulation and analyses of nuclear transient phenomena can be achieved if computer codes and their outputs are accessible from anywhere through the web. Such a web-based interactive interface can be very useful for geographically distributed groups when there is a need to share real-time data. Using mostly off-the-shelf technology, such a capability - a web-based transient analyzer based on a best-estimate code - has been developed. Specifically, the widely used best-estimate code RELAP5 is linked with a graphical interface. Moreover, a capability to web-cast is also available. This has been achieved by using the LabVIEW virtual instruments (VIs). In addition to the graphical display of the results, interactive control functions have also been added that allow operator's actions as well as, if permitted, by a distant user through the web.

  10. Improved nonlinear fault detection strategy based on the Hellinger distance metric: Plug flow reactor monitoring

    KAUST Repository

    Harrou, Fouzi


    Fault detection has a vital role in the process industry to enhance productivity, efficiency, and safety, and to avoid expensive maintenance. This paper proposes an innovative multivariate fault detection method that can be used for monitoring nonlinear processes. The proposed method merges advantages of nonlinear projection to latent structures (NLPLS) modeling and those of Hellinger distance (HD) metric to identify abnormal changes in highly correlated multivariate data. Specifically, the HD is used to quantify the dissimilarity between current NLPLS-based residual and reference probability distributions obtained using fault-free data. Furthermore, to enhance further the robustness of these methods to measurement noise, and reduce the false alarms due to modeling errors, wavelet-based multiscale filtering of residuals is used before the application of the HD-based monitoring scheme. The performances of the developed NLPLS-HD fault detection technique is illustrated using simulated plug flow reactor data. The results show that the proposed method provides favorable performance for detection of faults compared to the conventional NLPLS method.

  11. Synthesis of Model Based Robust Stabilizing Reactor Power Controller for Nuclear Power Plant

    Directory of Open Access Journals (Sweden)

    Arshad Habib Malik


    Full Text Available In this paper, a nominal SISO (Single Input Single Output model of PHWR (Pressurized Heavy Water Reactor type nuclear power plant is developed based on normal moderator pump-up rate capturing the moderator level dynamics using system identification technique. As the plant model is not exact, therefore additive and multiplicative uncertainty modeling is required. A robust perturbed plant model is derived based on worst case model capturing slowest moderator pump-up rate dynamics and moderator control valve opening delay. Both nominal and worst case models of PHWR-type nuclear power plant have ARX (An Autoregressive Exogenous structures and the parameters of both models are estimated using recursive LMS (Least Mean Square optimization algorithm. Nominal and worst case discrete plant models are transformed into frequency domain for robust controller design purpose. The closed loop system is configured into two port model form and H? robust controller is synthesized. The H?controller is designed based on singular value loop shaping and desired magnitude of control input. The selection of desired disturbance attenuation factor and size of the largest anticipated multiplicative plant perturbation for loop shaping of H? robust controller form a constrained multi-objective optimization problem. The performance and robustness of the proposed controller is tested under transient condition of a nuclear power plant in Pakistan and found satisfactory.

  12. Optimization of source-sample-detector geometries for bulk hydrogen analysis using epithermal neutrons. (United States)

    Csikai, J; Dóczi, R


    The advantages and limitations of epithermal neutrons in qualification of hydrocarbons via their H contents and C/H atomic ratios have been investigated systematically. Sensitivity of this method and the dimensions of the interrogated regions were determined for various types of hydrogenous samples. Results clearly demonstrate the advantages of direct neutron detection, e.g. by BF(3) counters as compared to the foil activation method in addition to using the hardness of the spectral shape of Pu-Be neutrons to that from a (252)Cf source.

  13. Metrology and quality of radiation therapy dosimetry of electron, photon and epithermal neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Kosunen, A


    In radiation therapy using electron and photon beams the dosimetry chain consists of several sequential phases starting by the realisation of the dose quantity in the Primary Standard Dosimetry Laboratory and ending to the calculation of the dose to a patient. A similar procedure can be described for the dosimetry of epithermal neutron beams in boron neutron capture therapy (BNCT). To achieve the required accuracy of the dose delivered to a patient the quality of all steps in the dosimetry procedure has to be considered. This work is focused on two items in the dosimetry chains: the determination of the dose in the reference conditions and the evaluation of the accuracy of dose calculation methods. The issues investigated and discussed in detail are: a)the calibration methods of plane parallel ionisation chambers used in electron beam dosimetry, (b) the specification of the critical dosimetric parameter i.e. the ratio of stopping powers for water to air, (S I ?){sup water} {sub air}, in photon beams, (c) the feasibility of the twin ionization chamber technique for dosimetry in epithermal neutron beams applied to BNCT and (d) the determination accuracy of the calculated dose distributions in phantoms in electron, photon, and epithermal neutron beams. The results demonstrate that up to a 3% improvement in the consistency of dose determinations in electron beams is achieved by the calibration of plane parallel ionisation chambers in high energy electron beams instead of calibrations in {sup 60}Co gamma beams. In photon beam dosimetry (S I ?){sup water} {sub air} can be determined with an accuracy of 0.2% using the percentage dose at the 10 cm depth, %dd(10), as a beam specifier. The use of %odd(10) requires the elimination of the electron contamination in the photon beam. By a twin ionisation chamber technique the gamma dose can be determined with uncertainty of 6% (1 standard deviation) and the total neutron dose with an uncertainty of 15 to 20% (1 standard deviation

  14. An optimisation-based decision support system framework for multi-objective in-core fuel management of nuclear reactor cores

    Directory of Open Access Journals (Sweden)

    Schlunz, Evert Barend


    Full Text Available The notion of in-core fuel management (ICFM involves decision making in respect of the specific arrangement of fuel assemblies in a nuclear reactor core. This arrangement, referred to as a reload configuration, influences the efficiency and effectiveness of fuel usage in a reactor. A decision support system (DSS may assist nuclear reactor operators in improving the quality of their reload configuration designs. In this paper, a generic optimisation-based DSS framework is proposed for multi-objective ICFM, with the intention of serving as a high-level formalisation of a computerised tool that can assist reactor operators in their complex ICFM decisions.

  15. Thermal power measurement based on Feynman-alpha correlation analysis in a low-power reactor

    Energy Technology Data Exchange (ETDEWEB)

    Miyoshi, Atsuko; Taninaka, Hiroshi [Interdisciplinary Graduate School of Science and Technology, Kinki University, 3-4-1, Kowakae, Higashi-Osaka, 577-8502 (Japan); Hashimoto, Kengo [Atomic Energy Research Institute, Kinki University, 3-4-1, Kowakae, Higashi-Osaka, 577-8502 (Japan)


    This paper presents applicability of the extended Feynman-a correlation method to reactor power measurement. In the extended method, higher-order difference filters are implemented and dead-time effect of neutron counter is considered. A series of the correlation measurements were performed in the UTR-KINKI reactor to demonstrate the applicability of the extended method. At a critical state, the reactor power inferred from saturated correlation amplitude is consistent with indication of linear power monitor of the reactor. At subcritical states, not only the correlation amplitudes but also the subcriticality of these states require for the determination of reactor power. In prompt decay constants and sub-criticalities obtained from the constants, detector-position dependence, i.e., spatial effect has significantly observed. These sub-criticalities have also led to the significant spatial dependence of the reactor power inferred. When reference sub-criticalities determined from source jerk experiment have employed instead of the spatially dependent sub-criticalities, the inferred reactor power has slight spatial dependence and agrees with indication of linear power monitor. (authors)

  16. Neutron scattering from α-Ce at epithermal neutron energies

    Indian Academy of Sciences (India)

    to the neutron spectra which yield parameters that are in good accord with Fermi liquid relations obtained for the ... erties of Ce-based systems is best illustrated with reference to the data on pseudo- binary compounds ..... [11] A P Murani, Z A Bowden, A D Taylor, R Osborn and W G Marshall, Phys. Rev. B48, 13981 (1993).

  17. Parameterized data-driven fuzzy model based optimal control of a semi-batch reactor. (United States)

    Kamesh, Reddi; Rani, K Yamuna


    A parameterized data-driven fuzzy (PDDF) model structure is proposed for semi-batch processes, and its application for optimal control is illustrated. The orthonormally parameterized input trajectories, initial states and process parameters are the inputs to the model, which predicts the output trajectories in terms of Fourier coefficients. Fuzzy rules are formulated based on the signs of a linear data-driven model, while the defuzzification step incorporates a linear regression model to shift the domain from input to output domain. The fuzzy model is employed to formulate an optimal control problem for single rate as well as multi-rate systems. Simulation study on a multivariable semi-batch reactor system reveals that the proposed PDDF modeling approach is capable of capturing the nonlinear and time-varying behavior inherent in the semi-batch system fairly accurately, and the results of operating trajectory optimization using the proposed model are found to be comparable to the results obtained using the exact first principles model, and are also found to be comparable to or better than parameterized data-driven artificial neural network model based optimization results. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  18. Plavica epithermal Au-Ag-Cu deposit in eastern Macedonia: Geology and 3D model of valuable component distribution in ore (United States)

    Serafimovski, T.; Volkov, A. V.; Serafimovski, D.; Tasev, G.; Ivanovski, I.; Murashov, K. Yu.


    The Plavica Au-Ag-Cu deposit is related to the large Neogene volcanic center, which complicates the paleocaldera in the central Kratovo-Zletovo ore district of eastern Macedonia. Based on the geology, ore mineralogy, wall-rock alteration, and fluid inclusions, the Plavica deposit has been referred to the epithermal high-sulfidation type. The general 3D model of orebody at this deposit is based on its general geological structure and complex distribution of metal contents. The framework of the 3D model, which has been constructed in the ArcGIS System, comprises 195 exploration boreholes 47295.8 m in total length. The 3D model allows to a better understanding of distribution of mineralization and supplements the geological data on the deposit.

  19. SACRD: a data base for fast reactor safety computer codes, contents and glossary of Version 1 of the system

    Energy Technology Data Exchange (ETDEWEB)

    Greene, N.M.; Forsberg, V.M.; Raiford, G.B.; Arwood, J.W.; Flanagan, G.F.


    SACRD is a data base of material properties and other handbook data needed in computer codes used for fast reactor safety studies. This document lists the contents of Version 1 and also serves as a glossary of terminology used in the data base. Data are available in the thermodynamics, heat transfer, fluid mechanics, structural mechanics, aerosol transport, meteorology, neutronics and dosimetry areas. Tabular, graphical and parameterized data are provided in many cases.

  20. The Chahnaly low sulfidation epithermal gold deposit, western Makran volcanic arc, southeastern Iran (United States)

    Sholeh, Ali; Rastad, Ebrahim; Huston, David L.; Gemmell, J. Bruce; Taylor, Ryan D.


    The Chahnaly low-sulfidation epithermal Au deposit and nearby Au prospects are located northwest of the intermittently active Bazman stratovolcano on the western end of the Makran volcanic arc, which formed as the result of subduction of the remnant Neo-Tethyan oceanic crust beneath the Lut block. The arc hosts the Siah Jangal epithermal and Kharestan porphyry prospects, near Taftan volcano, as well as the Saindak Cu-Au porphyry deposit and world-class Reko Diq Cu-Au porphyry deposit, near Koh-i-Sultan volcano to the east-northeast in Pakistan. The host rocks for the Chahnaly deposit include early Miocene andesite and andesitic volcaniclastic rocks that are intruded by younger dacitic domes. Unaltered late Miocene dacitic ignimbrites overlie these rocks. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb zircon geochronology data yield ages between 21.8 and 9.9 Ma for the acidic-intermediate regional volcanism. The most recent volcanic activity of the Bazman stratovolcano involved extrusion of an olivine basalt during Pliocene to Quaternary times. Interpretation of geochemical data indicate that the volcanic rocks are synsubduction and calc-alkaline to subalkaline. The lack of a significant negative Eu anomaly, a listric-shaped rare earth element pattern, and moderate La/Yb ratios of host suites indicate a high water content of the source magma.

  1. Composition Optimization of Lithium-Based Ternary Alloy Blankets for Fusion Reactors (United States)

    Jolodosky, Alejandra

    The goal of this dissertation is to examine the neutronic properties of a novel type of fusion reactor blanket material in the form of lithium-based ternary alloys. Pure liquid lithium, first proposed as a blanket for fusion reactors, is utilized as both a tritium breeder and a coolant. It has many attractive features such as high heat transfer and low corrosion properties, but most importantly, it has a very high tritium solubility and results in very low levels of tritium permeation throughout the facility infrastructure. However, lithium metal vigorously reacts with air and water and presents plant safety concerns including degradation of the concrete containment structure. The work of this thesis began as a collaboration with Lawrence Livermore National Laboratory in an effort to develop a lithium-based ternary alloy that can maintain the beneficial properties of lithium while reducing the reactivity concerns. The first studies down-selected alloys based on the analysis and performance of both neutronic and activation characteristics. First, 3-D Monte Carlo calculations were performed to evaluate two main neutronics performance parameters for the blanket: tritium breeding ratio (TBR), and energy multiplication factor (EMF). Alloys with adequate results based on TBR and EMF calculations were considered for activation analysis. Activation simulations were executed with 50 years of irradiation and 300 years of cooling. It was discovered that bismuth is a poor choice due to achieving the highest decay heat, contact dose rates, and accident doses. In addition, it does not meet the waste disposal ratings (WDR). The straightforward approach to obtain Monte Carlo TBR and EMF results required 231 simulations per alloy and became computationally expensive, time consuming, and inefficient. Consequently, alternate methods were pursued. A collision history-based methodology recently developed for the Monte Carlo code Serpent, calculates perturbation effects on practically

  2. Reactor Physics

    Energy Technology Data Exchange (ETDEWEB)

    Ait Abderrahim, A


    The Reactor Physics and MYRRHA Department of SCK-CEN offers expertise in various areas of reactor physics, in particular in neutronics calculations, reactor dosimetry, reactor operation, reactor safety and control and non-destructive analysis of reactor fuel. This expertise is applied in the Department's own research projects in the VENUS critical facility, in the BR1 reactor and in the MYRRHA project (this project aims at designing a prototype Accelerator Driven System). Available expertise is also used in programmes external to the Department such as the reactor pressure steel vessel programme, the BR2 reactor dosimetry, and the preparation and interpretation of irradiation experiments by means of neutron and gamma calculations. The activities of the Fuzzy Logic and Intelligent Technologies in Nuclear Science programme cover several domains outside the department. Progress and achievements in these topical areas in 2000 are summarised.

  3. CO{sub 2} capture from flue gases using three Ca-based sorbents in a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.S.; Fang, F.; Cai, N.S. [Tsinghua University, Beijing (China). Dept. of Thermal Engineering


    Abstract: Experiments of CO{sub 2} capture and sorbent regeneration characteristics of limestone, dolomite, and CaO/Ca{sub 1}2Al{sub 14}O{sub 3}3 at high temperature were investigated in a thermogravimetric analyzer (TGA) and a fluidized bed reactor. The effect of reactivity decay of limestone, dolomite, and CaO/Ca{sub 12}Al{sub 14}O{sub 3}3 sorbents on CO{sub 2} capture and sorbent regeneration processes was studied. The experimental results indicated that the operation time of high efficient CO{sub 2} capture stage declined continuously with increasing of the cyclic number due to the loss of the sorbent activity, and the final CO{sub 2} capture efficiency would remain nearly constant, due to the sorbent already reaching the final residual capture capacity. After the CO{sub 2} capture step, the Ca-based sorbents need to be regenerated to be used for a subsequent cycle, and the multiple calcination processes of Ca-based sorbent under different calcination conditions are studied and discussed. Reactivity loss of limestone, dolomite and CaO/Ca{sub 12}Al{sub 14}O{sub 3}3 sorbents from a fluidized bed reactor at both mild and severe calcination conditions was compared with the TGA data. At mild calcination conditions, TGA results of sorbent reactivity loss were similar to the experimental results of fluidized bed reactor for three sorbents at 850 degrees C calcination temperature, and this indicated that TGA experimental results can be used as a reference to predict sorbent reactivity loss behavior in fluidized bed reactor. At severe calcination condition, sorbent reactivity loss behavior for limestone and dolomite from TGA compare well with the result from a fluidized bed reactor.

  4. High Flux Isotope Reactor (HFIR) (United States)

    Federal Laboratory Consortium — The HFIR at Oak Ridge National Laboratory is a light-water cooled and moderated reactor that is the United States’ highest flux reactor-based neutron source. HFIR...

  5. Model-Based Reactor Design in Free-Radical Polymerization with Simultaneous Long-Chain Branching and Scission

    Directory of Open Access Journals (Sweden)

    Hidetaka Tobita


    Full Text Available Polymers are the products of processes and their microstructure can be changed significantly by the reactor systems employed, especially for nonlinear polymers. The Monte Carlo simulation technique, based on the random sampling technique, is used to explore the effect of reactor types on the branched polymer structure, formed through free-radical polymerization with simultaneous long-chain branching and scission, as in the case of low-density polyethylene synthesis. As a simplified model for a tower-type multi-zone reactor, a series of continuous stirred-tank reactors, consisting of one big tank and the same N-1 small tanks is considered theoretically. By simply changing the tank arrangement, various types of branched polymers, from star-like globular structure to a more randomly branched structure, can be obtained, while keeping the following properties of the final products, the monomer conversion to polymer, the average branching and scission densities, and the relationship between the mean-square radius of gyration and molecular weight.

  6. Production of β-Lactoglobulin hydrolysates by monolith based immobilized trypsin reactors. (United States)

    Mao, Yuhong; Černigoj, Urh; Zalokar, Viktor; Štrancar, Aleš; Kulozik, Ulrich


    Tryptic hydrolysis of β-Lactoglobulin (β-Lg) is attracting more and more attention due to the reduced allergenicity and the functionality of resulting hydrolysates. To produce hydrolysates in an economically viable way, immobilized trypsin reactors (IMTRs), based on polymethacrylate monolith with pore size 2.1 μm (N1) and 6 μm (N2), were developed and used in a flow-through system. IMTRs were characterized in terms of permeability and enzymatic activity during extensive usage. N1 showed twice the activity compared with N2, correlating well with its almost two times higher amount of immobilized trypsin. N2 showed high stability over 18 cycles, as well as over more than 30 weeks during storage. The efficiency of IMTRs on hydrolyzing β-Lg was compared with free trypsin, and the resulting hydrolysates were analyzed by MALDI-TOF/MS. The final hydrolysis degree by N1 reached 9.68% (86.58% cleavage sites) within 4 h, while only around 6% (53.67% cleavage sites) by 1.5 mg of free trypsin. Peptides analysis showed the different preference between immobilized trypsin and free trypsin. Under the experimental conditions used in this study, the potential cleavage site Lys135 -Phe136 was resistant against the immobilized trypsin in N1. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Treatment of Rural Wastewater Using a Spiral Fiber Based Salinity-Persistent Sequencing Batch Biofilm Reactor

    Directory of Open Access Journals (Sweden)

    Ying-Xin Zhao


    Full Text Available Differing from municipal wastewater, rural wastewater in salinization areas is characterized with arbitrary discharge and high concentration of salt, COD, nitrogen and phosphorus, which would cause severe deterioration of rivers and lakes. To overcome the limits of traditional biological processes, a spiral fiber based salinity-persistent Sequencing Biofilm Batch Reactor (SBBR was developed and investigated with synthetic rural wastewater (COD = 500 mg/L, NH4+-N = 50 mg/L, TP = 6 mg/L under different salinity (0.0–10.0 g/L of NaCl. Results indicated that a quick start-up could be achieved in 15 days, along with sufficient biomass up to 7275 mg/L. During operating period, the removal of COD, NH4+-N, TN was almost not disturbed by salt varying from 0.0 to 10.0 g/L with stable efficiency reaching 92%, 82% and 80%, respectively. Although TP could be removed at high efficiency of 90% in low salinity conditions (from 0.0 to 5.0 g/L of NaCl, it was seriously inhibited due to nitrite accumulation and reduction of Phosphorus Accumulating Organisms (PAOs after addition of 10.0 g/L of salt. The behavior proposed in this study will provide theoretical foundation and guidance for application of SBBR in saline rural wastewater treatment.

  8. Artificial neural network based modelling approach for municipal solid waste gasification in a fluidized bed reactor. (United States)

    Pandey, Daya Shankar; Das, Saptarshi; Pan, Indranil; Leahy, James J; Kwapinski, Witold


    In this paper, multi-layer feed forward neural networks are used to predict the lower heating value of gas (LHV), lower heating value of gasification products including tars and entrained char (LHVp) and syngas yield during gasification of municipal solid waste (MSW) during gasification in a fluidized bed reactor. These artificial neural networks (ANNs) with different architectures are trained using the Levenberg-Marquardt (LM) back-propagation algorithm and a cross validation is also performed to ensure that the results generalise to other unseen datasets. A rigorous study is carried out on optimally choosing the number of hidden layers, number of neurons in the hidden layer and activation function in a network using multiple Monte Carlo runs. Nine input and three output parameters are used to train and test various neural network architectures in both multiple output and single output prediction paradigms using the available experimental datasets. The model selection procedure is carried out to ascertain the best network architecture in terms of predictive accuracy. The simulation results show that the ANN based methodology is a viable alternative which can be used to predict the performance of a fluidized bed gasifier. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Remote Reactor Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, Adam [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dazeley, Steve [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dobie, Doug [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Marleau, Peter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brennan, Jim [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gerling, Mark [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sumner, Matthew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sweany, Melinda [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    The overall goal of the WATCHMAN project is to experimentally demonstrate the potential of water Cerenkov antineutrino detectors as a tool for remote monitoring of nuclear reactors. In particular, the project seeks to field a large prototype gadolinium-doped, water-based antineutrino detector to demonstrate sensitivity to a power reactor at ~10 kilometer standoff using a kiloton scale detector. The technology under development, when fully realized at large scale, could provide remote near-real-time information about reactor existence and operational status for small operating nuclear reactors out to distances of many hundreds of kilometers.

  10. Development of reactor graphite (United States)

    Haag, G.; Mindermann, D.; Wilhelmi, G.; Persicke, H.; Ulsamer, W.


    The German graphite development programme for High Temperature Reactors has been based on the assumption that reactor graphite for core components with lifetime fluences of up to 4 × 10 22 neutrons per cm 2 (EDN) at 400°C can be manufactured from regular pitch coke. The use of secondary coke and vibrational moulding techniques have allowed production of materials with very small anisotropy, high strength, and high purity which are the most important properties of reactor graphite. A variety of graphite grades has been tested in fast neutron irradiation experiments. The results show that suitable graphites for modern High Temperature Reactors with spherical fuel elements are available.

  11. Reactor safeguards

    CERN Document Server

    Russell, Charles R


    Reactor Safeguards provides information for all who are interested in the subject of reactor safeguards. Much of the material is descriptive although some sections are written for the engineer or physicist directly concerned with hazards analysis or site selection problems. The book opens with an introductory chapter on radiation hazards, the construction of nuclear reactors, safety issues, and the operation of nuclear reactors. This is followed by separate chapters that discuss radioactive materials, reactor kinetics, control and safety systems, containment, safety features for water reactor

  12. Reactor operation

    CERN Document Server

    Shaw, J


    Reactor Operation covers the theoretical aspects and design information of nuclear reactors. This book is composed of nine chapters that also consider their control, calibration, and experimentation.The opening chapters present the general problems of reactor operation and the principles of reactor control and operation. The succeeding chapters deal with the instrumentation, start-up, pre-commissioning, and physical experiments of nuclear reactors. The remaining chapters are devoted to the control rod calibrations and temperature coefficient measurements in the reactor. These chapters also exp

  13. Efficient cycles for carbon capture CLC power plants based on thermally balanced redox reactors

    KAUST Repository

    Iloeje, Chukwunwike


    © 2015 Elsevier Ltd. The rotary reactor differs from most alternative chemical looping combustion (CLC) reactor designs because it maintains near-thermal equilibrium between the two stages of the redox process by thermally coupling channels undergoing oxidation and reduction. An earlier study showed that this thermal coupling between the oxidation and reduction reactors increases the efficiency by up to 2% points when implemented in a regenerative Brayton cycle. The present study extends this analysis to alternative CLC cycles with the objective of identifying optimal configurations and design tradeoffs. Results show that the increased efficiency from reactor thermal coupling applies only to cycles that are capable of exploiting the increased availability in the reduction reactor exhaust. Thus, in addition to the regenerative cycle, the combined CLC cycle and the combined-regenerative CLC cycle are suitable for integration with the rotary reactor. Parametric studies are used to compare the sensitivity of the different cycle efficiencies to parameters like pressure ratio, turbine inlet temperature, carrier-gas fraction and purge steam generation. One of the key conclusions from this analysis is that while the optimal efficiency for regenerative CLC cycle was the highest of the three (56% at 3. bars, 1200. °C), the combined-regenerative cycle offers a trade-off that combines a reasonably high efficiency (about 54% at 12. bars, 1200. °C) with much lower gas volumetric flow rate and consequently, smaller reactor size. Unlike the other two cycles, the optimal compressor pressure ratio for the regenerative cycle is weakly dependent on the design turbine inlet temperature. For the regenerative and combined regenerative cycles, steam production in the regenerator below 2× fuel flow rate improves exhaust recovery and consequently, the overall system efficiency. Also, given that the fuel side regenerator flow is unbalanced, it is more efficient to generate steam from the

  14. Internal vein texture and vein evolution of the epithermal Shila-Paula district, southern Peru (United States)

    Chauvet, Alain; Bailly, Laurent; André, Anne-Sylvie; Monié, Patrick; Cassard, Daniel; Tajada, Fernando Llosa; Vargas, Juan Rosas; Tuduri, Johann


    The epithermal Shila-Paula Au-Ag district is characterized by numerous veins hosted in Tertiary volcanic rocks of the Western Cordillera (southern Peru). Field studies of the ore bodies reveal a systematic association of a main E-W vein with secondary N55-60°W veins—two directions that are also reflected by the orientation of fluid-inclusion planes in quartz crystals of the host rock. In areas where this pattern is not recognized, such as the Apacheta sector, vein emplacement seems to have been guided by regional N40°E and N40°W fractures. Two main vein-filling stages are identified. stage 1 is a quartz-adularia-pyrite-galena-sphalerite-chalcopyrite-electrum-Mn silicate-carbonate assemblage that fills the main E-W veins. stage 2, which contains most of the precious-metal mineralization, is divided into pre-bonanza and bonanza substages. The pre-bonanza substage consists of a quartz-adularia-carbonate assemblage that is observed within the secondary N45-60°W veins, in veinlets that cut the stage 1 assemblage, and in final open-space fillings. The two latter structures are finally filled by the bonanza substage characterized by a Fe-poor sphalerite-chalcopyrite-pyrite-galena-tennantite-tetrahedrite-polybasite-pearceite-electrum assemblage. The ore in the main veins is systematically brecciated, whereas the ore in the secondary veins and geodes is characteristic of open-space crystallization. Microthermometric measurements on sphalerite from both stages and on quartz and calcite from stage 2 indicate a salinity range of 0 to 15.5 wt% NaCl equivalent and homogenization temperatures bracketed between 200 and 330°C. Secondary CO2-, N2- and H2S-bearing fluid inclusions are also identified. The age of vein emplacement, based on 40Ar/39Ar ages obtained on adularia of different veins, is estimated at around 11 Ma, with some overlap between adularia of stage 1 (11.4±0.4 Ma) and of stage 2 (10.8±0.3 Ma). A three-phase tectonic model has been constructed to explain the

  15. Environmental impact assessment of the nuclear reactor at Vinca, based on the data on emission of radioactivity from the literature: A modeling approach

    Directory of Open Access Journals (Sweden)

    Gršić Z.


    Full Text Available Research activities of Vinca Institite have been based on two heavy water research reactors: 10 MW one, RA and zero power RB. Reactor RA was operational from 1962 to 1982. In 2010, spent fuel have been sent to the country of origin, and reactor now is in decommissioning. During operational phase of the reactor there were no recorded accidental releases into the environment just operational ones. Results of the environmental impact assessment, of the assumed emission of radionuclides, from the ventilation of nuclear reactor "RA" in Vinca, to the atmospheric boundary layer are presented in this paper. Evaluation was done by using the Gaussian straight-line diffusion model and taking into account characteristics of the reactor ventilation system, the assumed emission release of radioactivity (from the literature, site-specific meteorological data for six-year period and local topography around nuclear reactor, and corresponding dose factors for inventory of radionuclides. Based on the described approach, and assuming that the range of appropriate meteorological data for six year period for the application of described mathematical model is enough for this kind of analysis, it can be concluded that the nuclear reactor "RA", in the course of its work from 1962 to 1982, had no influence on the surrounding environment through the air above regulatory limits. [Projekat Ministarstva nauke Republike Srbije, br. III 45003

  16. Modeling nitrogen removal with partial nitritation and anammox in one floc-based sequencing batch reactor. (United States)

    Ni, Bing-Jie; Joss, Adriano; Yuan, Zhiguo


    Full-scale application of partial nitritation and anammox in a single floc-based sequencing batch reactor (SBR) has been achieved for high-rate nitrogen (N) removal, but mechanisms resulting in reliable operation are not well understood. In this work, a mathematical model was calibrated and validated to evaluate operating conditions that lead to out-competition of nitrite oxidizers (NOB) from the SBRs and allow to maintain high anammox activity during long-term operation. The validity of the model was tested using experimental data from two independent previously reported floc-based full-scale SBRs for N-removal via partial nitritation and anammox, with different aeration strategies at aeration phase (continuous vs. intermittent aeration). The model described the SBR cycle profiles and long-term dynamic data from the two SBR plants sufficiently and provided insights into the dynamics of microbial population fractions and N-removal performance. Ammonium oxidation and anammox reaction could occur simultaneously at DO range of 0.15-0.3 mg O2 L(-1) at aeration phase under continuous aeration condition, allowing simplified process control compared to intermittent aeration. The oxygen supply beyond prompt depletion by ammonium oxidizers (AOB) would lead to the growth of NOB competing with anammox for nitrite. NOB could also be washed out of the system and high anammox fractions could be maintained by controlling sludge age higher than 40 days and DO at around 0.2 mg O2 L(-1). Furthermore, the results suggest that N-removal in SBR occurs via both alternating nitritation/anammox and simultaneous nitritation/anammox, supporting an alternative strategy to improve N-removal in this promising treatment process, i.e., different anaerobic phases can be implemented in the SBR-cycle configuration. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Deployable nuclear fleet based on available quantities of uranium and reactor types – the case of fast reactors started up with enriched uranium

    Directory of Open Access Journals (Sweden)

    Baschwitz Anne


    Full Text Available International organizations regularly produce global energy demand scenarios. To account for the increasing population and GDP trends, as well as to encompass evolving energy uses while satisfying constraints on greenhouse gas emissions, long-term installed nuclear power capacity scenarios tend to be more ambitious, even after the Fukushima accident. Thus, the amounts of uranium or plutonium needed to deploy such capacities could be limiting factors. This study first considers light-water reactors (LWR, GEN III using enriched uranium, like most of the current reactor technologies. It then examines the contribution of future fast reactors (FR, GEN IV operating with an initial fissile load and then using depleted uranium and recycling their own plutonium. However, as plutonium is only available in limited quantity since it is only produced in nuclear reactors, the possibility of starting up these Generation IV reactors with a fissile load of enriched uranium is also explored. In one of our previous studies, the uranium consumption of a third-generation reactor like an EPR™ was compared with that of a fast reactor started up with enriched uranium (U5-FR. For a reactor lifespan of 60 years, the U5-FR consumes three times less uranium than the EPR and represents a 60% reduction in terms of separative work units (SWU, though its requirements are concentrated over the first few years of operation. The purpose of this study is to investigate the relevance of U5-FRs in a nuclear fleet deployment configuration. Considering several power demand scenarios and assuming different finite quantities of available natural uranium, this paper examines what types of reactors must be deployed to meet the demand. The deployment of light-water reactors only is not sustainable in the long run. Generation IV reactors are therefore essential. Yet when started up with plutonium, the number of reactors that can be deployed is also limited. In a fleet deployment

  18. JOSHUA modular data-based system. [For design and analysis of reactor charges; in FORTRAN IV for IBM computers

    Energy Technology Data Exchange (ETDEWEB)

    Honeck, H.C.; Anderson, M.M.


    The JOSHUA modular data-based system was developed at Savannah River primarily for the design and analysis of nuclear reactor charges. It is a very large computational system (over 300,000 FORTRAN source statements), and was made possible only by a carefully conceived and executed modular design approach. The JOSHUA modular approach and some of its benefits and shortcomings are described. 4 figures.

  19. Research Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Martens, Frederick H. [Argonne National Laboratory; Jacobson, Norman H.


    This booklet discusses research reactors - reactors designed to provide a source of neutrons and/or gamma radiation for research, or to aid in the investigation of the effects of radiation on any type of material.

  20. Neutron spectrum measurements at a radial beam port of the NUR research reactor using a Bonner spheres spectrometer. (United States)

    Mazrou, H; Nedjar, A; Seguini, T


    This paper describes the measurement campaign held around the neutron radiography (NR) facility of the Algerian 1MW NUR research reactor. The main objective of this work is to characterize accurately the neutron beam provided at one of the radial channels of the NUR research reactor taking benefit of the acquired CRNA Bonner spheres spectrometer (BSS). The specific objective was to improve the image quality of the NR facility. The spectrometric system in use is based on a central spherical (3)He thermal neutron proportional counter combined with high density polyethylene spheres of different diameters ranging from 3 to 12in. This counting system has good gamma ray discrimination and is able to cover an energy range from thermal to 20MeV. The measurements were performed at the sample distance of 0.6m from the beam port and at a height of 1.2m from the facility floor. During the BSS measurements, the reactor was operating at low power (100W) to avoid large dead times, pulse pileup and high level radiation exposures, in particular, during spheres handling. Thereafter, the neutron spectrum at the sample position was unfolded by means of GRAVEL and MAXED computer codes. The thermal, epithermal and fast neutron fluxes, the total neutron flux, the mean energy and the Cadmium ratio (RCd) were provided. A sensitivity analysis was performed taking into account various defaults spectra and ultimately a different response functions in the unfolding procedure. Overall, from the obtained results it reveals, unexpectedly, that the measured neutron spectrum at the sample position of the neutron radiography of the NUR reactor is being harder with a predominance of fast neutrons (>100keV) by about 60%. Finally, those results were compared to previous and more recent measurements obtained by activation foils detectors. The agreement was fairly good highlighting thereby the consistency of our findings. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Conceptual design based on scale laws and algorithms for sub-critical transmutation reactors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwang Gu; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)


    In order to conduct the effective integration of computer-aided conceptual design for integrated nuclear power reactor, not only is a smooth information flow required, but also decision making for both conceptual design and construction process design must be synthesized. In addition to the aboves, the relations between the one step and another step and the methodologies to optimize the decision variables are verified, in this paper especially, that is, scaling laws and scaling criteria. In the respect with the running of the system, the integrated optimization process is proposed in which decisions concerning both conceptual design are simultaneously made. According to the proposed reactor types and power levels, an integrated optimization problems are formulated. This optimization is expressed as a multi-objective optimization problem. The algorithm for solving the problem is also presented. The proposed method is applied to designing a integrated sub-critical reactors. 6 refs., 5 figs., 1 tab. (Author)

  2. Experimental and MCNP5 based evaluation of neutron and gamma flux in the irradiation ports of the University of Utah research reactor

    Directory of Open Access Journals (Sweden)

    Noble Brooklyn


    Full Text Available Neutron and gamma flux environment of various irradiation ports in the University of Utah training, research, isotope production, general atomics reactor were experimentally assessed and fully modeled using the MCNP5 code. The experimental measurements were based on the cadmium ratio in the irradiation ports of the reactor, flux profiling using nickel wire, and gamma dose measurements using thermo luminescence dosimeter. Full 3-D MCNP5 reactor model was developed to obtain the neutron flux distributions of the entire reactor core and to compare it with the measured flux focusing at the irradiation ports. Integration of all these analysis provided the updated comprehensive neutron-gamma flux maps of the existing irradiation facilities of the University of Utah TRIGA reactor.

  3. Simulation of the automatic depressurization system (Ads) for a boiling water reactor (BWR) based on RELAP; Simulacion del sistema de despresurizacion automatica (ADS) para un reactor de agua en ebullicion (BWR) basado en RELAP

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez G, C.; Chavez M, C., E-mail: [UNAM, Facultad de Ingenieria, Circuito Interior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)


    The automatic depressurization system (Ads) of the boiling water reactor (BWR) like part of the emergency cooling systems is designed to liberate the vapor pressure of the reactor vessel, as well as the main vapor lines. At the present time in the Engineering Faculty, UNAM personnel works in the simulation of the Laguna Verde reactor based on the nuclear code RELAP/SCADAP and in the incorporation to the same of the emergency cooling systems. The simulation of the emergency cooling systems began with the inclusion of two hydrodynamic volumes, one source and another drain, and the incorporation of the initiation logic for each emergency system. In this work is defined and designed a simplified model of Ads of the reactor, considering a detail level based on the main elements that compose it. As tool to implement the proposed model, the RELAP code was used. The simulated main functions of Ads are centered in the quick depressurization of the reactor by means of the vapor discharge through the relief/safety valves to the suppression pool, and, in the event of break of the main vapor line, the reduction of the vessel pressure operates for that the cooling systems of the core to low pressure (Lpcs and Lpci) they can begin their operation. (Author)

  4. Reactor mass flow data base prepared for the nonproliferation alternative systems assessment program

    Energy Technology Data Exchange (ETDEWEB)

    Primm III, R.T.C


    This report presents charge and discharge mass flow data for reactors judged to have received sufficient technical development to enable them to be demonstrated or commercially available by the year 2000. Brief descriptions of the reactors and fuel cycles evaluated are presented. A discussion of the neutronics methods used to produce the mass flow data is provided. Detailed charge and discharge fuel isotopics are presented. U/sub 3/O/sub 8/, separative work, and fissile material requirements are computed and provided for each fuel cycle.

  5. Epithermal Neutron Observations and Lunar South Pole Targeting for LCROSS Impact Planning using the Lunar Reconnaissance Orbiter (LRO), Lunar Exploring Neutron Detector (LEND) (United States)

    McClanahan, T. P.; Mitrofanov, I.; Boynton, W. V.; Chin, G.; Colaprete, A.; Evans, L. G.; Garvin, J.; Harshman, K.; Litvak, R.; Malakhov, A.; hide


    LCROSS impact targeting and planning efforts included quantifying South Polar epithermal neutron flux depressions in early LEND mapped results to maximize the expected plume Hydrogen (H) yield. Epithermal neutron surface fluxes are a key geochemical indicator of surface Hydrogen (H) concentration inferred to be elevated in polar permanent shadow regions (PSR). LCROSS impact target regions were delineated as (PSR) using illumination modeling of polar topography. To quantify targets potential yield for LCROSS, LEND epithermal neutron flux observations were integrated over LCROSS targets of interest and compared to background observations. Discussion will define methods review impact prior estimates and contrast post impact results.


    Energy Technology Data Exchange (ETDEWEB)

    Langton, C.; Stefanko, D.


    The objective of this report is to document laboratory testing of blended calcium aluminate - calcium hemihydrate grouts for P-Reactor vessel in-situ decommissioning. Blended calcium aluminate - calcium hemihydrate cement-based grout was identified as candidate material for filling (physically stabilizing) the 105-P Reactor vessel (RV) because it is less alkaline than portland cement-based grout which has a pH greater than 12.4. In addition, blended calcium aluminate - calcium hemihydrate cement compositions can be formulated such that the primary cementitious phase is a stable crystalline material. A less alkaline material (pH {<=} 10.5) was desired to address a potential materials compatibility issue caused by corrosion of aluminum metal in highly alkaline environments such as that encountered in portland cement grouts [Wiersma, 2009a and b, Wiersma, 2010, and Serrato and Langton, 2010]. Information concerning access points into the P-Reactor vessel and amount of aluminum metal in the vessel is provided elsewhere [Griffin, 2010, Stefanko, 2009 and Wiersma, 2009 and 2010, Bobbitt, 2010, respectively]. Radiolysis calculations are also provided in a separate document [Reyes-Jimenez, 2010].

  7. CONVECTION REACTOR (United States)

    Hammond, R.P.; King, L.D.P.


    An homogeneous nuclear power reactor utilizing convection circulation of the liquid fuel is proposed. The reactor has an internal heat exchanger looated in the same pressure vessel as the critical assembly, thereby eliminating necessity for handling the hot liquid fuel outside the reactor pressure vessel during normal operation. The liquid fuel used in this reactor eliminates the necessity for extensive radiolytic gas rocombination apparatus, and the reactor is resiliently pressurized and, without any movable mechanical apparatus, automatically regulates itself to the condition of criticality during moderate variations in temperature snd pressure and shuts itself down as the pressure exceeds a predetermined safe operating value.

  8. Design of a homogeneous subcritical nuclear reactor based on thorium with a source of californium 252; Diseno de un reactor nuclear subcritico homogeneo a base de Torio con una fuente de Californio 252

    Energy Technology Data Exchange (ETDEWEB)

    Delgado H, C. E.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Sajo B, L., E-mail: [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Apdo. 89000, 1080A Caracas (Venezuela, Bolivarian Republic of)


    Full text: One of the energy alternatives to fossil fuels which do not produce greenhouse gases is the nuclear energy. One of the drawbacks of this alternative is the generation of radioactive wastes of long half-life and its relation to the generation of nuclear materials to produce weapons of mass destruction. An option to these drawbacks of nuclear energy is to use Thorium as part of the nuclear fuel which it becomes in U{sup 233} when capturing neutrons, that is a fissile material. In this paper Monte Carlo methods were used to design a homogeneous subcritical reactor based on thorium. As neutron reflector graphite was used. The reactor core is homogeneous and is formed of 70% light water as moderator, 12% of enriched uranium UO{sub 2}(NO{sub 3}){sub 4} and 18% of thorium Th(NO{sub 3}){sub 4} as fuel. To start the nuclear fission chain reaction an isotopic source of californium 252 was used with an intensity of 4.6 x 10{sup 7} s{sup -1}. In the design the value of the effective multiplication factor, whose value turned out k{sub eff} <1 was calculated. Also, the neutron spectra at different distances from the source and the total fluence were calculated, as well as the values of the ambient dose equivalent in the periphery of the reactor. (Author)

  9. Effective dose evaluation for BNCT treatment in the epithermal neutron beam at THOR

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.N. [Department of Engineering and System Science, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Rd., Hsinchu 30013, Taiwan (China)] [Division of Health Physics, Institute of Nuclear Energy Research, No. 1000, Wenhua Rd., Jiaan Village, Longtan Township, Taoyuan County 32546, Taiwan (China); Huang, C.K. [Institute of Nuclear Engineering and Science, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Rd., Hsinchu 30013, Taiwan (China); Tsai, W.C. [Department of Engineering and System Science, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Rd., Hsinchu 30013, Taiwan (China); Liu, Y.H. [Nuclear Science and Technol. Develop. Center, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Rd., Hsinchu 30013, Taiwan (China); Jiang, S.H., E-mail: [Department of Engineering and System Science, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Rd., Hsinchu 30013, Taiwan (China)] [Institute of Nuclear Engineering and Science, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Rd., Hsinchu 30013, Taiwan (China)


    This paper aims to evaluate the effective dose as well as equivalent doses of several organs of an adult hermaphrodite mathematical phantom according to the definition of ICRP Publication 60 for BNCT treatments of brain tumors in the epithermal neutron beam at THOR. The MCNP5 Monte Carlo code was used for the calculation of the average absorbed dose of each organ. The effective doses for a typical brain tumor treatment with a tumor treatment dose of 20 Gy-eq were evaluated to be 0.59 and 0.35 Sv for the LLAT and TOP irradiation geometries, respectively. In addition to the stochastic effect, it was found that it is also likely to produce deterministic effects, such as cataracts and depression of haematopoiesis.

  10. Neutron spectra calculation and doses in a subcritical nuclear reactor based on thorium; Calculo de espectros de neutrones y dosis en un reactor nuclear subcritico a base de Torio

    Energy Technology Data Exchange (ETDEWEB)

    Medina C, D.; Hernandez A, P. L.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Sajo B, L., E-mail: [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Apdo. Postal 89000, Caracas 1080A (Venezuela, Bolivarian Republic of)


    This paper describes a heterogeneous subcritical nuclear reactor with molten salts based on thorium, with graphite moderator and a source of {sup 252}Cf, whose dose levels in the periphery allows its use in teaching and research activities. The design was done by the Monte Carlo method with the code MCNP5 where the geometry, dimensions and fuel was varied in order to obtain the best design. The result is a cubic reactor of 110 cm side with graphite moderator and reflector. In the central part they have 9 ducts that were placed in the direction of axis Y. The central duct contains the source of {sup 252}Cf, of 8 other ducts, are two irradiation ducts and the other six contain a molten salt ({sup 7}LiF - BeF{sub 2} - ThF{sub 4} - UF{sub 4}) as fuel. For design the k{sub eff}, neutron spectra and ambient dose equivalent was calculated. In the first instance the above calculation for a virgin fuel was called case 1, then a percentage of {sup 233}U was used and the percentage of Th was decreased and was called case 2. This with the purpose to compare two different fuels working inside the reactor. In the case 1 a value was obtained for the k{sub eff} of 0.13 and case 2 of 0.28, maintaining the subcriticality in both cases. In the dose levels the higher value is in case 2 in the axis Y with a value of 3.31 e-3 ±1.6% p Sv/Q this value is reported in for one. With this we can calculate the exposure time of personnel working in the reactor. (Author)

  11. Carbon nano-fiber based membrane reactor for selective nitrite hydrogenation

    NARCIS (Netherlands)

    Brunet Espinosa, Roger; Rafieian, D.; Lammertink, Rob G.H.; Lefferts, Leonardus


    Catalytic hydrogenation of nitrite in drinking water demands control over the selectivity towards nitrogen, minimizing the formation of ammonia. This selectivity is strongly influenced by the H/N ratio of reaction intermediates at the catalyst surface. Therefore, we fabricated a membrane reactor

  12. High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion (United States)

    Juhasz, Albert J.; Sawicki, Jerzy T.


    For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a partial energy conversion system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the reactor thermal energy for conversion to electric power. Most of the fusion reactor's output is in the form of charged plasma which is expanded through a magnetic nozzle of the interplanetary propulsion system. Reactor heat energy is ducted to the high temperature series radiator utilizing the electric power generated to drive a helium gas circulation fan. In addition to discussing the thermodynamic aspects of the system design the authors include a brief overview of the gas turbine and fan rotor-dynamics and proposed bearing support technology along with performance characteristics of the three phase AC electric power generator and fan drive motor.

  13. Innovative radiation-based direct heat exchanger (DHX) for liquid metal cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    De Santis, Andrea, E-mail: [“SAPIENZA” University of Rome, DIAEE, Corso Vittorio Emanuele II 244, 00186 Rome (Italy); Vitale Di Maio, Damiano; Caruso, Gianfranco [“SAPIENZA” University of Rome, DIAEE, Corso Vittorio Emanuele II 244, 00186 Rome (Italy); Manni, Fabio [S.R.S. Servizi di Ricerche e Sviluppo S.r.l., Rome (Italy)


    Highlights: • An innovative DHRS for liquid metal fast breeder reactors has been proposed. • A parametric CFD analyses of the DHX performances have been performed. • A comparison between SFR and LFR applications has been performed. -- Abstract: Considering the importance of safety features in the development of Generation IV nuclear reactors, an innovative and passive decay heat removal system (DHRS) has been proposed for liquid metal cooled reactors. The attention is here focused on the direct heat exchanger (DHX) of the system constituted by a bayonet tube that allows to remove the decay heat from the primary coolant; both primary and secondary fluids flow in natural circulation. Since each bayonet tube is equipped with a vacuum gap, the most important heat transfer mechanism characterizing the DHX is radiation. Furthermore, the presence of the vacuum gap guarantees a physical separation and a complete decoupling between primary and secondary fluids, enhancing the safety features of the whole system. Several CFD analyses have been carried out in order to obtain a characterization of the DHX both for sodium and lead cooled fast reactors, in order to optimize the DHX geometry on the basis of the specific application, and the results are discussed in the paper.

  14. Epithermal mineralization and ore controls of the Shasta Au-Ag deposit, Toodoggone District, British Columbia, Canada (United States)

    Thiersch, P. C.; Williams-Jones, A. E.; Clark, J. R.


    The Shasta gold-silver deposit, British Columbia, Canada, is an adularia-sericite-type epithermal deposit in which deposition of precious metals coincided with the transition of quartz- to calcite-dominant gangue. Mineralization is associated with stockwork-breccia zones in potassically altered dacitic lapilli tuffs and flows, and consists of pyrite, sphalerite, chalcopyrite, galena, acanthite, electrum and native silver. Pre- and post-ore veins consist solely of quartz and calcite, respectively. Fluid inclusion microthermometry indicates that ore minerals were deposited between 280 ° and 225 °C, from a relatively dilute hydrothermal fluid (˜1.5 wt.% NaCl equivalent). Abundant vapor-rich inclusions in ore-stage calcite are consistent with boiling. Oxygen and hydrogen isotopic data (δ18Ofluid = -1.5 to -4.1‰; δDfluid = -148 to -171‰) suggest that the fluid had a meteoric origin, but was 18O-enriched by interaction with volcanic wallrocks. Initial (˜280 °C) fluid pH and log f O2 conditions are estimated at 5.3 to 6.0, and -32.5 to -33 bar, respectively; during ore deposition, the fluid became more alkaline and oxidizing. Ore deposition at Shasta is attributed to localization of meteoric hydrothermal fluids by extensional faults; mineralization was controlled by boiling in response to hydraulic brecciation. Calcite and base metal sulfides precipitated due to the increase in pH that accompanied boiling, and the associated decrease in H2S concentration led to precipitation of gold and silver.

  15. Fuel lattice design in a boiling water reactor using an ant-colony-based system

    Energy Technology Data Exchange (ETDEWEB)

    Montes, Jose Luis, E-mail: [Instituto Nacional de Investigaciones Nucleares, Carr. Mexico-Toluca S/N, La Marquesa, Ocoyoacac, Estado de Mexico, CP 52750 (Mexico); Facultad de Ciencias, Universidad Autonoma del Estado de Mexico (Mexico); Francois, Juan-Luis, E-mail: [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532, Jiutepec, Mor., CP 62550 (Mexico); Ortiz, Juan Jose, E-mail: [Instituto Nacional de Investigaciones Nucleares, Carr. Mexico-Toluca S/N, La Marquesa, Ocoyoacac, Estado de Mexico, CP 52750 (Mexico); Martin-del-Campo, Cecilia, E-mail: [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532, Jiutepec, Mor., CP 62550 (Mexico); Perusquia, Raul, E-mail: [Instituto Nacional de Investigaciones Nucleares, Carr. Mexico-Toluca S/N, La Marquesa, Ocoyoacac, Estado de Mexico, CP 52750 (Mexico)


    Research highlights: > We present an ant-colony-based system for BWR fuel lattice design and optimization. > Assessment of candidate solutions at 0.0 MWd/kg {sup 235}U seems to have a limited scope. > Suitable heuristic rules enable more realistic fuel lattice designs. > The election of the objective has a large impact in CPU time. > ACS enables an important decrease of the initial average U-235 enrichment. - Abstract: This paper presents a new approach to deal with the boiling water reactor radial fuel lattice design. The goal is to optimize the distribution of both, the fissionable material, and the reactivity control poison material inside the fuel lattice at the beginning of its life. An ant-colony-based system was used to search for either: the optimum location of the poisoned pin inside the lattice, or the U{sup 235} enrichment and Gd{sub 2}O{sub 3} concentrations. In the optimization process, in order to know the parameters of the candidate solutions, the neutronic simulator CASMO-4 transport code was used. A typical 10 x 10 BWR fuel lattice with an initial average U{sup 235} enrichment of 4.1%, used in the current operation of Laguna Verde Nuclear Power Plant was taken as a reference. With respect to that reference lattice, it was possible to decrease the average U{sup 235} enrichment up to 3.949%, this obtained value represents a decrease of 3.84% with respect to the reference U{sup 235} enrichment; whereas, the k-infinity was inside the {+-}100 pcm's range, and there was a difference of 0.94% between the local power peaking factor and the lattice reference value. Particular emphasis was made on defining the objective function which is used for making the assessment of candidate solutions. In a typical desktop personal computer, about four hours of CPU time were necessary for the algorithm to fulfill the goals of the optimization process. The results obtained with the application of the implemented system showed that the proposed approach represents a

  16. Nuclear reactor design

    CERN Document Server


    This book focuses on core design and methods for design and analysis. It is based on advances made in nuclear power utilization and computational methods over the past 40 years, covering core design of boiling water reactors and pressurized water reactors, as well as fast reactors and high-temperature gas-cooled reactors. The objectives of this book are to help graduate and advanced undergraduate students to understand core design and analysis, and to serve as a background reference for engineers actively working in light water reactors. Methodologies for core design and analysis, together with physical descriptions, are emphasized. The book also covers coupled thermal hydraulic core calculations, plant dynamics, and safety analysis, allowing readers to understand core design in relation to plant control and safety.

  17. The Stypsi-Megala Therma porphyry-epithermal mineralization, Lesvos Island, Greece: new mineralogical and geochemical data (United States)

    Periferakis, Argyrios; Voudouris, Panagiotis; Melfos, Vasilios; Mavrogonatos, Constantinos; Alfieris, Dimitrios


    Lesvos Island is located at the NE part of the Aegean Sea and mostly comprises post-collisional Miocene volcanic rocks of shoshonitic to calc-alkaline geochemical affinities. In the northern part of the Island, the Stypsi Cu-Mo±Au porphyry prospect, part of the Stypsi caldera, is hosted within hydrothermally altered intrusives and volcanics [1]. Porphyry-style mineralization is developed in a microgranite porphyry that has intruded basaltic trachyandesitic lavas. Propylitic alteration occurs distal to the mineralization, whereas sodic-calcic alteration related to quartz-actinolite veinlets, and a phyllic overprint associated with a dense stockwork of banded black quartz±carbonate veinlets, characterizes the core of the system. Alunite-kaolinite advanced argillic alteration occurs at higher topographic levels and represents a barren lithocap to the porphyry mineralization. Intermediate-sulfidation (IS) milky quartz-carbonate veins overprint the porphyry mineralization along a NNE-trending fault that extends further northwards to Megala Therma, where it hosts IS base metal-rich Ag-Au mineralization [2]. New mineralogical data from the Megala Therma deposit suggest Ag-famatinite, Te-polybasite and Ag-tetrahedrite as the main carriers of Ag in the mineralization. Porphyry-style ores at Stypsi consist of magnetite postdated by pyrite and then by chalcopyrite, molybdenite, sphalerite, galena and bismuthinite within the black quartz stockworks or disseminated in the wallrock [1]. The dark coloration of quartz in the veinlets is due to abundant vapor-rich fluid inclusions. Quartz is granular and fine-grained and locally elongated perpendicular to the vein walls. Botryoidal textures are continuous through quartz grains, suggesting quartz recrystallization from a silica gel, a feature already described by [3] from banded quartz veinlets in porphyry Au deposits at Maricunga, Chile. Bulk ore analyses from porphyry-style mineralization at Stypsi displayed similar geochemical

  18. Laundry greywater treatment using a fluidized bed reactor: a proposed model based on greywater biodegradation and residence time distribution approach. (United States)

    David, Pierre-luc; Bulteau, Gaëlle; Humeau, Philippe; Gérente, Claire; Andrès, Yves


    The increasing demand for water and the decrease in global water resources require research into alternative solutions to preserve them. The present study deals with the optimization of a treatment process, i.e. an aerobic fluidized bed reactor and the modelling of the degradation that takes place within it. The methodology employed is based on the hydrodynamics of the treatment process linked to the biodegradation kinetics of greywater coming from a washing machine. The residence time distribution (RTD) approach is selected for the hydrodynamic study. Biodegradation kinetics are quantified by respirometry and dissolved organic carbon (DOC) analysis on several mass quantities of colonized particles. RTD determinations show that there are no dysfunctions in the fluidized bed. Its hydrodynamic behaviour is similar to the one of a continuous stirred-tank reactor. A first-order reaction is obtained from the DOC biodegradation study. A model describing the degradation that takes place into the reactor is proposed, and from a sensitive study, the influence of the operating conditions on DOC biodegradation is defined. The theoretical results calculated from the first-order equation C(t) = 0.593 x C(0) x e(-kt) are compared with the experimental results and validated by a Student test. The value of the kinetic constant k is 0.011 h(-1) in the presence of a biomass carrier. The results highlight that it is possible to design a reactor in order to obtain a carbon content lower than 15 mg C L(-1) when the characteristics of raw greywater are known.

  19. GeN-Foam: a novel OpenFOAM{sup ®} based multi-physics solver for 2D/3D transient analysis of nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Fiorina, Carlo, E-mail: [Paul Scherrer Institut, Nuclear Energy and Safety Department, Laboratory for Reactor Physics and Systems Behaviour – PSI, Villigen 5232 (Switzerland); Clifford, Ivor [Paul Scherrer Institut, Nuclear Energy and Safety Department, Laboratory for Reactor Physics and Systems Behaviour – PSI, Villigen 5232 (Switzerland); Aufiero, Manuele [LPSC-IN2P3-CNRS/UJF/Grenoble INP, 53 avenue des Martyrs, 38026 Grenoble Cedex (France); Mikityuk, Konstantin [Paul Scherrer Institut, Nuclear Energy and Safety Department, Laboratory for Reactor Physics and Systems Behaviour – PSI, Villigen 5232 (Switzerland)


    Highlights: • Development of a new multi-physics solver based on OpenFOAM{sup ®}. • Tight coupling of thermal-hydraulics, thermal-mechanics and neutronics. • Combined use of traditional RANS and porous-medium models. • Mesh for neutronics deformed according to the predicted displacement field. • Use of three unstructured meshes, adaptive time step, parallel computing. - Abstract: The FAST group at the Paul Scherrer Institut has been developing a code system for reactor analysis for many years. For transient analysis, this code system is currently based on a state-of-the-art coupled TRACE-PARCS routine. This work presents an attempt to supplement the FAST code system with a novel solver characterized by tight coupling between the different equations, parallel computing capabilities, adaptive time-stepping and more accurate treatment of some of the phenomena involved in a reactor transient. The new solver is based on OpenFOAM{sup ®}, an open-source C++ library for the solution of partial differential equations using finite-volume discretization. It couples together a multi-scale fine/coarse mesh sub-solver for thermal-hydraulics, a multi-group diffusion sub-solver for neutronics, a displacement-based sub-solver for thermal-mechanics and a finite-difference model for the temperature field in the fuel. It is targeted toward the analysis of pin-based reactors (e.g., liquid metal fast reactors or light water reactors) or homogeneous reactors (e.g., fast-spectrum molten salt reactors). This paper presents each “single-physics” sub-solver and the overall coupling strategy, using the sodium-cooled fast reactor as a test case, and essential code verification tests are described.

  20. Microwave-induced plasma reactor based on a domestic microwave oven for bulk solid state chemistry (United States)

    Brooks, David J.; Douthwaite, Richard E.


    A microwave-induced plasma (MIP) reactor has been constructed from a domestic microwave oven (DMO) and applied to the bulk synthesis of solid state compounds. Low pressure MIP can be initiated and maintained using a range of gases including Ar, N2, NH3, O2, Cl2, and H2S. In order to obtain reproducible synthesis conditions the apparatus is designed to allow control of gas flow rate, gas composition, and pressure. The use of the reactor is demonstrated by the synthesis of three binary metal nitrides formed in a NH3 MIP. The reactions are rapid and the products show good crystallinity and phase purity as judged by powder x-ray diffraction.

  1. A fuzzy rule base for the control of a nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Si-Fodil, M.; Guely, F.; Siarry, P. [Ecole Centrale de Paris, 92 - Chatenay-Malabry (France); Tyran, J.L. [Electricite de France (EDF), 78 - Chatou (France). Direction des Etudes et Recherches


    This paper presents the development of a real time fuzzy controller for the power axial-offset and the R control rods insertion in a pressurized water reactor (PWR). Fundamentally two parameters are concerned by this task : the power axial-offset and rods position. The focus of this study is the automation of the control of the power axial-offset by adding soluble boron, and by minimizing the flows through the water pump. Water or boron is injected into the reactor. It is also important to take into consideration the liquid waste volume. Our aim is to run the fuzzy controller at least as efficient as an expert operator. The system has been implemented in simulation using the Matlab-Simulink on a Sun workstation. (authors) 6 refs.

  2. Power level effects on thorium-based fuels in pressure-tube heavy water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Bromley, B.P.; Edwards, G.W.R., E-mail: [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Sambavalingam, P. [Univ. of Ontario Inst. of Technology, Oshawa, Ontario (Canada)


    Lattice and core physics modeling and calculations have been performed to quantify the impact of power/flux levels on the reactivity and achievable burnup for 35-element fuel bundles made with Pu/Th or U-233/Th. The fissile content in these bundles has been adjusted to produce on the order of 20 MWd/kg burnup in homogeneous cores in a 700 MWe-class pressure-tube heavy water reactor, operating on a once-through thorium cycle. Results demonstrate that the impact of the power/flux level is modest for Pu/Th fuels but significant for U-233/Th fuels. In particular, high power/flux reduces the breeding and burnup potential of U-233/Th fuels. Thus, there may be an incentive to operate reactors with U-233/Th fuels at a lower power density or to develop alternative refueling schemes that will lower the time-average specific power, thereby increasing burnup.(author)

  3. Simulation on reactor TRIGA Puspati core kinetics fueled with thorium (Th) based fuel element (United States)

    Mohammed, Abdul Aziz; Pauzi, Anas Muhamad; Rahman, Shaik Mohmmed Haikhal Abdul; Zin, Muhamad Rawi Muhammad; Jamro, Rafhayudi; Idris, Faridah Mohamad


    In confronting global energy requirement and the search for better technologies, there is a real case for widening the range of potential variations in the design of nuclear power plants. Smaller and simpler reactors are attractive, provided they can meet safety and security standards and non-proliferation issues. On fuel cycle aspect, thorium fuel cycles produce much less plutonium and other radioactive transuranic elements than uranium fuel cycles. Although not fissile itself, Th-232 will absorb slow neutrons to produce uranium-233 (233U), which is fissile. By introducing Thorium, the numbers of highly enriched uranium fuel element can be reduced while maintaining the core neutronic performance. This paper describes the core kinetic of a small research reactor core like TRIGA fueled with a Th filled fuel element matrix using a general purpose Monte Carlo N-Particle (MCNP) code.

  4. REACTOR COOLING (United States)

    Quackenbush, C.F.


    A nuclear reactor with provisions for selectively cooling the fuel elements is described. The reactor has a plurality of tubes extending throughout. Cylindrical fuel elements are disposed within the tubes and the coolant flows through the tubes and around the fuel elements. The fuel elements within the central portion of the reactor are provided with roughened surfaces of material. The fuel elements in the end portions of the tubes within the reactor are provlded with low conduction jackets and the fuel elements in the region between the central portion and the end portions are provided with smooth surfaces of high heat conduction material.

  5. Fast Breeder Reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Till, C.E.; Chang, Y.I.; Kittel, J.H.; Fauske, H.K.; Lineberry, M.J.; Stevenson, M.G.; Amundson, P.I.; Dance, K.D.


    This report is a compilation of Fast Breeder Reactor (FBR) resource documents prepared to provide the technical basis for the US contribution to the International Nuclear Fuel Cycle Evaluation. The eight separate parts deal with the alternative fast breeder reactor fuel cycles in terms of energy demand, resource base, technical potential and current status, safety, proliferation resistance, deployment, and nuclear safeguards. An Annex compares the cost of decommissioning light-water and fast breeder reactors. Separate abstracts are included for each of the parts.

  6. Fluid inclusion chemistry of adularia-sericite epithermal Au-Ag deposits of the southern Hauraki Goldfield, New Zealand (United States)

    Simpson, Mark P.; Strmic Palinkas, Sabina; Mauk, Jeffrey L.; Bodnar, Robert J.


    Microthermometry, laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), and Raman spectroscopy have been used to determine the temperature, apparent salinity, and composition of individual fluid inclusions in adularia-sericite Au-Ag epithermal veins from the Karangahake, Martha, Favona, and Waitekauri deposits, southern Hauraki goldfield, New Zealand. Quartz veins contain colloform to crustiform bands that alternate with coarse-grained quartz and amethyst. The ore mineralization occurs only in colloform to crustiform bands.

  7. Hubungan Kondisi Geologi terhadap Alterasi dan Mineralisasi Endapan Epithermal Daerah Sualan, Kecamatan Talegong, Kabupaten Garut, Provinsi Jawa Barat


    Kumala Sari, Paramitha Eka


    In exploration process of epithermal deposit, it is important to understand alteration and mineralization. The presence of alteration and mineralization zones help development of ore mineral exploration. Hydrothermal alteration is change of the chemistry, physics, mineralogy and origin textures of rocks as it interacts with the hydrothermal fluid. Alteration and mineralization zones has characteristics and certain minerals in each area.The research purposes are to determine the geological ...

  8. Experimental studies into the thermal-hydraulic performance of the VK-300 reactor based on a draft tube model

    Directory of Open Access Journals (Sweden)

    N.P. Serdun


    Full Text Available The paper presents an experimental study into the thermal-hydraulic performance of the VK-300 reactor based on a model of a single draft tube at a pressure of 3.4MPa, various flow rates and the model inlet relative enthalpies of –0.05 to 0.2. The experimental procedures include generation of a steam-water mixture circulation with a preset flow rate and a relative enthalpy through the test section at a pressure of 3.3 to 3.4MPa, and measurement of thermal-hydraulic parameters within the circuit's representative upflow and downflow lengths of practical interest. There have been confirmed the designs used to support the reactor facility serviceability and the assumptions concerning the thermal-hydraulic performance of a natural circulation circuit used in the analysis thereof. It has been shown that, across the analyzed range of the relative enthalpy values, the draft tube has an annular-dispersed or an annular flow of the steam-water mixture, both providing for the significant separation of the steam-water mixture (Ksep=0.4 at the draft tube edges and in the mixing chamber. The perforation in the upper part of the draft tubes allows the separation coefficient to be increased at the first stage and creates more favorable conditions for the second-stage separation. The measured values of the void fraction in the mixing chamber and in the draft tube are in a satisfactory agreement with calculations based on Z.L. Miropolskiy's method and the RELAP code and may be used to verify the VK-300 thermal-hydraulic codes. It has been shown that steam may enter the ring slit that simulates the annular space and reach the reactor core inlet. Further investigations need to be conducted to study this effect for its guaranteed exclusion and for the development of emergency response procedures.

  9. Prediction of the moderator temperature field in a heavy water reactor based on a cellular neural network

    Directory of Open Access Journals (Sweden)

    S.O. Starkov


    Full Text Available Reactors with heavy water coolants and moderators have been used extensively in today's power industry. Monitoring of the moderator condition plays an important role in ensuring normal operation of a power plant. A cellular neural network, the architecture of which has been adapted for hardware implementation, is proposed for use in a system for prediction of the heavy water moderator temperature. A reactor model composed in accordance with the CANDU Darlington heavy water reactor design was used to form the training sample collection and to control correct operation of the neural network structure. The sample components for the adjustment and configuration of the network topology include key parameters that characterize the energy generation process in the core. The paper considers the feasibility of the temperature prediction only for the calandria's central cross-section. To solve this problem, the cellular neural network architecture has been designed, and major parts of the digital computational element and methods for their implementation based on an FPLD have also been developed. The method is described for organizing an optical coupling between individual neural modules within the network, which enables not only the restructuring of the topology in the training process, but also the assignment of priorities for the propagation of the information signals of neurons depending on the activity in a situation analysis at the neural network structure inlet. Asynchronous activation of cells was used based on an oscillating fractal network, the basis for which was a modified ring oscillator. The efficiency of training the proposed architecture using stochastic diffusion search algorithms is evaluated. A comparative analysis of the model behavior and the results of the neural network operation have shown that the use of the neural network approach is effective in safety systems of power plants.

  10. Effects of salinity on simultaneous reduction of perchlorate and nitrate in a methane-based membrane biofilm reactor. (United States)

    Zhang, Yin; Chen, Jia-Xian; Wen, Li-Lian; Tang, Youneng; Zhao, He-Ping


    This study builds upon prior work showing that methane (CH4) could be utilized as the sole electron donor and carbon source in a membrane biofilm reactor (MBfR) for complete perchlorate (ClO4-) and nitrate (NO3-) removal. Here, we further investigated the effects of salinity on the simultaneous removal of the two contaminants in the reactor. By testing ClO4- and NO3- at different salinities, we found that the reactor performance was very sensitive to salinity. While 0.2 % salinity did not significantly affect the hydrogen-based MBfR for ClO4- and NO3- removals, 1 % salinity completely inhibited ClO4- reduction and significantly lowered NO3- reduction in the CH4-based MBfR. In salinity-free conditions, NO3- and ClO4- removal fluxes were 0.171 g N/m2-day and 0.091 g/m2-day, respectively, but NO3- removal fluxes dropped to 0.0085 g N/m2-day and ClO4- reduction was completely inhibited when the medium changed to 1 % salinity. Scanning electron microscopy (SEM) showed that the salinity dramatically changed the microbial morphology, which led to the development of wire-like cell structures. Quantitative real-time PCR (qPCR) indicated that the total number of microorganisms and abundances of functional genes significantly declined in the presence of NaCl. The relative abundances of Methylomonas (methanogens) decreased from 31.3 to 5.9 % and Denitratisoma (denitrifiers) decreased from 10.6 to 4.4 % when 1 % salinity was introduced.

  11. Transesterification of rapeseed oil for biodiesel production in trickle-bed reactors packed with heterogeneous Ca/Al composite oxide-based alkaline catalyst. (United States)

    Meng, Yong-Lu; Tian, Song-Jiang; Li, Shu-Fen; Wang, Bo-Yang; Zhang, Min-Hua


    A conventional trickle bed reactor and its modified type both packed with Ca/Al composite oxide-based alkaline catalysts were studied for biodiesel production by transesterification of rapeseed oil and methanol. The effects of the methanol usage and oil flow rate on the FAME yield were investigated under the normal pressure and methanol boiling state. The oil flow rate had a significant effect on the FAME yield for the both reactors. The modified trickle bed reactor kept over 94.5% FAME yield under 0.6 mL/min oil flow rate and 91 mL catalyst bed volume, showing a much higher conversion and operational stability than the conventional type. With the modified trickle bed reactor, both transesterification and methanol separation could be performed simultaneously, and glycerin and methyl esters were separated additionally by gravity separation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Detection system for location of fuel pebbles transported in pipes in a pebble-bed reactor based on vibration signal processing

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongbing, E-mail: [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education P. R. China, Beijing 100084 (China); Du, Dong, E-mail: [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education P. R. China, Beijing 100084 (China); Huang, An; Chang, Baohua; Han, Zandong [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education P. R. China, Beijing 100084 (China); He, Ayada [Shanghai Electric Power Generation Group Shanghai Generator Works, Shanghai 200240 (China)


    Highlights: • A detection system for locations of pebbles transported in pipes is introduced. • The detection system is based on vibration signal processing, which is original. • The characteristics of the vibration signals of the pipe are analyzed. • The experiment shows that the detection results are accurate. • The research provides an important basis for the design of the reactor. - Abstract: Pebble-bed high temperature gas-cooled reactors have many advantages such as inherent safety, high efficiency, etc., and have been considered as a candidate for Generation IV nuclear reactors. During the operation of the reactor, there are thousands of fuel pebbles transported in the pipes outside the core by gravity and helium flow. The pattern of the pipes which consist of straight and arc sections is very complex. When a fuel pebble is transported, it will constantly collide with the pipes, especially in the arc sections. The collisions will lead to the vibration of the pipes. This paper aims to provide a detection system for the location of fuel pebbles transported in pipes in a pebble-bed reactor based on vibration signal processing. Before the reactor is running, the system acquires the vibration signals of several key sections by sensors. Then the frequency characteristics of the signals are obtained by joint time–frequency analysis. When the reactor is running, the system detects the signals and processes them based on their frequency characteristics in real time. According to the results of the processing, the system can correctly judge whether the fuel pebble has passed through the section and records the time of the passing. The experiment validates the accuracy and reliability of the detection results. In this way, the operational condition of the reactor can be monitored so that the normal running of the reactor can be ensured. Additionally, the detection data are of great significance to the evaluation and optimization of the reactor performance

  13. Nuclear reactor construction with bottom supported reactor vessel (United States)

    Sharbaugh, John E.


    An improved liquid metal nuclear reactor construction has a reactor core and a generally cylindrical reactor vessel for holding a large pool of low pressure liquid metal coolant and housing the core within the pool. The reactor vessel has an open top end, a closed flat bottom end wall and a continuous cylindrical closed side wall interconnecting the top end and bottom end wall. The reactor also has a generally cylindrical concrete containment structure surrounding the reactor vessel and being formed by a cylindrical side wall spaced outwardly from the reactor vessel side wall and a flat base mat spaced below the reactor vessel bottom end wall. A central support pedestal is anchored to the containment structure base mat and extends upwardly therefrom to the reactor vessel and upwardly therefrom to the reactor core so as to support the bottom end wall of the reactor vessel and the lower end of the reactor core in spaced apart relationship above the containment structure base mat. Also, an annular reinforced support structure is disposed in the reactor vessel on the bottom end wall thereof and extends about the lower end of the core so as to support the periphery thereof. In addition, an annular support ring having a plurality of inward radially extending linear members is disposed between the containment structure base mat and the bottom end of the reactor vessel wall and is connected to and supports the reactor vessel at its bottom end on the containment structure base mat so as to allow the reactor vessel to expand radially but substantially prevent any lateral motions that might be imposed by the occurrence of a seismic event. The reactor construction also includes a bed of insulating material in sand-like granular form, preferably being high density magnesium oxide particles, disposed between the containment structure base mat and the bottom end wall of the reactor vessel and uniformly supporting the reactor vessel at its bottom end wall on the containment

  14. Multifunctional reactors

    NARCIS (Netherlands)

    Westerterp, K.R.


    Multifunctional reactors are single pieces of equipment in which, besides the reaction, other functions are carried out simultaneously. The other functions can be a heat, mass or momentum transfer operation and even another reaction. Multifunctional reactors are not new, but they have received much

  15. Reactor-based management of used nuclear fuel: assessment of major options. (United States)

    Finck, Phillip J; Wigeland, Roald A; Hill, Robert N


    This paper discusses the current status of the ongoing Advanced Fuel Cycle Initiative (AFCI) program in the U.S. Department of Energy that is investigating the potential for using the processing and recycling of used nuclear fuel to improve radioactive waste management, including used fuel. A key element of the strategies is to use nuclear reactors for further irradiation of recovered chemical elements to transmute certain long-lived highly-radioactive isotopes into less hazardous isotopes. Both thermal and fast neutron spectrum reactors are being studied as part of integrated nuclear energy systems where separations, transmutation, and disposal are considered. Radiotoxicity is being used as one of the metrics for estimating the hazard of used fuel and the processing of wastes resulting from separations and recycle-fuel fabrication. Decay heat from the used fuel and/or wastes destined for disposal is used as a metric for use of a geologic repository. Results to date indicate that the most promising options appear to be those using fast reactors in a repeated recycle mode to limit buildup of higher actinides, since the transuranic elements are a key contributor to the radiotoxicity and decay heat. Using such an approach, there could be much lower environmental impact from the high-level waste as compared to direct disposal of the used fuel, but there would likely be greater generation of low-level wastes that will also require disposal. An additional potential waste management benefit is having the ability to tailor waste forms and contents to one or more targeted disposal environments (i.e., to be able to put waste in environments best-suited for the waste contents and forms). Copyright © 2010 Health Physics Society

  16. Formation conditions of high-grade gold-silver ore of epithermal Tikhoe deposit, Russian Northeast (United States)

    Volkov, A. V.; Kolova, E. E.; Savva, N. E.; Sidorov, A. A.; Prokof'ev, V. Yu.; Ali, A. A.


    The Tikhoe epithermal deposit is located in the Okhotsk-Chukotka volcanic belt (OChVB) 250 km northeast of Magadan. Like other deposits belonging to the Ivan'insky volcanic-plutonic depression (VTD), the Tikhoe deposit is characterized by high-grade Au-Ag ore with an average Au grade of 23.13 gpt Au and Au/Ag ratio varying from 1: 1 to 1: 10. The detailed explored Tikhoe-1 orebody is accompanied by a thick (20 m) aureole of argillic alteration. Pyrite is predominant among ore minerals; galena, arsenopyrite, sphalerite, Ag sulfosalts, fahlore, electrum, and küstelite are less abundant. The ore is characterized by abundant Sebearing minerals. Cu-As geochemical specialization is noted for silver minerals. Elevated Se and Fe molar fractions of the main ore minerals are caused by their formation in the near-surface argillic alteration zone. The veins and veinlets of the Tikhoe-1 ore zone formed stepwise at a temperature of 230 to 105°C from Nachloride solution enriched in Mg and Ca cations with increasing salinity. The parameters of the ore-forming fluid correspond to those of epithermal low-sulfidation deposits and assume the formation of high-grade ore under a screening unit of volcanic rocks. In general, the composition of the ore-forming fluid fits the mineralogy and geochemistry of ore at this deposit. The similarity of the ore composition and parameters of the ore-forming fluid between the Tikhoe and Julietta deposits is noteworthy. Meanwhile, differences are mainly related to the lower temperature and fluid salinity at the Julietta deposit with respect to the Tikhoe deposit. The fluid at the Julietta deposit is depleted in most components compared with that at the Tikhoe deposit except for Sb, Cd, and Ag. The results testify to a different erosion level at the deposits as derivatives of the same ore-forming system. The large scale of the latter allows us to predict the discovery of new high-grade objects, including hidden mineralization, which is not exposed at

  17. History of the research reactor institute of Kyoto University in view of nuclear science information data base (KURRIP)

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Takayuki; Mizuma, Mitsuo (Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.); Kimura, Itsuro


    Since the Research Reactor Institute of Kyoto University was established as an inter-university research institute in 1963, a large number of cooperative research projects have been achieved by visiting scientists and its own staff in various research fields, making use of facilities centered around the Kyoto University Reactor, as well as the other experimental facilities. Ten years ago, the construction of the 'KURRIP' data base was initiated to grasp the whole aspect of the research activities at the Institute, in commemoration of its 20th anniversary. At the present time, KURRIP contains the information on 5,910 papers published for 29 years from 1963 to 1991. As this academic year is the 30th anniversary of the Institute, the history of its research activities was reviewed again using this data base. All of the publications were classified by authors's affiliations, kinds of papers, publishers, fields of studies, and research facilities used, and their historical variations are checked and discussed. (author).

  18. Calculation of reactor antineutrino spectra in TEXONO

    CERN Document Server

    Chen Dong Liang; Mao Ze Pu; Wong, T H


    In the low energy reactor antineutrino physics experiments, either for the researches of antineutrino oscillation and antineutrino reactions, or for the measurement of abnormal magnetic moment of antineutrino, the flux and the spectra of reactor antineutrino must be described accurately. The method of calculation of reactor antineutrino spectra was discussed in detail. Furthermore, based on the actual circumstances of NP2 reactors and the arrangement of detectors, the flux and the spectra of reactor antineutrino in TEXONO were worked out

  19. Phenomena-based Uncertainty Quantification in Predictive Coupled- Physics Reactor Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Marvin [Texas A & M Univ., College Station, TX (United States)


    This project has sought to develop methodologies, tailored to phenomena that govern nuclearreactor behavior, to produce predictions (including uncertainties) for quantities of interest (QOIs) in the simulation of steady-state and transient reactor behavior. Examples of such predictions include, for each QOI, an expected value as well as a distribution around this value and an assessment of how much of the distribution stems from each major source of uncertainty. The project has sought to test its methodologies by comparing against measured experimental outcomes. The main experimental platform has been a 1-MW TRIGA reactor. This is a flexible platform for a wide range of experiments, including steady state with and without temperature feedback, slow transients with and without feedback, and rapid transients with strong feedback. The original plan was for the primary experimental data to come from in-core neutron detectors. We made considerable progress toward this goal but did not get as far along as we had planned. We have designed, developed, installed, and tested vertical guide tubes, each able to accept a detector or stack of detectors that can be moved axially inside the tube, and we have tested several new detector designs. One of these shows considerable promise.

  20. Development of multi-physics code systems based on the reactor dynamics code DYN3D

    Energy Technology Data Exchange (ETDEWEB)

    Kliem, Soeren; Gommlich, Andre; Grahn, Alexander; Rohde, Ulrich [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany); Schuetze, Jochen [ANSYS Germany GmbH, Darmstadt (Germany); Frank, Thomas [ANSYS Germany GmbH, Otterfing (Germany); Gomez Torres, Armando M.; Sanchez Espinoza, Victor Hugo [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany)


    The reactor dynamics code DYN3D has been coupled with the CFD code ANSYS CFX and the 3D thermal hydraulic core model FLICA4. In the coupling with ANSYS CFX, DYN3D calculates the neutron kinetics and the fuel behavior including the heat transfer to the coolant. The physical data interface between the codes is the volumetric heat release rate into the coolant. In the coupling with FLICA4 only the neutron kinetics module of DYN3D is used. Fluid dynamics and related transport phenomena in the reactor's coolant and fuel behavior is calculated by FLICA4. The correctness of the coupling of DYN3D with both thermal hydraulic codes was verified by the calculation of different test problems. These test problems were set-up in such a way that comparison with the DYN3D stand-alone code was possible. This included steady-state and transient calculations of a mini-core consisting of nine real-size PWR fuel assemblies with ANSYS CFX/DYN3D as well as mini-core and a full core steady-state calculation using FLICA4/DYN3D. (orig.)

  1. Feasibility study of boiling water reactor core based on thorium-uranium fuel concept

    Energy Technology Data Exchange (ETDEWEB)

    Nunez-Carrera, Alejandro [Comision Nacional de Seguridad Nuclear y Salvaguardias, Dr. Barragan 779, Col Narvarte, 03020 Mexico D.F. (Mexico); Francois Lacouture, Juan Luis; Martin del Campo, Cecilia [Universidad Nacional Autonoma de Mexico, Facultad de Ingenieria, Paseo Cuauhnahuac 8532, Jiutepec, Mor. (Mexico); Espinosa-Paredes, Gilberto [Area de Ingenieria en Recursos Energeticos, Universidad Autonoma Metropolitana Iztapalapa, Apartado Postal 55-534, Mexico D.F. 09340 (Mexico)], E-mail:


    The design of a boiling water reactor (BWR) equilibrium core using the thorium-uranium (blanket-seed) concept in the same integrated fuel assembly is presented in this paper. The lattice design uses the thorium conversion capability to {sup 233}U in a BWR spectrum. A core design was developed to achieve an equilibrium cycle of one effective full power year in a standard BWR with a reload of 104 fuel assemblies designed with an average {sup 235}U enrichment of 7.5 w/o in the seed sub-lattice. The main core operating parameters were obtained. It was observed that the analyzed parameters behave like those obtained in a standard BWR. The economic analysis shows that the fuel cycle cost of the proposed core design can be competitive with a standard uranium core design. Finally, a comparison of the toxicity of the spent fuel showed that the toxicity is lower in the thorium cycle than in other fuel cycles (UO{sub 2} and MOX uranium and plutonium) in the case of the once through cycle for light water reactors (LWR)

  2. Reactor core stability monitoring method for BWR type reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kanemoto, Shigeru; Ebata, Shigeo.


    In an operation for a BWR type reactor, reactor power is usually increased or decreased by controlling both of control rods and reactor core flow rate. Under a certain condition, the reactor core is made unstable by the coupling of nuclear and thermohydrodynamic characteristics in the reactor. Therefore, the reactor power and the reactor core flow rate are changed within a range predetermined by a design calculation. However, if reactor core stability can be always measured and monitored, it is useful for safe operation, as well as an existent operation range can be extended to enable more effective operation. That is, autoregressive a coefficient is determined successively on real time based on fluctuation components of neutron flux signals. Based on the result, an amplification ratio, as a typical measure of the reactor core stability, is determined on a real time. A time constant of the successive calculation for the autoregressive coefficient can be made variable by the amplification ratio. Then, the amplification ratio is estimated at a constant accuracy. With such procedures, the reactor core stability can be monitored successively in an ON-line manner at a high accuracy, thereby enabling to improve the operation performance. (I.S.).

  3. Marine Gradients of Halogens in Moss Studied by Epithermal Neutron Activation Analysis

    CERN Document Server

    Frontasyeva, M V


    Epithermal neutron activation analysis is known to be a powerful technique for the simultaneous study of chlorine, bromine and iodine in environmental samples. In this paper it is shown to be useful to elucidate marine gradients of these elements. Examples are from a transect study in northern Norway where samples of the feather moss Hylocomium splendens were collected at distances 0-300 km from the coastline. All three elements decreased exponentially as a function of distance from the ocean in the moss samples, strongly indicating that atmospheric supply from the marine environment is the predominant source of these elements to the terrestrial ecosystem. These results are compared with similar data for surface soils along the same gradients. Comparison is also made with previous data for halogens in moss in Norway obtained by conventional NAA and covering similar transects in other geographical regions. The Cl/Br and Br/I ratios in moss showed a regular change distance from the ocean in all transects, and h...

  4. Epithermal Neutron Activation Analysis (ENAA) of Cr(VI)-reducer Basalt-inhabiting Bacteria

    CERN Document Server

    Tsibakhashvili, N Ya; Kirkesali, E I; Aksenova, N G; Kalabegishvili, T L; Murusidze, I G; Mosulishvili, L M; Holman, H Y N


    Epithermal neutron activation analysis (ENAA) has been applied to studying elemental composition of Cr(VI)-reducer bacteria isolated from polluted basalts from the Republic of Georgia. Cr(VI)-reducing ability of the bacteria was examined by electron spin resonance (ESR) demonstrating that the bacteria differ in the rates of Cr(VI) reduction. A well-pronounced correlation between the ability of the bacteria to accumulate Cr(V) and their ability to reduce Cr(V) to Cr(III) observed in our experiments is discussed. Elemental analysis of these bacteria also revealed that basalt-inhabiting bacteria are distinguished by relative contents of essential elements such as K, Na, Mg, Fe, Mn, Zn, and Co. A high rate of Cr(III) formation correlates with a high concentration of Co in the bacterium. ENAA detected some similarity in the elemental composition of the bacteria. The relatively high contents of Fe detected in the bacteria (140-340 $\\mu $g/g of dry weight) indicate bacterial adaptation to the environmental condition...

  5. Effects of salinity and COD/N on denitrification and bacterial community in dicyclic-type electrode based biofilm reactor. (United States)

    Zhai, Siyuan; Ji, Min; Zhao, Yingxin; Pavlostathis, Spyros G; Zhao, Qing


    A dicyclic-type electrode based biofilm electrode reactor (BER) was developed for advanced nitrate removal from saline municipal wastewater. The denitrification efficiency was evaluated with a synthetic feed (NO3(-)-N, 20 mg L(-1)) under different salinity and COD to nitrogen ratios (COD/N). As the salinity increased from 0% to 1.0%, the denitrification performance of both the traditional biofilm reactor (BR) and BER was inhibited; however, the BER showed better adaptation and ability to recover. The BER achieved a high nitrate removal efficiency (≥90%) at a salinity of 1.0% and a low COD/N of 2.5 (theoretical stoichiometric 2.86 ignoring microbial growth). The abundance of Methylotenera mobilis in BR and Clostridium sticklandii in BER was higher than in the initial sludge sample used as inoculum. Likewise, the abundance of napA, nirS and nosZ genes increased as the COD/N further decreased. Under high salinity stress, the BER had a higher denitrification efficiency and the consumption of the organic carbon source (i.e., methanol) was reduced compared to BR. The cooperation between heterotrophic and autotrophic denitrifiers in the BER system provides a more efficient and feasible solution for nitrate removal from saline municipal wastewater. Copyright © 2017. Published by Elsevier Ltd.

  6. A continuous stirred hydrogen-based polyvinyl chloride membrane biofilm reactor for the treatment of nitrate contaminated drinking water. (United States)

    Xia, Siqing; Zhang, YanHao; Zhong, FoHua


    A continuous stirred hydrogen-based polyvinyl chloride (PVC) membrane biofilm reactor (MBfR) was investigated to remove nitrate from the drinking water. The reactor was operated over 100 days, and the result showed that the average nitrate denitrification rate of 1.2 g NO(3)(-)-N/m(2) d and the total nitrogen (TN) removal of 95.1% were achieved with the influent nitrate concentration of 50 mg NO(3)(-)-N/L and the hydrogen pressure of 0.05 MPa. Under the same conditions, the average rate of hydrogen utilization by biofilm was 0.031 mg H(2)/cm(2) d, which was sufficient to remove 50 mg NO(3)(-)-N/L from the contaminated water with the effluent nitrate and nitrite concentrations below drinking water limit values. The average hydrogen utilization efficiency was achieved as high as 99.5%. Flux analysis demonstrated that, compared to sulfate reduction, nitrate reduction competed more strongly for hydrogen electron, and obtained more electrons in high influent nitrate loading.

  7. Optimization of process performance in a granule-based anaerobic ammonium oxidation (anammox) upflow anaerobic sludge blanket (UASB) reactor. (United States)

    Xing, Bao-Shan; Guo, Qiong; Zhang, Zheng-Zhe; Zhang, Jue; Wang, Hui-Zhong; Jin, Ren-Cun


    In this study, the individual and interactive effects of influent substrate concentration (TNinf), hydraulic retention time (HRT) and upflow velocity (Vup) on the performance of anaerobic ammonium oxidation (anammox) in a granule-based upflow anaerobic sludge blanket (UASB) reactor were investigated by employing response surface methodology (RSM) with a central composite design. The purpose of this work was to identify the optimal combination of TNinf, HRT and Vup with respect to the nitrogen removal efficiency (NRE) and nitrogen removal rate (NRR). The reduced cubic models developed for the responses indicated that the optimal conditions corresponded to a TNinf content of 644-728mgNL(-1), an HRT of 0.90-1.25h, and a Vup of 0.60-1.79mh(-1). The results of confirmation trials were similar to the predictions of the developed models. These results provide useful information for improving the nitrogen removal performance of the anammox process in a UASB reactor. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Designing visual displays and system models for safe reactor operations based on the user`s perspective of the system

    Energy Technology Data Exchange (ETDEWEB)

    Brown-VanHoozer, S.A.


    Most designers are not schooled in the area of human-interaction psychology and therefore tend to rely on the traditional ergonomic aspects of human factors when designing complex human-interactive workstations related to reactor operations. They do not take into account the differences in user information processing behavior and how these behaviors may affect individual and team performance when accessing visual displays or utilizing system models in process and control room areas. Unfortunately, by ignoring the importance of the integration of the user interface at the information process level, the result can be sub-optimization and inherently error- and failure-prone systems. Therefore, to minimize or eliminate failures in human-interactive systems, it is essential that the designers understand how each user`s processing characteristics affects how the user gathers information, and how the user communicates the information to the designer and other users. A different type of approach in achieving this understanding is Neuro Linguistic Programming (NLP). The material presented in this paper is based on two studies involving the design of visual displays, NLP, and the user`s perspective model of a reactor system. The studies involve the methodology known as NLP, and its use in expanding design choices from the user`s ``model of the world,`` in the areas of virtual reality, workstation design, team structure, decision and learning style patterns, safety operations, pattern recognition, and much, much more.

  9. Operational conditions for successful partial nitrification in a sequencing batch reactor (SBR) based on process kinetics. (United States)

    Liu, Xiaoguang; Kim, Mingu; Nakhla, George


    The objective of this study is to analyze the factors affecting the performance of partial nitrification in a sequencing batch reactor (SBR) using kinetic models. During the 4-month operation, dissolved oxygen (DO) and influent ammonia concentration were selected as operating variables to evaluate nitrite accumulation. Stable partial nitrification was observed with two conditions, influent ammonia concentration of 190 mg N/L and a DO of 0.6-3.0 mg/L as well as influent ammonia concentration of 100 mg N/L and a DO of 0.15-2.0 mg/L with intermittent aeration. At a DO of 0.6-3.0 mg O 2 /L and influent ammonia concentration of 90 mg N/L, nitrite-oxidizing bacteria growth was not suppressed. Kinetic parameters were determined or estimated with batch tests and model simulation. The kinetic model predicted the SBR performance well.

  10. An asymptotic observer-based monitoring scheme for a class of plug flow reactors. (United States)

    Aguilar-Garnica, Efrén; García-Sandoval, Juan Paulo; Aceves-Lara, César Arturo; Escalante, Froylán Mario E


    In this paper a monitoring tool is designed for a class of plug flow reactors whose mathematical model is described by a set of first-order partial differential equations with different coefficients in the convective terms. The infinite dimensional structure of such a tool is derived according to the methodology established in the design of the well-known asymptotic observer. As a consequence, it preserves the robustness of the aforementioned observer against the lack of information of the nonlinear terms involved in the model. The original structure of the estimator is then represented as a couple of integral equations by means of the method of characteristics and its behaviour is analyzed through simulation experiments. These simulations show that the mean square observation error is 0.58 when the proposed observer is implemented in a solid-waste anaerobic digestion process to estimate the evolution of biomass concentration.

  11. Spatial and model-order based reactor signal analysis methodology for BWR core stability evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dokhane, A. [Paul Scherrer Institute, Laboratory for Reactor Physics and Systems Behavior, CH-5232 Villigen PSI (Switzerland) and Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)]. E-mail:; Ferroukhi, H. [Paul Scherrer Institute, Laboratory for Reactor Physics and Systems Behavior, CH-5232 Villigen PSI (Switzerland)]. E-mail:; Zimmermann, M.A. [Paul Scherrer Institute, Laboratory for Reactor Physics and Systems Behavior, CH-5232 Villigen PSI (Switzerland); Aguirre, C. [Kernkraftwerk Leibstadt, CH-5325 Leibstadt (Switzerland)


    A new methodology for the boiling water reactor core stability evaluation from measured noise signals has been recently developed and adopted at the Paul Scherrer Institut (PSI). This methodology consists in a general reactor noise analysis where as much as possible information recorded during the tests is investigated prior to determining core representative stability parameters, i.e. the decay ratio (DR) and the resonance frequency, along with an associated estimate of the uncertainty range. A central part in this approach is that the evaluation of the core stability parameters is performed not only for a few but for ALL recorded neutron flux signals, allowing thereby the assessment of signal-related uncertainties. In addition, for each signal, three different model-order optimization methods are systematically employed to take into account the sensitivity upon the model-order. The current methodology is then applied to the evaluation of the core stability measurements performed at the Leibstadt NPP, Switzerland, during cycles 10, 13 and 19. The results show that as the core becomes very stable, the method-related uncertainty becomes the major contributor to the overall uncertainty range while for intermediate DR values, the signal-related uncertainty becomes dominant. However, as the core stability deteriorates, the method-related and signal-related spreads have similar contributions to the overall uncertainty, and both are found to be small. The PSI methodology identifies the origin of the different contributions to the uncertainty. Furthermore, in order to assess the results obtained with the current methodology, a comparative study is for completeness carried out with respect to results from previously developed and applied procedures. The results show a good agreement between the current method and the other methods.

  12. NUCLEAR REACTOR (United States)

    Miller, H.I.; Smith, R.C.


    This patent relates to nuclear reactors of the type which use a liquid fuel, such as a solution of uranyl sulfate in ordinary water which acts as the moderator. The reactor is comprised of a spherical vessel having a diameter of about 12 inches substantially surrounded by a reflector of beryllium oxide. Conventionnl control rods and safety rods are operated in slots in the reflector outside the vessel to control the operation of the reactor. An additional means for increasing the safety factor of the reactor by raising the ratio of delayed neutrons to prompt neutrons, is provided and consists of a soluble sulfate salt of beryllium dissolved in the liquid fuel in the proper proportion to obtain the result desired.

  13. Modification of the radial beam port of ITU TRIGA Mark II research reactor for BNCT applications. (United States)

    Akan, Zafer; Türkmen, Mehmet; Çakir, Tahir; Reyhancan, İskender A; Çolak, Üner; Okka, Muhittin; Kiziltaş, Sahip


    This paper aims to describe the modification of the radial beam port of ITU (İstanbul Technical University) TRIGA Mark II research reactor for BNCT applications. Radial beam port is modified with Polyethylene and Cerrobend collimators. Neutron flux values are measured by neutron activation analysis (Au-Cd foils). Experimental results are verified with Monte Carlo results. The results of neutron/photon spectrum, thermal/epithermal neutron flux, fast group photon fluence and change of the neutron fluxes with the beam port length are presented. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. NUCLEAR REACTOR (United States)

    Grebe, J.J.


    High temperature reactors which are uniquely adapted to serve as the heat source for nuclear pcwered rockets are described. The reactor is comprised essentially of an outer tubular heat resistant casing which provides the main coolant passageway to and away from the reactor core within the casing and in which the working fluid is preferably hydrogen or helium gas which is permitted to vaporize from a liquid storage tank. The reactor core has a generally spherical shape formed entirely of an active material comprised of fissile material and a moderator material which serves as a diluent. The active material is fabricated as a gas permeable porous material and is interlaced in a random manner with very small inter-connecting bores or capillary tubes through which the coolant gas may flow. The entire reactor is divided into successive sections along the direction of the temperature gradient or coolant flow, each section utilizing materials of construction which are most advantageous from a nuclear standpoint and which at the same time can withstand the operating temperature of that particular zone. This design results in a nuclear reactor characterized simultaneously by a minimum critiral size and mass and by the ability to heat a working fluid to an extremely high temperature.

  15. Neutron spectra at two beam ports of a TRIGA Mark III reactor loaded with HEU fuel. (United States)

    Vega-Carrillo, H R; Hernández-Dávila, V M; Aguilar, F; Paredes, L; Rivera, T


    The neutron spectra have been measured in two beam ports, one radial and another tangential, of the TRIGA Mark III nuclear reactor from the National Institute of Nuclear Research in Mexico. Measurements were carried out with the reactor core loaded with high enriched uranium fuel. Two reactor powers, 5 and 10 W, were used during neutron spectra measurements using a Bonner sphere spectrometer with a (6)LiI(Eu) scintillator and 2, 3, 5, 8, 10 and 12 in.-diameter high-density polyethylene spheres. The neutron spectra were unfolded using the NSDUAZ unfolding code. For each spectrum total flux, mean energy and ambient dose equivalent were determined. Measured spectra show fission, epithermal and thermal neutrons, being harder in the radial beam port. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Finite element based stress analysis of graphite component in high temperature gas cooled reactor core using linear and nonlinear irradiation creep models

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish, E-mail:; Majumdar, Saurindranath


    Highlights: • High temperature gas cooled reactor. • Finite element based stress analysis. • H-451 graphite. • Irradiation creep model. • Graphite reflector stress analysis. - Abstract: Irradiation creep plays a major role in the structural integrity of the graphite components in high temperature gas cooled reactors. Finite element procedures combined with a suitable irradiation creep model can be used to simulate the time-integrated structural integrity of complex shapes, such as the reactor core graphite reflector and fuel bricks. In the present work a comparative study was undertaken to understand the effect of linear and nonlinear irradiation creep on results of finite element based stress analysis. Numerical results were generated through finite element simulations of a typical graphite reflector.

  17. Derived release limits for the greek research reactor site based on a diagnostic atmospheric modeling system for irregular terrain. (United States)

    Varvayanni, M; Catsaros, N; Antonopoulos-Domis, M


    The upper limits for the rate of release of radionuclides into the atmosphere, i.e., the "derived release limits," are calculated for the Greek Research Reactor (GRR-1) in order to determine possible operational schemes compatible with the effective dose limits for the general population. GRR-1 is located at the northwestern foot of Hymettos Mountain and at the eastern border of the urbanized area of Athens basin. Due to the topographic complexity of the region, the meteorological and atmospheric dispersion calculations were based on a numerical modeling system that is especially designed to work over irregular terrains by using a prismatic unstructured grid. The calculation of derived release limits was made using guidelines and methods that conform to the system of dose limits prescribed by the European radiation protection regulations.

  18. Portovelo: a volcanic-hosted epithermal vein-system in Ecuador, South America (United States)

    van Thournout, F.; Salemink, J.; Valenzuela, G.; Merlyn, M.; Boven, A.; Muchez, P.


    The Portovelo epithermal vein-system in southwestern Ecuador has produced more than 120 tons of gold and about 250 tons of silver. The veins result from hydrothermal processes close to a Miocene volcano which produced an andesitic to dacitic sequence followed by collapse and post-collapse rhyolitec activity which generated most of the alteration and mineralization. Three main structural segments are defined by NW-trending strike-slip faults, which show later stages of vertical movement. These faults are responsible for development of an extensive N-S dilatational jog within andesitic rocks, which acted as the main host to ore-deposition. A large-scale propylitic aureole surrounds a quartz-chloritesericite-adularia core, centered on the rhyolites, within a system of collapse-related ring-structures. A quartz-chlorite-sericite-adularia-calcite assemblage is the most common wall-rock alteration close to the veins. The size (4 × 15 km) and vertical range (1400 m) of the vein-system is exceptional. Alteration, textures and mineral assemblage, including a quartz-calcite gangue, sulfides, abundant sulfosalts and free gold (electrum), are quite typical of an adularia-sericite epithermal deposit. Spatially, the mineralization is arranged in three zones. In addition, three successive stages can be distinguished. The bulk of economic mineralization was deposited during the second stage, in association with a clear quartz and calcite gangue. Tm-ice and Tm-clath data of fluid inclusions in the clear quartz indicate a high salinity (˜ 10.5 eq. wt% NaCI). The homogenization temperatures of fluid inclusions in the gangue minerals and in the altered host-rocks vary between 180° and 310°C. Quartz δ 18O-values from hydrothermally altered wall-rocks reflect the original isotopic values of the latter. These values show a narrower range in vein quartz ( δO18 between +7.7‰ and +11.57‰ SMOW). In addition, the δO18 values of the vein quartz increase systematically with

  19. Proterozoic low-sulfidation epithermal Au-Ag mineralization in the Mallery Lake area, Nunavut, Canada (United States)

    Turner, William; Richards, Jeremy; Nesbitt, Bruce; Muehlenbachs, Karlis; Biczok, John


    The Mallery Lake area contains pristine examples of ancient precious metal-bearing low-sulfidation epithermal deposits. The deposits are hosted by rhyolitic flows of the Early Proterozoic Pitz Formation, but are themselves apparently of Middle Proterozoic age. Gold mineralization occurs in stockwork quartz veins that cut the rhyolites, and highest gold grades (up to 24 g/t over 30 cm) occur in the Chalcedonic Stockwork Zone. Quartz veining occurs in two main types: barren A veins, characterized by fine- to coarse-grained comb quartz, with fluorite, calcite, and/or adularia; and mineralized B veins, characterized by banded chalcedonic silica and fine-grained quartz, locally intergrown with fine-grained gold or electrum. A third type of quartz vein (C), which crosscuts B veins at one locality, is characterized by microcrystalline quartz intergrown with fine-grained hematite and rare electrum. Fluid inclusions in the veins occur in two distinct assemblages. Assemblage 1 inclusions represent a moderate temperature (Th=150 to 220 °C), low salinity (~1 eq. wt% NaCl, with trace CO2), locally boiling fluid; this fluid type is found in both A and B veins and is thought to have been responsible for Au-Ag transport and deposition. Assemblage 2 inclusions represent a lower temperature (Th=90 to 150 °C), high salinity calcic brine (23 to 31 wt% CaCl2-NaCl), which occurs as primary inclusions only in the barren A veins. Assemblage 1 and 2 inclusions occur in alternating quartz growth bands in the A-type veins, where they appear to represent alternating fluxes of dilute fluid and local saline groundwater. No workable primary fluid inclusions were observed in the C veins. The A-vein quartz yields δ18O values from 8.3 to 14.5‰ (average=10.9±1.7‰ [1σ], n=30), whereas δ18O values for B-vein quartz range from 11.2 to 14.0‰ (average=13.0±0.9‰, n=12). Calculated δ18OH2O values for the dilute mineralizing fluid from B veins range from -2.6 to 0.2‰ (average=-0.8±0.9

  20. Lithologic controls on mineralization at the Lagunas Norte high-sulfidation epithermal gold deposit, northern Peru (United States)

    Cerpa, Luis M.; Bissig, Thomas; Kyser, Kurt; McEwan, Craig; Macassi, Arturo; Rios, Hugo W.


    The 13.1-Moz high-sulfidation epithermal gold deposit of Lagunas Norte, Alto Chicama District, northern Peru, is hosted in weakly metamorphosed quartzites of the Upper Jurassic to Lower Cretaceous Chimú Formation and in overlying Miocene volcanic rocks of dacitic to rhyolitic composition. The Dafne and Josefa diatremes crosscut the quartzites and are interpreted to be sources of the pyroclastic volcanic rocks. Hydrothermal activity was centered on the diatremes and four hydrothermal stages have been defined, three of which introduced Au ± Ag mineralization. The first hydrothermal stage is restricted to the quartzites of the Chimú Formation and is characterized by silice parda, a tan-colored aggregate of quartz-auriferous pyrite-rutile ± digenite infilling fractures and faults, partially replacing silty beds and forming cement of small hydraulic breccia bodies. The δ34S values for pyrite (1.7-2.2 ‰) and digenite (2.1 ‰) indicate a magmatic source for the sulfur. The second hydrothermal stage resulted in the emplacement of diatremes and the related volcanic rocks. The Dafne diatreme features a relatively impermeable core dominated by milled slate from the Chicama Formation, whereas the Josefa diatreme only contains Chimú Formation quartzite clasts. The third hydrothermal stage introduced the bulk of the mineralization and affected the volcanic rocks, the diatremes, and the Chimú Formation. In the volcanic rocks, classic high-sulfidation epithermal alteration zonation exhibiting vuggy quartz surrounded by a quartz-alunite and a quartz-alunite-kaolinite zone is observed. Company data suggest that gold is present in solid solution or micro inclusions in pyrite. In the quartzite, the alteration is subtle and is manifested by the presence of pyrophyllite or kaolinite in the silty beds, the former resulting from relatively high silica activities in the fluid. In the quartzite, gold mineralization is hosted in a fracture network filled with coarse alunite

  1. First evidence of epithermal gold occurrences in the SE Afar Rift, Republic of Djibouti (United States)

    Moussa, N.; Fouquet, Y.; Le Gall, B.; Caminiti, A. M.; Rolet, J.; Bohn, M.; Etoubleau, J.; Delacourt, C.; Jalludin, M.


    The geology of the Republic of Djibouti, in the SE Afar Triangle, is characterized by intense tectonic and bimodal volcanic activity that began as early as 25-30 Ma. Each magmatic event was accompanied by hydrothermal activity. Mineralization generally occurs as gold-silver bearing chalcedony veins and is associated with felsic volcanism. Eighty samples from mineralized hydrothermal chalcedony, quartz ± carbonate veins and breccias were studied from ten sites representing four major volcanic events that range in age from early Miocene to the present. The most recent veins are controlled by fractures at the edges of grabens established during the last 4 Myr. Gold in excess of 200 ppb is present in 30% of the samples, with values up to 16 ppm. Mineralogical compositions allowed us to identify different types of mineralization corresponding to different depths in the hydrothermal system: (1) surface and subsurface mineralization characterized by carbonate chimneys, gypsum, silica cap and quartz ± carbonate veins that are depleted in metals and Au; (2) shallow banded chalcedony ± adularia veins related to boiling that contain up to 16 ppm Au, occurring as native gold and electrum with pyrite, and tetradymite; (3) quartz veins with sulfides, and (4) epidote alteration in the deepest hydrothermal zones. Samples in which pyrite is enriched in As tend to have a high Au content. The association with bimodal volcanism, the occurrence of adularia and the native Au and electrum in banded chalcedony veins are typical of epithermal systems and confirm that this type of mineralization can occur in a young intracontinental rift system.

  2. Mineralogy and geochemistry of El Dorado epithermal gold deposit, El Sauce district, central-northern Chile (United States)

    Carrillo-Rosúa, J.; Morales-Ruano, S.; Morata, D.; Boyce, A. J.; Belmar, M.; Fallick, A. E.; Fenoll Hach-Alí, P.


    The El Dorado Au-Cu deposit is located in an extensive intra-caldera zone of hydrothermal alteration affecting Upper Cretaceous andesites of the Los Elquinos Formation at La Serena (≈ 29°47'S Lat., 70°43'W Long., Chile). Quartz-sulfide veins of economic potential are hosted by N25W and N20E fault structures associated with quartz-illite alteration (+supergene kaolinite). The main ore minerals in the deposit are pyrite, chalcopyrite ± fahlore (As/(As + Sb): 0.06-0.98), with electrum, sphalerite, galena, bournonite-seligmanite (As/(As + Sb): 0.21-0.31), marcasite, pyrrhotite being accessory phases. Electrum, with an Ag content between 32 and 37 at.%, occurs interstitial to pyrite aggregates or along pyrite fractures. Pyrite commonly exhibits chemical zonation with some zones up to 1.96 at.% As. Electron probe microanalyses of pyrite indicate that As-rich zones do not exhibit detectable Au values. Fluid inclusion microthermometry shows homogenization temperatures between 130 and 352 °C and salinities between 1.6 and 6.9 wt.% NaCl eq. Isotope data for quartz, ankerite and phyllosilicates and estimated temperatures show that δ18O and δD for the hydrothermal fluids were between 3 and 10‰ and between -95 and -75‰, respectively. These results suggest the mineralizing fluids were a mixture of meteoric and magmatic waters. An epithermal intermediate-sulfidation model is proposed for the formation of the El Dorado deposit.

  3. Chelpo - Kalate Choubak, Kashmar, NE Iran: an epithermal Sb-As deposit (United States)

    Hanna, B.; Mogk, D. W.; Ghaderi, M.; Narimani, A.


    Chelpo - Kalate Choubak Sb-As deposit is located 65 km north of Kashmar (Khorasan Province), northeast Iran. The area is a part of Central Iran structural zone. Paleogene gray-red marls and interbeds of tuff, sandstone and conglomerate comprise the main part of lithological sequence in the area. Paleogene units are intruded by monzonitic and micro-granitic plutons. Mafic dykes (diabasic-andesitic) are also present. Paleogene sequences are intensely folded and faulted making complex anticline and syncline structures. The deposit consists of veins and veinlets. The host rocks to mineralization are the Paleogene unit and micro-granites. The mineralized zone can be traced for about 6 km from Chelpo village in the east to Kalate Choubak village to the west. Argillic, pyritic and small amounts of silicic alterations accompany the mineralization. The mineralogy in the veins is simple and includes stibnite, stibiconite, kermesite, realgar, orpiment, pyrite, iron-hydroxide, calcite, gypsum and a small amount of quartz. Crustifide, open space filling, comb and colloform textures are present in the veins. Electron microprobe study was conducted to identify gold in stibnite, pyrite and realgar, but only As was detected in pyrite and stibnite. Geochemical studies of the drill hole cores show a positive correlation between Au and Sb and negative correlation between Au and As. Gold content increases slightly with depth. On the basis of evidences such as geometry, texture and structure, alteration, mineralogy, geochemistry and paragenesis, Chelpo - Kalateh Choubak can be regarded as an epithermal deposit. It seems that the veins formed as a result of hydrothermal system driven by subvolcanic microgranites.

  4. Natural precursor based hydrothermal synthesis of sodium carbide for reactor applications (United States)

    Swapna, M. S.; Saritha Devi, H. V.; Sebastian, Riya; Ambadas, G.; Sankararaman, S.


    Carbides are a class of materials with high mechanical strength and refractory nature which finds a wide range of applications in industries and nuclear reactors. The existing synthesis methods of all types of carbides have problems in terms of use of toxic chemical precursors, high-cost, etc. Sodium carbide (Na2C2) which is an alkali metal carbide is the least explored one and also that there is no report of low-cost and low-temperature synthesis of sodium carbide using the eco-friendly, easily available natural precursors. In the present work, we report a simple low-cost, non-toxic hydrothermal synthesis of refractory sodium carbide using the natural precursor—Pandanus. The formation of sodium carbide along with boron carbide is evidenced by the structural and morphological characterizations. The sample thus synthesized is subjected to field emission scanning electron microscopy (FESEM), x-ray powder diffraction (XRD), ultraviolet (UV)—visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman, and photoluminescent (PL) spectroscopic techniques.

  5. Development of Subspace-based Hybrid Monte Carlo-Deterministric Algorithms for Reactor Physics Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Khalik, Hany S. [North Carolina State Univ., Raleigh, NC (United States); Zhang, Qiong [North Carolina State Univ., Raleigh, NC (United States)


    The development of hybrid Monte-Carlo-Deterministic (MC-DT) approaches, taking place over the past few decades, have primarily focused on shielding and detection applications where the analysis requires a small number of responses, i.e. at the detector locations(s). This work further develops a recently introduced global variance reduction approach, denoted by the SUBSPACE approach is designed to allow the use of MC simulation, currently limited to benchmarking calculations, for routine engineering calculations. By way of demonstration, the SUBSPACE approach is applied to assembly level calculations used to generate the few-group homogenized cross-sections. These models are typically expensive and need to be executed in the order of 103 - 105 times to properly characterize the few-group cross-sections for downstream core-wide calculations. Applicability to k-eigenvalue core-wide models is also demonstrated in this work. Given the favorable results obtained in this work, we believe the applicability of the MC method for reactor analysis calculations could be realized in the near future.

  6. Biodegradation of toluene vapor in coir based upflow packed bed reactor by Trichoderma asperellum isolate. (United States)

    Gopinath, M; Mohanapriya, C; Sivakumar, K; Baskar, G; Muthukumaran, C; Dhanasekar, R


    In the present study, a new biofiltration system involving a selective microbial strain isolated from aerated municipal sewage water attached with coir as packing material was developed for toluene degradation. The selected fungal isolate was identified as Trichoderma asperellum by 16S ribosomal RNA (16S rRNA) sequencing method, and pylogenetic tree was constructed using BLASTn search. Effect of various factors on growth and toluene degradation by newly isolated T. asperellum was studied in batch studies, and the optimum conditions were found to be pH 7.0, temperature 30 °C, and initial toluene concentration 1.5 (v/v)%. Continuous removal of gaseous toluene was monitored in upflow packed bed reactor (UFPBR) using T. asperellum. Effect of various parameters like column height, flow rate, and the inlet toluene concentration were studied to evaluate the performance of the biofilter. The maximum elimination capacity (257 g m(-3) h(-1)) was obtained with the packing height of 100 cm with the empty bed residence time of 5 min. Under these optimum conditions, the T. asperellum showed better toluene removal efficiency. Kinetic models have been developed for toluene degradation by T. asperellum using macrokinetic approach of the plug flow model incorporated with Monod model.

  7. Retrofitting of TRIGA Mark I reactor with a microprocessor-based neutron monitoring system

    Energy Technology Data Exchange (ETDEWEB)

    Blotcky, A.J.; Claassen, J.P.


    The 20-kW TRIGA Mark I nuclear reactor at the Omaha Department of Veterans Affairs Medical Center was started up on June 26, 1959, and has been operating daily ever since with its original vacuum tube electronics. In 1965, the two 6.25-in. Varian strip chart recorders were replaced with a single Westronic dual-pen vacuum tube recorder. With the increasing role that solid-state devices have played in current instrumentation, it has been difficult to procure replacement balancing motors, choppers, and vacuum tubes for the Westronic recorder. Because of the age of some of the other component parts in the recorder, such as resistors, electrolytic capacitors, and gears, the authors found themselves continually repairing the instrument in order to decrease noise and dead band. Because the other elements of the console were still operating almost trouble free, they decided to replace only the neutron monitoring system. For the 1.7 yr that the system has been in operation, the system has demonstrated reliability in operation.

  8. Colloidal and physical transport textures exhibited by electrum and naumannite in bonanza epithermal veins from western USA, and their significance (United States)

    Saunders, James A.; Vikre, Peter G.; Unger, Derick L.; Beasley, Lee


    It is reasonably clear that disequilibrium or “far-from equilibrium” conditions lead to the formation of silica colloids and their deposition in many epithermal deposits. This implies ore-forming solutions had elevated concentrations of dissolved silica, well in excess of amorphous silica saturation. We have previously demonstrated that such colloidal silica particles were deposited in epithermal veins as silica gels and opal, which may later progress along a path to crystallize into more thermodynamically favored (less-soluble) silica phases such as quartz and chalcedony. Also, in some deposits, amorphous silica is co-deposited with precious-metal minerals, such as electrum in the banded super-bonanza ores of the Sleeper deposit (NV). Ore-mineral textures from some western USA bonanza epithermal ores indicate that two precious-metal phases (electrum and naumannite, Ag2Se) form colloidal particles that are transported by ore-forming fluids and are deposited either by aggregation (by sticking to other precious metal-particles) to make dendrites, or are deposited on the “lee” side of protrusion along vein walls (or perhaps by both processes). We can infer by analogy to silica that this also implies that ore-forming solutions contained elevated (supersaturated) dissolved concentrations of both gold and silver that formed colloidal particles under disequilibrium (often chaotic) conditions. Thus physical transport and deposition textures seem to indicate the presence of strongly precious-metal-enriched ore forming fluids, which led to (not surprisingly) the bonanza grades of these remarkable ores. What causes such a precious-metal-rich solution is debatable, but that is the subject of our continued investigations.

  9. Design of an equilibrium nucleus of a BWR type reactor based in a Thorium-Uranium fuel; Diseno de un nucleo de equilibrio de un reactor tipo BWR basado en un combustible de Torio-Uranio

    Energy Technology Data Exchange (ETDEWEB)

    Francois, J.L.; Nunez C, A. [Laboratorio de Analisis en Ingenieria de Reactores Nucleares, Facultad de Ingenieria-UNAM, Paseo Cuauhnahuac 8532, Jiutepec, Morelos (Mexico)


    In this work the design of the reactor nucleus of boiling water using fuel of thorium-uranium is presented. Starting from an integral concept based in a type cover-seed assemble is carried out the design of an equilibrium reload for the nucleus of a reactor like that of the Laguna Verde Central and its are analyzed some of the main design variables like the cycle length, the reload fraction, the burnt fuel, the vacuum distribution, the generation of lineal heat, the margin of shutdown, as well as a first estimation of the fuel cost. The results show that it is feasible to obtain an equilibrium reload, comparable to those that are carried out in the Laguna Verde reactors, with a good behavior of those analyzed variables. The cost of the equilibrium reload designed with the thorium-uranium fuel is approximately 2% high that the uranium reload producing the same energy. It is concluded that it is convenient to include burnable poisons, type gadolinium, in the fuel with the end of improving the reload design, the fuel costs and the margin of shutdown. (Author)

  10. Diverse subaerial and sublacustrine hot spring settings of the Cerro Negro epithermal system (Jurassic, Deseado Massif), Patagonia, Argentina (United States)

    Guido, Diego M.; Campbell, Kathleen A.


    The Late Jurassic (~ 150 Ma) Cerro Negro volcanic-epithermal-geothermal system (~ 15 km2 area), Deseado Massif, Patagonia, Argentina, includes two inferred volcanic emission centers characterized by rhyolitic domes linked along NW-SE regional faults that are associated with deeper level Au/Ag mineralization to the NW, and with shallow epithermal quartz veins and mainly travertine surface hot spring manifestations to the SE. Some travertines are silica-replaced, and siliceous and mixed silica-carbonate geothermal deposits also are found. Five hot spring-related facies associations were mapped in detail, which show morphological and textural similarities to Pleistocene-Recent geothermal deposits at Yellowstone National Park (U.S.A.), the Kenya Rift Valley, and elsewhere. They are interpreted to represent subaerial travertine fissure ridge/mound deposits (low-flow spring discharge) and apron terraces (high-flow spring discharge), as well as mixed silica-carbonate lake margin and shallow lake terrace vent-conduit tubes, stromatolitic mounds, and volcano-shaped cones. The nearly 200 mapped fossil vent-associated deposits at Cerro Negro are on a geographical and numerical scale comparable with subaerial and sublacustrine hydrothermal vents at Mammoth Hot Springs, and affiliated with Yellowstone Lake, respectively. Overall, the Cerro Negro geothermal system yields paleoenvironmentally significant textural details of variable quality, owing to both the differential preservation potential of particular subaerial versus subaqueous facies, as well as to the timing and extent of carbonate diagenesis and silica replacement of some deposits. For example, the western fault associated with the Eureka epithermal quartz vein facilitated early silicification of the travertine deposits in the SE volcanic emission center, thereby preserving high-quality, microbial macro- and micro-textures of this silica-replaced "pseudosinter." Cerro Negro provides an opportunity to reconstruct

  11. Application of Epithermal Neutron Activation Analysis to Investigate Accumulation and Adsorption of Mercury by Spirulina platensis Biomass

    CERN Document Server

    Mosulishvili, L M; Khizanishvili, A I; Frontasyeva, M V; Kirkesali, E I; Aksenova, N G


    Epithermal neutron activation analysis was used to study interaction of blue-green alga Spirulina platensis with toxic metal mercury. Various concentrations of Hg(II) were added to cell cultures in a nutrient medium. The dynamics of accumulation of Hg was investigated over several days in relation to Spirulina biomass growth. The process of Hg adsorption by Spirulina biomass was studied in short-time experiments. The isotherm of adsorption was carried out in Freindlich coordinates. Natural Spirulina biomass has potential to be used in the remediation of sewage waters at Hg concentrations \\sim 100 {\\mu}g/l.

  12. Development of the fast reactor group constant set JFS-3-J3.2R based on the JENDL-3.2

    CERN Document Server

    Chiba, G


    It is reported that the fast reactor group constant set JFS-3-J3.2 based on the newest evaluated nuclear data library JENDL3.2 has a serious error in the process of applying the weighting function. As the error affects greatly nuclear characteristics, and a corrected version of the reactor constant set, JFS-3-J3.2R, was developed, as well as lumped FP cross sections. The use of JFS-3-J3.2R improves the results of analyses especially on sample Doppler reactivity and reaction rate in the blanket region in comparison with those obtained using the JFS-3-J3.2.

  13. The research of the hot spot temperature of the dry-type reactor winding based on the inversed-heat conduction model (United States)

    Lai, Wenqing; Luo, Hanwu; Li, Wenpeng; Cao, Yongdong; Ye, Ligang; Guo, Kai; Ding, Renjie; Wang, Yongqiang


    There is an important significance for the design and the life time evaluation of the dry-type reactor based on the hot-spot temperature. At present the methods of obtaining the reactor's hot-spot temperature are as follows: direct measurement and numerical calculation. Direct measurement can obtain winding hot spot temperature through the optical fiber temperature sensor or thermocouple; the numerical calculation mostly uses the finite element or finite difference method. This paper establishes the inversed-heat transfer calculation model of high and low voltage winding using the high-precision infrared sensor to acquire the temperature of the high voltage winding. Through calculation the temperature distribution of the low voltage winding has been obtained and the hottest spot temperature of the winding is much closed to the result obtained by the IEEE model in a certain range. It provides a new method for the acquisition of the hottest spot temperature of the dry-type reactor.

  14. Reactor Neutrinos

    CERN Document Server

    Lasserre, T; Lasserre, Thierry; Sobel, Henry W.


    We review the status and the results of reactor neutrino experiments, that toe the cutting edge of neutrino research. Short baseline experiments have provided the measurement of the reactor neutrino spectrum, and are still searching for important phenomena such as the neutrino magnetic moment. They could open the door to the measurement of coherent neutrino scattering in a near future. Middle and long baseline oscillation experiments at Chooz and KamLAND have played a relevant role in neutrino oscillation physics in the last years. It is now widely accepted that a new middle baseline disappearance reactor neutrino experiment with multiple detectors could provide a clean measurement of the last undetermined neutrino mixing angle theta13. We conclude by opening on possible use of neutrinos for Society: NonProliferation of Nuclear materials and Geophysics.

  15. NEUTRONIC REACTORS (United States)

    Wigner, E.P.; Young, G.J.


    A method is presented for loading and unloading rod type fuel elements of a neutronic reactor of the heterogeneous, solld moderator, liquid cooled type. In the embodiment illustrated, the fuel rods are disposed in vertical coolant channels in the reactor core. The fuel rods are loaded and unloaded through the upper openings of the channels which are immersed in the coolant liquid, such as water. Unloading is accomplished by means of a coffer dam assembly having an outer sleeve which is placed in sealing relation around the upper opening. A radiation shield sleeve is disposed in and reciprocable through the coffer dam sleeve. A fuel rod engaging member operates through the axial bore in the radiation shield sleeve to withdraw the fuel rod from its position in the reactor coolant channel into the shield, the shield snd rod then being removed. Loading is accomplished in the reverse procedure.

  16. An operational protocol for facilitating start-up of single-stage autotrophic nitrogen-removing reactors based on process stoichiometry

    DEFF Research Database (Denmark)

    Mutlu, Ayten Gizem; Vangsgaard, Anna Katrine; Sin, Gürkan


    Start-up and operation of single-stage nitritation–anammox sequencing batch reactors (SBRs) for completely autotrophic nitrogen removal can be challenging and far from trivial. In this study, a step-wise procedure is developed based on stoichiometric analysis of the process performance from nitro...

  17. In-situ metrology in multiwafer reactors during MOVPE of AIN-based UV-LEDs (Conference Presentation) (United States)

    Knauer, Arne; Brunner, Frank; Kolbe, Tim; Hagedorn, Sylvia; Kueller, Viola; Weyers, Markus


    UV-LEDs are of great interest for applications like disinfection, gas sensing, and phototherapy. The cost sensitive LEDs are commonly grown by MOVPE on transparent AlN/sapphire templates. The large thermal and lattice mismatch between AlN and sapphire generates a very high dislocation density (DD) and causes big challenges in strain management. The threading dislocation density should be reduced to the order of low 108cm-2 for high internal efficiency of the AlGaN based UV-LED structures. The TDD will be reduced mainly by dislocation annihilation during the growth of thick Al(Ga)N layers, which is a challenge in terms of strain management. We present how in-situ reflectometry and curvature measurement (EpiCurveTT(at)LayTec) in commercial multiwafer growth reactors helps to optimize the growth processes concerning growth rates, surface roughening and avoidance of layer cracking on 2inch substrates and enhance the reproducibility of epitaxial growth. The growth of up to 3 μm thick planar AlN templates and up-to 10 μm thick AlN/sapphire templates by epitaxial lateral overgrowth of stripe patterned templates for UV-C LED structures will be highlighted. The implementation of different types of AlN/GaN superlattices for the subsequent growth of up to 5μm thick Al0.5Ga0.5N layer for UVB LED structures will be shown. Correlations to ex-situ measurements like X-ray diffraction and TEM analysis of defects in the LED structures will be shown. Some challenges of in-situ control through very narrow viewports as in Close Coupled Showerhead reactors will be discussed as well as the influence of silicon doping on curvature and dislocation density in Al(Ga)N layers.

  18. APPLICATIONS OF LASERS AND OTHER TOPICS IN LASER PHYSICS AND TECHNOLOGY: Hybrid reactor based on laser thermonuclear fusion (United States)

    Basov, N. G.; Belousov, N. I.; Grishunin, P. A.; Kalmykov, Yu K.; Lebo, I. G.; Rozanov, Vladislav B.; Sklizkov, G. V.; Subbotin, V. I.; Finkel'shteĭn, K. I.; Kharitonov, V. V.; Sherstnev, K. B.


    A physicotechnical and parametric analysis is used as the basis for a conceptual design of a thermonuclear inertial-confinement hybrid reactor as a breeder of fuel for fission nuclear power stations. It is proposed to use a laser as a driver in this reactor.

  19. Comparison of Kinetic-based and Artificial Neural Network Modeling Methods for a Pilot Scale Vacuum Gas Oil Hydrocracking Reactor

    Directory of Open Access Journals (Sweden)

    Sepehr Sadighi


    Full Text Available An artificial neural network (ANN and kinetic-based models for a pilot scale vacuum gas oil (VGO hydrocracking plant are presented in this paper. Reported experimental data in the literature were used to develop, train, and check these models. The proposed models are capable of predicting the yield of all main hydrocracking products including dry gas, light naphtha, heavy naphtha, kerosene, diesel, and unconverted VGO (residue. Results showed that kinetic-based and artificial neural models have specific capabilities to predict yield of hydrocracking products. The former is able to accurately predict the yield of lighter products, i.e. light naphtha, heavy naphtha and kerosene. However, ANN model is capable of predicting yields of diesel and residue with higher precision. The comparison shows that the ANN model is superior to the kinetic-base models.  © 2013 BCREC UNDIP. All rights reservedReceived: 9th April 2013; Revised: 13rd August 2013; Accepted: 18th August 2013[How to Cite: Sadighi, S., Zahedi, G.R. (2013. Comparison of Kinetic-based and Artificial Neural Network Modeling Methods for a Pilot Scale Vacuum Gas Oil Hydrocracking Reactor. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (2: 125-136. (doi:10.9767/bcrec.8.2.4722.125-136][Permalink/DOI:

  20. Recent progress on the hydrogen storage properties of ZrCo-based alloys applied in International Thermonuclear Experimental Reactor (ITER

    Directory of Open Access Journals (Sweden)

    Feng Wang


    Full Text Available Under the development of International Thermonuclear Experimental Reactor (ITER system aimed at realizing the controllable fusion reaction to solve the energy crisis fundamentally, there is an urgent need to find an appropriate material for tritium handling. ZrCo alloy is considered to be a promising candidate for the storage and delivery of hydrogen isotopes due to the favorable characteristics such as low plateau pressure for absorption, high dissociation pressure at moderate temperature and better ability of trapping 3He. However, the hydrogen induced disproportionation and the slower recovery/deliverty rate of ZrCo-based alloys have limited their further application in ITER system. This review summarizes the efforts towards enhancing the hydrogen storage properties of ZrCo-based alloys including element substitution, surface modification, disproportionation mechanism investigation and the isotope effect study. Element substitution and surface modification play positive role to improve the anti-disproportionation ability and kinetic property of the alloys. However, the ZrCo-based alloys require to be further modified by more attempts such as new composition, novelty modification method or catalyst addition in order to better satisfy the application demands for tritium handling. Moreover, new insight for further understanding the inner disproportionation mechanisms of this material is needed by combining the advance characterization and theoretical analysis, which is in favor of addressing the disproportionation problem of the ZrCo-based alloys essentially.

  1. Computation and comparison of Pd-based membrane reactor performances for water gas shift reaction and isotope swamping in view of highly tritiated water decontamination

    Energy Technology Data Exchange (ETDEWEB)

    Santucci, Alessia, E-mail: [Associazione ENEA-Euratom sulla Fusione, C.R. ENEA Frascati, Via E. Fermi 45, 00044 Frascati, RM (Italy); Rizzello, Claudio [Tesi Sas, Via Bolzano 28, Roma (Italy); Tosti, Silvano [Associazione ENEA-Euratom sulla Fusione, C.R. ENEA Frascati, Via E. Fermi 45, 00044 Frascati, RM (Italy)


    Highlights: • A dedicated detritiation process for highly tritiated water (HTW) has to be identified. • Water gas shift and isotopic swamping via Pd–Ag membrane reactor are possible processes. • A parametric analysis through two simulation codes is performed. • A comparison in terms of the decontamination factor is provided. -- Abstract: In a D–T fusion machine, due to the possible reaction between tritium and oxygen, some potential sources of highly tritiated water (HTW) can be identified. Therefore, a dedicated detritiation process has to be assessed either for economic and safety reasons. In this view, the use of a Pd-based membrane reactor performing isotopic exchange reactions can be considered since hydrogen isotopes exclusively permeate the Pd–Ag membrane and their exchange over the catalyst realizes the water detritiation. In this activity, the treatment of highly tritiated water, generated by an ITER-like machine (i.e. 2 kg of stoichiometric HTO containing up to 300 g of tritium), via a Pd-membrane reactor is studied in terms of decontamination capability. Especially, a parametric analysis of two processes (water gas shift and isotopic swamping) performed in a Pd-based membrane reactor is carried out by using two mathematical models previously developed and experimentally verified. Particularly, the effect of the reactor temperature, the membrane thickness, the reaction pressure and the protium sweep flow-rate is investigated. Moreover, a comparison in terms of the decontamination factor and the number of reactors necessary to detritiate the HTW are provided. Generally, the results reveal a higher decontamination capability of the WGS reaction respect with the IS (maximum DF values of about 120 and 1.6 in the case of WGS and IS, respectively). However some drawbacks, mainly related with the formation of tritiated species, can occur by performing the WGS.

  2. Simulation and analysis of a tubular fixed-bed Fischer-Tropsch synthesis reactor with Co-based catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J.; Zhang, H.; Ying, W.; Fang, D. [State Key Laboratory of Chemical Engineering, Engineering Research Center of Large-Scale Reactor Engineering and Technology, Ministry of Education, East China University of Science and Technology, Shanghai (China)


    A two-dimensional pseudohomogeneous reactor model is proposed to simulate the performance of fixed-bed Fischer-Tropsch synthesis (FTS) reactors by lumped thought. A CO consumption kinetics equation and a carbon chain growth probability model were incorporated into the reactor model. The model equations discretized by a two-dimensional orthogonal collocation method were solved by the Broyden method. Concentration and temperature profiles were obtained. The validity of the reactor model against the pilot plant test data was investigated. Satisfactory agreements between model prediction values and experiment results were obtained. Further simulations were carried out to investigate the effect of operating conditions on the reaction behavior of the fixed-bed FTS reactor. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  3. Flow-based method for epinephrine determination using a solid reactor based on molecularly imprinted poly(FePP-MAA-EGDMA)

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, Lucas Rossi [Programa de Pos-Graduacao em Ciencias Farmaceuticas, Universidade Federal de Alfenas (Unifal-MG), Rua Gabriel Monteiro da Silva, 714, 37130-000, Alfenas/MG (Brazil); Santos, Wilney de Jesus Rodrigues [Departamento de Quimica Analitica, Instituto de Quimica, Universidade Estadual de Campinas (Unicamp), Cidade Universitaria Zeferino Vaz s/n,13083-970, Campinas/SP (Brazil); Kubota, Lauro Tatsuo [Departamento de Quimica Analitica, Instituto de Quimica, Universidade Estadual de Campinas (Unicamp), Cidade Universitaria Zeferino Vaz s/n,13083-970, Campinas/SP (Brazil); Instituto Nacional de Ciencia e Tecnologia (INCT) de Bioanalitica, Universidade Estadual de Campinas (Unicamp), Instituto de Quimica, Departamento de Quimica Analitica, Cidade Universitaria Zeferino Vaz s/n, 13083-970, Campinas/SP (Brazil); Segatelli, Mariana Gava [Departamento de Quimica, Universidade Estadual de Londrina (UEL), Rod. Celso Garcia PR 445 Km 380, 86051-990, Londrina/PR (Brazil); Tarley, Cesar Ricardo Teixeira, E-mail: [Programa de Pos-Graduacao em Ciencias Farmaceuticas, Universidade Federal de Alfenas (Unifal-MG), Rua Gabriel Monteiro da Silva, 714, 37130-000, Alfenas/MG (Brazil); Instituto Nacional de Ciencia e Tecnologia (INCT) de Bioanalitica, Universidade Estadual de Campinas (Unicamp), Instituto de Quimica, Departamento de Quimica Analitica, Cidade Universitaria Zeferino Vaz s/n, 13083-970, Campinas/SP (Brazil)


    A solid phase reactor based on molecularly imprinted poly(iron (III) protoporphyrin-methacrylic acid-ethylene glycol dimethacrylate) (MIP-MAA) has been synthesized by bulk method and applied as an selective material for the epinephrine determination in the presence of hydrogen peroxide. In order to prove the selective behaviour of MIP, two blank polymers named non-imprinted polymer (NIP1), non-imprinted polymer in the absence of hemin (NIP2) as well as a poly(iron (III) protoporphyrin-4-vynilpyridine-ethylene glycol dimethacrylate) (MIP-4VPy) were synthesized. The epinephrine-selective MIP-MAA reactor was used in a flow injection system, in which an epinephrine solution (120 {mu}L) at pH 8.0 percolates in the presence of hydrogen peroxide (300 {mu}mol L{sup -1}) through MIP-MAA. The oxidation of epinephrine by hydrogen peroxide is increased by using MIP-MAA, being the product formed monitored by amperometry at 0.0 V vs. Ag/AgCl. The MIP-MAA showed better selective behaviour than NIP1, NIP2 and MIP-4VPy, demonstrating the effectiveness of molecular imprinting effect. Highly improved response was observed for epinephrine in detriment of similar substances (phenol, ascorbic acid, methyl-L-DOPA, p-aminophenol, catechol, L-DOPA and guaiacol). The method provided a calibration curve ranging from 10 to 500 {mu}mol L{sup -1} and a limit of detection of 5.2 {mu}mol L{sup -1}. Kinetic data indicated a value of maximum rate V{sub max} (0.993 {mu}A) and apparent Michaelis-Menten constant of K{sub m}{sup app}(725.6 {mu}mol L{sup -1}). The feasibility of biomimetic solid reactor was attested by its successful application for epinephrine determination in pharmaceutical formulation.

  4. Neutronic reactor (United States)

    Wende, Charles W. J.; Babcock, Dale F.; Menegus, Robert L.


    A nuclear reactor includes an active portion with fissionable fuel and neutron moderating material surrounded by neutron reflecting material. A control element in the active portion includes a group of movable rods constructed of neutron-absorbing material. Each rod is movable with respect to the other rods to vary the absorption of neutrons and effect control over neutron flux.

  5. Neutronic reactor

    Energy Technology Data Exchange (ETDEWEB)

    Babcock, D.F.; Menegus, R.L.; Wende, C.W.


    A nuclear reactor includes an active portion with fissionable fuel and neutron moderating material surrounded by neutron reflecting material. A control element in the active portion includes a group of movable rods constructed of neutron-absorbing material. Each rod is movable with respect to the other rods to vary the absorption of neutrons and effect control over neutron flux.

  6. Validation of the TRACE code for the system dynamic simulations of the molten salt reactor experiment and the preliminary study on the dual fluid molten salt reactor

    Energy Technology Data Exchange (ETDEWEB)

    He, Xun


    Molten Salt Reactor (MSR), which was confirmed as one of the six Generation IV reactor types by the GIF (Generation IV International Forum in 2008), recently draws a lot of attention all around the world. Due to the application of liquid fuels the MSR can be regarded as the most special one among those six GEN-IV reactor types in a sense. A unique advantage of using liquid nuclear fuel lies in that the core melting accident can be thoroughly eliminated. Besides, a molten salt reactor can have several fuel options, for instance, the fuel can be based on {sup 235}U, {sup 232}Th-{sup 233}U, {sup 238}U-{sup 239}Pu cycle or even the spent nuclear fuel (SNF), so the reactor can be operated as a breeder or as an actinides burner both with fast, thermal or epi-thermal neutron spectrum and hence, it has excellent features of the fuel sustainability and for the non-proliferation. Furthermore, the lower operating pressure not only means a lower risk of the explosion as well as the radioactive leakage but also implies that the reactor vessel and its components can be lightweight, thus lowering the cost of equipments. So far there is no commercial MSR being operated. However, the MSR concept and its technical validation dates back to the 1960s to 1970s, when the scientists and engineers from ORNL (Oak Ridge National Laboratory) in the United States managed to build and run the world's first civilian molten salt reactor called MSRE (Molten Salt Reactor Experiment). The MSRE was an experimental liquid-fueled reactor with 10 MW thermal output using {sup 4}LiF-BeF{sub 2}-ZrF{sub 4}-UF{sub 4} as the fuel also as the coolant itself. The MSRE is usually taken as a very important reference case for many current researches to validate their codes and simulations. Without exception it works also as a benchmark for this thesis. The current thesis actually consists of two main parts. The first part is about the validation of the current code for the old MSRE concept, while the second

  7. The genesis of the slab window-related Arzular low-sulfidation epithermal gold mineralization (eastern Pontides, NE Turkey

    Directory of Open Access Journals (Sweden)

    Enver Akaryalı


    Full Text Available The Arzular mineralization is one of the best examples of epithermal gold deposits in the eastern Pontides orogenic belt. The mineralization is hosted by the subduction-related basaltic andesites and is mainly controlled by E–W and NE–SW trending fracture zones. The main ore minerals are galena, sphalerite, pyrite, chalcopyrite, tetrahedrite and gold. Homogenization temperatures of fluid inclusions are between 130 and 295 °C for quartz and between 90 and 133 °C for sphalerite. Sulphur isotope values obtained from pyrite, galena and sphalerite vary between −1.2‰ and 3‰, indicating that sulphur belongs to magmatic origin and was derived from the Lutetian non-adakitic granitic intrusions in the region. Oxygen isotope values are between 15.0‰ and 16.7‰, and hydrogen isotope values are between −87‰ and −91‰. The sulphur isotope thermometer yielded temperatures in the range of 244–291 °C for the ore formation. Our results support the hypothesis that the Arzular mineralization is a low-sulfidation epithermal gold deposit associated with non-adakitic subduction-related granitic magmas that were generated by slab window-related processes in a south-dipping subduction zone during the Lutetian.

  8. Statistical Evaluation of the Geochemical Data from Akoluk Epithermal Gold Area (Ulubey-Ordu), NE Turkey (United States)

    Yaylalı-Abanuz, G.; Tüysüz, N.


    There are several economic epithermal gold deposits in the eastern Pontide arc basin in northeast of Turkey. These mineralizations are generally found as veins in NE-SW and NW-SE trending shear fractures. The presence of faults and associated suitable hydrothermal alteration in the study area has been important guide for the gold exploration. Since region is intensely covered with thick soil and rocks are exposed in limited areas, stream sediment and soil geochemistry studies are the most commonly used methods in the exploration of mineral deposits. In this study, the applicability of soil geochemistry surveys in the exploration of mineral deposits in areas of intense overburden is tested using statistical methods. A vein type gold occurence is confined to the fault zones crossing dacitic tuffs of Upper Cretaceous age. Faults appear to be a conjugate set of a shear system, striking N 45-50 E, and N 55-60 W dipping 80-85 SE and 70-80 NW respectively. Mineralization occurs generally as replacement of dacitic tuffs along the fault planes and less of void fillings. Main ore minerals are native gold, stibnite, zinkenite, pyrite, marcasite, realgar, orpiment, sphalerite, galena, chalcopyrite, malachite, and azurite, and the most common gangue mineral is barite. Soil is residual and well developed ranging in thickness from 0.5 m to 1 m. Elements analyzed and interpreted are the ones which are known to have close association with gold. Of these Au, Ag, Sb, As, Zn, Mo, W, and Ba show a single very significant anomaly pattern although several other small isolated anomalies are also recorded. The latter must be related to sampling artifacts. The significant one is circular in shape and has a diameter of approx. 200 m. It is strikingly of interest that anomaly shape does not imitate fracture system. This may be due to the fact that sampling interval is wider than the fault zones. However the circular pattern may suggest a granitic intrusion in subcrop as the main controller of

  9. GEANT4 used for neutron beam design of a neutron imaging facility at TRIGA reactor in Morocco (United States)

    Ouardi, A.; Machmach, A.; Alami, R.; Bensitel, A.; Hommada, A.


    Neutron imaging has a broad scope of applications and has played a pivotal role in visualizing and quantifying hydrogenous masses in metallic matrices. The field continues to expand into new applications with the installation of new neutron imaging facilities. In this scope, a neutron imaging facility for computed tomography and real-time neutron radiography is currently being developed around 2.0MW TRIGA MARK-II reactor at Maamora Nuclear Research Center in Morocco (Reuscher et al., 1990 [1]; de Menezes et al., 2003 [2]; Deinert et al., 2005 [3]). The neutron imaging facility consists of neutron collimator, real-time neutron imaging system and imaging process systems. In order to reduce the gamma-ray content in the neutron beam, the tangential channel was selected. For power of 250 kW, the corresponding thermal neutron flux measured at the inlet of the tangential channel is around 3×10 11 ncm 2/s. This facility will be based on a conical neutron collimator with two circular diaphragms with diameters of 4 and 2 cm corresponding to L/D-ratio of 165 and 325, respectively. These diaphragms' sizes allow reaching a compromise between good flux and efficient L/D-ratio. Convergent-divergent collimator geometry has been adopted. The beam line consists of a gamma filter, fast neutrons filter, neutron moderator, neutron and gamma shutters, biological shielding around the collimator and several stages of neutron collimator. Monte Carlo calculations by a fully 3D numerical code GEANT4 were used to design the neutron beam line ([4]). To enhance the neutron thermal beam in terms of quality, several materials, mainly bismuth (Bi) and sapphire (Al 2O 3) were examined as gamma and neutron filters respectively. The GEANT4 simulations showed that the gamma and epithermal and fast neutron could be filtered using the bismuth (Bi) and sapphire (Al 2O 3) filters, respectively. To get a good cadmium ratio, GEANT 4 simulations were used to

  10. Perspectives on reactor safety

    Energy Technology Data Exchange (ETDEWEB)

    Haskin, F.E. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering; Camp, A.L. [Sandia National Labs., Albuquerque, NM (United States)


    The US Nuclear Regulatory Commission (NRC) maintains a technical training center at Chattanooga, Tennessee to provide appropriate training to both new and experienced NRC employees. This document describes a one-week course in reactor, safety concepts. The course consists of five modules: (1) historical perspective; (2) accident sequences; (3) accident progression in the reactor vessel; (4) containment characteristics and design bases; and (5) source terms and offsite consequences. The course text is accompanied by slides and videos during the actual presentation of the course.

  11. Heat dissipating nuclear reactor (United States)

    Hunsbedt, A.; Lazarus, J.D.


    Disclosed is a nuclear reactor containment adapted to retain and cool core debris in the unlikely event of a core meltdown and subsequent breach in the reactor vessel. The reactor vessel is seated in a cavity which has a thick metal sidewall that is integral with a thick metal basemat at the bottom of the cavity. The basemat extends beyond the perimeter of the cavity sidewall. Underneath the basemat is a porous bed with water pipes and steam pipes running into it. Water is introduced into the bed and converted into steam which is vented to the atmosphere. A plurality of metal pilings in the form of H-beams extend from the metal base plate downwardly and outwardly into the earth.

  12. Digital computer operation of a nuclear reactor (United States)

    Colley, R.W.


    A method is described for the safe operation of a complex system such as a nuclear reactor using a digital computer. The computer is supplied with a data base containing a list of the safe state of the reactor and a list of operating instructions for achieving a safe state when the actual state of the reactor does not correspond to a listed safe state, the computer selects operating instructions to return the reactor to a safe state.

  13. A market based active/reactive dispatch including transformer taps and reactor and capacitor banks using Simulated Annealing

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Mario Helder [Departamento de Engenharia Electrotecnica, Instituto Politecnico de Tomar, Quinta do Contador, Estrada da Serra, 2300 Tomar (Portugal); Saraiva, Joao Tome [INESC Porto, Faculdade de Engenharia, Universidade do Porto, Campus da FEUP, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)


    This paper describes an optimization model to be used by System Operators in order to validate the economic schedules obtained by Market Operators together with the injections from Bilateral Contracts. These studies will be performed off-line in the day before operation and the developed model is based on adjustment bids submitted by generators and loads and it is used by System Operators if that is necessary to enforce technical or security constraints. This model corresponds to an enhancement of an approach described in a previous paper and it now includes discrete components as transformer taps and reactor and capacitor banks. The resulting mixed integer formulation is solved using Simulated Annealing, a well known metaheuristic specially suited for combinatorial problems. Once the Simulated Annealing converges and the values of the discrete variables are fixed, the resulting non-linear continuous problem is solved using Sequential Linear Programming to get the final solution. The developed model corresponds to an AC version, it includes constraints related with the capability diagram of synchronous generators and variables allowing the computation of the active power required to balance active losses. Finally, the paper includes a Case Study based on the IEEE 118 bus system to illustrate the results that it is possible to obtain and their interest. (author)

  14. Economics analysis of fuel cycle cost of fusion–fission hybrid reactors based on different fuel cycle strategies

    Energy Technology Data Exchange (ETDEWEB)

    Zu, Tiejun, E-mail:; Wu, Hongchun; Zheng, Youqi; Cao, Liangzhi


    Highlights: • Economics analysis of fuel cycle cost of FFHRs is carried out. • The mass flows of different fuel cycle strategies are established based on the equilibrium fuel cycle model. • The levelized fuel cycle costs of different fuel cycle strategies are calculated, and compared with current once-through fuel cycle. - Abstract: The economics analysis of fuel cycle cost of fusion–fission hybrid reactors has been performed to compare four fuel cycle strategies: light water cooled blanket burning natural uranium (Strategy A) or spent nuclear fuel (Strategy B), sodium cooled blanket burning transuranics (Strategy C) or minor actinides (Strategy D). The levelized fuel cycle costs (LFCC) which does not include the capital cost, operation and maintenance cost have been calculated based on the equilibrium mass flows. The current once-through (OT) cycle strategy has also been analyzed to serve as the reference fuel cycle for comparisons. It is found that Strategy A and Strategy B have lower LFCCs than OT cycle; although the LFCC of Strategy C is higher than that of OT cycle when the uranium price is at its nominal value, it would become comparable to that of OT cycle when the uranium price reaches its historical peak value level; Strategy D shows the highest LFCC, because it needs to reprocess huge mass of spent nuclear fuel; LFCC is sensitive to the discharge burnup of the nuclear fuel.

  15. Assessing the Effects of Radiation Damage on Ni-base Alloys for the Prometheus Space Reactor System

    Energy Technology Data Exchange (ETDEWEB)

    T Angeliu; J Ward; J Witter


    Ni-base alloys were considered for the Prometheus space reactor pressure vessel with operational parameters of {approx}900 K for 15 years and fluences up to 160 x 10{sup 20} n/cm{sup 2} (E > 0.1 MeV). This paper reviews the effects of irradiation on the behavior of Ni-base alloys and shows that radiation-induced swelling and creep are minor considerations compared to significant embrittlement with neutron exposure. While the mechanism responsible for radiation-induced embrittlement is not fully understood, it is likely a combination of helium embrittlement and solute segregation that can be highly dependent on the alloy composition and exposure conditions. Transmutation calculations show that detrimental helium levels would be expected at the end of life for the inner safety rod vessel (thimble) and possibly the outer pressure vessel, primarily from high energy (E > 1 MeV) n,{alpha} reactions with {sup 58}Ni. Helium from {sup 10}B is significant only for the outer vessel due to the proximity of the outer vessel to the BeO control elements. Recommendations for further assessments of the material behavior and methods to minimize the effects of radiation damage through alloy design are provided.

  16. Performance Evaluation of Monolith Based Immobilized Acetylcholinesterase Flow-Through Reactor for Copper(II Determination with Spectrophotometric Detection

    Directory of Open Access Journals (Sweden)

    Parawee Rattanakit


    Full Text Available A monolith based immobilized acetylcholinesterase (AChE flow-through reactor has been developed for the determination of copper(II using flow injection spectrophotometric system. The bioreactor was prepared inside a microcapillary column by in situ polymerization of butyl methacrylate, ethylene dimethacrylate, and 2,2-dimethoxy-1,2-diphynyletane-1-one in the presence of 1-decanol, followed by vinyl azlactone functionalization and AChE immobilization. The behavior of AChE before and after being immobilized on the monolith was evaluated by kinetic parameters from Lineweaver and Burk equation. The detection was based on measuring inhibition effect on the enzymatic activity of AChE by copper(II using Ellman’s reaction with spectrophotometric detection at 410 nm. The linear range of the calibration graph was obtained over the range of 0.02–3.00 mg L−1. The detection limit, defined as 10% inhibition (I10, was found to be 0.04 mg L−1. The repeatability was 3.35 % (n=5 for 1.00 mg L−1 of copper(II. The proposed method was applied to the determination of copper(II in natural water samples with sampling rate of 4 h−1.

  17. Assessing the Effects of Radiation Damage on Ni-base Alloys for the Prometheus Space Reactor System

    Energy Technology Data Exchange (ETDEWEB)

    T. Angeliu


    Ni-base alloys were considered for the Prometheus space reactor pressure vessel with operational parameters of {approx}900 K for 15 years and fluences up to 160 x 10{sup 20} n/cm{sup 2} (E > 0.1 MeV). This paper reviews the effects of irradiation on the behavior of Ni-base alloys and shows that radiation-induced swelling and creep are minor considerations compared to significant embrittlement with neutron ,exposure. While the mechanism responsible for radiation-induced embrittlement is not fully understood, it is likely a combination of helium embrittlement and solute segregation that can be highly dependent on the alloy composition and exposure conditions. Transmutation calculations show that detrimental helium levels would be expected at the end of life for the inner safety rod vessel (thimble) and possibly the outer pressure vessel, primarily from high energy (E > 1 MeV) n,{alpha} reactions with {sup 58}Ni. Helium from {sup 10}B is significant only for the outer vessel due to the proximity of the outer vessel to the Be0 control elements. Recommendations for further assessments of the material behavior and methods to minimize the effects of radiation damage through alloy design are provided.

  18. Deployment history and design considerations for space reactor power systems (United States)

    El-Genk, Mohamed S.


    The history of the deployment of nuclear reactors in Earth orbits is reviewed with emphases on lessons learned and the operation and safety experiences. The former Soviet Union's "BUK" power systems, with SiGe thermoelectric conversion and fast neutron energy spectrum reactors, powered a total of 31 Radar Ocean Reconnaissance Satellites (RORSATs) from 1970 to 1988 in 260 km orbit. Two of the former Soviet Union's TOPAZ reactors, with in-core thermionic conversion and epithermal neutron energy spectrum, powered two Cosmos missions launched in 1987 in ˜800 km orbit. The US' SNAP-10A system, with SiGe energy conversion and a thermal neutron energy spectrum reactor, was launched in 1965 in 1300 km orbit. The three reactor systems used liquid NaK-78 coolant, stainless steel structure and highly enriched uranium fuel (90-96 wt%) and operated at a reactor exit temperature of 833-973 K. The BUK reactors used U-Mo fuel rods, TOPAZ used UO 2 fuel rods and four ZrH moderator disks, and the SNAP-10A used moderated U-ZrH fuel rods. These low power space reactor systems were designed for short missions (˜0.5 kW e and ˜1 year for SNAP-10A, <3.0 kW e and <6 months for BUK, and ˜5.5 kW e and up to 1 year for TOPAZ). The deactivated BUK reactors at the end of mission, which varied in duration from a few hours to ˜4.5 months, were boosted into ˜800 km storage orbit with a decay life of more than 600 year. The ejection of the last 16 BUK reactor fuel cores caused significant contamination of Earth orbits with NaK droplets that varied in sizes from a few microns to 5 cm. Power systems to enhance or enable future interplanetary exploration, in-situ resources utilization on Mars and the Moon, and civilian missions in 1000-3000 km orbits would generate significantly more power of 10's to 100's kW e for 5-10 years, or even longer. A number of design options to enhance the operation reliability and safety of these high power space reactor power systems are presented and discussed.

  19. Effect of shock and mixed loading on the performance of SND based sequencing batch reactors (SBR) degrading nitrophenols. (United States)

    Kulkarni, P M


    The effect of nitrophenolic shock loads on the performance of three lab scale SBRs was studied using a synthetic feed. Nitrophenols were biotransformed by Simultaneous heterotrophic Nitrification and aerobic Denitrification (SND) using a specially designed single sludge biomass containing Thiosphaera pantotropha. Reactors R1, R2 and R3 were fed with 200mg/L concentration of 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP), and 2,4,6-trinitrophenol (2,4,6-TNP) whereas reactor R was used as a background control. Three nitrophenolic shock loadings of 400, 600 and 800 mg/Ld were administrated by increasing the influent nitrophenolic concentration while keeping the hydraulic retention time as 48 h. The shocks were given continuously for a period of 4 days before switching back to normal nitrophenolic loading (200mg/Ld). The reactors were allowed to recover to normal performance level before administrating the next nitrophenolic shock load. The study showed that a nitrophenolic shock load, as high as 600 mg/Ld was completely degraded by the 4-NP & 2,4-DNP bioreactors while almost half degraded by the 2,4,6-TNP bioreactor without affecting the reactor's performance irreversibly. After resuming the normal nitrophenolic loading, it took almost 8-10 days for the reactors to recover from the shock effect. The study was further extended to evaluate the maximum possible mixed nitrophenolic loading (4-NP:2,4-DNP:2,4,6-TNP 1:1:1) to which a reactor (R3) containing 2,4,6-TNP acclimated single sludge biomass can be exposed without hampering the reactor performance irreversibly. The reactor was able to achieve pseudo-steady-state at a mixed nitrophenolic loading of 300 mg/Ld with more than 90% removal of all the three nitrophenols, but could remove half of the mixed nitrophenolic loading of 600 mg/Ld. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. A study of temperature sensor location based on fractal analysis for cascade control schemes in tubular reactors

    DEFF Research Database (Denmark)

    Eduardo Ramirez-Castelan, Carlos; Moguel-Castañeda, Jazael; Puebla, Hector


    Temperature sensor location for cascade control schemes in tubular reactors is still an open research problem. Several studies have pointed out that most temperature sensitive zones along the length of the reactor are suitable to this end. In this work, we have studied the problem of sensor...... location in a cascade control configuration using fractal analysis of time series obtained by random forcing of the jacket rector. A benchmark dispersion axial model displaying different temperature profiles is used to illustrate our findings....

  1. Request for Naval Reactors Comment on Proposed Prometheus Space Flight Nuclear Reactor High Tier Reactor Safety Requirements and for Naval Reactors Approval to Transmit These Requirements to JPL

    Energy Technology Data Exchange (ETDEWEB)

    D. Kokkinos


    The purpose of this letter is to request Naval Reactors comments on the nuclear reactor high tier requirements for the PROMETHEUS space flight reactor design, pre-launch operations, launch, ascent, operation, and disposal, and to request Naval Reactors approval to transmit these requirements to Jet Propulsion Laboratory to ensure consistency between the reactor safety requirements and the spacecraft safety requirements. The proposed PROMETHEUS nuclear reactor high tier safety requirements are consistent with the long standing safety culture of the Naval Reactors Program and its commitment to protecting the health and safety of the public and the environment. In addition, the philosophy on which these requirements are based is consistent with the Nuclear Safety Policy Working Group recommendations on space nuclear propulsion safety (Reference 1), DOE Nuclear Safety Criteria and Specifications for Space Nuclear Reactors (Reference 2), the Nuclear Space Power Safety and Facility Guidelines Study of the Applied Physics Laboratory.

  2. Reactor Antineutrino Signals at Morton and Boulby

    CERN Document Server

    Dye, Steve


    Increasing the distance from which an antineutrino detector is capable of monitoring the operation of a registered reactor, or discovering a clandestine reactor, strengthens the Non-Proliferation of Nuclear Weapons Treaty. This report presents calculations of reactor antineutrino interactions, from quasi-elastic neutrino-proton scattering and elastic neutrino-electron scattering, in a water-based detector operated >10 km from a commercial power reactor. It separately calculates signal from the proximal reactor and background from all other registered reactors. The main results are interaction rates and kinetic energy distributions of charged leptons scattered from quasi-elastic and elastic processes. Comparing signal and background distributions evaluates reactor monitoring capability. Scaling the results to detectors of different sizes, target media, and standoff distances is straightforward. Calculations are for two examples of a commercial reactor (P_th~3 GW) operating nearby (L~20 km) an underground facil...

  3. Geological, mineralogical and geochemical characteristics of the Radzimowice Au As Cu deposit from the Kaczawa Mountains (Western Sudetes, Poland): an example of the transition of porphyry and epithermal style (United States)

    Mikulski, Stanislaw Z.


    The sheeted quartz sulfide veins of the Radzimowice Au As Cu deposit in the Kaczawa Mountains are related to Upper Carboniferous post-collisional potassic magmatism of the composite Zelezniak porphyry intrusion. Multiple intrusive activity ranges from early calc-alkaline to sub-alkaline and alkaline rocks and is followed by multiple hydrothermal events. Early crustally derived dacitic magma has low mg# (electrum of two generations, and minor maldonite (Au2Bi). Fluid inclusions from various quartz generations co-genetic with base-metal sulfides and associated with carbonates, tellurides and non-refractory gold indicate fluids with moderate salinity (9 15 wt% NaCl equiv.) and a temperature and pressure drop from 350 to 190°C and 1.2 to 0.8 kbar, respectively. According to the result of the sulfur isotope fractionation geothermometer the temperature of base-metal crystallization was in the range from 322 to 289°C. Preliminary results of oxygen isotope studies of quartz from veins indicate a gradual increase in the proportion of meteoric water in the epithermal stage. The gold to silver ratio in ore samples with >3 ppm Au is about 1:5 (geometric mean). Hydrothermal alteration started with sericitization, pyritization, and kaolinitization in vein selvages followed by alkaline hydrothermal alteration of propylitic character (illitization and chloritization), albitization and carbonatization. The mineralization of the Radzimowice deposit is considered as related to alkaline magmatism and is characterized by the superposition of low-sulfidation epithermal mineralization on higher-temperature and deeper-seated mesothermal/porphyry style.

  4. Gold nanoparticles production using reactor and cyclotron based methods in assessment of (196,198)Au production yields by (197)Au neutron absorption for therapeutic purposes. (United States)

    Khorshidi, Abdollah


    Medical nano-gold radioisotopes is produced regularly using high-flux nuclear reactors, and an accelerator-driven neutron activator can turn out higher yield of (197)Au(n,γ)(196,198)Au reactions. Here, nano-gold production via radiative/neutron capture was investigated using irradiated Tehran Research Reactor flux and also simulated proton beam of Karaj cyclotron in Iran. (197)Au nano-solution, including 20nm shaped spherical gold and water, was irradiated under Tehran reactor flux at 2.5E+13n/cm(2)/s for (196,198)Au activity and production yield estimations. Meanwhile, the yield was examined using 30MeV proton beam of Karaj cyclotron via simulated new neutron activator containing beryllium target, bismuth moderator around the target, and also PbF2 reflector enclosed the moderator region. Transmutation in (197)Au nano-solution samples were explored at 15 and 25cm distances from the target. The neutron flux behavior inside the water and bismuth moderators was investigated for nano-gold particles transmutation. The transport of fast neutrons inside bismuth material as heavy nuclei with a lesser lethargy can be contributed in enhanced nano-gold transmutation with long duration time than the water moderator in reactor-based method. Cyclotron-driven production of βeta-emitting radioisotopes for brachytherapy applications can complete the nano-gold production technology as a safer approach as compared to the reactor-based method. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification. (United States)

    Castro-Dominguez, Bernardo; Mardilovich, Ivan P; Ma, Liang-Chih; Ma, Rui; Dixon, Anthony G; Kazantzis, Nikolaos K; Ma, Yi Hua


    Palladium-based catalytic membrane reactors (CMRs) effectively remove H₂ to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H₂, CO and CO₂. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H₂O, CO₂ and H₂. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H₂ and induce higher methane and CO conversions while yielding ultrapure H₂ and compressed CO₂ ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H₂ permeance and purity, high CH₄ conversion levels and reduced CO yields.

  6. A lab-in-a-foil microfluidic reactor based on phaseguiding

    DEFF Research Database (Denmark)

    Eriksen, Johan; Schira, Julien; Vincent, Nadine


    by controlled guiding of the air/liquid interface in a rectangular array of pillars. The operation of the device is demonstrated by performing isothermal DNA amplification in nL volumes. In our device, 28 pg of DNA from λ-phage, a virus with a 48 kilo base genome, is amplified 500 times thus the amplification...... product is suitable for library preparation for second generation sequencing. We show that fabrication by hot embossing does not introduce significant contamination and that our device is performing comparably well to test tube amplification and current PDMS-based chip technology....

  7. Intermediate temperature embrittlement of one new Ni-26W-6Cr based superalloy for molten salt reactors

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Li [Thorium Molten Salts Reactor Center, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Science, Beijing 100049 (China); Ye, Xiangxi [University of Chinese Academy of Science, Beijing 100049 (China); Cui, Chuanyong [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Huang, Hefei; Leng, Bin [Thorium Molten Salts Reactor Center, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, Zhijun, E-mail: [Thorium Molten Salts Reactor Center, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhou, Xingtai [Thorium Molten Salts Reactor Center, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)


    Ni-26W-6Cr based superalloy is considered a potential structure material for the molten salt reactors due to its high strength and good compatibility with the fluoride salt. In the present work, the temperature dependence of the tensile behavior of the alloy was studied by tensile tests in the temperature range of 25–850 °C. This alloy exhibited a good ductility at RT and 450 °C, a ductility minimum from 650 to 750 °C and an intermediate ductility at 850 °C. TEM and EBSD characterization was performed on specimens tested at three typical temperature points (RT, 650 °C and 850 °C) to determine the deformation and fracture mechanisms accounting for the intermediate temperature embrittlement. At RT, the grain boundaries can accommodate enough dislocations to provide compatibility of the sliding between adjacent grains, then M{sub 6}C carbides act as crack origins and cause the fracture. In case of 650 °C, the grain boundaries cannot withstand the local stress even if only a small number of dislocation pile-ups exist. The premature cracks at grain boundaries impede the development of plastic deformation from single slips to multiple ones and cause the low ductility. If tested at 850 °C, the fracture process is retarded by the dynamic recovery and local dynamic recrystallization at crack tips.

  8. Model-Based Analysis and Efficient Operation of a Glucose Isomerization Reactor Plant

    DEFF Research Database (Denmark)

    Papadakis, Emmanouil; Madsen, Ulrich; Pedersen, Sven


    The application of computer-aided model based methods within an integrated systematic framework is illustrated with the objective to assist the multi-purpose pharmaceutical/biochemical industry to systematically solve the complex problems that are experienced when aiming at improving the process ...

  9. A fuzzy-logic based diagnosis and control of a reactor performing complete autotrophic nitrogen removal

    DEFF Research Database (Denmark)

    Mauricio Iglesias, Miguel; Vangsgaard, Anna Katrine; Gernaey, Krist


    This contribution explores the use of diagnosis and control modules based on fuzzy set theory and logic for bioreactor monitoring and control. With this aim, two independent modules were used jointly to carry out first the diagnosis of the state of the system and then use transfer this information...

  10. Rotary Bed Reactor for Chemical-Looping Combustion with Carbon Capture. Part 2: Base Case and Sensitivity Analysis

    KAUST Repository

    Zhao, Zhenlong


    Part 1 (10.1021/ef3014103) of this series describes a new rotary reactor for gas-fueled chemical-looping combustion (CLC), in which, a solid wheel with microchannels rotates between the reducing and oxidizing streams. The oxygen carrier (OC) coated on the surfaces of the channels periodically adsorbs oxygen from air and releases it to oxidize the fuel. A one-dimensional model is also developed in part 1 (10.1021/ef3014103). This paper presents the simulation results based on the base-case design parameters. The results indicate that both the fuel conversion efficiency and the carbon separation efficiency are close to unity. Because of the relatively low reduction rate of copper oxide, fuel conversion occurs gradually from the inlet to the exit. A total of 99.9% of the fuel is converted within 75% of the channel, leading to 25% redundant length near the exit, to ensure robustness. In the air sector, the OC is rapidly regenerated while consuming a large amount of oxygen from air. Velocity fluctuations are observed during the transition between sectors because of the complete reactions of OCs. The gas temperature increases monotonically from 823 to 1315 K, which is mainly determined by the solid temperature, whose variations with time are limited within 20 K. The overall energy in the solid phase is balanced between the reaction heat release, conduction, and convective cooling. In the sensitivity analysis, important input parameters are identified and varied around their base-case values. The resulting changes in the model-predicted performance revealed that the most important parameters are the reduction kinetics, the operating pressure, and the feed stream temperatures. © 2012 American Chemical Society.

  11. Light Water Reactor Sustainability Program: Computer-Based Procedures for Field Activities: Results from Three Evaluations at Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Oxstrand, Johanna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Le Blanc, Katya [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bly, Aaron [Idaho National Lab. (INL), Idaho Falls, ID (United States)


    The Computer-Based Procedure (CBP) research effort is a part of the Light-Water Reactor Sustainability (LWRS) Program, which is a research and development (R&D) program sponsored by Department of Energy (DOE) and performed in close collaboration with industry R&D programs that provides the technical foundations for licensing and managing the long-term, safe, and economical operation of current nuclear power plants. One of the primary missions of the LWRS program is to help the U.S. nuclear industry adopt new technologies and engineering solutions that facilitate the continued safe operation of the plants and extension of the current operating licenses. One area that could yield tremendous savings in increased efficiency and safety is in improving procedure use. Nearly all activities in the nuclear power industry are guided by procedures, which today are printed and executed on paper. This paper-based procedure process has proven to ensure safety; however, there are improvements to be gained. Due to its inherent dynamic nature, a CBP provides the opportunity to incorporate context driven job aids, such as drawings, photos, and just-in-time training. Compared to the static state of paper-based procedures (PBPs), the presentation of information in CBPs can be much more flexible and tailored to the task, actual plant condition, and operation mode. The dynamic presentation of the procedure will guide the user down the path of relevant steps, thus minimizing time spent by the field worker to evaluate plant conditions and decisions related to the applicability of each step. This dynamic presentation of the procedure also minimizes the risk of conducting steps out of order and/or incorrectly assessed applicability of steps.

  12. Analysis of neutron flux distribution for the validation of computational methods for the optimization of research reactor utilization. (United States)

    Snoj, L; Trkov, A; Jaćimović, R; Rogan, P; Zerovnik, G; Ravnik, M


    In order to verify and validate the computational methods for neutron flux calculation in TRIGA research reactor calculations, a series of experiments has been performed. The neutron activation method was used to verify the calculated neutron flux distribution in the TRIGA reactor. Aluminium (99.9 wt%)-Gold (0.1 wt%) foils (disks of 5mm diameter and 0.2mm thick) were irradiated in 33 locations; 6 in the core and 27 in the carrousel facility in the reflector. The experimental results were compared to the calculations performed with Monte Carlo code MCNP using detailed geometrical model of the reactor. The calculated and experimental normalized reaction rates in the core are in very good agreement for both isotopes indicating that the material and geometrical properties of the reactor core are modelled well. In conclusion one can state that our computational model describes very well the neutron flux and reaction rate distribution in the reactor core. In the reflector however, the accuracy of the epithermal and thermal neutron flux distribution and attenuation is lower, mainly due to lack of information about the material properties of the graphite reflector surrounding the core, but the differences between measurements and calculations are within 10%. Since our computational model properly describes the reactor core it can be used for calculations of reactor core parameters and for optimization of research reactor utilization. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Fast Reactor Fuel Type and Reactor Safety Performance

    Energy Technology Data Exchange (ETDEWEB)

    R. Wigeland; J. Cahalan


    thermophysical properties of the fuel and their compatibility with the reactor coolant, with corresponding differences in the challenges presented to the reactor developers. Accident phenomena are discussed for the sodium-cooled fast reactor based on the mechanistic progression of conditions from accident initiation to accident termination, whether a benign state is achieved or more severe consequences are expected. General principles connecting accident phenomena and fuel properties are developed from the oxide and metal fuel safety analyses, providing guidelines that can be used as part of the evaluation for selection of fuel type for the sodium-cooled fast reactor.

  14. Genesis of Middle Miocene Yellowstone hotspot-related bonanza epithermal Au-Ag deposits, Northern Great Basin, USA (United States)

    Saunders, J. A.; Unger, D. L.; Kamenov, G. D.; Fayek, M.; Hames, W. E.; Utterback, W. C.


    Epithermal deposits with bonanza Au-Ag veins in the northern Great Basin (NGB) are spatially and temporally associated with Middle Miocene bimodal volcanism that was related to a mantle plume that has now migrated to the Yellowstone National Park area. The Au-Ag deposits formed between 16.5 and 14 Ma, but exhibit different mineralogical compositions, the latter due to the nature of the country rocks hosting the deposits. Where host rocks were primarily of meta-sedimentary or granitic origin, adularia-rich gold mineralization formed. Where glassy rhyolitic country rocks host veins, colloidal silica textures and precious metal-colloid aggregation textures resulted. Where basalts are the country rocks, clay-rich mineralization (with silica minerals, adularia, and carbonate) developed. Oxygen isotope data from quartz (originally amorphous silica and gels) from super-high-grade banded ores from the Sleeper deposit show that ore-forming solutions had δ 18O values up to 10‰ heavier than mid-Miocene meteoric water. The geochemical signature of the ores (including their Se-rich nature) is interpreted here to reflect a mantle source for the “epithermal suite” elements (Au, Ag, Se, Te, As, Sb, Hg) and that signature is preserved to shallow crustal levels because of the similar volatility and aqueous geochemical behavior of the “epithermal suite” elements. A mantle source for the gold in the deposits is further supported by the Pb isotopic signature of the gold ores. Apparently the host rocks control the mineralization style and gangue mineralogy of ores. However, all deposits are considered to have derived precious metals and metalloids from mafic magmas related to the initial emergence of the Yellowstone hotspot. Basalt-derived volatiles and metal(loid)s are inferred to have been absorbed by meteoric-water-dominated geothermal systems heated by shallow rhyolitic magma chambers. Episodic discharge of volatiles and metal(loid)s from deep basaltic magmas mixed with

  15. Ore deposits and epithermal evidences associated with intra-magmatic faults at Aïn El Araâr-Oued Belif ring structure (NW of Tunisia) (United States)

    Aissa, Wiem Ben; Aissa, Lassaâd Ben; Amara, Abdesslem Ben Haj; Tlig, Said; Alouani, Rabah


    Hydrothermal ore deposits at Aïn El Araâr-Oued Belif location are classified as epithermal deposits type. The ore bodies are hosted by upper Turonian (8-9 M.y) volcanic rhyodacitic complex. Polymetallic sulfide orebodies are mainly concentrated within intra-magmatic faults. Petrographic, XRD, and TEM-STEM investigations revealed that ore minerals are essentially, arsenopyrite, pyrite, chalcopyrite, pyrrhotite, hematite, goethite and magnetite with Au, Ag and Pt trace metals. Gangue minerals are mainly adularia, quartz, sericite, alunite, tridymite, chlorite, phlogopite and smectite. Epithermal alteration is well zoned with four successive characteristic zones: (1) zone of quartz-adularia-sericite and rare alunite; (2) zone of kaolinite and plagioclase albitization; (3) intermediate zone of illite-sericite; (4) sapropelic alteration type zone of chlorite-smectite and rare illite. This can be interpreted as a telescoping of two different acidity epithermal phases; low sulfidation (adularia-sericite) and high sulfidation (quartz-alunite), separated in time or due to a gradual increase of fluids acidity and oxicity within the same mineralization phase. Brecciated macroscopic facies with fragments hosting quartz-adularia-sericite minerals (low-sulfidation phase) without alunite, support the last hypothesis. Geodynamic context and mineral alteration patterns are closely similar to those of Maria Josefa gold mine at SE of Spain which exhibit a volcanic-hosted epithermal ore deposit in a similar vein system, within rhyolitic ignimbrites, altered to an argillic assemblage (illite-sericite abundant and subordinate kaolinite) that grades outwards into propylitic alteration (Sanger-von Oepen et al. (1990)). Mineralogical and lithologic study undertaken in the volcanic host rock at Aïn El Araâr-Oued Belif reveals a typical epithermal low-sulfidation and high-sulfidation ore deposits with dominance of low-sulfidation. Host rocks in these systems range from silicic to

  16. Heating device for nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shiratori, Yoshitake; Ijima, Takashi; Katano, Yoshiaki; Saito, Masaki


    The present invention provides a control system of a heating device which elevates the temperature of a reactor from a normal temperature to an operation temperature by using a nuclear heating. Namely, the device of the present invention comprises (1) means for detecting reactor temperature, (2) means for detecting reactor power, (3) means for memorizing the corresponding relation of each value of the means (1) and means (2) as standard data when temperature is elevated at a predetermined temperature elevation rate, (4) means for calculating the power corresponding to the current temperature based on the standard data upon elevation of the reactor temperature, and (5) means for controlling the progress or retraction of the power control material of the reactor core based on the power calculated by the means (4). With such a constitution, since the current reactor power elevation rate corresponding to the coolants is controlled based on the standard data upon actual start-up of the reactor, the control for the temperature of coolants can be facilitated. (I.S.)

  17. Improving the performance of the Egyptian second testing nuclear research reactor using interval type-2 fuzzy logic controller tuned by modified biogeography-based optimization

    Energy Technology Data Exchange (ETDEWEB)

    Sayed, M.M., E-mail:; Saad, M.S.; Emara, H.M.; Abou El-Zahab, E.E.


    Highlights: • A modified version of the BBO was proposed. • A novel method for interval type-2 FLC design tuned by MBBO was proposed. • The performance of the ETRR-2 was improved by using IT2FLC tuned by MBBO. -- Abstract: Power stabilization is a critical issue in nuclear reactors. The conventional proportional derivative (PD) controller is currently used in the Egyptian second testing research reactor (ETRR-2). In this paper, we propose a modified biogeography-based optimization (MBBO) algorithm to design the interval type-2 fuzzy logic controller (IT2FLC) to improve the performance of the Egyptian second testing research reactor (ETRR-2). Biogeography-based optimization (BBO) is a novel evolutionary algorithm that is based on the mathematical models of biogeography. Biogeography is the study of the geographical distribution of biological organisms. In the BBO model, problem solutions are represented as islands, and the sharing of features between solutions is represented as immigration and emigration between the islands. A modified version of the BBO is applied to design the IT2FLC to get the optimal parameters of the membership functions of the controller. We test the optimal IT2FLC obtained by modified biogeography-based optimization (MBBO) using the integral square error (ISE) and is compared with the currently used PD controller.

  18. Design and Analysis of Thorium-fueled Reduced Moderation Boiling Water Reactors (United States)

    Gorman, Phillip Michael

    The Resource-renewable Boiling Water Reactors (RBWRs) are a set of light water reactors (LWRs) proposed by Hitachi which use a triangular lattice and high void fraction to incinerate fuel with an epithermal spectrum, which is highly atypical of LWRs. The RBWRs operate on a closed fuel cycle, which is impossible with a typical thermal spectrum reactor, in order to accomplish missions normally reserved for sodium fast reactors (SFRs)--either fuel self-sufficiency or waste incineration. The RBWRs also axially segregate the fuel into alternating fissile "seed" regions and fertile "blanket" regions in order to enhance breeding and leakage probability upon coolant voiding. This dissertation focuses on thorium design variants of the RBWR: the self-sufficient RBWR-SS and the RBWR-TR, which consumes reprocessed transuranic (TRU) waste from PWR used nuclear fuel. These designs were based off of the Hitachi-designed RBWR-AC and the RBWR-TB2, respectively, which use depleted uranium (DU) as the primary fertile fuel. The DU-fueled RBWRs use a pair of axially segregated seed sections in order to achieve a negative void coefficient; however, several concerns were raised with this multi-seed approach, including difficulty with controlling the reactor and unacceptably high axial power peaking. Since thorium-uranium fuel tends to have much more negative void feedback than uranium-plutonium fuels, the thorium RBWRs were designed to use a single elongated seed to avoid these issues. A series of parametric studies were performed in order to find the design space for the thorium RBWRs, and optimize the designs while meeting the required safety constraints. The RBWR-SS was optimized to maximize the discharge burnup, while the RBWR-TR was optimized to maximize the TRU transmutation rate. These parametric studies were performed on an assembly level model using the MocDown simulator, which calculates an equilibrium fuel composition with a specified reprocessing scheme. A full core model was

  19. Gold grade distribution within an epithermal quartz vein system, Kestanelik, NW Turkey: implications for gold exploration (United States)

    Gulyuz, Nilay; Shipton, Zoe; Gulyuz, Erhan; Lord, Richard; Kaymakci, Nuretdin; Kuscu, İlkay


    Vein-hosted gold deposits contribute a large part to the global gold production. Discovery of these deposits mainly include drilling of hundreds of holes, collecting thousands of soil and rock samples and some geophysical surveys which are expensive and time consuming. Understanding the structures hosting the veins and the variations in gold concentrations within the veins is crucial to constrain a more economic exploration program. The main aim of this study is to investigate the gold grade distribution in the mineralized quartz veins of a well exposed epithermal gold deposit hosted by Paleozoic schist and Eocene quartz-feldspar-hornblende porphyry in Lapseki, NW Turkey. We have constructed 3D architecture of the vein surfaces by mapping their outcrop geometries using a highly sensitive Trimble GPS, collecting detailed field data, well-logs and geochemistry data from 396 drill holes (255 diamond cut and 141 reverse circulation holes). Modelling was performed in MOVE Structural Modelling and Analysis software granted by Midland Valley's Academic Software Initiative, and GIS application softwares Global Mapper and Esri-ArcGIS. We envisaged that while fluid entering the conduit ascents, a sudden thickness increase in the conduit would lead to a drop in the fluid pressure causing boiling (the most dominant gold precipitation mechanism) and associated gold precipitation. Regression analysis was performed between the orthogonal thickness values and gold grades of each vein, and statistical analyses were performed to see if the gold is concentrated at specific structural positions along dip. Gold grades in the alteration zones were compared to those in the adjacent veins to understand the degree of mineralization in alteration zones. A possible correlation was also examined between the host rock type and the gold grades in the veins. These studies indicated that gold grades are elevated in the adjacent alteration zones where high gold grades exist in the veins. Schist

  20. The component content of active particles in a plasma-chemical reactor based on volume barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Soloshenko, I A [Institute of Physics of National Academy of Sciences of Ukraine, 46 Nauki Avenue, 03028, Kiev (Ukraine); Tsiolko, V V [Institute of Physics of National Academy of Sciences of Ukraine, 46 Nauki Avenue, 03028, Kiev (Ukraine); Pogulay, S S [Institute of Physics of National Academy of Sciences of Ukraine, 46 Nauki Avenue, 03028, Kiev (Ukraine); Terent' yeva, A G [Institute of Physics of National Academy of Sciences of Ukraine, 46 Nauki Avenue, 03028, Kiev (Ukraine); Bazhenov, V Yu [Institute of Physics of National Academy of Sciences of Ukraine, 46 Nauki Avenue, 03028, Kiev (Ukraine); Shchedrin, A I [Institute of Physics of National Academy of Sciences of Ukraine, 46 Nauki Avenue, 03028, Kiev (Ukraine); Ryabtsev, A V [Institute of Physics of National Academy of Sciences of Ukraine, 46 Nauki Avenue, 03028, Kiev (Ukraine); Kuzmichev, A I [National Technical University ' KPI' , 37 Peremogy Avenue, KPI-2230, 03056, Kiev, (Ukraine)


    In this paper the results of theoretical and experimental studies of the component content of active particles formed in a plasma-chemical reactor composed of a multiple-cell generator of active particles, based on volume barrier discharge, and a working chamber are presented. For calculation of the content of uncharged plasma components an approach is proposed which is based on averaging of the power introduced over the entire volume. Advantages of such an approach lie in an absence of fitting parameters, such as the dimensions of microdischarges, their surface density and rate of breakdown. The calculation and the experiment were accomplished with the use of dry air (20% relative humidity) as the plasma generating medium. Concentrations of O{sub 3}, HNO{sub 3}, HNO{sub 2}, N{sub 2} O{sub 5} and NO{sub 3} were measured experimentally in the discharge volume and working chamber for the residence time of particles on a discharge of 0.3 s and more and discharge specific power of 1.5 W cm{sup -3}. It has been determined that the best agreement between the calculation and the experiment occurs at calculated gas medium temperatures in the discharge plasma of about 400-425 K, which correspond to the experimentally measured rotational temperature of nitrogen. In most cases the calculated concentrations of O{sub 3}, HNO{sub 3}, HNO{sub 2}, N{sub 2}O{sub 5} and NO{sub 3} for the barrier discharge and the working chamber are in fairly good agreement with the respective measured values.

  1. Nuclear Reactors. Revised. (United States)

    Hogerton, John F.

    This publication is one of a series of information booklets for the general public published by the United States Atomic Energy Commission. Among the topics discussed are: How Reactors Work; Reactor Design; Research, Teaching, and Materials Testing; Reactors (Research, Teaching and Materials); Production Reactors; Reactors for Electric Power…

  2. Energy Efficient Microlith-Based Catalytic Reactor and Recuperator for Air Quality Control Applications (United States)

    Vilekar, Saurabh A.; Hawley, Kyle; Junaedi, Christian; Crowder, Bruce; Prada, Julian; Mastanduno, Richard; Perry, Jay L.; Kayatin, Matthew J.


    Precision Combustion, Inc. (PCI) and NASA’s Marshall Space Flight Center (MSFC) have been developing, characterizing, and optimizing high temperature catalytic oxidizers (HTCO) based on PCI’s patented Microlith technology to meet the requirements of future extended human spaceflight explorations. Previous efforts focused on integrating PCI’s HTCO unit with a compact, simple recuperative heat exchanger to reduce the overall system size and weight. Significant improvement was demonstrated over traditional approaches of integrating the HTCO with an external recuperative heat exchanger. While the critical target performance metrics were achieved, the thermal effectiveness of PCI’s recuperator remained a potential area of improvement to further reduce the energy requirements of the integrated system. Using the same material combinations and an improved recuperator design, the redesigned prototype has experimentally demonstrated 20 – 30% reduction (flow dependent) in steady state power consumption compared to the earlier prototype without compromising the destruction efficiency of methane and volatile organic compounds (VOCs). Moreover, design modifications and improvements allow our redesigned prototype to be more easily manufactured compared to traditional brazed plate-fin recuperator designs. The redesigned prototype was delivered to MSFC for validation testing. Here, we report and discuss the performance of the improved prototype HTCO unit with a high efficiency recuperative heat exchanger based on testing at PCI and MSFC. The device is expected to provide a reliable and robust means of disposing of trace levels of methane and VOCs by oxidizing them into carbon dioxide and water in order to maintain clean air in enclosed spaces, such as crewed spacecraft cabins.

  3. Metallogeny of the Gold Quadrilateral: style and characteristics of epithermal - subvolcanic mineralized structures, South Apuseni Mts., Romania

    Directory of Open Access Journals (Sweden)

    S̡erban-Nicolae Vlad


    Full Text Available The Romanian territory contains numerous ore deposits mined since pre-Roman times. An assessment of historical gold production of the Gold Quadri-lateral (GQ yielded a total estimate of 55.7 Moz of gold throughout an area of 2400 km2. Interpreted in terms of mineralization density this is 23,208 oz of gold/ km2. The geological setting of the GQ is represented mainly by Tertiary (14.7 My to 7.4 My calc-alkaline volcano-plutonic complexes of intermediate character in sedimentary basins of molasse type. These basins are tectonically controlled by NW-SE lineation across early Alpine magmatic products, i.e. subduction related Jurassic-Lower Cretaceous igneous association (island arc ophiolites and granitoids and Upper Cretaceous igneous association (banatites. The Tertiary magmatism is associated with extensional tectonics caused by NE escape of the Pannonian region during Upper Oligocene-Lower Miocene times. As a result of tectono-magmatic and mineralization-alteration characteristics, two metallogenetical types were separated in the GQ, i.e. calc-alkaline andesitic (CAM and sub-alkaline rhyodacitic (SRM. Both develop almost entirely low-sulfidation type of Au epithermal mineralization. However, two subtypes, -rich in sulfide (2-7% and -poor in sulfide (7-20% were delineated and correlated with CAM type and SRM type respectively. Furthermore, CAM is connected at deeper levels with Cu-Au+/-Mo porphyry systems in contrast with SRM, which is a non-porphyry environment. The Brad-Săcărâmb district contains mainly CAM type andesitic structures. It is a porphyry environment with epithermal low-sulfidation-rich sulfide vein halo (Barza, Troiţa-Bolcana deposits. However, a few SRM type patterns, such as Măgura Ţebii, Băiţa-Crăciuneşti and Săcărâmb, deposits exhibit Au-Ag-Te low-sulfidation-poor sulfide epithermal vein halo. The Zlatna-Stănija district exhibits similar characteristics, with Au-Ag+/-Pb, Zn veins in Cu-Au subvolcanic

  4. Geochemistry of sediments and surface soils from the Nile Delta and lower Nile valley studied by epithermal neutron activation analysis (United States)

    Arafa, Wafaa M.; Badawy, Wael M.; Fahmi, Naglaa M.; Ali, Khaled; Gad, Mohamed S.; Duliu, Octavian G.; Frontasyeva, Marina V.; Steinnes, Eiliv


    The distributions of 36 major and trace elements in 40 surface soil and sediment samples collected from the Egyptian section of the river Nile were determined by epithermal neutron activation analysis and compared with corresponding data for the Upper Continental Crust and North American Shale Composite. Their relative distributions indicate the presence of detrital material of igneous origin, most probably resulting from weathering on Ethiopian highlands and transported by the Blue Nile, the Nile main tributary. The distributions of the nickel, zinc, and arsenic contents suggest that the lower part of the Nile and its surroundings including the Nile Delta is not seriously polluted with metals from local human activity. The geographical distributions of Na, Cl, and I as well as results of principal component analysis suggest atmospheric supply of these elements from the ocean. In general the present data may contribute to a better understanding of the geochemistry of the Nile sediments.

  5. Stabilized Spheromak Fusion Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, T


    The U.S. fusion energy program is focused on research with the potential for studying plasmas at thermonuclear temperatures, currently epitomized by the tokamak-based International Thermonuclear Experimental Reactor (ITER) but also continuing exploratory work on other plasma confinement concepts. Among the latter is the spheromak pursued on the SSPX facility at LLNL. Experiments in SSPX using electrostatic current drive by coaxial guns have now demonstrated stable spheromaks with good heat confinement, if the plasma is maintained near a Taylor state, but the anticipated high current amplification by gun injection has not yet been achieved. In future experiments and reactors, creating and maintaining a stable spheromak configuration at high magnetic field strength may require auxiliary current drive using neutral beams or RF power. Here we show that neutral beam current drive soon to be explored on SSPX could yield a compact spheromak reactor with current drive efficiency comparable to that of steady state tokamaks. Thus, while more will be learned about electrostatic current drive in coming months, results already achieved in SSPX could point to a productive parallel development path pursuing auxiliary current drive, consistent with plans to install neutral beams on SSPX in the near future. Among possible outcomes, spheromak research could also yield pulsed fusion reactors at lower capital cost than any fusion concept yet proposed.

  6. The evolution of doses in the IEA-R1 reactor environment and tendencies based on the current results; Evolucao das doses no ambiente do Reator IEA-R1 e tendencias com base nos resultados atuais

    Energy Technology Data Exchange (ETDEWEB)

    Toyoda, Eduardo Yoshio


    The IPEN / CNEN-SP have a Nuclear Research Reactor-NRR named IEA-R1, in operation from 1957. It is an open swimming pool reactor using light water as shielding, moderator and as cooling, the volume of this pool is 273m{sup 3}.Until 1995 the reactor operated daily at a power of 2,0 MW. From June of that year, after a few safety modifications the reactor began operating in continuous way from Monday to Wednesday without shutdown totalizing 64 hours per week and the power was increased to 4,5MW also. Because of these changes, continuous operation and increased power, workers' doses would tend to increase. In the past several studies were conducted seeking ways to reduce the workers' doses. A study was made on the possibility to introduce a shielding at the top of the reactor core with a hot water layer. Studies have shown that a major limitation for operating a reactor at high power comes from the gamma radiation emitted by the sodium-24. Other elements such as magnesium-27, aluminum-28, Argon-51, contribute considerably to the water activity of the pool. The introduction of a hot water layer on the swimming pool would form a layer of surface, stable and free of radioactive elements with a 1.5m to 2m thickness creates a shielding to radiation from radioactive elements dissolved in water. Optimization studies proved that the installation of the hot layer was not necessary for the regime and the current power reactor operation, because other procedures adopted were more effective. From this decision the Radiological Protection Reactor Team, set up a dose assessment program to ensure them remained in low values based on principles established in national and international standards. The purpose of this paper is to analyze the individual doses of OEI (Occupationally Exposed Individual), which will be checked increasing doses resulting from recent changes in reactor operation regime and suggested viable safety and protection options, in the first instance to

  7. Photocatalytic reactor (United States)

    Bischoff, Brian L.; Fain, Douglas E.; Stockdale, John A. D.


    A photocatalytic reactor for processing selected reactants from a fluid medium comprising at least one permeable photocatalytic membrane having a photocatalytic material. The material forms an area of chemically active sites when illuminated by light at selected wavelengths. When the fluid medium is passed through the illuminated membrane, the reactants are processed at these sites separating the processed fluid from the unprocessed fluid. A light source is provided and a light transmitting means, including an optical fiber, for transmitting light from the light source to the membrane.

  8. Recent upgrades and new scientific infrastructure of MARIA research reactor, Otwock-Swierk, Poland

    Energy Technology Data Exchange (ETDEWEB)



    The MARIA reactor is open-pool type, water and beryllium moderated. It has two independent primary cooling systems: fuel and pool cooling system. Each fuel assembly is cooled down separately in pressurized channels with individual performances characterization. The fuel assemblies consist of five layers of bent plates or six concentric tubes. Currently it is one of the most powerful research reactors in Europe with operation availability at least up to 2030. Its nominal thermal power is 30 MW. It is characterized by high neutron flux density: up to 3x10{sup 14} n cm{sup -2} s{sup -1} in case of thermal neutrons, and up to 2x10{sup 13} n cm{sup -2} s{sup -1} in case of fast neutrons. The reactor is operated for ca. 4000 h per year. The reactor facility is equipped with fully equipped three hot cells with shielding up to 10{sup 15} Bq. Adjacent to the reactor facility, the radio-pharmaceutics plant (POLATOM) and Material Research Laboratory are located. They are equipped with a number of hot cells with instrumentation. The transport system of radioactive materials from reactor facility to Material Research Laboratory is available. During 2014 the MARIA reactor has been operated with three different types of fuel the same time: previous 36% enriched fuel, and two types of new LEU fuels. In the meantime, molybdenum irradiation programme has been developed. Maria is a multifunctional research tool, with a notable application in production of radioisotopes, radio-pharmaceutics manufacturing (ca. 600 TBq/y), {sup 99}Mo for medical scintigraphy (ca. 6000 TBq/y), neutron transmutation doping of silicon single crystals, wide scientific research based on neutron beams utilization. From the beginning MARIA reactor was intended for loop and fuel testing research activities. Currently it is used mostly as material testing and irradiation facility and for that reason it has wide experimental capabilities. There are eight horizontal irradiation channels from among whom six of them

  9. Thermal and epithermal neutron fluence rate gradient measurements by PADC detectors in LINAC radiotherapy treatments-field

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, M. T., E-mail:; Barros, H.; Pino, F.; Sajo-Bohus, L. [Universidad Simón Bolívar, Nuclear Physics Laboratory, Sartenejas, Caracas (Venezuela, Bolivarian Republic of); Dávila, J. [Física Médica C. A. and Universidad Central de Venezuela, Caracas (Venezuela, Bolivarian Republic of)


    LINAC VARIAN 2100 is where energetic electrons produce Bremsstrahlung radiation, with energies above the nucleon binding energy (E≈5.5MeV). This radiation induce (γ,n) and (e,e’n) reactions mainly in the natural tungsten target material (its total photoneutron cross section is about 4000 mb in a energy range from 9-17 MeV). These reactions may occur also in other components of the system (e.g. multi leaf collimator). During radiation treatment the human body may receive an additional dose inside and outside the treated volume produced by the mentioned nuclear reactions. We measured the neutron density at the treatment table using nuclear track detectors (PADC-NTD). These covered by a boron-converter are employed, including a cadmium filter, to determine the ratio between two groups of neutron energy, i.e. thermal and epithermal. The PADC-NTD detectors were exposed to the radiation field at the iso-center during regular operation of the accelerator. Neutron are determined indirectly by the converting reaction {sup 10}B(n,α){sup 7}Li the emerging charged particle leave their kinetic energy in the PADC forming a latent nuclear track, enlarged by chemical etching (6N, NaOH, 70°C). Track density provides information on the neutron density through calibration coefficient (∼1.6 10{sup 4} neutrons /track) obtained by a californium source. We report the estimation of the thermal and epithermal neutron field and its gradient for photoneutrons produced in radiotherapy treatments with 18 MV linear accelerators. It was obsered that photoneutron production have higher rate at the iso-center.

  10. Microlith-Based Catalytic Reactor for Air Quality and Trace Contaminant Control Applications (United States)

    Vilekar, Saurabh; Hawley, Kyle; Junaedi, Christian; Crowder, Bruce; Prada, Julian; Mastanduno, Richard; Perry, Jay L.; Kayatin, Matthew J.


    Traditionally, gaseous compounds such as methane, carbon monoxide, and trace contaminants have posed challenges for maintaining clean air in enclosed spaces such as crewed spacecraft cabins as they are hazardous to humans and are often difficult to remove by conventional adsorption technology. Catalytic oxidizers have provided a reliable and robust means of disposing of even trace levels of these compounds by converting them into carbon dioxide and water. Precision Combustion, Inc. (PCI) and NASA - Marshall (MSFC) have been developing, characterizing, and optimizing high temperature catalytic oxidizers (HTCO) based on PCI's patented Microlith® technology to meet the requirements of future extended human spaceflight explorations. Current efforts have focused on integrating the HTCO unit with a compact, simple recuperative heat exchanger to reduce the overall system size and weight while also reducing its energy requirements. Previous efforts relied on external heat exchangers to recover the waste heat and recycle it to the oxidizer to minimize the system's power requirements; however, these units contribute weight and volume burdens to the overall system. They also result in excess heat loss due to the separation of the HTCO and the heat recuperator, resulting in lower overall efficiency. Improvements in the recuperative efficiency and close coupling of HTCO and heat recuperator lead to reductions in system energy requirements and startup time. Results from testing HTCO units integrated with heat recuperators at a variety of scales for cabin air quality control and heat melt compactor applications are reported and their benefits over previous iterations of the HTCO and heat recuperator assembly are quantified in this paper.

  11. Hybrid adsorptive membrane reactor

    Energy Technology Data Exchange (ETDEWEB)

    Tsotsis, Theodore T [Huntington Beach, CA; Sahimi, Muhammad [Altadena, CA; Fayyaz-Najafi, Babak [Richmond, CA; Harale, Aadesh [Los Angeles, CA; Park, Byoung-Gi [Yeosu, KR; Liu, Paul K. T. [Lafayette Hill, PA


    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  12. D and DR Reactors (United States)

    Federal Laboratory Consortium — The world's second full-scale nuclear reactor was the D Reactor at Hanford which was built in the early 1940's and went operational in December of 1944.D Reactor ran...

  13. Reactor transient

    Energy Technology Data Exchange (ETDEWEB)

    Menegus, R.L.


    The authors are planning a calculation to be done on the Univac at the Louviers Building to estimate the effect of xenon transients, a high reactor power. This memorandum outlines the reasons why they prefer to do the work at Louviers rather than at another location, such as N.Y.U. They are to calculate the response of the reactor to a sudden change in position of the half rods. Qualitatively, the response will be a change in the rooftop ratio of the neutron flux. The rooftop ratio may oscillate with high damping, or, instead, it may oscillate for many cycles. It has not been possible for them to determine this response by hand calculation because of the complexity of the problem, and yet it is important for them to be certain that high power operation will not lead us to inherently unstable operation. Therefore they have resorted to machine computation. The system of differential equations that describes the response has seven dependent variables; therefore there are seven equations, each coupled with one or more of the others. The authors have discussed the problem with R.R. Haefner at the plant, and it is his opinion that the IBM 650 cannot adequately handle the system of seven equations because the characteristic time constants vary over a range of about 10{sup 8}. The Univac located at the Louviers Building is said to be satisfactory for this computation.

  14. Microchannel Methanation Reactors Using Nanofabricated Catalysts Project (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and the Pennsylvania State University (Penn State) propose to develop and demonstrate a microchannel methanation reactor based on...

  15. Mineralized breccia clasts: a window into hidden porphyry-type mineralization underlying the epithermal polymetallic deposit of Cerro de Pasco (Peru) (United States)

    Rottier, Bertrand; Kouzmanov, Kalin; Casanova, Vincent; Bouvier, Anne-Sophie; Baumgartner, Lukas P.; Wälle, Markus; Fontboté, Lluís


    Cerro de Pasco (Peru) is known for its large epithermal polymetallic (Zn-Pb-Ag-Cu-Bi) mineralization emplaced at shallow level, a few hundred meters below the paleo-surface, at the border of a large diatreme-dome complex. Porphyry-style veins crosscutting hornfels and magmatic rock clasts are found in the diatreme breccia and in quartz-monzonite porphyry dikes. Such mineralized veins in clasts allow investigation of high-temperature porphyry-style mineralization developed in the deep portions of magmatic-hydrothermal systems. Quartz in porphyry-style veins contains silicate melt inclusions as well as fluid and solid mineral inclusions. Two types of high-temperature (> 600 °C) quartz-molybdenite-(chalcopyrite)-(pyrite) veins are found in the clasts. Early, thin (1-2 mm), and sinuous HT1 veins are crosscut by slightly thicker (up to 2 cm) and more regular HT2 veins. The HT1 vein quartz hosts CO2- and sulfur-rich high-density vapor inclusions. Two subtypes of the HT1 veins have been defined, based on the nature of mineral inclusions hosted in quartz: (i) HT1bt veins with inclusions of K-feldspar, biotite, rutile, and minor titanite and (ii) HT1px veins with inclusions of actinolite, augite, titanite, apatite, and minor rutile. Using an emplacement depth of the veins of between 2 and 3 km (500 to 800 bar), derived from the diatreme breccia architecture and the supposed erosion preceding the diatreme formation, multiple mineral thermobarometers are applied. The data indicate that HT1 veins were formed at temperatures > 700 °C. HT2 veins host assemblages of polyphase brine inclusions, generally coexisting with low-density vapor-rich inclusions, trapped at temperatures around 600 °C. Rhyolitic silicate melt inclusions found in both HT1 and HT2 veins represent melt droplets transported by the ascending hydrothermal fluids. LA-ICP-MS analyses reveal a chemical evolution coherent with the crystallization of an evolved rhyolitic melt. Quartz from both HT1 and HT2 veins

  16. Flexible modified candle burnup scheme based long life Pb-Bi cooled fast reactor with natural uranium as fuel cycle input employing coupled core

    Energy Technology Data Exchange (ETDEWEB)

    Su' ud, Zaki; SNM, Rida [Physics Dept., ITB, Jl. Ganesha 10, Bandung, West Java 40132 (Indonesia); Sekimoto, Hiroshi [Tokyo Inst. of Technology (Japan)


    calculation is then brought back to SRAC code for cell burn-up calculation. This iteration is repeated until the convergence is reached. Using the coupling dual core concept after some optimization we got several design which can fulfill the criteria can be obtained. Among of the main results are the design of long-life Pb-Bi cooled fast reactors which fuel cycle input is natural uranium but the maximum burnup level can be adjusted from about 10% HM to 40% HM. The results show that the twin(coupling )core concept can work well and give excellent configuration of modified CANDLE with flexible maximum burnup level up which can reach current fast reactors fuel technology. References: 1. H. Sekimoto, Light a CANDLE An Innovative Burnup Strategy of Nuclear Reactors, COE INES, Research Lab. For Nuclear Reactors, Tokyo Institute of Technology, Japan. 2. H. Sekimoto, et al, 'CANDLE: The New Burnup Strategy', Nuclear Science and Engineering, 139, 1-12 (2001), 3. Zaki S and H. Sekimoto: 'Optimization of Modified Candle Burnup Scheme Based Long Life Pb-Bi Cooled Fast Reactor with Natural Uranium as Fuel Cycle Input', PBNC 2008 Conference, Oct. 11-18, 2008, Aomori Japan. 4. Zaki S and H. Sekimoto: 'Design Study Of Long Life Pb-Bi Cooled Fast Reactor With Natural Uranium As Fuel Cycle Input Using Modified Candle Burnup Scheme' Submitted to Annals of Nuclear Energy. (authors)

  17. Assessment of General Atomics accelerator transmutation of waste concept based on gas-turbine-modular helium cooled reactor technology.

    Energy Technology Data Exchange (ETDEWEB)

    Gohar, Y.; Taiwo, T. A.; Cahalan, J. E.; Finck, P. J.


    An assessment has been performed for an Accelerator Transmutation of Waste (ATW) concept based on the use of the high temperature gas reactor technology. The concept has been proposed by General Atomics for the ATW system. The assessment was jointly conducted at Argonne National Laboratory (ANL) and Los Alamos national laboratory to assess and to define the potential candidates for the ATW system. This report represents the assessment work performed at ANL. The concept uses recycled light water reactor (LWR)-discharge-transuranic extracted from irradiated oxide fuel in a critical and sub-critical accelerator driven gas-cooled transmuter. In this concept, the transmuter operates at 600 MWt first in the critical mode for three cycles and then operates in a subcritical accelerator-driven mode for a single cycle. The transmuter contains both thermal and fast spectrum transmutation zones. The thermal zone is fueled with the TRU oxide material in the form of coated particles, which are mixed with graphite powder, packed into cylindrical compacts, and loaded in hexagonal graphite blocks with cylindrical channels; the fast zone is fueled with TRU-oxide material in the form of coated particles without the graphite powder and the graphite blocks that has been burned in the thermal region for three critical cycles and one additional accelerator-driven cycle. The fuel loaded into the fast zone is irradiated for four additional cycles. This fuel management scheme is intended to achieve a high Pu isotopes consumption in the thermal spectrum zone, and to consume the minor actinides in the fast-spectrum zone. Monte Carlo and deterministic codes have been used to assess the system performance and to determine the feasibility of achieving high TRU consumption levels. The studies revealed the potential for high consumption of Pu-239 (97%), total Pu (71%) and total TRU (64%) in the system. The analyses confirmed the need for burnable absorber for both suppressing the initial excess

  18. A new model for anaerobic processes of up-flow anaerobic sludge blanket reactors based on cellular automata

    DEFF Research Database (Denmark)

    Skiadas, Ioannis V.; Ahring, Birgitte Kiær


    The advantageous performance of the UASB reactors is due to the immobilisation of the active biomass, since bacteria coagulate forming aggregates usually called granules. Changes in organic loading rate, hydraulic loading rate or influent substrate composition usually result in changes in granule...

  19. Student Collaboration in a Series of Integrated Experiments to Study Enzyme Reactor Modeling with Immobilized Cell-Based Invertase (United States)

    Taipa, M. A^ngela; Azevedo, Ana M.; Grilo, Anto´nio L.; Couto, Pedro T.; Ferreira, Filipe A. G.; Fortuna, Ana R. M.; Pinto, Ine^s F.; Santos, Rafael M.; Santos, Susana B.


    An integrative laboratory study addressing fundamentals of enzyme catalysis and their application to reactors operation and modeling is presented. Invertase, a ß-fructofuranosidase that catalyses the hydrolysis of sucrose, is used as the model enzyme at optimal conditions (pH 4.5 and 45 °C). The experimental work involves 3 h of laboratory time…

  20. Electrochemical Biosensors Based on Enzymatic Reactors Filled by Various Types of Silica and Amalgam Powders for Measurements in Flow Systems

    Czech Academy of Sciences Publication Activity Database

    Josypčuk, Oksana; Barek, J.; Josypčuk, Bohdan


    Roč. 28, č. 12 (2016), s. 3028-3038 ISSN 1040-0397 R&D Projects: GA ČR(CZ) GA15-03139S Institutional support: RVO:61388955 Keywords : electrochemical biosensors * enzymatic reactor * silica powders Subject RIV: CG - Electrochemistry Impact factor: 2.851, year: 2016

  1. An operation protocol for facilitating start-up of single-stage autotrophic nitrogen removing reactors based on process stoichiometry

    DEFF Research Database (Denmark)

    Mutlu, A. Gizem; Vangsgaard, Anna Katrine; Sin, Gürkan


    Start-up and operation of single-stage nitritation/anammox reactor employing complete autotrophic nitrogen can be difficult. Keeping the performance criteria and monitoring the microbial community composition may not be easy or fast enough to take action on time. In this study, a control strategy...

  2. Contribution to development of SPNDs for instantaneous and selective measurement of different radiation fields in nuclear reactors; Contribution au developpement de collectrons pour la mesure instantanee et selective des differents champs de rayonnements en reacteurs nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Blandin, Christophe [Institut National Polytechnique, 38 - Grenoble (France)


    The objective of this work was conceiving and experimentally optimizing the SPNDs (Self-Powdered Neutron Detector) able to control fast power transients in test reactors and also to cope with requirements of surveillanceand protection of EDF reactors. Thus, different SPND emitters of platinum, gadolinium, hafnium and cobalt were provided according to their nature with sheathing and stainless steel plugs as well as with zirconium over-sheathing in order to render them faster, more selective and adapted for wear checking. Special experimental devices were designed for measuring inside the Siloe reactor the promptness of the signals from SPND, on one hand, and their sensitivity to thermal and epithermal neutrons as well as to gamma rays, on the other hand. The follow-up of power transients in test reactors is ensured by the instantaneous measurement of thermal and epithermal neutron flux as well as of gamma field by means of three special SPND with gadolinium, hafnium and platinum. Also, we have defined the characteristics of a new SPND with cobalt, that delivers a current of unique neutronic origin, able to ensure the surveillance and protection of a power reactor over a period of at least six years.

  3. Nuclear reactor neutron shielding (United States)

    Speaker, Daniel P; Neeley, Gary W; Inman, James B


    A nuclear reactor includes a reactor pressure vessel and a nuclear reactor core comprising fissile material disposed in a lower portion of the reactor pressure vessel. The lower portion of the reactor pressure vessel is disposed in a reactor cavity. An annular neutron stop is located at an elevation above the uppermost elevation of the nuclear reactor core. The annular neutron stop comprises neutron absorbing material filling an annular gap between the reactor pressure vessel and the wall of the reactor cavity. The annular neutron stop may comprise an outer neutron stop ring attached to the wall of the reactor cavity, and an inner neutron stop ring attached to the reactor pressure vessel. An excore instrument guide tube penetrates through the annular neutron stop, and a neutron plug comprising neutron absorbing material is disposed in the tube at the penetration through the neutron stop.

  4. Investigation of Isfahan miniature neutron source reactor (MNSR for boron neutron capture therapy by MCNP simulation

    Directory of Open Access Journals (Sweden)

    S.Z Kalantari


    Full Text Available One of the important neutron sources for Boron Neutron Capture Therapy (BNCT is a nuclear reactor. It needs a high flux of epithermal neutrons. The optimum conditions of the neutron spectra for BNCT are provided by the International Atomic Energy Agency (IAEA. In this paper, Miniature Neutron Source Reactor (MNSR as a neutron source for BNCT was investigated. For this purpose, we designed a Beam Shaping Assembly (BSA for the reactor and the neutron transport from the core of the reactor to the output windows of BSA was simulated by MCNPX code. To optimize the BSA performance, two sets of parameters should be evaluated, in-air and in-phantom parameters. For evaluating in-phantom parameters, a Snyder head phantom was used and biological dose rate and dose-depth curve were calculated in brain normal and tumor tissues. Our calculations showed that the neutron flux of the MNSR reactor can be used for BNCT, and the designed BSA in optimum conditions had a good therapeutic characteristic for BNCT.

  5. On-Site Determination and Monitoring of Real-Time Fluence Delivery for an Operating UV Reactor Based on a True Fluence Rate Detector. (United States)

    Li, Mengkai; Li, Wentao; Qiang, Zhimin; Blatchley, Ernest R


    At present, on-site fluence (distribution) determination and monitoring of an operating UV system represent a considerable challenge. The recently developed microfluorescent silica detector (MFSD) is able to measure the approximate true fluence rate (FR) at a fixed position in a UV reactor that can be compared with a FR model directly. Hence it has provided a connection between model calculation and real-time fluence determination. In this study, an on-site determination and monitoring method of fluence delivery for an operating UV reactor was developed. True FR detectors, a UV transmittance (UVT) meter, and a flow rate meter were used for fundamental measurements. The fluence distribution, as well as reduction equivalent fluence (REF), 10th percentile dose in the UV fluence distribution (F 10 ), minimum fluence (F min ), and mean fluence (F mean ) of a test reactor, was calculated in advance by the combined use of computational fluid dynamics and FR field modeling. A field test was carried out on the test reactor for disinfection of a secondary water supply. The estimated real-time REF, F 10 , F min , and F mean decreased 73.6%, 71.4%, 69.6%, and 72.9%, respectively, during a 6-month period, which was attributable to lamp output attenuation and sleeve fouling. The results were analyzed with synchronous data from a previously developed triparameter UV monitoring system and water temperature sensor. This study allowed demonstration of an accurate method for on-site, real-time fluence determination which could be used to enhance the security and public confidence of UV-based water treatment processes.

  6. Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification (United States)

    Castro-Dominguez, Bernardo; Mardilovich, Ivan P.; Ma, Liang-Chih; Ma, Rui; Dixon, Anthony G.; Kazantzis, Nikolaos K.; Ma, Yi Hua


    Palladium-based catalytic membrane reactors (CMRs) effectively remove H2 to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H2, CO and CO2. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H2O, CO2 and H2. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H2 and induce higher methane and CO conversions while yielding ultrapure H2 and compressed CO2 ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H2 permeance and purity, high CH4 conversion levels and reduced CO yields. PMID:27657143

  7. Microchannel Reactors for ISRU Applications (United States)

    Carranza, Susana; Makel, Darby B.; Blizman, Brandon; Ward, Benjamin J.


    Affordable planning and execution of prolonged manned space missions depend upon the utilization of local resources and the waste products which are formed in manned spacecraft and surface bases. Successful in-situ resources utilization (ISRU) will require component technologies which provide optimal size, weight, volume, and power efficiency. Microchannel reactors enable the efficient chemical processing of in situ resources. The reactors can be designed for the processes that generate the most benefit for each mission. For instance, propellants (methane) can be produced from carbon dioxide from the Mars atmosphere using the Sabatier reaction and ethylene can be produced from the partial oxidation of methane. A system that synthesizes ethylene could be the precursor for systems to synthesize ethanol and polyethylene. Ethanol can be used as a nutrient for Astrobiology experiments, as well as the production of nutrients for human crew (e.g. sugars). Polyethylene can be used in the construction of habitats, tools, and replacement parts. This paper will present recent developments in miniature chemical reactors using advanced Micro Electro Mechanical Systems (MEMS) and microchannel technology to support ISRU of Mars and lunar missions. Among other applications, the technology has been demonstrated for the Sabatier process and for the partial oxidation of methane. Microchannel reactors were developed based on ceramic substrates as well as metal substrates. In both types of reactors, multiple layers coated with catalytic material are bonded, forming a monolithic structure. Such reactors are readily scalable with the incorporation of extra layers. In addition, this reactor structure minimizes pressure drop and catalyst settling, which are common problems in conventional packed bed reactors.

  8. Reactor based plutonium disposition - physics and fuel behaviour benchmark studies of an OECD/NEA experts group

    Energy Technology Data Exchange (ETDEWEB)

    D' Hondt, P. [SCK.CEN, Mol (Belgium); Gehin, J. [ORNL, Oak Ridge, TN (United States); Na, B.C.; Sartori, E. [Organisation for Economic Co-Operation and Development, Nuclear Energy Agency, 92 - Issy les Moulineaux (France); Wiesenack, W. [Organisation for Economic Co-Operation and Development/HRP, Halden (Norway)


    One of the options envisaged for disposing of weapons grade plutonium, declared surplus for national defence in the Russian Federation and Usa, is to burn it in nuclear power reactors. The scientific/technical know-how accumulated in the use of MOX as a fuel for electricity generation is of great relevance for the plutonium disposition programmes. An Expert Group of the OECD/Nea is carrying out a series of benchmarks with the aim of facilitating the use of this know-how for meeting this objective. This paper describes the background that led to establishing the Expert Group, and the present status of results from these benchmarks. The benchmark studies cover a theoretical reactor physics benchmark on a VVER-1000 core loaded with MOX, two experimental benchmarks on MOX lattices and a benchmark concerned with MOX fuel behaviour for both solid and hollow pellets. First conclusions are outlined as well as future work. (author)

  9. The origin of Ag-Au-S-Se minerals in adularia-sericite epithermal deposits: constraints from the Broken Hills deposit, Hauraki Goldfield, New Zealand (United States)

    Cocker, Helen A.; Mauk, Jeffrey L.; Rabone, Stuart D. C.


    The 7.1 Ma Broken Hills adularia-sericite Au-Ag deposit is currently the only producing rhyolite-hosted epithermal deposit in the Hauraki Goldfield of New Zealand. The opaque minerals include pyrite, electrum, acanthite (Ag2S), sphalerite, and galena, which are common in other adularia-sericite epithermal deposits in the Hauraki Goldfield and elsewhere worldwide. Broken Hills ores also contain the less common minerals aguilarite (Ag4SeS), naumannite (Ag2Se), petrovskaite (AuAgS), uytenbogaardtite (Ag3AuS2), fischesserite (Ag3AuSe2), an unnamed silver chloride (Ag2Cl), and unnamed Ag ± Au minerals. Uytenbogaardtite and petrovskaite occur with high-fineness electrum. Broken Hills is the only deposit in the Hauraki Goldfield where uytenbogaardtite and petrovskaite have been identified, and these phases appear to have formed predominantly from unmixing of a precursor high-temperature phase under hypogene conditions. Supergene minerals include covellite, chalcocite, Au-rich electrum, barite, and a variety of iron oxyhydroxide minerals. Uytenbogaardtite can form under supergene and hypogene conditions, and textural relationships between uytenbogaardtite and associated high-fineness electrum may be similar in both conditions. Distinguishing the likely environment of formation rests principally on identification of other supergene minerals and documenting their relationships with uytenbogaardtite. The presence of aguilarite, naumannite, petrovskaite, and fischesserite at Broken Hills reflects a Se-rich mineral assemblage. In the Hauraki Goldfield and the western Great Basin, USA, Se-rich minerals are more abundant in provinces that are characterized by bimodal rhyolite-andesite volcanism, but in other epithermal provinces worldwide, the controls on the occurrences of Se-bearing minerals remain poorly constrained, in spite of the unusually high grades associated with many Se-rich epithermal deposits.

  10. 8-group relative delayed neutron yields for epithermal neutron induced fission of sup 2 sup 3 sup 5 U and sup 2 sup 3 sup 9 Pu

    CERN Document Server

    Piksaikin, V M; Kazakov, L E; Korolev, G G; Roshchenko, V A; Tertychnyj, R G


    An 8-group representation of relative delayed neutron yields was obtained for epithermal neutron induced fission of sup 2 sup 3 sup 5 U and sup 2 sup 3 sup 9 Pu. These data were compared with ENDF/B-VI data in terms of the average half- life of the delayed neutron precursors and on the basis of the dependence of reactivity on the asymptotic period.

  11. Noble gas data from Goldfield and Tonopah epithermal Au-Ag deposits, ancestral Cascades Arc, USA: Evidence for a primitive mantle volatile source (United States)

    Manning, Andrew H.; Hofstra, Albert H.


    The He, Ne, and Ar isotopic composition of fluid inclusions in ore and gangue minerals were analyzed to determine the source of volatiles in the high-grade Goldfield and Tonopah epithermal Au-Ag deposits in southwestern Nevada, USA. Ar and Ne are mainly atmospheric, whereas He has only a minor atmospheric component. Corrected 3He/4He ratios (with atmospheric He removed) range widely from 0.05 to 35.8 times the air 3He/4He ratio (RA), with a median of 1.43 RA. Forty-one percent of measured 3He/4He ratios are ≥4 RA, corresponding to ≥50% mantle He assuming a mantle ratio of 8 RA. These results suggest that mafic magmas were part of the magmatic-hydrothermal system underlying Goldfield and Tonopah, and that associated mantle-sourced volatiles may have played a role in ore formation. The three highest corrected 3He/4He ratios of 17.0, 23.7, and 35.8 RAindicate a primitive mantle He source and are the highest yet reported for any epithermal-porphyry system and for the Cascades arc region. Compiled 3He/4He measurements from epithermal-porphyry systems in subduction-related magmatic arcs around the world (n = 209) display a statistically significant correlation between 3He/4He and Au-Ag grade. The correlation suggests that conditions which promote higher fluid inclusion 3He/4He ratios (abundance of mantle volatiles and focused upward volatile transport) have some relation to conditions that promote higher Au-Ag grades (focused flow of metal-bearing fluids and efficient chemical traps). Results of this and previous investigations of He isotopes in epithermal-porphyry systems are consistent with the hypothesis posed in recent studies that mafic magmas serve an important function in the formation of these deposits.

  12. Tests of a new CCD-camera based neutron radiography detector system at the reactor stations in Munich and Vienna

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E.; Pleinert, H. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Schillinger, B. [Technische Univ. Muenchen (Germany); Koerner, S. [Atominstitut der Oesterreichischen Universitaeten, Vienna (Austria)


    The performance of the new neutron radiography detector designed at PSI with a cooled high sensitive CCD-camera was investigated under real neutronic conditions at three beam ports of two reactor stations. Different converter screens were applied for which the sensitivity and the modulation transfer function (MTF) could be obtained. The results are very encouraging concerning the utilization of this detector system as standard tool at the radiography stations at the spallation source SINQ. (author) 3 figs., 5 refs.

  13. Application of a PID controller based on fuzzy logic to reduce variations in the control parameters in PWR reactors

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, Wagner Eustaquio de; Lira, Carlos Alberto Brayner de Oliveira; Brito, Thiago Souza Pereira de; Afonso, Antonio Claudio Marques, E-mail:, E-mail:, E-mail:, E-mail: [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Centro de Tecnologia e Geociencias. Departamento de Energia Nuclear; Cruz Filho, Antonio Jose da; Marques, Jose Antonio, E-mail:, E-mail: [Universidade Catolica de Pernambuco (CCT/PUC-PE), Recife, PE (Brazil). Centro de Ciencias e Tecnologia; Teixeira, Marcello Goulart, E-mail: [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Matematica. Dept. de Matematica


    Nuclear reactors are in nature nonlinear systems and their parameters vary with time as a function of power level. These characteristics must be considered if large power variations occur in power plant operational regimes, such as in load-following conditions. A PWR reactor has a component called pressurizer, whose function is to supply the necessary high pressure for its operation and to contain pressure variations in the primary cooling system. The use of control systems capable of reducing fast variations of the operation variables and to maintain the stability of this system is of fundamental importance. The best-known controllers used in industrial control processes are proportional-integral-derivative (PID) controllers due to their simple structure and robust performance in a wide range of operating conditions. However, designing a fuzzy controller is seen to be a much less difficult task. Once a Fuzzy Logic controller is designed for a particular set of parameters of the nonlinear element, it yields satisfactory performance for a range of these parameters. The objective of this work is to develop fuzzy proportional-integral-derivative (fuzzy-PID) control strategies to control the level of water in the reactor. In the study of the pressurizer, several computer codes are used to simulate its dynamic behavior. At the fuzzy-PID control strategy, the fuzzy logic controller is exploited to extend the finite sets of PID gains to the possible combinations of PID gains in stable region. Thus the fuzzy logic controller tunes the gain of PID controller to adapt the model with changes in the water level of reactor. The simulation results showed a favorable performance with the use to fuzzy-PID controllers. (author)

  14. Magmatism and Epithermal Gold-Silver Deposits of the Southern Ancestral Cascade Arc, Western Nevada and Eastern California (United States)

    John, David A.; du Bray, Edward A.; Henry, Christopher D.; Vikre, Peter


    Many epithermal gold-silver deposits are temporally and spatially associated with late Oligocene to Pliocene magmatism of the southern ancestral Cascade arc in western Nevada and eastern California. These deposits, which include both quartz-adularia (low- and intermediate-sulfidation; Comstock Lode, Tonopah, Bodie) and quartz-alunite (high-sulfidation; Goldfield, Paradise Peak) types, were major producers of gold and silver. Ancestral Cascade arc magmatism preceded that of the modern High Cascades arc and reflects subduction of the Farallon plate beneath North America. Ancestral arc magmatism began about 45 Ma, continued until about 3 Ma, and extended from near the Canada-United States border in Washington southward to about 250 km southeast of Reno, Nevada. The ancestral arc was split into northern and southern segments across an inferred tear in the subducting slab between Mount Shasta and Lassen Peak in northern California. The southern segment extends between 42°N in northern California and 37°N in western Nevada and was active from about 30 to 3 Ma. It is bounded on the east by the northeast edge of the Walker Lane. Ancestral arc volcanism represents an abrupt change in composition and style of magmatism relative to that in central Nevada. Large volume, caldera-forming, silicic ignimbrites associated with the 37 to 19 Ma ignimbrite flareup are dominant in central Nevada, whereas volcanic centers of the ancestral arc in western Nevada consist of andesitic stratovolcanoes and dacitic to rhyolitic lava domes that mostly formed between 25 and 4 Ma. Both ancestral arc and ignimbrite flareup magmatism resulted from rollback of the shallowly dipping slab that began about 45 Ma in northeast Nevada and migrated south-southwest with time. Most southern segment ancestral arc rocks have oxidized, high potassium, calc-alkaline compositions with silica contents ranging continuously from about 55 to 77 wt%. Most lavas are porphyritic and contain coarse plagioclase

  15. Two conceptual designs of helical fusion reactor FFHR-d1A based on ITER technologies and challenging ideas (United States)

    Sagara, A.; Miyazawa, J.; Tamura, H.; Tanaka, T.; Goto, T.; Yanagi, N.; Sakamoto, R.; Masuzaki, S.; Ohtani, H.; The FFHR Design Group


    The Fusion Engineering Research Project (FERP) at the National Institute for Fusion Science (NIFS) is conducting conceptual design activities for the LHD-type helical fusion reactor FFHR-d1A. This paper newly defines two design options, ‘basic’ and ‘challenging.’ Conservative technologies, including those that will be demonstrated in ITER, are chosen in the basic option in which two helical coils are made of continuously wound cable-in-conduit superconductors of Nb3Sn strands, the divertor is composed of water-cooled tungsten monoblocks, and the blanket is composed of water-cooled ceramic breeders. In contrast, new ideas that would possibly be beneficial for making the reactor design more attractive are boldly included in the challenging option in which the helical coils are wound by connecting high-temperature REBCO superconductors using mechanical joints, the divertor is composed of a shower of molten tin jets, and the blanket is composed of molten salt FLiNaBe including Ti powers to increase hydrogen solubility. The main targets of the challenging option are early construction and easy maintenance of a large and three-dimensionally complicated helical structure, high thermal efficiency, and, in particular, realistic feasibility of the helical reactor.

  16. Start-Up Characteristics of a Granule-Based Anammox UASB Reactor Seeded with Anaerobic Granular Sludge

    Directory of Open Access Journals (Sweden)

    Lei Xiong


    Full Text Available The granulation of anammox sludge plays an important role in the high nitrogen removal performance of the anammox reactor. In this study, anaerobic granular sludge was selected as the seeding sludge to start up anammox reactor in order to directly obtain anammox granules. Results showed that the anammox UASB reactor was successfully started up by inoculating anaerobic granular sludge, with substrate capacity of 4435.2 mg/(L·d and average ammonium and nitrite removal efficiency of 90.36% and 93.29%, respectively. During the start-up course, the granular sludge initially disintegrated and then reaggregated and turned red, suggesting the high anammox performance. Zn-Fe precipitation was observed on the surface of granules during the operation by SEM-EDS, which would impose inhibition to the anammox activity of the granules. Accordingly, it is suggested to relatively reduce the trace metals concentrations, of Fe and Zn in the conventional medium. The findings of this study are expected to be used for a shorter start-up and more stable operation of anammox system.

  17. A next-generation reactor concept: The Integral Fast Reactor (IFR)

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Y.I.


    The Integral Fast Reactor (IFR) is an advanced liquid metal reactor concept being developed at Argonne National Laboratory as reactor technology for the 21st century. It seeks to specifically exploit the inherent properties of liquid metal cooling and metallic fuel in a way that leads to substantial improvements in the characteristics of the complete reactor system, in particular passive safety and waste management. The IFR concept consists of four technical features: (1) liquid sodium cooling, (2) pool-type reactor configuration, (3) metallic fuel, and (4) fuel cycle closure based on pyroprocessing.

  18. A next-generation reactor concept: The Integral Fast Reactor (IFR)

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Y.I.


    The Integral Fast Reactor (IFR) is an advanced liquid metal reactor concept being developed at Argonne National Laboratory as reactor technology for the 21st century. It seeks to specifically exploit the inherent properties of liquid metal cooling and metallic fuel in a way that leads to substantial improvements in the characteristics of the complete reactor system, in particular passive safety and waste management. The IFR concept consists of four technical features: (1) liquid sodium cooling, (2) pool-type reactor configuration, (3) metallic fuel, and (4) fuel cycle closure based on pyroprocessing.

  19. Radiation injury of boron neutron capture therapy using mixed epithermal- and thermal neutron beams in patients with malignant glioma

    Energy Technology Data Exchange (ETDEWEB)

    Kageji, T. E-mail:; Nagahiro, S.; Mizobuchi, Y.; Toi, H.; Nakagawa, Y.; Kumada, H


    The purpose of this study was to clarify the radiation injury in acute or delayed stage after boron neutron capture therapy (BNCT) using mixed epithermal- and thermal neutron beams in patients with malignant glioma. Eighteen patients with malignant glioma underwent mixed epithermal- and thermal neutron beam and sodium borocaptate between 1998 and 2004. The radiation dose (i.e. physical dose of boron n-alpha reaction) in the protocol used between 1998 and 2000 (Protocol A, n=8) prescribed a maximum tumor volume dose of 15 Gy. In 2001, a new dose-escalated protocol was introduced (Protocol B, n=4); it prescribes a minimum tumor volume dose of 18 Gy or, alternatively, a minimum target volume dose of 15 Gy. Since 2002, the radiation dose was reduced to 80-90% dose of Protocol B because of acute radiation injury. A new Protocol was applied to 6 glioblastoma patients (Protocol C, n=6). The average values of the maximum vascular dose of brain surface in Protocol A, B and C were 11.4{+-}4.2 Gy, 15.7{+-}1.2 and 13.9{+-}3.6 Gy, respectively. Acute radiation injury such as a generalized convulsion within 1 week after BNCT was recognized in three patients of Protocol B. Delayed radiation injury such as a neurological deterioration appeared 3-6 months after BNCT, and it was recognized in 1 patient in Protocol A, 5 patients in Protocol B. According to acute radiation injury, the maximum vascular dose was 15.8{+-}1.3 Gy in positive and was 12.6{+-}4.3 Gy in negative. There was no significant difference between them. According to the delayed radiation injury, the maximum vascular dose was 13.8{+-}3.8 Gy in positive and was 13.6{+-}4.9 Gy in negative. There was no significant difference between them. The dose escalation is limited because most patients in Protocol B suffered from acute radiation injury. We conclude that the maximum vascular dose does not exceed over 12 Gy to avoid the delayed radiation injury, especially, it should be limited under 10 Gy in the case that tumor

  20. The geochemistry of host arc volcanic rocks to the Co-O epithermal gold deposit, Eastern Mindanao, Philippines (United States)

    Sonntag, Iris; Kerrich, Robert; Hagemann, Steffen G.


    Mindanao is the second largest island of the Philippines and is located in the southern part of the archipelago. It comprises the suture zone between the Eurasian and the Philippine plate, which is displayed in the Philippine Mobile Belt. Eastern Mindanao is part of the Philippine Mobile Belt and outcropping rocks are mainly Eocene to Pliocene in age related to episodes of arc volcanism alternating with sedimentation. New high-precision elemental analysis of the Oligocene magma series, hosting the Co-O epithermal Au deposit, which represents an arc segment in the central part of Eastern Mindanao, revealed dominantly calc-alkaline rocks ranging in composition between basalt and dacites. Major element trends (MgO vs. TiO2 and Fe2O3) are comparable to other magmas in Central and Eastern Mindanao as well as other SW Pacific Islands such as Borneo. Rare earth and trace element distribution patterns display typical island arc signatures highlighted by the conjunction of LILE-enrichment with troughs at Nb, Ta, and Ti. Ratios of Zr/Nb in basalts vary between 17 and 39, signifying a depleted subarc mantle wedge comparable to the range of MORB, and other Indonesian island arc basalts. In basalts, Nb/Ta and Zr/Sm ratios are 12-37 and 14-27 respectively indicative of deep melts of rutile-eclogite subducted slab, as well as fluids, infiltrating the mantle wedge source of basalts. Moderate large ion lithophile element contents and low Th/La and Th/Ce ratios suggest no significant slab-derived components such as sediment or crustal fragments. The comparatively low Ce and Yb values in basalts, but also andesites and dacites, are consistent with a thin arc crust related to an intraoceanic convergent margin setting. This is further supported by Nb contents in basalts that range between 1 and 3 ppm and are within the range of modern oceanic convergent margin basalts. The range of HREE fractionation signifies that basaltic melts separated at deeper levels of the subarc wedge, possibly

  1. Design of the core of a breed/burn fast reactor with the deterministic code KANEXT; Diseno del nucleo de un reactor rapido de cria/quemado con el codigo deterministico KANEXT

    Energy Technology Data Exchange (ETDEWEB)

    Lopez S, R. C.; Francois L, J. L., E-mail: [UNAM, Facultad de Ingenieria, Departamento de Sistemas Energeticos, Paseo Cuauhnahuac 8532, 62550 Jiutepec, Morelos (Mexico)


    The breeding fast reactors are interesting because they generate more plutonium than they consume, however, the fuel has to be reprocessed for the generated plutonium is used in another reactor. In a breed/burn reactor (BBR) the plutonium is generated and used -in situ- inside the same reactor, reducing this way costs and the proliferation possibility. In this work, the core of a BBR was designed; cooled by sodium that consists of 210 active assemblies and 7 spaces for control rods, each assembly consists of 169 pines. The design differs from other BBR it includes a blanket in the reactor center. The above-mentioned was to take advantage of the fact by geometry that the population of fast and epithermal neutrons will be high in the area, due to the fissions in adjacent fissile areas. Favorable results were obtained, although not definitive with exchange scheme of spent fuel. Efforts should be made in the future to homogenize the power generation within the reactor and replace the spent assemblies more efficiently. (Author)

  2. Reference worldwide model for antineutrinos from reactors (United States)

    Baldoncini, Marica; Callegari, Ivan; Fiorentini, Giovanni; Mantovani, Fabio; Ricci, Barbara; Strati, Virginia; Xhixha, Gerti


    Antineutrinos produced at nuclear reactors constitute a severe source of background for the detection of geoneutrinos, which bring to the Earth's surface information about natural radioactivity in the whole planet. In this framework, we provide a reference worldwide model for antineutrinos from reactors, in view of reactors operational records yearly published by the International Atomic Energy Agency. We evaluate the expected signal from commercial reactors for ongoing (KamLAND and Borexino), planned (SNO +), and proposed (Juno, RENO-50, LENA, and Hanohano) experimental sites. Uncertainties related to reactor antineutrino production, propagation, and detection processes are estimated using a Monte Carlo-based approach, which provides an overall site-dependent uncertainty on the signal in the geoneutrino energy window on the order of 3%. We also implement the off-equilibrium correction to the reference reactor spectra associated with the long-lived isotopes, and we estimate a 2.4% increase of the unoscillated event rate in the geoneutrino energy window due to the storage of spent nuclear fuels in the cooling pools. We predict that the research reactors contribute to less than 0.2% to the commercial reactor signal in the investigated 14 sites. We perform a multitemporal analysis of the expected reactor signal over a time lapse of ten years using reactor operational records collected in a comprehensive database published at

  3. A feasibility study of a deuterium-deuterium neutron generator-based boron neutron capture therapy system for treatment of brain tumors. (United States)

    Hsieh, Mindy; Liu, Yingzi; Mostafaei, Farshad; Poulson, Jean M; Nie, Linda H


    Boron neutron capture therapy (BNCT) is a binary treatment modality that uses high LET particles to achieve tumor cell killing. Deuterium-deuterium (DD) compact neutron generators have advantages over nuclear reactors and large accelerators as the BNCT neutron source, such as their compact size, low cost, and relatively easy installation. The purpose of this study is to design a beam shaping assembly (BSA) for a DD neutron generator and assess the potential of a DD-based BNCT system using Monte Carlo (MC) simulations. The MC model consisted of a head phantom, a DD neutron source, and a BSA. The head phantom had tally cylinders along the centerline for computing neutron and photon fluences and calculating the dose as a function of depth. The head phantom was placed at 4 cm from the BSA. The neutron source was modeled to resemble the source of our current DD neutron generator. A BSA was designed to moderate and shape the 2.45-MeV DD neutrons to the epithermal (0.5 eV to 10 keV) range. The BSA had multiple components, including moderator, reflector, collimator, and filter. Various materials and configurations were tested for each component. Each BSA layout was assessed in terms of the in-air and in-phantom parameters. The maximum brain dose was limited to 12.5 Gray-Equivalent (Gy-Eq) and the skin dose to 18 Gy-Eq. The optimized BSA configuration included 30 cm of lead for reflector, 45 cm of LiF, and 10 cm of MgF2 for moderator, 10 cm of lead for collimator, and 0.1 mm of cadmium for thermal neutron filter. Epithermal flux at the beam aperture was 1.0 × 105  nepi /cm2 -s; thermal-to-epithermal neutron ratio was 0.05; fast neutron dose per epithermal was 5.5 × 10-13  Gy-cm2 /φepi , and photon dose per epithermal was 2.4 × 10-13  Gy-cm2 /φepi . The AD, AR, and the advantage depth dose rate were 12.1 cm, 3.7, and 3.2 × 10-3  cGy-Eq/min, respectively. The maximum skin dose was 0.56 Gy-Eq. The DD neutron yield that is needed to irradiate in

  4. Experiment and modeling of CO{sub 2} capture from flue gases at high temperature in a fluidized bed reactor with Ca-based sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Fan Fang; Zhen-Shan Li; Ning-Sheng Cai [Tsinghua University, Beijing (China). Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education (MOE)


    The cyclic CO{sub 2} capture and CaCO{sub 3} regeneration characteristics in a small fluidized bed reactor were experimentally investigated with limestone and dolomite sorbents. Kinetic rate constants for carbonation and calcination were determined using thermogravimetric analysis (TGA) data. Mathematical models developed to model the Ca-based sorbent multiple cycles of CO{sub 2} capture and calcination in the bubbling fluidized bed reactor agreed with the experimental data. The experimental and simulated results showed that the CO{sub 2} in flue gases could be absorbed efficiently by limestone and dolomite. The time for high-efficiency CO{sub 2} capture decreased with an increasing number of cycles because of the loss of sorbent activity, and the final CO{sub 2} capture efficiency remained nearly constant as the sorbent reached its final residual capture capacity. In a continuous carbonation and calcination system, corresponding to the sorbent activity loss, the carbonation kinetic rates of sorbent undergoing various cycles are different, and the carbonation kinetic rates of sorbent circulating N times in the carbonation/calcination cycles are also different because of the different residence time of sorbent in the carbonator. Therefore, the average carbonation rate was given based on the mass balance and exit age distribution for sorbent in the carbonator. The CO{sub 2} capture characteristics in a continuous carbonation/calcination system were predicted, taking into consideration the mass balance, sorbent circulation rate, sorbent activity loss, and average carbonation kinetic rate, to give useful information for the reactor design and operation of multiple carbonation/calcination reaction cycles. 27 refs., 15 figs., 1 tab.

  5. Monte Carlo based protocol for cell survival and tumour control probability in BNCT. (United States)

    Ye, S J


    A mathematical model to calculate the theoretical cell survival probability (nominally, the cell survival fraction) is developed to evaluate preclinical treatment conditions for boron neutron capture therapy (BNCT). A treatment condition is characterized by the neutron beam spectra, single or bilateral exposure, and the choice of boron carrier drug (boronophenylalanine (BPA) or boron sulfhydryl hydride (BSH)). The cell survival probability defined from Poisson statistics is expressed with the cell-killing yield, the 10B(n,alpha)7Li reaction density, and the tolerable neutron fluence. The radiation transport calculation from the neutron source to tumours is carried out using Monte Carlo methods: (i) reactor-based BNCT facility modelling to yield the neutron beam library at an irradiation port; (ii) dosimetry to limit the neutron fluence below a tolerance dose (10.5 Gy-Eq); (iii) calculation of the 10B(n,alpha)7Li reaction density in tumours. A shallow surface tumour could be effectively treated by single exposure producing an average cell survival probability of 10(-3)-10(-5) for probable ranges of the cell-killing yield for the two drugs, while a deep tumour will require bilateral exposure to achieve comparable cell kills at depth. With very pure epithermal beams eliminating thermal, low epithermal and fast neutrons, the cell survival can be decreased by factors of 2-10 compared with the unmodified neutron spectrum. A dominant effect of cell-killing yield on tumour cell survival demonstrates the importance of choice of boron carrier drug. However, these calculations do not indicate an unambiguous preference for one drug, due to the large overlap of tumour cell survival in the probable ranges of the cell-killing yield for the two drugs. The cell survival value averaged over a bulky tumour volume is used to predict the overall BNCT therapeutic efficacy, using a simple model of tumour control probability (TCP).

  6. Wavelength feature mapping as a proxy to mineral chemistry for investigating geologic systems: An example from the Rodalquilar epithermal system (United States)

    van der Meer, Freek; Kopačková, Veronika; Koucká, Lucie; van der Werff, Harald M. A.; van Ruitenbeek, Frank J. A.; Bakker, Wim H.


    The final product of a geologic remote sensing data analysis using multi spectral and hyperspectral images is a mineral (abundance) map. Multispectral data, such as ASTER, Landsat, SPOT, Sentinel-2, typically allow to determine qualitative estimates of what minerals are in a pixel, while hyperspectral data allow to quantify this. As input to most image classification or spectral processing approach, endmembers are required. An alternative approach to classification is to derive absorption feature characteristics such as the wavelength position of the deepest absorption, depth of the absorption and symmetry of the absorption feature from hyperspectral data. Two approaches are presented, tested and compared in this paper: the 'Wavelength Mapper' and the 'QuanTools'. Although these algorithms use a different mathematical solution to derive absorption feature wavelength and depth, and use different image post-processing, the results are consistent, comparable and reproducible. The wavelength images can be directly linked to mineral type and abundance, but more importantly also to mineral chemical composition and subtle changes thereof. This in turn allows to interpret hyperspectral data in terms of mineral chemistry changes which is a proxy to pressure-temperature of formation of minerals. We show the case of the Rodalquilar epithermal system of the southern Spanish Gabo de Gata volcanic area using HyMAP airborne hyperspectral images.

  7. Gold-Silver mineralization in porphyry-epithermal systems of the Baimka trend, western Chukchi Peninsula, Russia (United States)

    Nikolaev, Yu. N.; Baksheev, I. A.; Prokofiev, V. Yu.; Nagornaya, E. V.; Marushchenko, L. I.; Sidorina, Yu. N.; Chitalin, A. F.; Kal'ko, I. A.


    Mineralogical, fluid inclusion, and geochemical studies of precious metal mineralization within the Baimka trend in the western Chukchi Peninsula have been preformed. Porphyry copper-molybdenum-gold deposits and prospects of the Baimka trend are spatially related to monzonitic rocks of the Early Cretaceous Egdygkych Complex. Four types of precious metal-bearing assemblages have been identified: (1) chalcopyrite + bornite + quartz with high-fineness native gold enclosed in bornite, (2) low-Mn dolomite + quartz + sulfide (chalcopyrite, sphalerite, galena, tennantite-tetrahedrite) ± tourmaline with low-fineness native gold and hessite, (3) rhodochrosite + high-Mn dolomite + quartz + sulfide (chalcopyrite, sphalerite, galena, tennantite- tetrahedrite) with low-fineness native gold, electrum, acanthite, Ag and Au-Ag tellurides, and Ag sulfosalts, and (4) calcite + quartz + sulfide (chalcopyrite, sphalerite, galena) with low-fineness native gold, Ag sulfides and selenides, and Ag-bearing sulfosalts. Study of fluid inclusions from quartz, sphalerite, and fluorite have revealed that hydrothermal ores within the Baimka trend precipitated from fluids with strongly variable salinity at temperatures and pressures ranging from 594 to 104°C and from 1200 to 170 bar, respectively. An indicator of vertical AgPbZn/CuBiMo geochemical zoning is proposed. The value range of this indicator makes it possible to estimate the erosion level of the porphyry-epithermal system. The erosion level of the Baimka deposits and prospects deepens in the following order: Vesenny deposit → Pryamoi prospect → Nakhodka prospect → Peschanka deposit → III Vesenny prospect.

  8. Study on the Impact of Thermal Agitation on Doppler Coefficient in Epithermal Range for Gd-Bearing Fuel

    Directory of Open Access Journals (Sweden)

    Satoshi Takeda


    Full Text Available The impact of thermal agitation on Doppler coefficient for Gd-bearing fuel was analyzed. It was found through the analysis that the impact increases when a small amount of Gd2O3 is added to pure UO2 fuel although the impact decreases for a large amount of Gd2O3. This tendency was discussed with the usage of simplified expression for the difference of Doppler coefficient. The simplified expression was used to consider the tendency, and it was revealed that the tendency mainly comes from the rapid decrement of multiplication factor and the relatively slow decrement of the magnitude of sensitivity coefficient of U-238 capture cross section at low Gd2O3 concentration. Similar tendency which shows a maximum impact on Doppler coefficient at interior concentration is expected for other UO2 fuel with a slight content of strong absorber. This indicates that Doppler coefficient of UO2 fuel system with low content of strong absorber should be analyzed carefully by considering thermal agitation in epithermal range.

  9. Thermal Energetic Reactor with High Reproduction of Fission Materials

    Directory of Open Access Journals (Sweden)

    Vladimir M. Kotov


    On the base of thermal reactors with high fission materials reproduction world atomic power engineering development supplying higher power and requiring smaller speed of raw uranium mining, than in the variant with fast reactors, is possible.

  10. Performance of a multipurpose research electrochemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Henquin, E.R. [Programa de Electroquimica Aplicada e Ingenieria Electroquimica (PRELINE), Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829, S3000AOM Santa Fe (Argentina); Bisang, J.M., E-mail: [Programa de Electroquimica Aplicada e Ingenieria Electroquimica (PRELINE), Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829, S3000AOM Santa Fe (Argentina)


    Highlights: > For this reactor configuration the current distribution is uniform. > For this reactor configuration with bipolar connection the leakage current is small. > The mass-transfer conditions are closely uniform along the electrode. > The fluidodynamic behaviour can be represented by the dispersion model. > This reactor represents a suitable device for laboratory trials. - Abstract: This paper reports on a multipurpose research electrochemical reactor with an innovative design feature, which is based on a filter press arrangement with inclined segmented electrodes and under a modular assembly. Under bipolar connection, the fraction of leakage current is lower than 4%, depending on the bipolar Wagner number, and the current distribution is closely uniform. When a turbulence promoter is used, the local mass-transfer coefficient shows a variation of {+-}10% with respect to its mean value. The fluidodynamics of the reactor responds to the dispersion model with a Peclet number higher than 10. It is concluded that this reactor is convenient for laboratory research.

  11. Sequencing Bacth Reactors; Reactores biologicos secuenciados

    Energy Technology Data Exchange (ETDEWEB)

    Nolasco, D.; Manoharan, M.


    The application of sequencing batch reactors (SBR) for wastewater treatment is becoming increasingly popular. However, published information on process performance and construction costs for SBRs is scarce. For this reason. Environment Canada, the Ontario Ministry of the Environment (MOE), and the Water Environment Association of Ontario (WEAO) decided to sponsor a program to evaluate the performance of 75 municipal SBRs in Canada and the United States. Effluent quality, construction costs, and design and operating problems were investigated. Areas for optimization found as a result of this investigation were classified an prioritized based on their impact on operational costs, treatment capacity, effluent quality, and frequency of occurrence. A list of recommendations for process optimization was prepared. A construction cost comparison between activated sludge systems of continuous flow and SBRs was prepared. (Author) 12 refs.

  12. Advanced Neutron Source Cross Section Libraries (ANSL-V): ENDF/B-V based multigroup cross-section libraries for advanced neutron source (ANS) reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Ford, W.E. III; Arwood, J.W.; Greene, N.M.; Moses, D.L.; Petrie, L.M.; Primm, R.T. III; Slater, C.O.; Westfall, R.M.; Wright, R.Q.


    Pseudo-problem-independent, multigroup cross-section libraries were generated to support Advanced Neutron Source (ANS) Reactor design studies. The ANS is a proposed reactor which would be fueled with highly enriched uranium and cooled with heavy water. The libraries, designated ANSL-V (Advanced Neutron Source Cross Section Libraries based on ENDF/B-V), are data bases in AMPX master format for subsequent generation of problem-dependent cross-sections for use with codes such as KENO, ANISN, XSDRNPM, VENTURE, DOT, DORT, TORT, and MORSE. Included in ANSL-V are 99-group and 39-group neutron, 39-neutron-group 44-gamma-ray-group secondary gamma-ray production (SGRP), 44-group gamma-ray interaction (GRI), and coupled, 39-neutron group 44-gamma-ray group (CNG) cross-section libraries. The neutron and SGRP libraries were generated primarily from ENDF/B-V data; the GRI library was generated from DLC-99/HUGO data, which is recognized as the ENDF/B-V photon interaction data. Modules from the AMPX and NJOY systems were used to process the multigroup data. Validity of selected data from the fine- and broad-group neutron libraries was satisfactorily tested in performance parameter calculations.

  13. Treatment of agro based industrial wastewater in sequencing batch reactor: performance evaluation and growth kinetics of aerobic biomass. (United States)

    Lim, J X; Vadivelu, V M


    A sequencing batch reactor (SBR) with a working volume of 8 L and an exchange ratio of 25% was used to enrich biomass for the treatment of the anaerobically treated low pH palm oil mill effluent (POME). The influent concentration was stepwise increased from 5000 ± 500 mg COD/L to 11,500 ± 500 mg COD/L. The performance of the reactor was monitored at different organic loading rates (OLRs). It was found that approximately 90% of the COD content of the POME wastewater was successfully removed regardless of the OLR applied to the SBR. Cycle studies of the SBR show that the oxygen uptake by the biomass while there is no COD reduction may be due to the oxidation of the storage product by the biomass. Further, the growth kinetic parameters of the biomass were determined in batch experiments using respirometer. The maximum specific growth rate (μmax) was estimated to be 1.143 day(-1) while the half saturation constant (Ks) with respect to COD was determined to be 0.429 g COD/L. The decay coefficient (bD) and biomass yield (Y) were found to be 0.131 day(-1) and 0.272 mg biomass/mg COD consumed, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.


    Directory of Open Access Journals (Sweden)



    Full Text Available Here, we present a method to produce carbon nanotubes (CNTs based on the coupling between two conventional techniques used for the preparation of nanostructures: an arc-jet as a source of plasma and a chemical vapour deposition (CVD system. We call this system as an “atmospheric pressure plasma (APP-enhanced CVD” (APPE-CVD. This reactor was used to grow CNTs on non-flat aluminosilicate substrates by the decomposition of toluene (carbon source in the presence of ferrocene (as a catalyst. Both, CNTs and by-products of carbon were collected at three different temperatures (780, 820 and 860 °C in different regions of the APPE-CVD system. These samples were analysed by thermogravimetric analysis (TGA and DTG, scanning electron microscopy (SEM and Raman spectroscopy in order to determine the effect of APP on the thermal stability of the as-grown CNTs. It was found that the amount of metal catalyst in the synthesised CNTs is reduced by applying APP, being 820 °C the optimal temperature to produce CNTs with a high yield and carbon purity (95 wt. %. In contrast, when the synthesis temperature was fixed at 780 °C or 860 °C, amorphous carbon or CNTs with different structural defects, respectively, was formed through APEE-CVD reactor. We recommended the use of non-flat aluminosilicate particles as supports to increase CNT yield and facilitate the removal of deposits from the substrate surface. The approach that we implemented (to synthesise CNTs by using the APPE-CVD reactor may be useful to produce these nanostructures on a gram-scale for use in basic studies. The approach may also be scaled up for mass production.

  15. Modeling Geometric Arrangements of TiO2-Based Catalyst Substrates and Isotropic Light Sources to Enhance the Efficiency of a Photocatalystic Oxidation (PCO) Reactor (United States)

    Richards, Jeffrey T.; Levine, Lanfang H.; Husk, Geoffrey K.


    The closed confined environments of the ISS, as well as in future spacecraft for exploration beyond LEO, provide many challenges to crew health. One such challenge is the availability of a robust, energy efficient, and re-generable air revitalization system that controls trace volatile organic contaminants (VOCs) to levels below a specified spacecraft maximum allowable concentration (SMAC). Photocatalytic oxidation (PCO), which is capable of mineralizing VOCs at room temperature and of accommodating a high volumetric flow, is being evaluated as an alternative trace contaminant control technology. In an architecture of a combined air and water management system, placing a PCO unit before a condensing heat exchanger for humidity control will greatly reduce the organic load into the humidity condensate loop ofthe water processing assembly (WPA) thereby enhancing the life cycle economics ofthe WPA. This targeted application dictates a single pass efficiency of greater than 90% for polar VOCs. Although this target was met in laboratory bench-scaled reactors, no commercial or SBIR-developed prototype PCO units examined to date have achieved this goal. Furthermore, the formation of partial oxidation products (e.g., acetaldehyde) was not eliminated. It is known that single pass efficiency and partial oxidation are strongly dependent upon the contact time and catalyst illumination, hence the requirement for an efficient reactor design. The objective of this study is to maximize the apparent contact time and illuminated catalyst surface area at a given reactor volume and volumetric flow. In this study, a Ti02-based photocatalyst is assumed to be immobilized on porous substrate panels and illumination derived from linear isotropic light sources. Mathematical modeling using computational fluid dynamics (CFD) analyses were performed to investigate the effect of: 1) the geometry and configuration of catalyst-coated substrate panels, 2) porosity of the supporting substrate, and 3

  16. Seasonal variation in communities of ammonia-oxidizing bacteria based on polymerase chain reaction - denaturing gradient gel electrophoresis in a biofilm reactor for drinking water pretreatment. (United States)

    Zhang, Xiao-Wen; Qin, Ying-Ying; Ren, Hong-Qiang; Li, Dao-Tang; Yang, Hong


    The diversity and variation of total and active ammonia-oxidizing bacteria in a full-scale aerated submerged biofilm reactor for drinking water pretreatment were characterized by clone libraries and denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA and its gene during a whole year. Sequences obtained from clone libraries affiliated with the Nitrosomonas oligotropha lineage and the Nitrosomonas communis lineage. An uncultured subgroup of Nitrosomonas communis lineage was also detected. Seasonal variations in both total and active ammonia-oxidizing bacteria communities were observed in the DGGE profiles, but an RNA-based analysis reflected more obvious dynamic changes in ammonia-oxidizer community than a DNA-based approach. Statistical study based on canonical correspondence analysis showed that a community shift of active ammonia oxidizers was significantly influenced by temperature and pH, but no significant correlation was found between environmental variables and total ammonia-oxidizer community shift.

  17. Reactor coolant pump flywheel (United States)

    Finegan, John Raymond; Kreke, Francis Joseph; Casamassa, John Joseph


    A flywheel for a pump, and in particular a flywheel having a number of high density segments for use in a nuclear reactor coolant pump. The flywheel includes an inner member and an outer member. A number of high density segments are provided between the inner and outer members. The high density segments may be formed from a tungsten based alloy. A preselected gap is provided between each of the number of high density segments. The gap accommodates thermal expansion of each of the number of segments and resists the hoop stress effect/keystoning of the segments.

  18. Mineralogy and geochemical environment of formation of the Perama Hill high-sulfidation epithermal Au-Ag-Te-Se deposit, Petrota Graben, NE Greece (United States)

    Voudouris, Panagiotis Christos; Melfos, Vasilios; Spry, Paul G.; Moritz, Robert; Papavassiliou, Constantinos; Falalakis, George


    The Perama Hill deposit is a high-sulfidation Au-Ag-Te-Se epithermal system hosted in silicic- and argillic altered andesitic rocks and overlying sandstones, which were emplaced on the eastern margin of the Petrota graben, northeastern Greece. The deposit evolved from an early stage silica-pyrite rock and argillic alteration followed by the deposition of sulfide-, sulfosalt- and telluride-bearing quartz-barite veins and stockworks. Early ore formation is characterized by a high-sulfidation-type enargite-galena-bearing ore assemblage (consisting of enargite, watanabeite, Fe-free sphalerite, covellite, kesterite, bismuthinite, selenian bismuthinite, lillianite homologues, kawazulite-tetradymite, goldfieldite, and native gold), followed by the formation of an intermediate-sulfidation-type tennantite-bearing assemblage characterized by ferrian/zincian tennantite, tellurobismuthite, tetradymite, melonite, native tellurium, Au-Ag-tellurides (calaverite, krennerite, sylvanite, hessite, petzite, stützite), altaite and electrum. Quartz, barite, kaolinite, sericite and minor aluminum-phosphate-sulfate minerals are gangue minerals. Fluid inclusion data demonstrate that the ore system evolved from an initial high temperature (up to 330°C) and low salinity (up to 4.9 wt.% NaCl equiv.) fluid towards a cooler (200°C) and very low salinity (0.7 wt.% NaCl equiv.) hydrothermal fluid suggesting progressive cooling and dilution of the ore fluid. The ore minerals at Perama Hill reflect variable fS2 and fTe2 conditions during base and precious metal deposition. Early ore deposition took place at ~300°C, at log fS2 values between ≈-8.2 and -5.5, and log fTe2 from -11.8 and -7.8. Late ore deposition occurred at log fS2 = -11.8 to -9.8 and log fTe2 of ≈-9.2 and -7.8. These data and paragenetic studies indicate a shift towards higher log fTe2 and lower log fS2 and log fSe2 values for the mineralizing fluids with time. The kawazulite/tetradymitess-gold association at Perama Hill

  19. Antineutrino monitoring of thorium reactors (United States)

    Akindele, Oluwatomi A.; Bernstein, Adam; Norman, Eric B.


    Various groups have demonstrated that antineutrino monitoring can be successful in assessing the plutonium content in water-cooled nuclear reactors for nonproliferation applications. New reactor designs and concepts incorporate nontraditional fuel types and chemistry. Understanding how these properties affect the antineutrino emission from a reactor can extend the applicability of antineutrino monitoring. Thorium molten salt reactors breed 233U, that if diverted constitute a direct use material as defined by the International Atomic Energy Agency (IAEA). The antineutrino spectrum from the fission of 233U has been estimated for the first time, and the feasibility of detecting the diversion of 8 kg of 233U, within a 30 day timeliness goal has been evaluated. The antineutrino emission from a thorium reactor operating under normal conditions is compared to a diversion scenario by evaluating the daily antineutrino count rate and the energy spectrum of the detected antineutrinos at a 25 m standoff. It was found that the diversion of a significant quantity of 233U could not be detected within the current IAEA timeliness detection goal using either tests. A rate-time based analysis exceeded the timeliness goal by 23 days, while a spectral based analysis exceeds this goal by 31 days.

  20. The First Reactor, 40th Anniversary (rev.)

    Energy Technology Data Exchange (ETDEWEB)

    Allardice, Corbin; Trapnell, Edward R; Fermi, Enrico; Fermi, Laura; Williams, Robert C


    This booklet, an updated version of the original booklet describing the first nuclear reactor, was written in honor of the 40th anniversary of the first reactor or "pile". It is based on firsthand accounts told to Corbin Allardice and Edward R. Trapnell, and includes recollections of Enrico and Laura Fermi.

  1. Helix reactor: great potential for flow chemistry

    NARCIS (Netherlands)

    Geerdink, P.; Runstraat, A. van den; Roelands, C.P.M.; Goetheer, E.L.V.


    The Helix reactor is highly suited for precise reaction control based on good hydrodynamics. The hydrodynamics are controlled by the Dean vortices, which create excellent heat transfer properties, approach plug flow and avoid turbulence. The flexibility of this reactor has been demonstrated using a

  2. Hybrid plasmachemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lelevkin, V. M., E-mail:; Smirnova, Yu. G.; Tokarev, A. V. [Kyrgyz-Russian Slavic University (Kyrgyzstan)


    A hybrid plasmachemical reactor on the basis of a dielectric barrier discharge in a transformer is developed. The characteristics of the reactor as functions of the dielectric barrier discharge parameters are determined.

  3. Attrition reactor system (United States)

    Scott, Charles D.; Davison, Brian H.


    A reactor vessel for reacting a solid particulate with a liquid reactant has a centrifugal pump in circulatory flow communication with the reactor vessel for providing particulate attrition, resulting in additional fresh surface where the reaction can occur.

  4. Guidebook to nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Nero, A.V. Jr.


    A general introduction to reactor physics and theory is followed by descriptions of commercial nuclear reactor types. Future directions for nuclear power are also discussed. The technical level of the material is suitable for laymen.

  5. Steady-state CFD simulations of an EPR™ reactor pressure vessel: A validation study based on the JULIETTE experiments

    Energy Technology Data Exchange (ETDEWEB)

    Puragliesi, R., E-mail: [Laboratory for Reactor Physics and Systems Behaviour, PSI, 5232 Villigen (Switzerland); Zhou, L. [Science and Technology on Reactor System Design Technology Laboratory, NPIC, Chengdu (China); Zerkak, O.; Pautz, A. [Laboratory for Reactor Physics and Systems Behaviour, PSI, 5232 Villigen (Switzerland)


    Highlights: • CFD validation of k–ε (RANS model of EPR RPV. • Flat inlet velocity profile is not sufficient to correctly predict the pressure drops. • Swirl is responsible for asymmetric loads at the core barrel. • Parametric study to the turbulent Schmidt number for better predictions of passive-scalar transport. • The optimal turbulent Schmidt number was found to be one order of magnitude smaller than the standard value. - Abstract: Validating computational fluid dynamics (CFD) models against experimental measurements is a fundamental step towards a broader acceptance of CFD as a tool for reactor safety analysis when best-estimate one-dimensional thermal-hydraulic codes present strong modelling limitations. In the present paper numerical results of steady-state RANS analyses are compared to pressure, volumetric flow rate and concentration distribution measurements in different locations of an Areva EPR™ reactor pressure vessel (RPV) mock-up named JULIETTE. Several flow configurations are considered: Three different total volumetric flow rates, cold leg velocity field with or without swirl, three or four reactor coolant pumps functioning. Investigations on the influence of two types of inlet boundary profiles (i.e. flat or 1/7th power-law) and the turbulent Schmidt number have shown that the first affects sensibly the pressure loads at the core barrel whereas the latter parameter strongly affects the transport and the mixing of the tracer (passive scalar) and consequently its distribution at the core inlet. Furthermore, the introduction of an integral parameter as the swirl number has helped to decrease the large epistemic uncertainty associated with the swirling device. The swirl is found to be the cause of asymmetric loads on the walls of the core barrel and also asymmetries are enhanced for the tracer concentration distribution at the core inlet. The k–ϵ CFD model developed with the commercial code STAR-CCM+ proves to be able to predict

  6. Determination of α and f parameters at the 14-MW TRIGA reactor at Pitesti, Romania (United States)

    Bărbos, D.; Păunoiu, C.; Roth, C.


    For experimental α determination the two-monitor method has been applied to determine α parameter in the irradiation channels at TRIGA 14 MW reactor (SCN Pitesti). The modified two-monitor method by using Cd ratio measurements eliminates the introducing of systematic errors due to the inaccuracy of absolute nuclear data. This characterization of the epithermal neutron spectrum is used in the k0-method of NAA, implemented at the SCN Pitesti. Neutron spectrum parameters were determined in the inner irradiation channel XC-1 and for outer irradiation channels: Beryllium J-6, Beryllium J-7, and Beryllium K-11. For α and f parameter verification a standard reference material denominated ECRM379-1 was analyzed using k0 standardization.

  7. Biofilm carrier migration model describes reactor performance. (United States)

    Boltz, Joshua P; Johnson, Bruce R; Takács, Imre; Daigger, Glen T; Morgenroth, Eberhard; Brockmann, Doris; Kovács, Róbert; Calhoun, Jason M; Choubert, Jean-Marc; Derlon, Nicolas


    The accuracy of a biofilm reactor model depends on the extent to which physical system conditions (particularly bulk-liquid hydrodynamics and their influence on biofilm dynamics) deviate from the ideal conditions upon which the model is based. It follows that an improved capacity to model a biofilm reactor does not necessarily rely on an improved biofilm model, but does rely on an improved mathematical description of the biofilm reactor and its components. Existing biofilm reactor models typically include a one-dimensional biofilm model, a process (biokinetic and stoichiometric) model, and a continuous flow stirred tank reactor (CFSTR) mass balance that [when organizing CFSTRs in series] creates a pseudo two-dimensional (2-D) model of bulk-liquid hydrodynamics approaching plug flow. In such a biofilm reactor model, the user-defined biofilm area is specified for each CFSTR; thereby, Xcarrier does not exit the boundaries of the CFSTR to which they are assigned or exchange boundaries with other CFSTRs in the series. The error introduced by this pseudo 2-D biofilm reactor modeling approach may adversely affect model results and limit model-user capacity to accurately calibrate a model. This paper presents a new sub-model that describes the migration of Xcarrier and associated biofilms, and evaluates the impact that Xcarrier migration and axial dispersion has on simulated system performance. Relevance of the new biofilm reactor model to engineering situations is discussed by applying it to known biofilm reactor types and operational conditions.

  8. Beryllium irradiation element analysis in the IEA-R1m reactor; Analise do elemento de irradiacao de berilio no reator IEA-R1m

    Energy Technology Data Exchange (ETDEWEB)

    Ricci Filho, Walter


    The IEA-R1 reactor at IPEN-Sao Paulo has undergone a modernization to increase its operating power to 5 MW, in order to allow a more efficient production of the {sup 99} Mo radioisotope. An irradiation element made of Be was acquired for the reactor and studies have been carried out to determine its performance when compared to other irradiators available in the reactor namely, the water and graphite irradiation elements. The results obtained showed some advantages of the Beryllium irradiation element for producing {sup 99} Mo: the epithermal neutron flux in the Be irradiation element is approximately 22% greater than that in the graphite irradiation element and 12% greater than that of the water irradiation element; the neutron reaction rate in molybdenum wires inside in irradiation capsule filled with Mo O{sub 3} 10,6% greater them that in the water irradiation element in the same conditions; the negative reactivity introduced in the reactor by the Be irradiation element it substantially smaller than the those introduced by the other elements: -1636 pcm for the Be irradiator, -2977 for the water irradiator and -2568 pcm for the graphite irradiator. It is possible to conclude that the production of the {sup 99} Mo radioisotope with the Be irradiation element can be increased by 12 to 15% in the IEA-R1m reactor. It also requires less fuel for the reactor operation due to the smaller negative reactivity introduced in the reactor core. (author)

  9. Final Report, NERI Project: ''An Innovative Reactor Analysis Methodology Based on a Quasidiffusion Nodal Core Model''

    Energy Technology Data Exchange (ETDEWEB)

    Dmitriy Y. Anistratov; Marvin L. Adams; Todd S. Palmer; Kord S. Smith; Kevin Clarno; Hikaru Hiruta; Razvan Nes


    OAK (B204) Final Report, NERI Project: ''An Innovative Reactor Analysis Methodology Based on a Quasidiffusion Nodal Core Model'' The present generation of reactor analysis methods uses few-group nodal diffusion approximations to calculate full-core eigenvalues and power distributions. The cross sections, diffusion coefficients, and discontinuity factors (collectively called ''group constants'') in the nodal diffusion equations are parameterized as functions of many variables, ranging from the obvious (temperature, boron concentration, etc.) to the more obscure (spectral index, moderator temperature history, etc.). These group constants, and their variations as functions of the many variables, are calculated by assembly-level transport codes. The current methodology has two main weaknesses that this project addressed. The first weakness is the diffusion approximation in the full-core calculation; this can be significantly inaccurate at interfaces between different assemblies. This project used the nodal diffusion framework to implement nodal quasidiffusion equations, which can capture transport effects to an arbitrary degree of accuracy. The second weakness is in the parameterization of the group constants; current models do not always perform well, especially at interfaces between unlike assemblies. The project developed a theoretical foundation for parameterization and homogenization models and used that theory to devise improved models. The new models were extended to tabulate information that the nodal quasidiffusion equations can use to capture transport effects in full-core calculations.

  10. Artificial intelligence based model for optimization of COD removal efficiency of an up-flow anaerobic sludge blanket reactor in the saline wastewater treatment. (United States)

    Picos-Benítez, Alain R; López-Hincapié, Juan D; Chávez-Ramírez, Abraham U; Rodríguez-García, Adrián


    The complex non-linear behavior presented in the biological treatment of wastewater requires an accurate model to predict the system performance. This study evaluates the effectiveness of an artificial intelligence (AI) model, based on the combination of artificial neural networks (ANNs) and genetic algorithms (GAs), to find the optimum performance of an up-flow anaerobic sludge blanket reactor (UASB) for saline wastewater treatment. Chemical oxygen demand (COD) removal was predicted using conductivity, organic loading rate (OLR) and temperature as input variables. The ANN model was built from experimental data and performance was assessed through the maximum mean absolute percentage error (= 9.226%) computed from the measured and model predicted values of the COD. Accordingly, the ANN model was used as a fitness function in a GA to find the best operational condition. In the worst case scenario (low energy requirements, high OLR usage and high salinity) this model guaranteed COD removal efficiency values above 70%. This result is consistent and was validated experimentally, confirming that this ANN-GA model can be used as a tool to achieve the best performance of a UASB reactor with the minimum requirement of energy for saline wastewater treatment.

  11. Hollow fiber membrane based H-2 diffusion for efficient in situ biogas upgrading in an anaerobic reactor

    DEFF Research Database (Denmark)

    Luo, Gang; Angelidaki, Irini


    of bicarbonate concentration were related with the increase of the H2 flow rate. The CH4 content increased from 78.4 % to 90.2 % with the increase of the H2 flow rate from 930 to 1,440 ml/(l  day), while the pH in the reactor remained below 8.0. An even higher CH4 content (96.1 %) was achieved when the H2 flow...... rate was increased to 1,760 ml/(l  day); however, the pH increased to around 8.3 due to bicarbonate consumption which hampered the anaerobic process. The biofilm formed on the HFM was found not to be beneficial for the process since it increased the resistance of H2 diffusion to the liquid. The study...

  12. A Novel Fractional-Order PID Controller for Integrated Pressurized Water Reactor Based on Wavelet Kernel Neural Network Algorithm

    Directory of Open Access Journals (Sweden)

    Yu-xin Zhao


    Full Text Available This paper presents a novel wavelet kernel neural network (WKNN with wavelet kernel function. It is applicable in online learning with adaptive parameters and is applied on parameters tuning of fractional-order PID (FOPID controller, which could handle time delay problem of the complex control system. Combining the wavelet function and the kernel function, the wavelet kernel function is adopted and validated the availability for neural network. Compared to the conservative wavelet neural network, the most innovative character of the WKNN is its rapid convergence and high precision in parameters updating process. Furthermore, the integrated pressurized water reactor (IPWR system is established by RELAP5, and a novel control strategy combining WKNN and fuzzy logic rule is proposed for shortening controlling time and utilizing the experiential knowledge sufficiently. Finally, experiment results verify that the control strategy and controller proposed have the practicability and reliability in actual complicated system.

  13. An alternative strategy for low specific power reactors to power interplanetary spacecraft, based on exploiting lasers and lunar resources

    Energy Technology Data Exchange (ETDEWEB)

    Logan, B.G.


    A key requirement setting the minimum electric propulsion performance (specific power ..cap alpha../sub e/ = kW/sub e//kg) for manned missions to Mars is the maximum allowable radiation dose to the crew during the long transits between Earth and Mars. Penetrating galactic cosmic rays and secondary neutron showers give about 0.1-rem/day dose, which only massive shielding (e.g., a meter of concrete) can reduce significantly. With a humane allowance for cabin space, the shielding mass becomes so large that it prohibitively escalates the propellant consumption required for reasonable trip times. This paper covers various proposed methods for using reactor power to propel spacecraft. 7 refs., 6 figs., 1 tab.

  14. Production of gaseous fuel from jatropha oil by cerium oxide based catalytic fuel reactor and its utilisation on diesel engine

    Directory of Open Access Journals (Sweden)

    Mylswamy Thirunavukkarasu


    Full Text Available In this study, an attempt is made to produce a hydrocarbon fuel from jatropha vegetable oil for Diesel engine applications. The “catalytic cracking” a process recently introduced by the researchers is chosen as an alternative method to trans-esterification process to match the fuel properties to diesel. Jatropha vegetable oil was cracked into a gas using the cerium oxide catalyst in a fixed bed catalytic reactor. The produced gas is introduced at constant rate into the inlet manifold of the Diesel engine. The experimental work was carried out in single cylinder water cooled direct injection Diesel engine coupled with eddy current dynamometer. The combustion parameters are measured by AVL combustion analyser. From the experimental results, the increase in brake thermal efficiency of the engine for full load was observed to be 10% (relative compared with diesel. Notably, emissions such as HC, CO, and smoke are reduced by 18%, 61%, and 18%, respectively, when compared with diesel.


    Epler, E.P.; Hanauer, S.H.; Oakes, L.C.


    A control system is described for a nuclear reactor using enriched uranium fuel of the type of the swimming pool and other heterogeneous nuclear reactors. Circuits are included for automatically removing and inserting the control rods during the course of normal operation. Appropriate safety circuits close down the nuclear reactor in the event of emergency.

  16. Seismic attenuation system for a nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Liszkai, Tamas; Cadell, Seth


    A system for attenuating seismic forces includes a reactor pressure vessel containing nuclear fuel and a containment vessel that houses the reactor pressure vessel. Both the reactor pressure vessel and the containment vessel include a bottom head. Additionally, the system includes a base support to contact a support surface on which the containment vessel is positioned in a substantially vertical orientation. An attenuation device is located between the bottom head of the reactor pressure vessel and the bottom head of the containment vessel. Seismic forces that travel from the base support to the reactor pressure vessel via the containment vessel are attenuated by the attenuation device in a direction that is substantially lateral to the vertical orientation of the containment vessel.

  17. A citation-based assessment of the performance of U.S. boiling water reactors following extended power up-rates (United States)

    Heidrich, Brenden J.

    multiple independent variables on the event rate. Both the Cox and Weibull formulations were tested. The Cox formulation is more commonly used in survival analysis because of its flexibility. The best Cox model included fixed effects at the multi-reactor site level. The Weibull parametric formulation has the same base hazard rate as the Crow/AMSAA model. This theoretical connection was confirmed through a series of tests that demonstrated both models predicted the same base hazard rates. The Weibull formulation produced a model with most of the same statistically significant variables as the Cox model. The beneficial effect of extended power up-rates was predicted in the proportional hazards models as well as the Crow/AMSAA model. The Weibull model also indicated an effect that can be traced back to a plant’s construction. Performance was also found to improve in plants that had been divested from their original owners. This research developed a consistent evaluation toolkit for nuclear power plant performance using either a univariate method that allows for simple graphical evaluation at its heart or a more complex multivariate method that includes the effects of several independent variables with data that are available from public sources. Utilities or regulators with access to proprietary data may be able to expand upon this research with additional data that is not readily available to an academic researcher. Even without access to special data, the methods developed are valuable tools in evaluating and predicting nuclear power plant reliability performance.

  18. The Bi'r Tawilah deposit, central western Saudi Arabia: Supergene enrichment of a Pan-African epithermal gold mineralization (United States)

    Surour, Adel A.; Harbi, Hesham M.; Ahmed, Ahmed H.


    The Bi'r Tawilah gold deposit in central western Saudi Arabia represents a Pan-African example of gold mineralization in which both hypogene and supergene ores are recorded. The sulphidic gold ore is hosted in intermediate to felsic intrusions that occur along the N-S trending thrust-fault zone within the so-called “Nabitah orogenic zone”. There are four rock units present (from oldest to youngest): serpentinites and related listwaenites, diorites, granitic rocks and porphyries. Hydrothermal alteration consists of chloritization, sericitization, carbonatization and silicification and affects all rock types. Chloritization of biotite results in abundant rutile, whereas sulphidization coincides with carbonatization. The Bi'r Tawilah ore is confined to NW-trending shears (Riedel fractures) related to N-S slip of the pre-existing Tawilah thrust due to activation within the Najd fault system. Samples from the boreholes show macro- and microscopic evidence of shearing such as micro-shear planes and strain shadows of pyrite. Sulphides and gold are present in most rock types. Paragenetically, the sulphides consist of abundant pyrite and relatively lesser amounts of arsenopyrite, in addition to very minor chalcopyrite, sphalerite and galena. In all boreholes, it was noticed that the abundance of arsenopyrite increases with depth. The elevated silver content of electrum (∼13-22 wt%) at Bi'r Tawilah is typical of gold deposits and low-sulphidation epithermal deposits. The early mineralization stage took place in proximity to hydrothermally altered intermediate to felsic intrusions. The aerially restricted hydrothermal alteration by carbon-aqueous fluids led to ore remobilization in which gold amounts up to 4.3 g/t. Finally, gold enrichment (up to 5.4 g/t) resulted from supergene alteration that took place during weathering above the water table at a depth of ∼20-25 m.

  19. Epithermal uranium deposits in a volcanogenic context: the example of Nopal 1 deposit, Sierra de Pena Blanca, Mexico (United States)

    Calas, G.; Angiboust, S.; Fayek, M.; Camacho, A.; Allard, T.; Agrinier, P.


    The Peña Blanca molybdenum-uranium field (Chihuahua, Mexico) exhibits over 100 airborne anomalies hosted in tertiary ignimbritic ash-flow tuffs (44 Ma) overlying the Pozos conglomerate and a sequence of Cretaceous carbonate rocks. Uranium occurrences are associated with breccia zones at the intersection of two or more fault systems. Periodic reactivation of these structures associated with Basin and Range and Rio Grande tectonic events resulted in the mobilization of U and other elements by meteoric fluids heated by geothermal activity. Trace element geochemistry (U, Th, REE) provides evidence for local mobilization of uranium under oxidizing conditions. In addition, O- and H-isotope geochemistry of kaolinite, smectite, opal and calcite suggests that argillic alteration proceeded at shallow depth with meteoric water at 25-75 °C. Focussed along breccia zones, fluids precipitated several generations of pyrite and uraninite together with kaolinite, as in the Nopal 1 mine, indicating that mineralization and hydrothermal alteration of volcanic tuffs are contemporaneous. Low δ34S values (~ -24.5 ‰) of pyrites intimately associated with uraninite suggest that the reducing conditions at the origin of the U-mineralization arise from biological activity. Later, the uplift of Sierra Pena Blanca resulted in oxidation and remobilization of uranium, as confirmed by the spatial distribution of radiation-induced defect centers in kaolinites. These data show that tectonism and biogenic reducing conditions can play a major role in the formation and remobilization of uranium in epithermal deposits. By comparison with the other uranium deposits at Sierra Pena Blanca and nearby Sierra de Gomez, Nopal 1 deposit is one of the few deposits having retained a reduced uranium mineralization.

  20. STARFIRE: a commercial tokamak reactor

    Energy Technology Data Exchange (ETDEWEB)


    The purpose of this document is to provide an interim status report on the STARFIRE project for the period of May to September 1979. The basic objective of the STARFIRE project is to develop a design concept for a commercial tokamak fusion electric power plant based on the deuterium/tritium/lithium fuel cycle. The key technical objective is to develop the best embodiment of the tokamak as a power reactor consistent with credible engineering solutions to design problems. Another key goal of the project is to give careful attention to the safety and environmental features of a commercial fusion reactor.

  1. Fundamentals of Nuclear Reactor Physics

    CERN Document Server

    Lewis, E E


    This new streamlined text offers a one-semester treatment of the essentials of how the fission nuclear reactor works, the various approaches to the design of reactors, and their safe and efficient operation. The book includes numerous worked-out examples and end-of-chapter questions to help reinforce the knowledge presented. This textbook offers an engineering-oriented introduction to nuclear physics, with a particular focus on how those physics are put to work in the service of generating nuclear-based power, particularly the importance of neutron reactions and neutron behavior. Engin

  2. Nuclear reactor overflow line (United States)

    Severson, Wayne J.


    The overflow line for the reactor vessel of a liquid-metal-cooled nuclear reactor includes means for establishing and maintaining a continuous bleed flow of coolant amounting to 5 to 10% of the total coolant flow through the overflow line to prevent thermal shock to the overflow line when the reactor is restarted following a trip. Preferably a tube is disposed concentrically just inside the overflow line extending from a point just inside the reactor vessel to an overflow tank and a suction line is provided opening into the body of liquid metal in the reactor vessel and into the annulus between the overflow line and the inner tube.

  3. Light water reactor safety

    CERN Document Server

    Pershagen, B


    This book describes the principles and practices of reactor safety as applied to the design, regulation and operation of light water reactors, combining a historical approach with an up-to-date account of the safety, technology and operating experience of both pressurized water reactors and boiling water reactors. The introductory chapters set out the basic facts upon which the safety of light water reactors depend. The central section is devoted to the methods and results of safety analysis. The accidents at Three Mile Island and Chernobyl are reviewed and their implications for light wate

  4. Nuclear reactor physics

    CERN Document Server

    Stacey, Weston M


    Nuclear reactor physics is the core discipline of nuclear engineering. Nuclear reactors now account for a significant portion of the electrical power generated worldwide, and new power reactors with improved fuel cycles are being developed. At the same time, the past few decades have seen an ever-increasing number of industrial, medical, military, and research applications for nuclear reactors. The second edition of this successful comprehensive textbook and reference on basic and advanced nuclear reactor physics has been completely updated, revised and enlarged to include the latest developme

  5. Autonomous Control of Space Nuclear Reactors (United States)

    Merk, John


    safety requirements of a nuclear reactor and provides high availability to the host system. The RICS is intended to interface with a host computer (the computer of the spacecraft where the reactor is mounted). The RICS leverages the safety features inherent in Earth-based reactors and also integrates the wide range neutron detector (WRND). A neutron detector provides the input that allows the RICS to do its job. The RICS is based on proven technology currently in use at a nuclear research facility. In its most basic form, the RICS is a ruggedized, compact data-acquisition and control system that could be adapted to support a wide variety of harsh environments. As such, the RICS could be a useful instrument outside the scope of a nuclear reactor, including military applications where failsafe data acquisition and control is required with stringent size, weight, and power constraints.

  6. Spinning fluids reactor (United States)

    Miller, Jan D; Hupka, Jan; Aranowski, Robert


    A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.

  7. The improvement of the energy resolution in epi-thermal neutron region of Bonner sphere using boric acid water solution moderator. (United States)

    Ueda, H; Tanaka, H; Sakurai, Y


    Bonner sphere is useful to evaluate the neutron spectrum in detail. We are improving the energy resolution in epi-thermal neutron region of Bonner sphere, using boric acid water solution as a moderator. Its response function peak is narrower than that for polyethylene moderator and the improvement of the resolution is expected. The resolutions between polyethylene moderator and boric acid water solution moderator were compared by simulation calculation. Also the influence in the uncertainty of Bonner sphere configuration to spectrum estimation was simulated. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Simulation of the aspersion system of the core low pressure (LPCS) for a boiling water reactor (BWR) based on RELAP; Simulacion del sistema de aspersion del nucleo a baja presion (LPCS) para un reactor de agua en ebullicion (BWR) basado en RELAP

    Energy Technology Data Exchange (ETDEWEB)

    Membrillo G, O. E.; Chavez M, C., E-mail: [UNAM, Facultad de Ingenieria, Circuito Interior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)


    The present work presents the modeling and simulation of the aspersion system to low pressure of reactor of the nuclear power plant of Laguna Verde using the nuclear code RELAP/SCDAP. The objective of the emergency systems inside a nuclear reactor is the cooling of the core, nor caring the performance of any other emergency system in the case of an accident design base for coolant loss. To obtain a simulation of the system is necessary to have a model based on their main components, pipes, pumps, valves, etc. This article describes the model for the simulation of the main line and the test line for the HPCS. At the moment we have the simulation of the reactor vessel and their systems associated to the nuclear power plant of Laguna Verde, this work will allow to associate the emergency system model LPCS to the vessel model. The simulation of the vessel and the emergency systems will allow knowing the behavior of the reactor in the stage of the coolant loos, giving the possibility to analyze diverse scenarios. The general model will provide an auxiliary tool for the training in classroom and at distance in the operation of nuclear power plants. (Author)

  9. A task-based parallelism and vectorized approach to 3D Method of Characteristics (MOC) reactor simulation for high performance computing architectures (United States)

    Tramm, John R.; Gunow, Geoffrey; He, Tim; Smith, Kord S.; Forget, Benoit; Siegel, Andrew R.


    In this study we present and analyze a formulation of the 3D Method of Characteristics (MOC) technique applied to the simulation of full core nuclear reactors. Key features of the algorithm include a task-based parallelism model that allows independent MOC tracks to be assigned to threads dynamically, ensuring load balancing, and a wide vectorizable inner loop that takes advantage of modern SIMD computer architectures. The algorithm is implemented in a set of highly optimized proxy applications in order to investigate its performance characteristics on CPU, GPU, and Intel Xeon Phi architectures. Speed, power, and hardware cost efficiencies are compared. Additionally, performance bottlenecks are identified for each architecture in order to determine the prospects for continued scalability of the algorithm on next generation HPC architectures.

  10. Tensile properties of vanadium-base alloys irradiated in the Fusion-1 low-temperature experiment in the BOR-60 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Gazda, J.; Nowicki, L.J.; Billone, M.C.; Smith, D.L. [Argonne National Lab., IL (United States)


    The irradiation has been completed and the test specimens have been retrieved from the lithium-bonded capsule at the Research Institute of Atomic Reactors (RIAR) in Russia. During this reporting period, the Argonne National Laboratory (ANL) tensile specimens were received from RIAR and initial testing and examination of these specimens at ANL has been completed. The results, corroborating previous findings showed a significant loss of work hardening capability in the materials. There appears to be no significant difference in behavior among the various heats of vanadium-base alloys in the V-(4-5)Cr-(4-5)Ti composition range. The variations in the preirradiation annealing conditions also produced no notable differences.

  11. Catalytic wet air oxidation of bisphenol A solution in a batch-recycle trickle-bed reactor over titanate nanotube-based catalysts. (United States)

    Kaplan, Renata; Erjavec, Boštjan; Senila, Marin; Pintar, Albin


    Catalytic wet air oxidation (CWAO) is classified as an advanced oxidation process, which proved to be highly efficient for the removal of emerging organic pollutant bisphenol A (BPA) from water. In this study, BPA was successfully removed in a batch-recycle trickle-bed reactor over bare titanate nanotube-based catalysts at very short space time of 0.6 min gCAT g(-1). The as-prepared titanate nanotubes, which underwent heat treatment at 600 °C, showed high activity for the removal of aqueous BPA. Liquid-phase recycling (5- or 10-fold recycle) enabled complete BPA conversion already at 200 °C, together with high conversion of total organic carbon (TOC), i.e., 73 and 98 %, respectively. The catalyst was chemically stable in the given range of operating conditions for 189 h on stream.

  12. Effect of pH on nitrate and selenate reduction in flue gas desulfurization brine using the H2-based membrane biofilm reactor (MBfR). (United States)

    Van Ginkel, Steven W; Yang, Ziming; Kim, Bi-o; Sholin, Mark; Rittmann, Bruce E


    Increased tightening of air regulations is leading more electric utilities to install flue gas desulfurization (FGD) systems. These systems produce brine containing high concentrations of nitrate, nitrite, and selenate which must be removed before discharge. The H2-based membrane biofilm reactor (MBfR) was shown to consistently remove nitrate, nitrite, and selenate at high efficiencies. The maximum selenate removal flux reached 362 mgSe m(-2)d(-1) and was higher than that observed in earlier research, which shows continual improvement of the biofilm for selenate reduction. A low pH of 6.8 inhibited precipitation when treating actual FGD brine, yet did not inhibit removal. SO4(2-) was not removed and therefore did not compete with nitrate, nitrite, and selenate reduction for the available H2.

  13. Design of a multi-model observer-based estimator for Fault Detection and Isolation (FDI strategy: application to a chemical reactor

    Directory of Open Access Journals (Sweden)

    Y. Chetouani


    Full Text Available This study presents a FDI strategy for nonlinear dynamic systems. It shows a methodology of tackling the fault detection and isolation issue by combining a technique based on the residuals signal and a technique using the multiple Kalman filters. The usefulness of this combination is the on-line implementation of the set of models, which represents the normal mode and all dynamics of faults, if the statistical decision threshold on the residuals exceeds a fixed value. In other cases, one Extended Kalman Filter (EKF is enough to estimate the process state. After describing the system architecture and the proposed FDI methodology, we present a realistic application in order to show the technique's potential. An algorithm is described and applied to a chemical process like a perfectly stirred chemical reactor functioning in a semi-batch mode. The chemical reaction used is an oxido reduction one, the oxidation of sodium thiosulfate by hydrogen peroxide.

  14. NMR and MALDI-TOF MS based characterization of exopolysaccharides in anaerobic microbial aggregates from full-scale reactors. (United States)

    Gonzalez-Gil, Graciela; Thomas, Ludivine; Emwas, Abdul-Hamid; Lens, Piet N L; Saikaly, Pascal E


    Anaerobic granular sludge is composed of multispecies microbial aggregates embedded in a matrix of extracellular polymeric substances (EPS). Here we characterized the chemical fingerprint of the polysaccharide fraction of EPS in anaerobic granules obtained from full-scale reactors treating different types of wastewater. Nuclear magnetic resonance (NMR) signals of the polysaccharide region from the granules were very complex, likely as a result of the diverse microbial population in the granules. Using nonmetric multidimensional scaling (NMDS), the (1)H NMR signals of reference polysaccharides (gellan, xanthan, alginate) and those of the anaerobic granules revealed that there were similarities between the polysaccharides extracted from granules and the reference polysaccharide alginate. Further analysis of the exopolysaccharides from anaerobic granules, and reference polysaccharides using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) revealed that exopolysaccharides from two of the anaerobic granular sludges studied exhibited spectra similar to that of alginate. The presence of sequences related to the synthesis of alginate was confirmed in the metagenomes of the granules. Collectively these results suggest that alginate-like exopolysaccharides are constituents of the EPS matrix in anaerobic granular sludge treating different industrial wastewater. This finding expands the engineered environments where alginate has been found as EPS constituent of microbial aggregates.

  15. Modeling of secondary emission processes in the negative ion based electrostatic accelerator of the International Thermonuclear Experimental Reactor

    Directory of Open Access Journals (Sweden)

    G. Fubiani


    Full Text Available The negative ion electrostatic accelerator for the neutral beam injector of the International Thermonuclear Experimental Reactor (ITER is designed to deliver a negative deuterium current of 40 A at 1 MeV. Inside the accelerator there are several types of interactions that may create secondary particles. The dominating process originates from the single and double stripping of the accelerated negative ion by collision with the residual molecular deuterium gas (≃29% losses. The resulting secondary particles (positive ions, neutrals, and electrons are accelerated and deflected by the electric and magnetic fields inside the accelerator and may induce more secondaries after a likely impact with the accelerator grids. This chain of reactions is responsible for a non-negligible heat load on the grids and must be understood in detail. In this paper, we will provide a comprehensive summary of the physics involved in the process of secondary emission in a typical ITER-like negative ion electrostatic accelerator together with a precise description of the numerical method and approximations involved. As an example, the multiaperture-multigrid accelerator concept will be discussed.

  16. Biohydrogen and Bioethanol Production from Biodiesel-Based Glycerol by Enterobacter aerogenes in a Continuous Stir Tank Reactor

    Directory of Open Access Journals (Sweden)

    Rujira Jitrwung


    Full Text Available Crude glycerol from the biodiesel manufacturing process is being produced in increasing quantities due to the expanding number of biodiesel plants. It has been previously shown that, in batch mode, semi-anaerobic fermentation of crude glycerol by Enterobacter aerogenes can produce biohydrogen and bioethanol simultaneously. The present study demonstrated the possible scaling-up of this process from small batches performed in small bottles to a 3.6-L continuous stir tank reactor (CSTR. Fresh feed rate, liquid recycling, pH, mixing speed, glycerol concentration, and waste recycling were optimized for biohydrogen and bioethanol production. Results confirmed that E. aerogenes uses small amounts of oxygen under semi-anaerobic conditions for growth before using oxygen from decomposable salts, mainly NH4NO3, under anaerobic condition to produce hydrogen and ethanol. The optimal conditions were determined to be 500 rpm, pH 6.4, 18.5 g/L crude glycerol (15 g/L glycerol and 33% liquid recycling for a fresh feed rate of 0.44 mL/min. Using these optimized conditions, the process ran at a lower media cost than previous studies, was stable after 7 days without further inoculation and resulted in yields of 0.86 mol H2/mol glycerol and 0.75 mol ethanol/mole glycerol.

  17. Biohydrogen and Bioethanol Production from Biodiesel-Based Glycerol by Enterobacter aerogenes in a Continuous Stir Tank Reactor. (United States)

    Jitrwung, Rujira; Yargeau, Viviane


    Crude glycerol from the biodiesel manufacturing process is being produced in increasing quantities due to the expanding number of biodiesel plants. It has been previously shown that, in batch mode, semi-anaerobic fermentation of crude glycerol by Enterobacter aerogenes can produce biohydrogen and bioethanol simultaneously. The present study demonstrated the possible scaling-up of this process from small batches performed in small bottles to a 3.6-L continuous stir tank reactor (CSTR). Fresh feed rate, liquid recycling, pH, mixing speed, glycerol concentration, and waste recycling were optimized for biohydrogen and bioethanol production. Results confirmed that E. aerogenes uses small amounts of oxygen under semi-anaerobic conditions for growth before using oxygen from decomposable salts, mainly NH4NO3, under anaerobic condition to produce hydrogen and ethanol. The optimal conditions were determined to be 500 rpm, pH 6.4, 18.5 g/L crude glycerol (15 g/L glycerol) and 33% liquid recycling for a fresh feed rate of 0.44 mL/min. Using these optimized conditions, the process ran at a lower media cost than previous studies, was stable after 7 days without further inoculation and resulted in yields of 0.86 mol H2/mol glycerol and 0.75 mol ethanol/mole glycerol.

  18. Biohydrogen and Bioethanol Production from Biodiesel-Based Glycerol by Enterobacter aerogenes in a Continuous Stir Tank Reactor (United States)

    Jitrwung, Rujira; Yargeau, Viviane


    Crude glycerol from the biodiesel manufacturing process is being produced in increasing quantities due to the expanding number of biodiesel plants. It has been previously shown that, in batch mode, semi-anaerobic fermentation of crude glycerol by Enterobacter aerogenes can produce biohydrogen and bioethanol simultaneously. The present study demonstrated the possible scaling-up of this process from small batches performed in small bottles to a 3.6-L continuous stir tank reactor (CSTR). Fresh feed rate, liquid recycling, pH, mixing speed, glycerol concentration, and waste recycling were optimized for biohydrogen and bioethanol production. Results confirmed that E. aerogenes uses small amounts of oxygen under semi-anaerobic conditions for growth before using oxygen from decomposable salts, mainly NH4NO3, under anaerobic condition to produce hydrogen and ethanol. The optimal conditions were determined to be 500 rpm, pH 6.4, 18.5 g/L crude glycerol (15 g/L glycerol) and 33% liquid recycling for a fresh feed rate of 0.44 mL/min. Using these optimized conditions, the process ran at a lower media cost than previous studies, was stable after 7 days without further inoculation and resulted in yields of 0.86 mol H2/mol glycerol and 0.75 mol ethanol/mole glycerol. PMID:25970750

  19. Development of An Embedded FPGA-Based Data Acquisition System Dedicated to Zero Power Reactor Noise Experiments

    Directory of Open Access Journals (Sweden)

    Arkani Mohammad


    Full Text Available An embedded time interval data acquisition system (DAS is developed for zero power reactor (ZPR noise experiments. The system is capable of measuring the correlation or probability distribution of a random process. The design is totally implemented on a single Field Programmable Gate Array (FPGA. The architecture is tested on different FPGA platforms with different speed grades and hardware resources. Generic experimental values for time resolution and inter-event dead time of the system are 2.22 ns and 6.67 ns respectively. The DAS can record around 48-bit x 790 kS/s utilizing its built-in fast memory. The system can measure very long time intervals due to its 48-bit timing structure design. As the architecture can work on a typical FPGA, this is a low cost experimental tool and needs little time to be established. In addition, revisions are easily possible through its reprogramming capability. The performance of the system is checked and verified experimentally.

  20. Design of a boiling water reactor core based on an integrated blanket-seed thorium-uranium concept

    Energy Technology Data Exchange (ETDEWEB)

    Nunez-Carrera, Alejandro [Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Laboratorio de Analisis en Ingenieria de Reactores Nucleares, Paseo Cuauhnahuac 8532, 62550 Jiutepec, Mor. (Mexico); Comision Nacional de Seguridad Nuclear y Salvaguardias, Dr. Barragan 779, Col. Narvarte, 03020 Mexico, D.F. (Mexico); Francois, Juan Luis [Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Laboratorio de Analisis en Ingenieria de Reactores Nucleares, Paseo Cuauhnahuac 8532, 62550 Jiutepec, Mor. (Mexico)]. E-mail:; Martin-del-Campo, Cecilia [Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Laboratorio de Analisis en Ingenieria de Reactores Nucleares, Paseo Cuauhnahuac 8532, 62550 Jiutepec, Mor. (Mexico); Espinosa-Paredes, Gilberto [Area de Ingenieria en Recursos Energeticos, Universidad Autonoma Metropolitana, Avenida San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico, D.F. (Mexico)


    This paper is concerned with the design of a boiling water reactor (BWR) equilibrium core using thorium as a nuclear material in an integrated blanket-seed (BS) assembly. The integrated BS concept comes from the fact that the blanket and the seed rods are located in the same assembly, and are burned out in a once-through cycle. The idea behind the lattice design is to use the thorium conversion capability in a BWR spectrum, taking advantage of the {sup 233}U build-up. A core design was developed to achieve an equilibrium cycle of 365 effective full power days in a standard BWR with a reload of 104 fuel assemblies designed with an average {sup 235}U enrichment of 7.5 w/o in the seed sub-lattice. The main operating parameters, like power, linear heat generation rate and void distributions were obtained as well as the shutdown margin. It was observed that the analyzed parameters behave like those obtained in a standard BWR. The shutdown margin design criterion was fulfilled by addition of a burnable poison region in the fuel assembly.

  1. NMR and MALDI-TOF MS based characterization of exopolysaccharides in anaerobic microbial aggregates from full-scale reactors

    KAUST Repository

    Gonzalez-Gil, Graciela


    Anaerobic granular sludge is composed of multispecies microbial aggregates embedded in a matrix of extracellular polymeric substances (EPS). Here we characterized the chemical fingerprint of the polysaccharide fraction of EPS in anaerobic granules obtained from full-scale reactors treating different types of wastewater. Nuclear magnetic resonance (NMR) signals of the polysaccharide region from the granules were very complex, likely as a result of the diverse microbial population in the granules. Using nonmetric multidimensional scaling (NMDS), the 1H NMR signals of reference polysaccharides (gellan, xanthan, alginate) and those of the anaerobic granules revealed that there were similarities between the polysaccharides extracted from granules and the reference polysaccharide alginate. Further analysis of the exopolysaccharides from anaerobic granules, and reference polysaccharides using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) revealed that exopolysaccharides from two of the anaerobic granular sludges studied exhibited spectra similar to that of alginate. The presence of sequences related to the synthesis of alginate was confirmed in the metagenomes of the granules. Collectively these results suggest that alginate-like exopolysaccharides are constituents of the EPS matrix in anaerobic granular sludge treating different industrial wastewater. This finding expands the engineered environments where alginate has been found as EPS constituent of microbial aggregates.

  2. The Effect of p53 Status of Tumor Cells on Radiosensitivity of Irradiated Tumors With Carbon-Ion Beams Compared With γ-Rays or Reactor Neutron Beams. (United States)

    Masunaga, Shin-Ichiro; Uzawa, Akiko; Hirayama, Ryoichi; Matsumoto, Yoshitaka; Sakurai, Yoshinori; Tanaka, Hiroki; Tano, Keizo; Sanada, Yu; Suzuki, Minoru; Maruhashi, Akira; Ono, Koji


    The aim of the study was to clarify the effect of p53 status of tumor cells on radiosensitivity of solid tumors following accelerated carbon-ion beam irradiation compared with γ-rays or reactor neutron beams, referring to the response of intratumor quiescent (Q) cells. Human head and neck squamous cell carcinoma cells transfected with mutant TP53 (SAS/mp53) or with neo vector (SAS/neo) were injected subcutaneously into hind legs of nude mice. Tumor-bearing mice received 5-bromo-2'-deoxyuridine (BrdU) continuously to label all intratumor proliferating (P) cells. They received γ-rays or accelerated carbon-ion beams at a high or reduced dose-rate. Other tumor-bearing mice received reactor thermal or epithermal neutrons at a reduced dose-rate. Immediately or 9 hours after the high dose-rate irradiation (HDRI), or immediately after the reduced dose-rate irradiation (RDRI), the tumor cells were isolated and incubated with a cytokinesis blocker, and the micronucleus (MN) frequency in cells without BrdU labeling (Q cells) was determined using immunofluorescence staining for BrdU. The difference in radiosensitivity between the total (P + Q) and Q cells after γ-ray irradiation was markedly reduced with reactor neutron beams or carbon-ion beams, especially with a higher linear energy transfer (LET) value. Following γ-ray irradiation, SAS/neo tumor cells, especially intratumor Q cells, showed a marked reduction in sensitivity due to the recovery from radiation-induced damage, compared with the total or Q cells within SAS/mp53 tumors that showed little repair capacity. In both total and Q cells within both SAS/neo and SAS/mp53 tumors, carbon-ion beam irradiation, especially with a higher LET, showed little recovery capacity through leaving an interval between HDRI and the assay or decreasing the dose-rate. The recovery from radiation-induced damage after γ-ray irradiation was a p53-dependent event, but little recovery was found after carbon-ion beam irradiation. With RDRI

  3. Neutron fluxes in test reactors

    Energy Technology Data Exchange (ETDEWEB)

    Youinou, Gilles Jean-Michel [Idaho National Lab. (INL), Idaho Falls, ID (United States)


    Communicate the fact that high-power water-cooled test reactors such as the Advanced Test Reactor (ATR), the High Flux Isotope Reactor (HFIR) or the Jules Horowitz Reactor (JHR) cannot provide fast flux levels as high as sodium-cooled fast test reactors. The memo first presents some basics physics considerations about neutron fluxes in test reactors and then uses ATR, HFIR and JHR as an illustration of the performance of modern high-power water-cooled test reactors.

  4. Neutron spectra in two beam ports of the TRIGA Mark III reactor

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R.; Hernandez D, V. M. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas (Mexico); Aguilar, F.; Paredes, L. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Rivera M, T., E-mail: [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria, Av. Legaria 694, 11500 Mexico D. F. (Mexico)


    The neutron spectra have been measured in two beam ports, radial and tangential, of the TRIGA Mark III nuclear reactor from the National Institute of Nuclear Research. Measurements were carried out with the core with mixed fuel (Leu 8.5/20 and Flip Heu 8.5/70). Two reactor powers, 5 and 10 W, were used during neutron spectra measurements using a Bonner sphere spectrometer with a {sup 6}Lil(Eu) scintillator and 2, 3, 5, 8, 10 and 12 inches-diameter high density polyethylene spheres. The neutron spectra were unfolded using the NSDUAZ unfolding code; from each spectrum the total neutron flux, the neutron mean energy and the neutron ambient dose equivalent dose were determined. Measured spectra show fission (E≥ 0.1 MeV), epithermal (from 0.4 eV up to 0.1 MeV) and thermal neutrons (E≤ 0.4 eV). For both reactor powers the spectra in the radial beam port have similar features which are different to the neutron spectrum characteristics in the tangential beam port. (Author)


    Treshow, M.


    Reactors of the boiling water type are described wherein water serves both as the moderator and coolant. The reactor system consists essentially of a horizontal pressure vessel divided into two compartments by a weir, a thermal neutronic reactor core having vertical coolant passages and designed to use water as a moderator-coolant posltioned in one compartment, means for removing live steam from the other compartment and means for conveying feed-water and water from the steam compartment to the reactor compartment. The system further includes auxiliary apparatus to utilize the steam for driving a turbine and returning the condensate to the feed-water inlet of the reactor. The entire system is designed so that the reactor is self-regulating and has self-limiting power and self-limiting pressure features.

  6. Fast Spectrum Reactors

    CERN Document Server

    Todd, Donald; Tsvetkov, Pavel


    Fast Spectrum Reactors presents a detailed overview of world-wide technology contributing to the development of fast spectrum reactors. With a unique focus on the capabilities of fast spectrum reactors to address nuclear waste transmutation issues, in addition to the well-known capabilities of breeding new fuel, this volume describes how fast spectrum reactors contribute to the wide application of nuclear power systems to serve the global nuclear renaissance while minimizing nuclear proliferation concerns. Readers will find an introduction to the sustainable development of nuclear energy and the role of fast reactors, in addition to an economic analysis of nuclear reactors. A section devoted to neutronics offers the current trends in nuclear design, such as performance parameters and the optimization of advanced power systems. The latest findings on fuel management, partitioning and transmutation include the physics, efficiency and strategies of transmutation, homogeneous and heterogeneous recycling, in addit...

  7. Monitoring and control of anaerobic reactors

    DEFF Research Database (Denmark)

    Pind, Peter Frode; Angelidaki, Irini; Ahring, Birgitte Kiær


    The current status in monitoring and control of anaerobic reactors is reviewed. The influence of reactor design and waste composition on the possible monitoring and control schemes is examined. After defining the overall control structure, and possible control objectives, the possible process mea...... control approaches that have been used are comprehensively described. These include simple and adaptive controllers, as well as more recent developments such as fuzzy controllers, knowledge-based controllers and controllers based on neural networks....


    Spinrad, B.I.


    A novel thermal reactor was designed in which a first reflector formed from a high atomic weight, nonmoderating material is disposed immediately adjacent to the reactor core. A second reflector composed of a moderating material is disposed outwardly of the first reflector. The advantage of this novel reflector arrangement is that the first reflector provides a high slow neutron flux in the second reflector, where irradiation experiments may be conducted with a small effect on reactor reactivity.

  9. Conceptual design of a nucleo electric simulator with PBMR reactor based in Reduced order models; Diseno conceptual de un simulador de nucleo electrica con reactor PBMR basado en modelos de orden reducido

    Energy Technology Data Exchange (ETDEWEB)

    Valle H, J.; Morales S, J.B. [UNAM, DEPFI, Campus Morelos, en IMTA Jiutepec, Morelos (Mexico)]. e-mail:


    This project has as purpose to know to depth the operation of a PBMR nucleo electric type (Pebble Bed Modular Reactor), which has a reactor of moderate graphite spheres and fuel of uranium dioxide cooled with Helium and Brayton thermodynamic cycle. The simulator seeks to describe the dynamics of the one process of energy generation in the nuclear fuel, the process of transport toward the coolant one and the conversion to mechanical energy in the turbo-generators as well as in the heat exchangers indispensable for the process. The dynamics of reload of the fuel elements it is not modeled in detail but their effects are represented in the parameters of the pattern. They are modeled also the turbo-compressors of the primary circuit of the work fluid. The control of the power of the nuclear reactor is modeled by means of reactivity functions specified in the simulation platform. The proposed mathematical models will be settled in the platform of simulation of Simulink-Mat Lab. The proposed control panels for this simulator can be designed and to implement using the box of tools of Simulink that facilitates this process. The work presents the mathematical models more important used for their future implementation in Simulink. (Author)

  10. Effect of kinetic parameters on simultaneous ramp reactivity insertion plus beam tube flooding accident in a typical low enriched U{sub 3}Si{sub 2}-Al fuel-based material testing reactor-type research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Nasir, Rubina; Mirza, Nasir M. [Dept. of, Physics, Air University, Islamabad (Pakistan); Mirza, Sikander M. [Dept. of, Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences, Post Office Nilore, Islamabad (Pakistan)


    This work looks at the effect of changes in kinetic parameters on simultaneous reactivity insertions and beam tube flooding in a typical material testing reactor-type research reactor with low enriched high density (U{sub 3}Si{sub 2}-Al) fuel. Using a modified PARET code, various ramp reactivity insertions (from $0.1/0.5 s to $1.3/0.5 s) plus beam tube flooding ($0.5/0.25 s) accidents under uncontrolled conditions were analyzed to find their effects on peak power, net reactivity, and temperature. Then, the effects of changes in kinetic parameters including the Doppler coefficient, prompt neutron lifetime, and delayed neutron fractions on simultaneous reactivity insertion and beam tube flooding accidents were analyzed. Results show that the power peak values are significantly sensitive to the Doppler coefficient of the system in coupled accidents. The material testing reactor-type system under such a coupled accident is not very sensitive to changes in the prompt neutron life time; the core under such a coupled transient is not very sensitive to changes in the effective delayed neutron fraction.

  11. ORNL breeder reactor safety quarterly technical progress report, July-September 1980

    Energy Technology Data Exchange (ETDEWEB)

    Fontana, M H; Wantland, J L


    Six tasks are reported upon: THORS (Thermal-Hydraulic Out-of-Reactor Safety) program, environmental assessment of alternate FBR fuels, model evaluation of breeder reactor radioactivity releases, nuclear safety information center activities, breeder reactor reliability data analysis center activities, and central data base for breeder reactor safety codes. (DLC)

  12. Oscillatory flow chemical reactors

    National Research Council Canada - National Science Library

    Slavnić Danijela S; Bugarski Branko M; Nikačević Nikola M


    .... However, the reactions of interests for the mentioned industry sectors are often slow, thus continuous tubular reactors would be impractically long for flow regimes which provide sufficient heat...

  13. Membrane reactors at Degussa. (United States)

    Wöltinger, Jens; Karau, Andreas; Leuchtenberger, Wolfgang; Drauz, Karlheinz


    The review covers the development of membrane reactor technologies at Degussa for the synthesis of fine chemicals. The operation of fed-batch or continuous biocatalytic processes in the enzyme membrane reactor (EMR) is well established at Degussa. Degussa has experience of running EMRs from laboratory gram scale up to a production scale of several hundreds of tons per year. The transfer of the enzyme membrane reactor from biocatalysis to chemical catalysis in the chemzyme membrane reactor (CMR) is discussed. Various homogeneous catalysts have been investigated in the CMR, and the scope and limitation of this new technique is discussed.

  14. Pressurizing new reactors

    Energy Technology Data Exchange (ETDEWEB)

    Neill, J.S.


    The Technical Division was asked recently to consider designs for new reactors that would add 8000 MW capacity to the Savannah River Plant. One modification of the existing SRP design that would enable a higher power rating, and therefore require fewer new reactors, is an increase in the maximum pressure in the D{sub 2}O system. The existing reactors at SRP are designed for a maximum pressure in the gas plenum of only 5 psig. Higher pressures enable higher D{sub 2} temperatures and higher sheath temperatures without local boiling or burnout. The requirements in reactor cooling facilities at any given power level would therefore be reduced by pressurizing.


    King, L.D.P.


    A homogeneous nuclear power reactor utilizing forced circulation of the liquid fuel is described. The reactor does not require fuel handling outside of the reactor vessel during any normal operation including complete shutdown to room temperature, the reactor being selfregulating under extreme operating conditions and controlled by the thermal expansion of the liquid fuel. The liquid fuel utilized is a uranium, phosphoric acid, and water solution which requires no gus exhaust system or independent gas recombining system, thereby eliminating the handling of radioiytic gas.

  16. Development of a system based in a digital signal processor (DSP) for a simulator of power regulation in a reactor: first stage; Desarrollo de un sistema basado en un DSP para un simulador de regulacion de potencia en un reactor: 1. etapa

    Energy Technology Data Exchange (ETDEWEB)

    Benitez R, J.S.; Perez C, B. [Instituto Nacional de Investigaciones Nucleares, Km. 36.5 Carretera Mexico-Toluca, Municipio de Ocoyoacac, 52045 Estado de Mexico (Mexico)


    The first stage of the development of a digital system based on a DSP is presented which forms part of an hybrid simulator for the power regulation in am model of the punctual kinetics of a TRIGA reactor type. The DSP performs the regulation, using a Mandami type algorithm of diffuse control. In the algorithm, the universe of the output variable is discretized for performing in an unique stage the aggregation functions and dis-diffusization. (Author)

  17. Reactor performances and microbial communities of biogas reactors: effects of inoculum sources. (United States)

    Han, Sheng; Liu, Yafeng; Zhang, Shicheng; Luo, Gang


    Anaerobic digestion is a very complex process that is mediated by various microorganisms, and the understanding of the microbial community assembly and its corresponding function is critical in order to better control the anaerobic process. The present study investigated the effect of different inocula on the microbial community assembly in biogas reactors treating cellulose with various inocula, and three parallel biogas reactors with the same inoculum were also operated in order to reveal the reproducibility of both microbial communities and functions of the biogas reactors. The results showed that the biogas production, volatile fatty acid (VFA) concentrations, and pH were different for the biogas reactors with different inocula, and different steady-state microbial community patterns were also obtained in different biogas reactors as reflected by Bray-Curtis similarity matrices and taxonomic classification. It indicated that inoculum played an important role in shaping the microbial communities of biogas reactor in the present study, and the microbial community assembly in biogas reactor did not follow the niche-based ecology theory. Furthermore, it was found that the microbial communities and reactor performances of parallel biogas reactors with the same inoculum were different, which could be explained by the neutral-based ecology theory and stochastic factors should played important roles in the microbial community assembly in the biogas reactors. The Bray-Curtis similarity matrices analysis suggested that inoculum affected more on the microbial community assembly compared to stochastic factors, since the samples with different inocula had lower similarity (10-20 %) compared to the samples from the parallel biogas reactors (30 %).

  18. Advanced fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, Yukihiro [National Inst. for Fusion Science, Toki, Gifu (Japan)


    The main subjects on fusion research are now on D-T fueled fusion, mainly due to its high fusion reaction rate. However, many issues are still remained on the wall loading by the 14 MeV neutrons. In the case of D-D fueled fusion, the neutron wall loading is still remained, though the technology related to tritium breeding is not needed. The p-{sup 6}Li and p-{sup 11}B fueled fusions are not estimated to be the next generation candidate until the innovated plasma confinement technologies come in useful to achieve the high performance plasma parameters. The fusion reactor of D-{sup 3}He fuels has merits on the smaller neutron wall loading and tritium handling. However, there are difficulties on achieving the high temperature plasma more than 100 keV. Furthermore the high beta plasma is needed to decrease synchrotron radiation loss. In addition, the efficiency of the direct energy conversion from protons coming out from fusion reaction is one of the key parameters in keeping overall power balance. Therefore, open magnetic filed lines should surround the plasma column. In this paper, we outlined the design of the commercial base reactor (ARTEMIS) of 1 GW electric output power configured by D-{sup 3}He fueled FRC (Field Reversed Configuration). The ARTEMIS needs 64 kg of {sup 3}He per a year. On the other hand, 1 million tons of {sup 3}He is estimated to be in the moon. The {sup 3}He of about 10{sup 23} kg are to exist in gaseous planets such as Jupiter and Saturn. (Y. Tanaka)

  19. Technical specifications, Hanford production reactors

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, W.D. [comp.


    These technical specifications are applicable to the eight operating production reactor facilities, B, C, D, DR, F, H, KE, and KW. Covered are operating and performance restrictions and administrative procedures. Areas covered by the operating and performance restrictions are reactivity, reactor control and safety elements, power level, temperature and heat flux, reactor fuel loadings, reactor coolant systems, reactor confinement, test facilities, code compliance, and reactor scram set points. Administrative procedures include process control procedures, training programs, audits and inspections, and reports and records.

  20. Reactor Materials Research

    Energy Technology Data Exchange (ETDEWEB)

    Van Walle, E


    The activities of the Reactor Materials Research Department of the Belgian Nuclear Research Centre SCK-CEN in 2000 are summarised. The programmes within the department are focussed on studies concerning (1) fusion, in particular mechanical testing; (2) Irradiation Assisted Stress Corrosion Cracking (IASCC); (3) nuclear fuel; and (4) Reactor Pressure Vessel Steel (RPVS)

  1. Space Nuclear Reactor Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Poston, David Irvin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    We needed to find a space reactor concept that could be attractive to NASA for flight and proven with a rapid turnaround, low-cost nuclear test. Heat-pipe-cooled reactors coupled to Stirling engines long identified as the easiest path to near-term, low-cost concept.


    Fraas, A.P.


    A reflector for nuclear reactors that comprises an assembly of closely packed graphite rods disposed with their major axes substantially perpendicular to the interface between the reactor core and the reflector is described. Each graphite rod is round in transverse cross section at (at least) its interface end and is provided, at that end, with a coaxial, inwardly tapering hole. (AEC)

  3. Heterogeneous Recycling in Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Forget, Benoit; Pope, Michael; Piet, Steven J.; Driscoll, Michael


    Current sodium fast reactor (SFR) designs have avoided the use of depleted uranium blankets over concerns of creating weapons grade plutonium. While reducing proliferation risks, this restrains the reactor design space considerably. This project will analyze various blanket and transmutation target configurations that could broaden the design space while still addressing the non-proliferation issues. The blanket designs will be assessed based on the transmutation efficiency of key minor actinide (MA) isotopes and also on mitigation of associated proliferation risks. This study will also evaluate SFR core performance under different scenarios in which depleted uranium blankets are modified to include minor actinides with or without moderators (e.g. BeO, MgO, B4C, and hydrides). This will be done in an effort to increase the sustainability of the reactor and increase its power density while still offering a proliferation resistant design with the capability of burning MA waste produced from light water reactors (LWRs). Researchers will also analyze the use of recycled (as opposed to depleted) uranium in the blankets. The various designs will compare MA transmutation efficiency, plutonium breeding characteristics, proliferation risk, shutdown margins and reactivity coefficients with a current reference sodium fast reactor design employing homogeneous recycling. The team will also evaluate the out-of-core accumulation and/or burn-down rates of MAs and plutonium isotopes on a cycle-by-cycle basis. This cycle-by-cycle information will be produced in a format readily usable by the fuel cycle systems analysis code, VISION, for assessment of the sustainability of the deployment scenarios.

  4. Design of a rotary reactor for chemical-looping combustion. Part 2: Comparison of copper-, nickel-, and iron-based oxygen carriers

    KAUST Repository

    Zhao, Zhenlong


    Chemical-looping combustion (CLC) is a novel and promising option for several applications including carbon capture (CC), fuel reforming, H 2 generation, etc. Previous studies demonstrated the feasibility of performing CLC in a novel rotary design with micro-channel structures. Part 1 of this series studied the fundamentals of the reactor design and proposed a comprehensive design procedure, enabling a systematic methodology of designing and evaluating the rotary CLC reactor with different OCs and operating conditions. This paper presents the application of the methodology to the designs with three commonly used OCs, i.e., copper, nickel, and iron. The physical properties and the reactivities of the three OCs are compared at operating conditions suitable for the rotary CLC. Nickel has the highest reduction rate, but relatively slow oxidation reactivity while the iron reduction rate is most sensitive to the fuel concentration. The design parameters and the operating conditions for the three OCs are selected, following the strategies proposed in Part 1, and the performances are evaluated using a one-dimensional plug-flow model developed previously. The simulations show that for all OCs, complete fuel conversion and high carbon separation efficiency can be achieved at periodic stationary state with reasonable operational stabilities. The nickel-based design includes the smallest dimensions because of its fast reduction rate. The operation of nickel case is mainly limited to the slow oxidation rate, and hence a relatively large share of air sector is used. The iron-based design has the largest size, due to its slow reduction reactivity near the exit or in the fuel purge sector where the fuel concentration is low. The gas flow temperature increases monotonically for all the cases, and is mainly determined by the solid temperature. In the periodic state, the local temperature variation is within 40 K and the thermal distortion is limited. The design of the rotary CLC is

  5. Mirror reactor surface study

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, A. L.; Damm, C. C.; Futch, A. H.; Hiskes, J. R.; Meisenheimer, R. G.; Moir, R. W.; Simonen, T. C.; Stallard, B. W.; Taylor, C. E.


    A general survey is presented of surface-related phenomena associated with the following mirror reactor elements: plasma first wall, ion sources, neutral beams, director converters, vacuum systems, and plasma diagnostics. A discussion of surface phenomena in possible abnormal reactor operation is included. Several studies which appear to merit immediate attention and which are essential to the development of mirror reactors are abstracted from the list of recommended areas for surface work. The appendix contains a discussion of the fundamentals of particle/surface interactions. The interactions surveyed are backscattering, thermal desorption, sputtering, diffusion, particle ranges in solids, and surface spectroscopic methods. A bibliography lists references in a number of categories pertinent to mirror reactors. Several complete published and unpublished reports on surface aspects of current mirror plasma experiments and reactor developments are also included.

  6. Status of French reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ballagny, A. [Commissariat a l`Energie Atomique, Saclay (France)


    The status of French reactors is reviewed. The ORPHEE and RHF reactors can not be operated with a LEU fuel which would be limited to 4.8 g U/cm{sup 3}. The OSIRIS reactor has already been converted to LEU. It will use U{sub 3}Si{sub 2} as soon as its present stock of UO{sub 2} fuel is used up, at the end of 1994. The decision to close down the SILOE reactor in the near future is not propitious for the start of a conversion process. The REX 2000 reactor, which is expected to be commissioned in 2005, will use LEU (except if the fast neutrons core option is selected). Concerning the end of the HEU fuel cycle, the best option is reprocessing followed by conversion of the reprocessed uranium to LEU.

  7. Prolongation of the BOR-60 reactor operation

    Directory of Open Access Journals (Sweden)

    Alexey l. Izhutov


    Full Text Available The fast neutron reactor BOR-60 is one of the key experimental facilities worldwide to perform large-scale tests of fuel, absorbing, and structural materials for advanced reactors. The BOR-60 reactor was put into operation in December 1969, and by the end of 2014 it had been operating on power for ∼265,000 hours. BOR-60 still demonstrates potential capabilities to extend the lifetime of sodium-cooled fast reactors. The BOR-60 lifetime should have expired at the end of 2014. Over the past few years, a great scope of work has been performed to justify the possibility of extending its lifetime. The work included inspection of the equipment conditions, calculations and experimental research on operating parameters and the conditions of nonremovable components, investigation of the structural material samples after their long-term operation under irradiation, etc. Based on the results of the work performed, the residual lifetime was evaluated and the reactor operator made a decision to extend the lifetime period of the BOR-60 reactor. After considering both a set of documents about the reactor conditions and the positive decision of independent experts, the Regulatory Authority of the Russian Federation extended the BOR-60 operating license up to 2020.

  8. Proposed Advanced Reactor Adaptation of the Standard Review Plan NUREG-0800 Chapter 4 (Reactor) for Sodium-Cooled Fast Reactors and Modular High-Temperature Gas-Cooled Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Belles, Randy [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Poore, III, Willis P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brown, Nicholas R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Flanagan, George F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holbrook, Mark [Idaho National Lab. (INL), Idaho Falls, ID (United States); Moe, Wayne [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sofu, Tanju [Argonne National Lab. (ANL), Argonne, IL (United States)


    This report proposes adaptation of the previous regulatory gap analysis in Chapter 4 (Reactor) of NUREG 0800, Standard Review Plan (SRP) for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR [Light Water Reactor] Edition. The proposed adaptation would result in a Chapter 4 review plan applicable to certain advanced reactors. This report addresses two technologies: the sodium-cooled fast reactor (SFR) and the modular high temperature gas-cooled reactor (mHTGR). SRP Chapter 4, which addresses reactor components, was selected for adaptation because of the possible significant differences in advanced non-light water reactor (non-LWR) technologies compared with the current LWR-based description in Chapter 4. SFR and mHTGR technologies were chosen for this gap analysis because of their diverse designs and the availability of significant historical design detail.

  9. Study of molybdenum-99 production in IEA-R1m reactor using a beryllium irradiator; Estudos sobre a producao de molibdenio no reator IEA-R1m utilizando um irradiador de berilio

    Energy Technology Data Exchange (ETDEWEB)

    Ricci Filho, Walter [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Moreira, Joao M.L. [Centro Tecnologico da Marinha (CTMSP), Sao Paulo, SP (Brazil)


    The IEA-R1 reactor has undergone a modernization to increase its operating power to 5 MW, in order to allow a more efficient production of the {sup 99} Mo radioisotope. An irradiation element made of Be was acquired for the reactor and studies were initiated for determining its performance when compared to other irradiators available in the reactor, the water and graphite types. The results obtained showed some advantages of the Be irradiation element for producing {sup 99} Mo: the epithermal neutron flux in the irradiation element is approximately 15% greater than in the water and in the graphite irradiation elements; the negative reactivity introduced in the reactor by the Be irradiation element is substantially smaller than the those introduced by the other elements: - 1636 pcm for the Be irradiator, -2568 for the graphite irradiator and -2977 pcm for the water irradiator. It is concluded that the production of the {sup 99M}o radioisotope with the Be irradiation element can be increased by 15% in the IEA-R1m reactor. It also requires less fuel for the reactor operation due to the smaller negative reactivity introduced in the reactor core. (author) 4 refs., 9 figs., 1 tab.

  10. Novel oscillatory flow reactors for biotechnological applications


    Reis, N.


    Tese de Doutoramento em Engenharia Química e Biológica This thesis explores the biotechnological applications of two novel scale-down oscillatory flow reactors (OFRs). A micro-bioreactor (working mostly in batch) and a continuous meso-reactor systems were developed based on a 4.4 mm internal diameter tube with smooth periodic constrictions (SPC), both operating under oscillatory flow mixing (OFM). The first part is dedicated to the flow characterisation in the novel SPC geom...

  11. System and method for the analysis of one or more compounds and/or species produced by a solution-based nuclear reactor (United States)

    Policke, Timothy A; Nygaard, Eric T


    The present invention relates generally to both a system and method for determining the composition of an off-gas from a solution nuclear reactor (e.g., an Aqueous Homogeneous Reactor (AHR)) and the composition of the fissioning solution from those measurements. In one embodiment, the present invention utilizes at least one quadrupole mass spectrometer (QMS) in a system and/or method designed to determine at least one or more of: (i) the rate of production of at least one gas and/or gas species from a nuclear reactor; (ii) the effect on pH by one or more nitrogen species; (iii) the rate of production of one or more fission gases; and/or (iv) the effect on pH of at least one gas and/or gas species other than one or more nitrogen species from a nuclear reactor.

  12. Evaluation of thermal neutron irradiation field using a cyclotron-based neutron source for alpha autoradiography. (United States)

    Tanaka, H; Sakurai, Y; Suzuki, M; Masunaga, S; Mitsumoto, T; Kinashi, Y; Kondo, N; Narabayashi, M; Nakagawa, Y; Watanabe, T; Fujimoto, N; Maruhashi, A; Ono, K


    It is important to measure the microdistribution of (10)B in a cell to predict the cell-killing effect of new boron compounds in the field of boron neutron capture therapy. Alpha autoradiography has generally been used to detect the microdistribution of (10)B in a cell. Although it has been performed using a reactor-based neutron source, the realization of an accelerator-based thermal neutron irradiation field is anticipated because of its easy installation at any location and stable operation. Therefore, we propose a method using a cyclotron-based epithermal neutron source in combination with a water phantom to produce a thermal neutron irradiation field for alpha autoradiography. This system can supply a uniform thermal neutron field with an intensity of 1.7×10(9) (cm(-2)s(-1)) and an area of 40mm in diameter. In this paper, we give an overview of our proposed system and describe a demonstration test using a mouse liver sample injected with 500mg/kg of boronophenyl-alanine. Copyright © 2014. Published by Elsevier Ltd.

  13. Performance of a microbial fuel cell-based biosensor for online monitoring in an integrated system combining microbial fuel cell and upflow anaerobic sludge bed reactor. (United States)

    Jia, Hui; Yang, Guang; Wang, Jie; Ngo, Huu Hao; Guo, Wenshan; Zhang, Hongwei; Zhang, Xinbo


    A hybrid system integrating a microbial fuel cell (MFC)-based biosensor with upflow anaerobic sludge blanket (UASB) was investigated for real-time online monitoring of the internal operation of the UASB reactor. The features concerned were its rapidity and steadiness with a constant operation condition. In addition, the signal feedback mechanism was examined by the relationship between voltage and time point of changed COD concentration. The sensitivity of different concentrations was explored by comparing the signal feedback time point between the voltage and pH. Results showed that the electrical signal feedback was more sensitive than pH and the thresholds of sensitivity were S=3×10(-5)V/(mg/L) and S=8×10(-5)V/(mg/L) in different concentration ranges, respectively. Although only 0.94% of the influent COD was translated into electricity and applied for biosensing, this integrated system indicated great potential without additional COD consumption for real-time monitoring. Copyright © 2016. Published by Elsevier Ltd.

  14. Sequencing batch reactor technology: the key to a BP refinery (Bulwer Island) upgraded environmental protection system--a low cost lagoon based retro-fit. (United States)

    Hudson, N; Doyle, J; Lant, P; Roach, N; de Bruyn, B; Staib, C


    BP Refinery (Bulwer Island) Ltd (BP) located on the eastern Australian coast is currently undergoing a major expansion as a part of the Queensland Clean Fuels Project. The associated wastewater treatment plant upgrade will provide a better quality of treated effluent than is currently possible with the existing infrastructure, and which will be of a sufficiently high standard to meet not only the requirements of imposed environmental legislation but also BP's environmental objectives. A number of challenges were faced when considering the upgrade, particularly; cost constraints and limited plot space, highly variable wastewater, toxicity issues, and limited hydraulic head. Sequencing Batch Reactor (SBR) Technology was chosen for the lagoon upgrade based on the following; SBR technology allowed a retro-fit of the existing earthen lagoon without the need for any additional substantial concrete structures, a dual lagoon system allowed partial treatment of wastewaters during construction, SBRs give substantial process flexibility, SBRs have the ability to easily modify process parameters without any physical modifications, and significant cost benefits. This paper presents the background to this application, an outline of laboratory studies carried out on the wastewater and details the full scale design issues and methods for providing a cost effective, efficient treatment system using the existing lagoon system.

  15. Chaboche-based cyclic material hardening models for 316 SS–316 SS weld under in-air and pressurized water reactor water conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish, E-mail:; Soppet, William K.; Majumdar, Saurindranath; Natesan, Krishnamurti


    Highlights: • 316 SS–316 SS weld cyclically harden/soften while undergoing fatigue loading. • Cyclic hardening/softening creates cycle dependent stress-strain curves. • This necessitate to estimate the cycle dependence of material properties. • Cyclic evolution of Chaboche parameters are estimated under different conditions. - Abstract: This paper discusses a material hardening models for welds made from 316 stainless steel (SS) to 316 SS. The model parameters were estimated from the strain-versus-stress curves obtained from tensile and fatigue tests conducted under different conditions (air at room temperature, air at 300 °C, and primary loop water conditions for a pressurized water reactor). These data were used to check the fatigue cycle dependency of the material hardening parameters (yield stress, parameters related to Chaboche-based linear and nonlinear kinematic hardening models, etc.). The details of the experimental results, material hardening models, and associated calculated results are published in an Argonne report (ANL/LWRS-15/2). This paper summarizes the reported material parameters for 316 SS–316 SS welds and their dependency on fatigue cycles and other test conditions.

  16. Nuclear reactor control column (United States)

    Bachovchin, Dennis M.


    The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest cross-sectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor.

  17. Reactor Safety Research Programs

    Energy Technology Data Exchange (ETDEWEB)

    Edler, S. K.


    This document summarizes the work performed by Pacific Northwest Laboratory (PNL) from January 1 through March 31, 1981, for the Division of Reactor Safety Research within the U.S. Nuclear Regulatory Commission (NRC). Evaluations of nondestructive examination (NDE) techniques and instrumentation are reported; areas of investigation include demonstrating the feasibility of determining the strength of structural graphite, evaluating the feasibility of detecting and analyzing flaw growth in reactor pressure boundary systems, examining NDE reliability and probabilistic fracture mechanics, and assessing the integrity of pressurized water reactor (PWR) steam generator tubes where service-induced degradation has been indicated. Experimental data and analytical models are being provided to aid in decision-making regarding pipeto- pipe impacts following postulated breaks in high-energy fluid system piping. Core thermal models are being developed to provide better digital codes to compute the behavior of full-scale reactor systems under postulated accident conditions. Fuel assemblies and analytical support are being provided for experimental programs at other facilities. These programs include loss-ofcoolant accident (LOCA) simulation tests at the NRU reactor, Chalk River, Canada; fuel rod deformation, severe fuel damage, and postaccident coolability tests for the ESSOR reactor Super Sara Test Program, Ispra, Italy; the instrumented fuel assembly irradiation program at Halden, Norway; and experimental programs at the Power Burst Facility, Idaho National Engineering Laboratory (INEL). These programs will provide data for computer modeling of reactor system and fuel performance during various abnormal operating conditions.

  18. Reactor power monitoring device

    Energy Technology Data Exchange (ETDEWEB)

    Oda, Naotaka; Igawa, Shinji; Kitazono, Hideaki


    The present invention provides a reactor power monitoring device capable of ensuring circumstance resistance, high reliability and high speed transmission even if an APRM is disposed in a reactor building (R/B). Namely, signal processing sections (APRM) for transmitting data to a central control chamber are distributed in the reactor building at an area at the lowest temperature among areas where the temperature control in an emergency state is regulated, and a transmission processing section (APRM-I/F) for transmitting data to the other systems is disposed to the central control chamber. An LPRM signal transmission processing section is constituted such that LPRM signals can be transmitted at a high speed by DMA. Set values relevant to reactor tripping (neutron flux high, thermal output high and sudden reduction of a reactor core flow rate) are stored in the APRM-I/F, and reactor tripping calculation is conducted in the APRM-I/F. With such procedure, a reactor power monitoring device having enhanced control function can be attained. (N.H.)

  19. Chemical reactor modeling multiphase reactive flows

    CERN Document Server

    Jakobsen, Hugo A


    Chemical Reactor Modeling closes the gap between Chemical Reaction Engineering and Fluid Mechanics.  The second edition consists of two volumes: Volume 1: Fundamentals. Volume 2: Chemical Engineering Applications In volume 1 most of the fundamental theory is presented. A few numerical model simulation application examples are given to elucidate the link between theory and applications. In volume 2 the chemical reactor equipment to be modeled are described. Several engineering models are introduced and discussed. A survey of the frequently used numerical methods, algorithms and schemes is provided. A few practical engineering applications of the modeling tools are presented and discussed. The working principles of several experimental techniques employed in order to get data for model validation are outlined. The monograph is based on lectures regularly taught in the fourth and fifth years graduate courses in transport phenomena and chemical reactor modeling, and in a post graduate course in modern reactor m...

  20. Nuclear reactor reflector (United States)

    Hopkins, R.J.; Land, J.T.; Misvel, M.C.


    A nuclear reactor reflector is disclosed that comprises a stack of reflector blocks with vertical water flow passages to cool the reflector. The interface between blocks is opposite support points for reactor fuel rods. Water flows between the reflector and the reactor barrel from passages in a bottom block. The top block contains a flange to limit this flow and the flange has a slot to receive an alignment pin that is welded to the barrel. The pin is held in the slot by two removable shims. Alignment bars extend the length of the stack in slots machined in each block when the stack is assembled. 12 figs.

  1. Reactor flux calculations

    Energy Technology Data Exchange (ETDEWEB)

    Lhuillier, D. [Commissariat à l' Énergie Atomique et aux Énergies Alternatives, Centre de Saclay, IRFU/SPhN, 91191 Gif-sur-Yvette (France)


    The status of the prediction of reactor anti-neutrino spectra is presented. The most accurate method is still the conversion of total β spectra of fissionning isotopes as measured at research reactors. Recent re-evaluations of the conversion process led to an increased predicted flux by few percent and were at the origin of the so-called reactor anomaly. The up to date predictions are presented with their main sources of error. Perspectives are given on the complementary ab-initio predictions and upcoming experimental cross-checks of the predicted spectrum shape.


    Metcalf, H.E.


    Methods of controlling reactors are presented. Specifically, a plurality of neutron absorber members are adjustably disposed in the reactor core at different distances from the center thereof. The absorber members extend into the core from opposite faces thereof and are operated by motive means coupled in a manner to simultaneously withdraw at least one of the absorber members while inserting one of the other absorber members. This feature effects fine control of the neutron reproduction ratio by varying the total volume of the reactor effective in developing the neutronic reaction.

  3. Nuclear reactor reflector (United States)

    Hopkins, Ronald J.; Land, John T.; Misvel, Michael C.


    A nuclear reactor reflector is disclosed that comprises a stack of reflector blocks with vertical water flow passages to cool the reflector. The interface between blocks is opposite support points for reactor fuel rods. Water flows between the reflector and the reactor barrel from passages in a bottom block. The top block contains a flange to limit this flow and the flange has a slot to receive an alignment pin that is welded to the barrel. The pin is held in the slot by two removable shims. Alignment bars extend the length of the stack in slots machined in each block when the stack is assembled.

  4. Microfluidic electrochemical reactors (United States)

    Nuzzo, Ralph G [Champaign, IL; Mitrovski, Svetlana M [Urbana, IL


    A microfluidic electrochemical reactor includes an electrode and one or more microfluidic channels on the electrode, where the microfluidic channels are covered with a membrane containing a gas permeable polymer. The distance between the electrode and the membrane is less than 500 micrometers. The microfluidic electrochemical reactor can provide for increased reaction rates in electrochemical reactions using a gaseous reactant, as compared to conventional electrochemical cells. Microfluidic electrochemical reactors can be incorporated into devices for applications such as fuel cells, electrochemical analysis, microfluidic actuation, pH gradient formation.

  5. A class-based search for the in-core fuel management optimization of a pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Alvarenga de Moura Meneses, Anderson, E-mail: ameneses@lmp.ufrj.b [Federal University of Rio de Janeiro, COPPE, Nuclear Engineering Program, CP 68509, CEP 21.941-972, Rio de Janeiro, RJ (Brazil); Rancoita, Paola [IDSIA (Dalle Molle Institute for Artificial Intelligence), Galleria 2, 6982 Manno-Lugano, TI (Switzerland); Mathematics Department, Universita degli Studi di Milano (Italy); Schirru, Roberto [Federal University of Rio de Janeiro, COPPE, Nuclear Engineering Program, CP 68509, CEP 21.941-972, Rio de Janeiro, RJ (Brazil); Gambardella, Luca Maria [IDSIA (Dalle Molle Institute for Artificial Intelligence), Galleria 2, 6982 Manno-Lugano, TI (Switzerland)


    The In-Core Fuel Management Optimization (ICFMO) is a prominent problem in nuclear engineering, with high complexity and studied for more than 40 years. Besides manual optimization and knowledge-based methods, optimization metaheuristics such as Genetic Algorithms, Ant Colony Optimization and Particle Swarm Optimization have yielded outstanding results for the ICFMO. In the present article, the Class-Based Search (CBS) is presented for application to the ICFMO. It is a novel metaheuristic approach that performs the search based on the main nuclear characteristics of the fuel assemblies, such as reactivity. The CBS is then compared to the one of the state-of-art algorithms applied to the ICFMO, the Particle Swarm Optimization. Experiments were performed for the optimization of Angra 1 Nuclear Power Plant, located at the Southeast of Brazil. The CBS presented noticeable performance, providing Loading Patterns that yield a higher average of Effective Full Power Days in the simulation of Angra 1 NPP operation, according to our methodology.

  6. Analysis and evaluation of the Dual Fluid Reactor concept

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiang


    The Dual Fluid Reactor is a molten salt fast reactor developed by IFK in Berlin based on the Gen-IV Molten-Salt Reactor concept and the Liquid-Metal Cooled Reactor. The design aims to combine these two concepts to improve these two concepts. The Dissertation focuses on the concept and performs diverse calculations and estimations on the subjects of neutron physics, depletion and thermal-hydraulic behaviors to validate the new features of the concept. Based on the results it is concluded that this concept is feasible to its desired purpose and with great potential.

  7. New reactor type proposed

    CERN Multimedia


    "Russian scientists at the Research Institute of Nuclear Power Engineering in Moscow are hoping to develop a new reactor that will use lead and bismuth as fuel instead of uranium and plutonium" (1/2 page).

  8. Assessment of the Neutronic and Fuel Cycle Performance of the Transatomic Power Molten Salt Reactor Design

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Sean [Transatomic Power Corp., Cambridge, MA (United States); Dewan, Leslie [Transatomic Power Corp., Cambridge, MA (United States); Massie, Mark [Transatomic Power Corp., Cambridge, MA (United States); Davidson, Eva E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Betzler, Benjamin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Worrall, Andrew [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Powers, Jeffrey J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)


    This report presents results from a collaboration between Transatomic Power Corporation (TAP) and Oak Ridge National Laboratory (ORNL) to provide neutronic and fuel cycle analysis of the TAP core design through the Department of Energy Gateway for Accelerated Innovation in Nuclear (GAIN) Nuclear Energy Voucher program. The TAP concept is a molten salt reactor using configurable zirconium hydride moderator rod assemblies to shift the neutron spectrum in the core from mostly epithermal at beginning of life to thermal at end of life. Additional developments in the ChemTriton modeling and simulation tool provide the critical moderator-to-fuel ratio searches and time-dependent parameters necessary to simulate the continuously changing physics in this complex system. The implementation of continuous-energy Monte Carlo transport and depletion tools in ChemTriton provide for full-core three-dimensional modeling and simulation. Results from simulations with these tools show agreement with TAP-calculated performance metrics for core lifetime, discharge burnup, and salt volume fraction, verifying the viability of reducing actinide waste production with this concept. Additional analyses of mass feed rates and enrichments, isotopic removals, tritium generation, core power distribution, core vessel helium generation, moderator rod heat deposition, and reactivity coeffcients provide additional information to make informed design decisions. This work demonstrates capabilities of ORNL modeling and simulation tools for neutronic and fuel cycle analysis of molten salt reactor concepts.

  9. Two-Dimensional Neutronic and Fuel Cycle Analysis of the Transatomic Power Molten Salt Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Betzler, Benjamin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Powers, Jeffrey J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Worrall, Andrew [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Robertson, Sean [Transatomic Power Corporation, Cambridge, MA (United States); Dewan, Leslie [Transatomic Power Corporation, Cambridge, MA (United States); Massie, Mark [Transatomic Power Corporation, Cambridge, MA (United States)


    This status report presents the results from the first phase of the collaboration between Transatomic Power Corporation (TAP) and Oak Ridge National Laboratory (ORNL) to provide neutronic and fuel cycle analysis of the TAP core design through the Department of Energy Gateway for Accelerated Innovation in Nuclear, Nuclear Energy Voucher program. The TAP design is a molten salt reactor using movable moderator rods to shift the neutron spectrum in the core from mostly epithermal at beginning of life to thermal at end of life. Additional developments in the ChemTriton modeling and simulation tool provide the critical moderator-to-fuel ratio searches and time-dependent parameters necessary to simulate the continuously changing physics in this complex system. Results from simulations with these tools show agreement with TAP-calculated performance metrics for core lifetime, discharge burnup, and salt volume fraction, verifying the viability of reducing actinide waste production with this design. Additional analyses of time step sizes, mass feed rates and enrichments, and isotopic removals provide additional information to make informed design decisions. This work further demonstrates capabilities of ORNL modeling and simulation tools for analysis of molten salt reactor designs and strongly positions this effort for the upcoming three-dimensional core analysis.

  10. Analysis of reactor lattice and core parameters in view of nuclear data modifications

    Energy Technology Data Exchange (ETDEWEB)

    Becker Maarten [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany). Inst. fuer Neutronenphysik und Reaktortechnik


    A detailed assessment of the JEFF 3.1 and ENDF/B VII.0 nuclear data libraries with the KANEXT code system has been performed on each level of the reactor simulation steps. This allowed for the sensitivity estimation of the lattice and core parameters to changes in nuclide and specific reaction cross section. The direct calculation of cross section data influence, in particular for specific reaction types, is possible due to the unique substitution feature of the group constant module GRUCAL. Further on, the different impact of several reaction types on the lattice versus core calculation points out the 'engineering uncertainty' using the two major libraries for the identical problem. MCNP(X) and KANEXT cell models can be mutually adjusted such that differences between stochastic and deterministic data processing can be identified. The current analysis emphasizes, that the two major nuclear data libraries JEFF 3.1 and ENDF/B VII.0 exhibit to some extent compensation of deviations rather than reliable integral data calculation. On a special type of a fast reactor application we show that exchange of JEFF 3.1 and ENDF/B VII.0 cross sections introduce large discrepancies. A major part is attributed to the inelastic cross section. Further investigated discrepancies concerning the capture and the fission cross section in the epithermal energy range might be also a concern for LWR which was beyond the scope of the current study. (orig.)

  11. Department of Reactor Technology

    DEFF Research Database (Denmark)

    Risø National Laboratory, Roskilde

    The general development of the Department of Reactor Technology at Risø during 1981 is presented, and the activities within the major subject fields are described in some detail. Lists of staff, publications, and computer programs are included.......The general development of the Department of Reactor Technology at Risø during 1981 is presented, and the activities within the major subject fields are described in some detail. Lists of staff, publications, and computer programs are included....

  12. Natural convection reactor

    Energy Technology Data Exchange (ETDEWEB)

    Babcock, D.F.; Bernath, L.; Menegus, R.L.; Ring, H.F.


    A previous report described the conceptual design of a plutonium producing reactor that may be characterized as follows: Power output (2000 MW); cooling - (natural convection of light water through the reactor, up through a draft tube to an evaporative cooling pond, then back to the reactor, and fuel (400 to 500 tons of uranium enriched to 1.2% U-235). Because this reactor would be cooled by the natural convection of light water, it is believed that the construction costs would be significantly less than for a Savannah or Hanford type reactor. Such expensive items as water treatment and water pumping facilities would be eliminated entirely. The inventory of 500 tons of slightly enriched uranium, however, is an unattractive feature. It represents not only a large dollar investment but also makes the reactor less attractive for construction during periods of national emergency because of the almost certain scarcity of even slightly enriched uranium at that time. The Atomic Energy Commission asked that the design be reviewed with the objective of reducing the inventory of uranium, The results of this review are given in this report.

  13. Development and validation of a model TRIGA Mark III reactor with code MCNP5; Desarrollo y validacion de un modelo del reactor Triga Mark III con el codigo MCNP5

    Energy Technology Data Exchange (ETDEWEB)

    Galicia A, J.; Francois L, J. L. [UNAM, Facultad de Ingenieria, Departamento de Sistemas Energeticos, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Aguilar H, F., E-mail: [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)


    The main purpose of this paper is to obtain a model of the reactor core TRIGA Mark III that accurately represents the real operating conditions to 1 M Wth, using the Monte Carlo code MCNP5. To provide a more detailed analysis, different models of the reactor core were realized by simulating the control rods extracted and inserted in conditions in cold (293 K) also including an analysis for shutdown margin, so that satisfied the Operation Technical Specifications. The position they must have the control rods to reach a power equal to 1 M Wth, were obtained from practice entitled Operation in Manual Mode performed at Instituto Nacional de Investigaciones Nucleares (ININ). Later, the behavior of the K{sub eff} was analyzed considering different temperatures in the fuel elements, achieving calculate subsequently the values that best represent the actual reactor operation. Finally, the calculations in the developed model for to obtain the distribution of average flow of thermal, epithermal and fast neutrons in the six new experimental facilities are presented. (Author)


    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; Daniel S. Wendt; Steven P. Antal; Michael Z. Podowski


    The purpose of this paper is to document the review of several open-literature sources of both experimental capabilities and published hydrodynamic data to aid in the validation of a Computational Fluid Dynamics (CFD) based model of a slurry bubble column (SBC). The review included searching the Web of Science, ISI Proceedings, and Inspec databases, internet searches as well as other open literature sources. The goal of this study was to identify available experimental facilities and relevant data. Integral (i.e., pertaining to the SBC system), as well as fundamental (i.e., separate effects are considered), data are included in the scope of this effort. The fundamental data is needed to validate the individual mechanistic models or closure laws used in a Computational Multiphase Fluid Dynamics (CMFD) simulation of a SBC. The fundamental data is generally focused on simple geometries (i.e., flow between parallel plates or cylindrical pipes) or custom-designed tests to focus on selected interfacial phenomena. Integral data covers the operation of a SBC as a system with coupled effects. This work highlights selected experimental capabilities and data for the purpose of SBC model validation, and is not meant to be an exhaustive summary.


    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; Daniel S. Wendt


    The purpose of this paper is to document the review of several open-literature sources of both experimental capabilities and published hydrodynamic data to aid in the validation of a Computational Fluid Dynamics (CFD) based model of a slurry bubble column (SBC). The review included searching the Web of Science, ISI Proceedings, and Inspec databases, internet searches as well as other open literature sources. The goal of this study was to identify available experimental facilities and relevant data. Integral (i.e., pertaining to the SBC system), as well as fundamental (i.e., separate effects are considered), data are included in the scope of this effort. The fundamental data is needed to validate the individual mechanistic models or closure laws used in a Computational Multiphase Fluid Dynamics (CMFD) simulation of a SBC. The fundamental data is generally focused on simple geometries (i.e., flow between parallel plates or cylindrical pipes) or custom-designed tests to focus on selected interfacial phenomena. Integral data covers the operation of a SBC as a system with coupled effects. This work highlights selected experimental capabilities and data for the purpose of SBC model validation, and is not meant to be an exhaustive summary.

  16. Microfluidic Reactors Based on Rechargeable Catalytic Porous Supports: Heterogeneous Enzymatic Catalysis via Reversible Host-Guest Interactions. (United States)

    de León, Alberto Sanz; Vargas-Alfredo, Nelson; Gallardo, Alberto; Fernández-Mayoralas, Alfonso; Bastida, Agatha; Muñoz-Bonilla, Alexandra; Rodríguez-Hernández, Juan


    We report on the fabrication of a microfluidic device in which the reservoir contains a porous surface with enzymatic catalytic activity provided by the reversible immobilization of horseradish peroxidase onto micrometer size pores. The porous functional reservoir was obtained by the Breath Figures approach by casting in a moist environment a solution containing a mixture of high molecular weight polystyrene (HPS) and a poly(styrene-co-cyclodextrin based styrene) (P(S-co-SCD)) statistical copolymer. The pores enriched in CD were employed to immobilize horseradish peroxidase (previously modified with adamantane) by host-guest interactions (HRP-Ada). These surfaces exhibit catalytic activity that remains stable during several reaction cycles. Moreover, the porous platforms could be recovered by using free water-soluble β-CD with detergents. An excess of β-CD/TritonX100 in solution disrupts the interactions between HRP-Ada and the CD-modified substrate thus allowing us to recover the employed enzyme and reuse the platform.

  17. Effects of inoculum type and bulk dissolved oxygen concentration on achieving partial nitrification by entrapped-cell-based reactors. (United States)

    Rongsayamanont, Chaiwat; Limpiyakorn, Tawan; Khan, Eakalak


    An entrapment of nitrifiers into gel matrix is employed as a tool to fulfill partial nitrification under non-limiting dissolved oxygen (DO) concentrations in bulk solutions. This study aims to clarify which of these two attributes, inoculum type and DO concentration in bulk solutions, is the decisive factor for partial nitrification in an entrapped-cell based system. Four polyvinyl alcohol entrapped inocula were prepared to have different proportions of nitrite-oxidizing bacteria (NOB) and nitrite-oxidizing activity. At a DO concentration of 3 mg l(-1), the number of active NOB cells in an inoculum was the decisive factor for partial nitrification enhancement. However, when the DO concentration was reduced to 2 mg l(-1), all entrapped cell inocula showed similar degrees of partial nitrification. The results suggested that with the lower bulk DO concentration, the preparation of entrapped cell inocula is not useful as the DO level becomes the decisive factor for achieving partial nitrification. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Actinide transmutation in nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Bultman, J.H.


    An optimization method is developed to maximize the burning capability of the ALMR while complying with all constraints imposed on the design for reliability and safety. This method leads to a maximal transuranics enrichment, which is being limited by constraints on reactivity. The enrichment can be raised by using the neutrons less efficiently by increasing leakage from the fuel. With the developed optimization method, a metallic and an oxide fueled ALMR were optimized. Both reactors perform equally well considering the burning of transuranics. However, metallic fuel has a much higher heat conductivity coefficient, which in general leads to better safety characteristics. In search of a more effective waste transmuter, a modified Molten Salt Reactor was designed. A MSR operates on a liquid fuel salt which makes continuous refueling possible, eliminating the issue of the burnup reactivity loss. Also, a prompt negative reactivity feedback is possible for an overmoderated reactor design, even when the Doppler coefficient is positive, due to the fuel expansion with fuel temperature increase. Furthermore, the molten salt fuel can be reprocessed based on a reduction process which is not sensitive to the short-lived spontaneously fissioning actinides. (orig./HP).

  19. The ARIES tokamak reactor study

    Energy Technology Data Exchange (ETDEWEB)


    The ARIES study is a community effort to develop several visions of tokamaks as fusion power reactors. The aims are to determine the potential economics, safety, and environmental features of a range of possible tokamak reactors, and to identify physics and technology areas with the highest leverage for achieving the best tokamak reactor. Three ARIES visions are planned, each having a different degree of extrapolation from the present data base in physics and technology. The ARIES-I design assumes a minimum extrapolation from current tokamak physics (e.g., 1st stability) and incorporates technological advances that can be available in the next 20 to 30 years. ARIES-II is a DT-burning tokamak which would operate at a higher beta in the 2nd MHD stability regime. It employs both potential advances in the physics and expected advances in technology and engineering. ARIES-II will examine the potential of the tokamak and the D{sup 3}He fuel cycle. This report is a collection of 14 papers on the results of the ARIES study which were presented at the IEEE 13th Symposium on Fusion Engineering (October 2-6, 1989, Knoxville, TN). This collection describes the ARIES research effort, with emphasis on the ARIES-I design, summarizing the major results, the key technical issues, and the central conclusions.

  20. Superheated Water-Cooled Small Modular Underwater Reactor Concept


    Shirvan, Koroush; Kazimi, Mujid


    A novel fully passive small modular superheated water reactor (SWR) for underwater deployment is designed to produce 160 MWe with steam at 500ºC to increase the thermodynamic efficiency compared with standard light water reactors. The SWR design is based on a conceptual 400-MWe integral SWR using the internally and externally cooled annular fuel (IXAF). The coolant boils in the external channels throughout the core to approximately the same quality as a conventional boiling water reactor and ...

  1. Small Modular Reactors: Licensing constraints and the way forward


    Sainati, T; Locatelli, G; Brookes, N


    SMR (Small Modular Reactor) is an acronym for a group of nuclear power plant designs receiving an increasing deal of attention from the industry and policy makers. A large number of SMRs need to be built in the same site and across the word to compensate diseconomies of scale and be cost competitive with large reactors and other base-load technologies. A major barrier is the licensing process, historically developed for large reactors, preventing the simply deployment of several identical uni...

  2. Control of SHARON reactor for autotrophic nitrogen removal in two-reactor configuration

    DEFF Research Database (Denmark)

    Valverde Perez, Borja; Mauricio Iglesias, Miguel; Sin, Gürkan


    With the perspective of investigating a suitable control design for autotrophic nitrogen removal, this work explores the control design for a SHARON reactor. With this aim, a full model is developed, including the pH dependency, in order to simulate the reactor and determine the optimal operating...... conditions. Then, the screening of controlled variables and pairing is carried out by an assessment of the effect of the disturbances based on the closed loop disturbance gain plots. Two controlled structures are obtained and benchmarked by their capacity to reject the disturbances before the Anammox reactor....

  3. Design options for a bunsen reactor.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Robert Charles


    This work is being performed for Matt Channon Consulting as part of the Sandia National Laboratories New Mexico Small Business Assistance Program (NMSBA). Matt Channon Consulting has requested Sandia's assistance in the design of a chemical Bunsen reactor for the reaction of SO2, I2 and H2O to produce H2SO4 and HI with a SO2 feed rate to the reactor of 50 kg/hour. Based on this value, an assumed reactor efficiency of 33%, and kinetic data from the literature, a plug flow reactor approximately 1%E2%80%9D diameter and and 12 inches long would be needed to meet the specification of the project. Because the Bunsen reaction is exothermic, heat in the amount of approximately 128,000 kJ/hr would need to be removed using a cooling jacket placed around the tubular reactor. The available literature information on Bunsen reactor design and operation, certain support equipment needed for process operation and a design that meet the specification of Matt Channon Consulting are presented.

  4. Geologic setting and genesis of the Mule Canyon low-sulfidation epithermal gold-silver deposit, north-central Nevada (United States)

    John, D.A.; Hofstra, A.H.; Fleck, R.J.; Brummer, J.E.; Saderholm, E.C.


    The Mule Canyon mine exploited shallow, low-sulfidation, epithermal Au-Ag deposits that lie near the west side of the Northern Nevada rift in northern Lander County, Nevada. Mule Canyon consists of six small deposits that contained premining reserves of about 8.2 Mt at an average grade of 3.81 g Au/tonne. It is an uncommon mafic end member of low-sulfidation Au-Ag deposits associated with tholeiitic bimodal basalt-rhyolite magmatism. The ore is hosted by a basalt-andesite eruptive center that formed between about 16.4 to 15.8 Ma during early mafic eruptions related to regionally extensive bimodal magmatism. Hydrothermal alteration and Au-Ag ores formed at about 15.6 Ma and were tightly controlled by north-northwest- to north-striking high-angle fault and breccia zones developed during rifting, emplacement of mafic dikes, and eruption of mafic lava flows. Hydrothermal alteration assemblages are zoned outward from fluid conduits in the sequence silica-adularia, adularia-smectite, smectite (intermediate argillic), and smectite-carbonate (propylitic). All alteration types contain abundant pyrite and/or marcasite ?? arsenopyrite. Field relations indicate that silica-adularia alteration is superimposed on argillic and propylitic alteration. Little or no steam-heated acid-sulfate alteration is present, probably the result of a near-surface water table during hydrothermal alteration and ore deposition. Two distinct ore types are present at Mule Canyon: early replacement and later open-space filling. Replacement ores consist of disseminated and vesicle-filling pyrite, marcasite, and arsenopyrite in argillically altered or weakly silicified rocks. Ore minerals consist of Au-bearing arsenopyrite and arsenian pyrite overgrowths on earlier-formed pyrite and marcasite. Open-space filling ores include narrow stockwork quartz-adularia veins, banded and crustiform opaline and chalcedonic silica-adularia veins, silica-adularia cemented breccias, and sparse carbonate-pyrite and

  5. Developments and Tendencies in Fission Reactor Concepts (United States)

    Adamov, E. O.; Fuji-Ie, Y.

    ) - as an advanced and promising reactor system that offers solutions to the above problems. The difference (not confrontation) between the approaches to nuclear power development based on the principles of “inherent safety” and “natural safety” is demonstrated.

  6. Reactor-specific spent fuel discharge projections, 1987-2020

    Energy Technology Data Exchange (ETDEWEB)

    Walling, R.C.; Heeb, C.M.; Purcell, W.L.


    The creation of five reactor-specific spent fuel data bases that contain information on the projected amounts of spent fuel to be discharged from U.S. commercial nuclear reactors through the year 2020 is described. The data bases contain detailed spent fuel information from existing, planned, and projected pressurized water reactors (PWR) and boiling water eactors (BWR), and one existing high temperature gas reactor (HTGR). The projections are based on individual reactor information supplied by the U.S. reactor owners. The basic information is adjusted to conform to Energy Information Administration (EIA) forecasts for nuclear installed capacity, generation, and spent fuel discharged. The EIA cases considered are: No New Orders (assumes increasing burnup), No New Orders with No Increased Burnup, Upper Reference (assumes increasing burnup), Upper Reference with No Increased Burnup, and Lower Reference (assumes increasing burnup). Detailed, by-reactor tables are provided for annual discharged amounts of spent fuel, for storage requirements assuming maximum at-reactor storage, and for storage requirements assuming maximum at-reactor storage plus intra-utility transshipment of spent fuel. 8 refs., 8 figs., 10 tabs.

  7. Reactor-specific spent fuel discharge projections: 1986 to 2020

    Energy Technology Data Exchange (ETDEWEB)

    Heeb, C.M.; Walling, R.C.; Purcell, W.L.


    The creation of five reactor-specific spent fuel data bases that contain information on the projected amounts of spent fuel to be discharged from US commercial nuclear reactors through the year 2020 is described. The data bases contain detailed spent-fuel information from existing, planned, and projected pressurized water reactors (PWR) and boiling water reactors (BWR). The projections are based on individual reactor information supplied by the US reactor owners. The basic information is adjusted to conform to Energy Information Agency (EIA) forecasts for nuclear installed capacity, generation, and spent fuel discharged. The EIA cases considered are: (1) No new orders with extended burnup, (2) No new orders with constant burnup, (3) Upper reference (which assumes extended burnup), (4) Upper reference with constant burnup, and (5) Lower reference (which assumes extended burnup). Detailed, by-reactor tables are provided for annual discharged amounts of spent fuel, for storage requirements assuming maximum-at-reactor storage, and for storage requirements assuming maximum-at-reactor plus intra-utility transshipment of spent fuel. 6 refs., 8 figs., 8 tabs.

  8. Technology selection for offshore underwater small modular reactors

    Energy Technology Data Exchange (ETDEWEB)

    Shivan, Koroush; Ballinger, Ronald; Buongiorno, Jacopo; Forsberg, Charles; Kazimi, Mujid; Todreas, Neil [Dept. of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge (United States)


    This work examines the most viable nuclear technology options for future underwater designs that would meet high safety standards as well as good economic potential, for construction in the 2030-2040 time frame. The top five concepts selected from a survey of 13 nuclear technologies were compared to a small modular pressurized water reactor (PWR) designed with a conventional layout. In order of smallest to largest primary system size where the reactor and all safety systems are contained, the top five designs were: (1) a lead-bismuth fast reactor based on the Russian SVBR-100; (2) a novel organic cooled reactor; (3) an innovative superheated water reactor; (4) a boiling water reactor based on Toshiba's LSBWR; and (5) an integral PWR featuring compact steam generators. A similar study on potential attractive power cycles was also performed. A condensing and recompression supercritical CO{sub 2} cycle and a compact steam Rankine cycle were designed. It was found that the hull size required by the reactor, safety systems and power cycle can be significantly reduced (50-80%) with the top five designs compared to the conventional PWR. Based on the qualitative economic consideration, the organic cooled reactor and boiling water reactor designs are expected to be the most cost effective options.

  9. Technology Selection for Offshore Underwater Small Modular Reactors

    Directory of Open Access Journals (Sweden)

    Koroush Shirvan


    Full Text Available This work examines the most viable nuclear technology options for future underwater designs that would meet high safety standards as well as good economic potential, for construction in the 2030–2040 timeframe. The top five concepts selected from a survey of 13 nuclear technologies were compared to a small modular pressurized water reactor (PWR designed with a conventional layout. In order of smallest to largest primary system size where the reactor and all safety systems are contained, the top five designs were: (1 a lead–bismuth fast reactor based on the Russian SVBR-100; (2 a novel organic cooled reactor; (3 an innovative superheated water reactor; (4 a boiling water reactor based on Toshiba's LSBWR; and (5 an integral PWR featuring compact steam generators. A similar study on potential attractive power cycles was also performed. A condensing and recompression supercritical CO2 cycle and a compact steam Rankine cycle were designed. It was found that the hull size required by the reactor, safety systems and power cycle can be significantly reduced (50–80% with the top five designs compared to the conventional PWR. Based on the qualitative economic consideration, the organic cooled reactor and boiling water reactor designs are expected to be the most cost effective options.

  10. Reactor Safety Planning for Prometheus Project, for Naval Reactors Information

    Energy Technology Data Exchange (ETDEWEB)

    P. Delmolino


    The purpose of this letter is to submit to Naval Reactors the initial plan for the Prometheus project Reactor Safety work. The Prometheus project is currently developing plans for cold physics experiments and reactor prototype tests. These tests and facilities may require safety analysis and siting support. In addition to the ground facilities, the flight reactor units will require unique analyses to evaluate the risk to the public from normal operations and credible accident conditions. This letter outlines major safety documents that will be submitted with estimated deliverable dates. Included in this planning is the reactor servicing documentation and shipping analysis that will be submitted to Naval Reactors.

  11. RSMASS-D models: An improved method for estimating reactor and shield mass for space reactor applications

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, A.C.


    Three relatively simple mathematical models have been developed to estimate minimum reactor and radiation shield masses for liquid-metal-cooled reactors (LMRs), in-core thermionic fuel element (TFE) reactors, and out-of-core thermionic reactors (OTRs). The approach was based on much of the methodology developed for the Reactor/Shield Mass (RSMASS) model. Like the original RSMASS models, the new RSMASS-derivative (RSMASS-D) models use a combination of simple equations derived from reactor physics and other fundamental considerations, along with tabulations of data from more detailed neutron and gamma transport theory computations. All three models vary basic design parameters within a range specified by the user to achieve a parameter choice that yields a minimum mass for the power level and operational time of interest. The impact of critical mass, fuel damage, and thermal limitations are accounted for to determine the required fuel mass. The effect of thermionic limitations are also taken into account for the thermionic reactor models. All major reactor component masses are estimated, as well as instrumentation and control (I&C), boom, and safety system masses. A new shield model was developed and incorporated into all three reactor concept models. The new shield model is more accurate and simpler to use than the approach used in the original RSMASS model. The estimated reactor and shield masses agree with the mass predictions from separate detailed calculations within 15 percent for all three models.

  12. Scaleable, High Efficiency Microchannel Sabatier Reactor Project (United States)

    National Aeronautics and Space Administration — A Microchannel Sabatier Reactor System (MSRS) consisting of cross connected arrays of isothermal or graded temperature reactors is proposed. The reactor array...

  13. Measurements of the thermal neutron flux for an accelerator-based photoneutron source. (United States)

    Taheri, Ali; Pazirandeh, Ali


    To have access to an appropriate neutron source is one of the most demanding requirements for neutron studies. This is important specially in laboratory and clinical applications, which need more compact and accessible sources. The most known neutron sources are fission reactors and natural isotopes, but there is an increasing interest for using accelerator based neutron sources because of their advantages. In this paper, we shall present a photo-neutron source prototype which is designed and fabricated to be used for different neutron researches including in-laboratory neutron activation analysis and neutron imaging, and also preliminary studies in boron neutron capture therapy (BNCT). Series of experimental tests were conducted to examine the intensity and quality of the neutron field produced by this source. Monte-Carlo simulations were also utilized to provide more detailed evaluation of the neutron spectrum, and determine the accuracy of the experiments. The experiments demonstrated a thermal neutron flux in the order of 10(7) (n/cm(2).s), while simulations affirmed this flux and showed a neutron spectrum with a sharp peak at thermal energy region. According to the results, about 60 % of produced neutrons are in the range of thermal to epithermal neutrons.

  14. High-Speed Neutron and Gamma Flux Sensor for Monitoring Surface Nuclear Reactors Project (United States)

    National Aeronautics and Space Administration — NASA needs compact nuclear reactors to power future bases on the moon and/or Mars. These reactors require robust automatic control systems using low mass, rapid...

  15. High-Speed Neutron and Gamma Flux Sensor for Monitoring Surface Nuclear Reactors Project (United States)

    National Aeronautics and Space Administration — NASA needs compact nuclear reactors to power future bases on the moon and Mars. These reactors require robust automatic control systems using low mass, rapid...

  16. Reactor and process design in sustainable energy technology

    CERN Document Server

    Shi, Fan


    Reactor Process Design in Sustainable Energy Technology compiles and explains current developments in reactor and process design in sustainable energy technologies, including optimization and scale-up methodologies and numerical methods. Sustainable energy technologies that require more efficient means of converting and utilizing energy can help provide for burgeoning global energy demand while reducing anthropogenic carbon dioxide emissions associated with energy production. The book, contributed by an international team of academic and industry experts in the field, brings numerous reactor design cases to readers based on their valuable experience from lab R&D scale to industry levels. It is the first to emphasize reactor engineering in sustainable energy technology discussing design. It provides comprehensive tools and information to help engineers and energy professionals learn, design, and specify chemical reactors and processes confidently. Emphasis on reactor engineering in sustainable energy techn...

  17. New reactor concepts; Nieuwe rectorconcepten - nouveaux reacteurs nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Meskens, G.; Govaerts, P.; Baugnet, J.-M.; Delbrassine, A


    The document gives a summary of new nuclear reactor concepts from a technological point of view. Belgium supports the development of the European Pressurized-Water Reactor, which is an evolutionary concept based on the European experience in Pressurized-Water Reactors. A reorientation of the Belgian choice for this evolutionary concept may be required in case that a decision is taken to burn plutonium, when the need for flexible nuclear power plants arises or when new reactor concepts can demonstrate proved benefits in terms of safety and cost.

  18. Savannah River Site K-Reactor Probabilistic Safety Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Brandyberry, M.D.; Bailey, R.T.; Baker, W.H.; Kearnaghan, D.P.; O`Kula, K.R.; Wittman, R.S.; Woody, N.D. [Westinghouse Savannah River Co., Aiken, SC (United States); Amos, C.N.; Weingardt, J.J. [Science Applications International Corp. (United States)


    This report gives the results of a Savannah River Site (SRS) K-Reactor Probabilistic Safety Assessment (PSA). Measures of adverse consequences to health and safety resulting from representations of severe accidents in SRS reactors are presented. In addition, the report gives a summary of the methods employed to represent these accidents and to assess the resultant consequences. The report is issued to provide useful information to the U. S. Department of Energy (DOE) on the risk of operation of SRS reactors, for insights into severe accident phenomena that contribute to this risk, and in support of improved bases for other DOE programs in Heavy Water Reactor safety.


    Directory of Open Access Journals (Sweden)

    Reinaldy Nazar


    Full Text Available Reactor TRIGA 2000 Bandung is result of upgrading TRIGA Mark II reactor from nominal power of 1 MW becomes 2 MW and has been opened its the operation in the year 2000. In this period change of operation parameters had been occurred, especially the parameter related to thermo-hydraulic aspect, like the height of reactor core temperature and the formation of vapor bubble in the core, which is on the contrary with the safety aspect. Safety is the priority in the reactor operation, hence reactor core temperature and vapor bubble in core need to be reduced. One of methods to reduce the core temperature and vapor bubble formation is the operation at limited power of 1000 kW. To examine the safety margin of Bandung TRIGA 2000 reactor operation at 1000 kW power, the analysis of thermo-hydraulic characteristic have been carried out by theoretical study using computer code of CFD (Computational of Fluid Dynamics and RELAP5/Mod3.2 (Reactor Excursion and Leak Analysis Program. The result of the study indicates that reactor reaches steady state condition at 1000 kW power in 1500 seconds after critical condition, and maximum temperature of reactor core is in C4 position, whereas the maximum temperature of fuel center, cladding, and cooling water at related fuel are 529.35 °C, 103.12 °C, and 90.67 °C, respectively. Maximum temperature of cladding and primary cooling water at related fuel are below saturation temperature (112.4 °C, so the sub-cooled boiling or bubbling of saturation and vapor bubble formation can be predicted not to be happened. Besides when the reactor was operated at 1200 kW and 1250 kW power was obtained the maximum temperature of fuel cladding are 111.04 °C and 115.53 °C, respectively. This thing informs that, when the reactor was operated up to 1200 kW power sub-cooled boiling has not happened, but when the reactor was operated at 1250 kW power has started the happening of the sub-cooled boiling and the formation of vapour bubble

  20. Cs-137 geochronology, epithermal neutron activation analysis, and principal component analysis of heavy metals pollution of the Black Sea anoxic continental shelf sediments (United States)

    Duliu, O. G.; Cristache, C.; Oaie, G.; Culicov, O. A.; Frontasyeva, M. V.


    Anthropogenic Cs-137 Gamma-ray Spectroscopy assay (GrSA) performed at the National Institute of Research and Development for Physics and Nuclear Engineering - Bucharest (Romania) in correlation with Epithermal Neutrons Activation Analysis (ENAA) performed at the Joint Institute of Nuclear Researches - Dubna (Russia) were used to investigate a 50 cm core containing unconsolidated sediments collected at a depth of 600 m off Romanian town of Constantza, located in the anoxic zone of the Black Sea Continental Shelf. A digital radiography showed the presence of about 265 distinct laminae, 1 to 3 mm thick, a fact attesting a stationary sedimentary process, completely free of bioturbation. After being radiographed, the core was sliced into 45 segments whose thickness gradually increased from 0.5 to 5 cm, such that the minimum thickness corresponded to the upper part of the core. From each segment two aliquots of about 0.5 g and 50 g were extracted for subsequent ENAA and Cs-137 GrSA. The Cs-137 vertical profile evidenced two maxima, one of them was very sharp and localized at a depth of 1 cm and the other very broad, almost undistinguished at about 8 cm depth, the first one being attributed to 1986 Chernobyl accident. Based on these date, we have estimated a sedimentation ratio of about 0.5 mm/year, value taken as reference for further assessment of recent pollution history. By means of ENAA we have determined the vertical content of five presumed pollutants, e.i. Zn, As, Br, Sn and Sb and of Sc, as natural, nonpolluting element. In the first case, all five elements presented a more or less similar vertical profile consisting of an almost exponential decrease for the first 10 cm below sediment surface followed by a plateau until the core base, i.e. 50 cm below surface, dependency better described by the equation: c(z) = c0 [1+k exp (-z/Z)] (1) where: where c(z) represents the concentration vertical profile; z represents depth (in absolute value); c0 represents the plateau