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Sample records for reactor study mars

  1. Mirror Advanced Reactor Study (MARS). Final report. Volume 2. Commercial fusion synfuels plant

    Energy Technology Data Exchange (ETDEWEB)

    Donohue, M.L.; Price, M.E. (eds.)

    1984-07-01

    Volume 2 contains the following chapters: (1) synfuels; (2) physics base and parameters for TMR; (3) high-temperature two-temperature-zone blanket system for synfuel application; (4) thermochemical hydrogen processes; (5) interfacing the sulfur-iodine cycle; (6) interfacing the reactor with the thermochemical process; (7) tritium control in the blanket system; (8) the sulfur trioxide fluidized-bed composer; (9) preliminary cost estimates; and (10) fuels beyond hydrogen. (MOW)

  2. Mars Rover RTG Study

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred

    1989-11-27

    This report summarizes the results of a Radioisotope Thermoelectric Generator (RTG) design study conducted by Fairchild Space Company at the direction of the U.S. Department of Energy's Office of Special Applications, in support of the Mars Rover and Sample Return mission under investigation at NASA's Jet Propulsion Laboratory. Presented at the 40th Congress of the IAF, Oct. 7-13, 1989 in Torremolinos, Malaga-Spain. The paper describes the design and analysis of Radioisotope Thermoelectric Generators (RTGs) for powering the Mars Rover vehicle, which is a critical element of the unmanned Mars Rover and Sample Return mission (MRSR). The RTG design study was conducted by Fairchild Space for the U.S. DOE in support of the JPL MRSR Project. The paper briefly describes a reference mission scenario, an illustrative Rover design and activity pattern on Mars, and its power system requirements and environmental constraints, including the RTG cooling requirements during transit to Mars. It summarizes the baseline RTG's mass breakdown, and presents a detailed description of its thermal, thermoelectric, and electrical analysis. The results presented show the RTG performance achievable with current technology, and the performance improvements that would be achievable with various technology developments. It provides a basis for selecting the optimum strategy for meeting the Mars Rover design goals with minimal programmatic risk and cost. Cross Reference CID #7135 dated 10/1989. There is a duplicate copy. This document is not relevant to the OSTI Library. Do not send.

  3. Mars Rover RTG Study

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred

    1989-10-01

    Presented at the 40th Congress of the IAF, Oct. 7-13, 1989 in Torremolinos, Malaga-Spain. The paper describes the design and analysis of Radioisotope Thermoelectric Generators (RTGs) for powering the Mars Rover vehicle, which is a critical element of the unmanned Mars Rover and Sample Return mission (MRSR). The RTG design study was conducted by Fairchild Space for the U.S. DOE in support of the JPL MRSR Project. The paper briefly describes a reference mission scenario, an illustrative Rover design and activity pattern on Mars, and its power system requirements and environmental constraints, including the RTG cooling requirements during transit to Mars. It summarizes the baseline RTG's mass breakdown, and presents a detailed description of its thermal, thermoelectric, and electrical analysis. The results presented show the RTG performance achievable with current technology, and the performance improvements that would be achievable with various technology developments. It provides a basis for selecting the optimum strategy for meeting the Mars Rover design goals with minimal programmatic risk and cost. There is a duplicate copy and three copies in the file.

  4. 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.

    1976-09-01

    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.

  5. Mars Rover RTG Study

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred

    1989-08-25

    This report summarizes the results of a Radioisotope Thermoelectric Generator (RTG) design study conducted by Fairchild Space Company at the direction of the U.S. Department of Energy's Office of SpecialApplications, in suppport of the Mars Rover and Sample Return mission under investigation at NASA's Jet Propulsion Laboratory. The report is a rearranged, updated, and significantly expanded amalgam of three interrelated papers presented at the 24th Intersocity Energy Conversion Engineering Conference (IECEC) at Arlington, Virginia, on August 10, 1989.

  6. Slurry reactor design studies

    Energy Technology Data Exchange (ETDEWEB)

    Fox, J.M.; Degen, B.D.; Cady, G.; Deslate, F.D.; Summers, R.L. (Bechtel Group, Inc., San Francisco, CA (USA)); Akgerman, A. (Texas A and M Univ., College Station, TX (USA)); Smith, J.M. (California Univ., Davis, CA (USA))

    1990-06-01

    The objective of these studies was to perform a realistic evaluation of the relative costs of tublar-fixed-bed and slurry reactors for methanol, mixed alcohols and Fischer-Tropsch syntheses under conditions where they would realistically be expected to operate. The slurry Fischer-Tropsch reactor was, therefore, operated at low H{sub 2}/CO ratio on gas directly from a Shell gasifier. The fixed-bed reactor was operated on 2.0 H{sub 2}/CO ratio gas after adjustment by shift and CO{sub 2} removal. Every attempt was made to give each reactor the benefit of its optimum design condition and correlations were developed to extend the models beyond the range of the experimental pilot plant data. For the methanol design, comparisons were made for a recycle plant with high methanol yield, this being the standard design condition. It is recognized that this is not necessarily the optimum application for the slurry reactor, which is being proposed for a once-through operation, coproducing methanol and power. Consideration is also given to the applicability of the slurry reactor to mixed alcohols, based on conditions provided by Lurgi for an Octamix{trademark} plant using their standard tubular-fixed reactor technology. 7 figs., 26 tabs.

  7. Helias reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Beidler, C.D. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Grieger, G. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Harmeyer, E. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Kisslinger, J. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Karulin, N. [Nuclear Fusion Institute, Moscow (Russian Federation); Maurer, W. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany); Nuehrenberg, J. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Rau, F. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Sapper, J. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Wobig, H. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

    1995-10-01

    The present status of Helias reactor studies is characterised by the identification and investigation of specific issues which result from the particular properties of this type of stellarator. On the technical side these are issues related to the coil system, while physics studies have concentrated on confinement, alpha-particle behaviour and ignition conditions. The usual assumptions have been made in those fields which are common to all toroidal fusion reactors: blanket and shield, refuelling and exhaust, safety and economic aspects. For blanket and shield sufficient space has been provided, a detailed concept will be developed in future. To date more emphasis has been placed on scoping and parameter studies as opposed to fixing a specific set of parameters and providing a detailed point study. One result of the Helias reactor studies is that physical dimensions are on the same order as those of tokamak reactors. However, it should be noticed that this comparison is difficult in view of the large spectrum of tokamak reactors ranging from a small reactor like Aries, to a large device such as SEAFP. The notion that the large aspect ratio of 10 or more in Helias configurations also leads to large reactors is misleading, since the large major radius of 22 m is compensated by the average plasma radius of 1.8 m and the average coil radius of 5 m. The plasma volume of 1400 m{sup 3} is about the same as the ITER reactor and the magnetic energy of the coil system is about the same or even slightly smaller than envisaged in ITER. (orig.)

  8. Mirror Advanced Reactor Study interim design report

    Energy Technology Data Exchange (ETDEWEB)

    1983-04-01

    The status of the design of a tenth-of-a-kind commercial tandem-mirror fusion reactor is described at the midpoint of a two-year study. When completed, the design is to serve as a strategic goal for the mirror fusion program. The main objectives of the Mirror Advanced Reactor Study (MARS) are: (1) to design an attractive tandem-mirror fusion reactor producing electricity and synfuels (in alternate versions), (2) to identify key development and technology needs, and (3) to exploit the potential of fusion for safety, low activation, and simple disposal of radioactive waste. In the first year we have emphasized physics and engineering of the central cell and physics of the end cell. Design optimization and trade studies are continuing, and we expect additional modifications in the end cells to further improve the performance of the final design.

  9. Thermionic Reactor Design Studies

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred

    1994-06-01

    During the 1960's and early 70's the author performed extensive design studies, analyses, and tests aimed at thermionic reactor concepts that differed significantly from those pursued by other investigators. Those studies, like most others under Atomic Energy Commission (AEC and DOE) and the National Aeronautics and Space Administration (NASA) sponsorship, were terminated in the early 1970's. Some of this work was previously published, but much of it was never made available in the open literature. U.S. interest in thermionic reactors resumed in the early 80's, and was greatly intensified by reports about Soviet ground and flight tests in the late 80's. This recent interest resulted in renewed U.S. thermionic reactor development programs, primarily under Department of Defense (DOD) and Department of Energy (DOE) sponsorship. Since most current investigators have not had an opportunity to study all of the author's previous work, a review of the highlights of that work may be of value to them. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling. Where the author's concepts differed from the later Topaz-2 design was in the relative location of the emitter and the collector. Placing the fueled emitter on the outside of the cylindrical diodes permits much higher axial conductances to reduce ohmic

  10. New reactors for laboratory studies

    Energy Technology Data Exchange (ETDEWEB)

    Berty, J.M.

    1978-02-01

    Recent developments in design of laboratory and bench-scale reactors reflect mostly the developments in reaction engineering; that is the improved understanding of physical and chemical rate limiting processes, their interactions, and their effects on commercial-scale reactor performance. Whether a laboratory reactor is used to study the fundamentals of a commercial process or for pure scientific interest, it is important to know what physical or chemical process is limiting or influencing the rate and selectivity. To clarify this, a definition is required of the regime where physical influences exist, and study the intrinsic kinetics at conditions where physical processes do not affect the rate. Reactors are illustrated whose design was influenced by the above considerations. These reactors produce results which are independent of the reactors in which they were measured, and which can be scaled up with up-to-date reaction engineering techniques.

  11. Neutrino Oscillation Studies with Reactors

    CERN Document Server

    Vogel, Petr; Zhang, Chao

    2015-01-01

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Over the past several decades reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle $\\theta_{13}$. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  12. 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.

    1980-07-01

    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.

  13. Thermionic Reactor Design Studies

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred

    1994-08-01

    Paper presented at the 29th IECEC in Monterey, CA in August 1994. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their (thermionic reactor) performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling.

  14. A 50-100 kWe gas-cooled reactor for use on Mars.

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Curtis D. (.)

    2006-04-01

    In the space exploration field there is a general consensus that nuclear reactor powered systems will be extremely desirable for future missions to the outer solar system. Solar systems suffer from the decreasing intensity of solar radiation and relatively low power density. Radioisotope Thermoelectric Generators are limited to generating a few kilowatts electric (kWe). Chemical systems are short-lived due to prodigious fuel use. A well designed 50-100 kWe nuclear reactor power system would provide sufficient power for a variety of long term missions. This thesis will present basic work done on a 50-100 kWe reactor power system that has a reasonable lifespan and would function in an extraterrestrial environment. The system will use a Gas-Cooled Reactor that is directly coupled to a Closed Brayton Cycle (GCR-CBC) power system. Also included will be some variations on the primary design and their effects on the characteristics of the primary design. This thesis also presents a variety of neutronics related calculations, an examination of the reactor's thermal characteristics, feasibility for use in an extraterrestrial environment, and the reactor's safety characteristics in several accident scenarios. While there has been past work for space reactors, the challenges introduced by thin atmospheres like those on Mars have rarely been considered.

  15. Mars

    CERN Document Server

    Payment, Simone

    2017-01-01

    This curriculum-based, fun, and approachable book offers everything young readers need to know to begin their study of the Red Planet. They will learn about the fundamental aspects of the Mars, including its size, mass, surface features, interior, orbit, and spin. Further, they will learn about the history of the missions to Mars, including the Viking spacecraft and the Curiosity and MAVEN rovers. Finally, readers will learn about why scientists think there's a chance that Mars is or was suitable for life. With stunning imagery from NASA itself, readers will have a front seat-view of the missi

  16. Mars power system concept definition study. Volume 1: Study results

    Science.gov (United States)

    Littman, Franklin D.

    1994-12-01

    A preliminary top level study was completed to define power system concepts applicable to Mars surface applications. This effort included definition of power system requirements and selection of power systems with the potential for high commonality. These power systems included dynamic isotope, Proton Exchange Membrane (PEM) regenerative fuel cell, sodium sulfur battery, photovoltaic, and reactor concepts. Design influencing factors were identified. Characterization studies were then done for each concept to determine system performance, size/volume, and mass. Operations studies were done to determine emplacement/deployment maintenance/servicing, and startup/shutdown requirements. Technology development roadmaps were written for each candidate power system (included in Volume 2). Example power system architectures were defined and compared on a mass basis. The dynamic isotope power system and nuclear reactor power system architectures had significantly lower total masses than the photovoltaic system architectures. Integrated development and deployment time phasing plans were completed for an example DIPS and reactor architecture option to determine the development strategies required to meet the mission scenario requirements.

  17. Estimates of power requirements for a manned Mars rover powered by a nuclear reactor

    Science.gov (United States)

    Morley, Nicholas J.; El-Genk, Mohamed S.; Cataldo, Robert; Bloomfield, Harvey

    1991-01-01

    This paper assesses the power requirement for a Manned Mars Rover vehicle. Auxiliary power needs are fulfilled using a hybrid solar photovoltaic/regenerative fuel cell system, while the primary power needs are met using an SP-100 type reactor. The primary electric power needs, which include 30-kWe net user power, depend on the reactor thermal power and the efficiency of the power conversion system. Results show that an SP-100 type reactor coupled to a Free Piston Stirling Engine (FPSE) yields the lowest total vehicle mass and lowest specific mass for the power system. The second lowest mass was for a SP-100 reactor coupled to a Closed Brayton Cycle (CBC) using He/Xe as the working fluid. The specific mass of the nuclear reactor power systrem, including a man-rated radiation shield, ranged from 150-kg/kWe to 190-kg/kWe and the total mass of the Rover vehicle varied depend upon the cruising speed.

  18. The ARIES tokamak reactor study

    Energy Technology Data Exchange (ETDEWEB)

    1989-10-01

    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.

  19. D-D tokamak reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Evans, K.E. Jr.; Baker, C.C.; Brooks, J.N.; Ehst, D.A.; Finn, P.A.; Jung, J.; Mattas, R.F.; Misra, B.; Smith, D.L.; Stevens, H.C.

    1980-11-01

    A tokamak D-D reactor design, utilizing the advantages of a deuterium-fueled reactor but with parameters not unnecessarily extended from existing D-T designs, is presented. Studies leading to the choice of a design and initial studies of the design are described. The studies are in the areas of plasma engineering, first-wall/blanket/shield design, magnet design, and tritium/fuel/vacuum requirements. Conclusions concerning D-D tokamak reactors are stated.

  20. Reactors

    CERN Document Server

    International Electrotechnical Commission. Geneva

    1988-01-01

    This standard applies to the following types of reactors: shunt reactors, current-limiting reactors including neutral-earthing reactors, damping reactors, tuning (filter) reactors, earthing transformers (neutral couplers), arc-suppression reactors, smoothing reactors, with the exception of the following reactors: small reactors with a rating generally less than 2 kvar single-phase and 10 kvar three-phase, reactors for special purposes such as high-frequency line traps or reactors mounted on rolling stock.

  1. Studies on a membrane reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, K.; Govind, R.

    1988-10-01

    Simulation is used to evaluate the performance of a catalytic reactor with permeable wall (membrane reactor) in shifting the equilibrium of three reversible reactions (cyclohexane dehydrogenation, hydrogen iodide decomposition, and propylene disproportionation). It is found that the preferred choice of cocurrernt or countercurrent operation is dependent on the physical properties and operating conditions. Methods of enhancing conversion are suggested and temperature effects are discussed.

  2. Mars

    CERN Document Server

    Elkins-Tanton, Linda T

    2010-01-01

    Mars exploration has never been more active, and our understanding of the planet is advancing rapidly. New discoveries reveal gullies carved by recent groundwater flow, thick ice deposits protected by rocks and soil even at the equator, and new evidence for lakes and seas in Mars' past. The Martian surface has some of the oldest planetary crust in the solar system, containing clues to conditions in early planets that cannot be obtained elsewhere.Beginning with a discussion of Mars as a planet in orbit, Mars, Revised Edition covers fundamental facts about this planet, including its mass and siz

  3. Advanced Demonstration and Test Reactor Options Study

    Energy Technology Data Exchange (ETDEWEB)

    Petti, David Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hill, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Gehin, J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gougar, Hans David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Strydom, Gerhard [Idaho National Lab. (INL), Idaho Falls, ID (United States); Heidet, F. [Argonne National Lab. (ANL), Argonne, IL (United States); Kinsey, J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Grandy, Christopher [Argonne National Lab. (ANL), Argonne, IL (United States); Qualls, A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brown, Nicholas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Powers, J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hoffman, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Croson, D. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-01-01

    Global efforts to address climate change will require large-scale decarbonization of energy production in the United States and elsewhere. Nuclear power already provides 20% of electricity production in the United States (U.S.) and is increasing in countries undergoing rapid growth around the world. Because reliable, grid-stabilizing, low emission electricity generation, energy security, and energy resource diversity will be increasingly valued, nuclear power’s share of electricity production has a potential to grow. In addition, there are non electricity applications (e.g., process heat, desalination, hydrogen production) that could be better served by advanced nuclear systems. Thus, the timely development, demonstration, and commercialization of advanced nuclear reactors could diversify the nuclear technologies available and offer attractive technology options to expand the impact of nuclear energy for electricity generation and non-electricity missions. The purpose of this planning study is to provide transparent and defensible technology options for a test and/or demonstration reactor(s) to be built to support public policy, innovation and long term commercialization within the context of the Department of Energy’s (DOE’s) broader commitment to pursuing an “all of the above” clean energy strategy and associated time lines. This planning study includes identification of the key features and timing needed for advanced test or demonstration reactors to support research, development, and technology demonstration leading to the commercialization of power plants built upon these advanced reactor platforms. This planning study is consistent with the Congressional language contained within the fiscal year 2015 appropriation that directed the DOE to conduct a planning study to evaluate “advanced reactor technology options, capabilities, and requirements within the context of national needs and public policy to support innovation in nuclear energy

  4. Mars

    CERN Document Server

    Day, Trevor

    2006-01-01

    Discusses the fundamental facts concerning this mysterious planet, including its mass, size, and atmosphere, as well as the various missions that helped planetary scientists document the geological history of Mars. This volume also describes Mars'' seasons with their surface effects on the planet and how they have changed over time.

  5. Spheromak reactor-design study

    Energy Technology Data Exchange (ETDEWEB)

    Les, J.M.

    1981-06-30

    A general overview of spheromak reactor characteristics, such as MHD stability, start up, and plasma geometry is presented. In addition, comparisons are made between spheromaks, tokamaks and field reversed mirrors. The computer code Sphero is also discussed. Sphero is a zero dimensional time independent transport code that uses particle confinement times and profile parameters as input since they are not known with certainty at the present time. More specifically, Sphero numerically solves a given set of transport equations whose solutions include such variables as fuel ion (deuterium and tritium) density, electron density, alpha particle density and ion, electron temperatures.

  6. Antineutrino reactor safeguards - a case study

    CERN Document Server

    Christensen, Eric; Jaffke, Patrick

    2013-01-01

    Antineutrinos have been proposed as a means of reactor safeguards for more than 30 years and there has been impressive experimental progress in neutrino detection. In this paper we conduct, for the first time, a case study of the application of antineutrino safeguards to a real-world scenario - the North Korean nuclear crisis in 1994. We derive detection limits to a partial or full core discharge in 1989 based on actual IAEA safeguards access and find that two independent methods would have yielded positive evidence for a second core with very high confidence. To generalize our results, we provide detailed estimates for the sensitivity to the plutonium content of various types of reactors, including most types of plutonium production reactors, based on detailed reactor simulations. A key finding of this study is that a wide class of reactors with a thermal power of less than 0.1-1 GWth can be safeguarded achieving IAEA goals for quantitative sensitivity and timeliness with detectors right outside the reactor ...

  7. Study on water cooled high conversion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ochiai, Masaaki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1999-12-01

    As a part of study on advanced reactors for the future, conceptual design of high conversion water cooled reactors is being studied, aiming at the contribution to nuclear fuel cycle by the LWR technology, since the utilization of LWRs will extend over a long period of time . We are studying on the reactor core concepts for BWR and PWR reactor systems. As for BWR system, three types of reactor cores are investigating for three different design goals; long operation period, high conversion ratio and high applicability for the existing BWR system. In all the cases, we have obtained a fair prospect of a large core concept with a capacity of 1,000 MWe class having negative void reactivity coefficient. This study is a part of JAERI-JAPCO (Japan Atomic Power Company) cooperative studies. Various kinds of conceptual designs will be created until the end of FY 1999. The designs will be checked and reviewed at that time, then experimental studies on the realization of the concepts will start with further design works from FY 2000. (author)

  8. Power reactor noise studies and applications

    Energy Technology Data Exchange (ETDEWEB)

    Arzhanov, V

    2002-03-01

    The present thesis deals with the neutron noise arising in power reactor systems. Generally, it can be divided into two major parts: first, neutron noise diagnostics, or more specifically, novel methods and algorithms to monitor nuclear industrial reactors; and second, contributions to neutron noise theory as applied to power reactor systems. Neutron noise diagnostics is presented by two topics. The first one is a theoretical study on the possibility to use a newly proposed current-flux (C/F) detector in Pressurised Water Reactors (PWR) for the localisation of anomalies. The second topic concerns various methods to detect guide tube impacting in Boiling Water Reactors (BWR). The significance of these problems comes from the operational experience. The thesis describes a novel method to localise vibrating control rods in a PWR by using only one C/F detector. Another novel method, based on wavelet analysis, is put forward to detect impacting guide tubes in a BWR. Neutron noise theory is developed for both Accelerator Driven Systems (ADS) and traditional reactors. By design the accelerator-driven systems would operate in a subcritical mode with a strong external source. This calls for a revision of many concepts and methods that have been developed for traditional reactors and also it poses a number of new problems. As for the latter, the thesis investigates the space-dependent neutron noise caused by a fluctuating source. It is shown that the frequency-dependent spatial behaviour exhibits some new properties that are different from those known in traditional critical systems. On the other hand, various reactor physics approximations (point kinetic, adiabatic etc.) have not been defined yet for the subcritical systems. In this respect the thesis presents a systematic formulation of the above mentioned approximations as well as investigations of their properties. Another important problem in neutron noise theory is the treatment of moving boundaries. In this case one

  9. Small Liquid Metal Cooled Reactor Safety Study

    Energy Technology Data Exchange (ETDEWEB)

    Minato, A; Ueda, N; Wade, D; Greenspan, E; Brown, N

    2005-11-02

    The Small Liquid Metal Cooled Reactor Safety Study documents results from activities conducted under Small Liquid Metal Fast Reactor Coordination Program (SLMFR-CP) Agreement, January 2004, between the Central Research Institute of the Electric Power Industry (CRIEPI) of Japan and the Lawrence Livermore National Laboratory (LLNL)[1]. Evaluations were completed on topics that are important to the safety of small sodium cooled and lead alloy cooled reactors. CRIEPI investigated approaches for evaluating postulated severe accidents using the CANIS computer code. The methods being developed are improvements on codes such as SAS 4A used in the US to analyze sodium cooled reactors and they depend on calibration using safety testing of metal fuel that has been completed in the TREAT facility. The 4S and the small lead cooled reactors in the US are being designed to preclude core disruption from all mechanistic scenarios, including selected unprotected transients. However, postulated core disruption is being evaluated to support the risk analysis. Argonne National Laboratory and the University of California Berkeley also supported LLNL with evaluation of cores with small positive void worth and core designs that would limit void worth. Assessments were also completed for lead cooled reactors in the following areas: (1) continuing operations with cladding failure, (2) large bubbles passing through the core and (3) recommendations concerning reflector control. The design approach used in the US emphasizes reducing the reactivity in the control mechanisms with core designs that have essentially no, or a very small, reactivity change over the core life. This leads to some positive void worth in the core that is not considered to be safety problem because of the inability to identify scenarios that would lead to voiding of lead. It is also believed that the void worth will not dominate the severe accident analysis. The approach used by 4S requires negative void worth throughout

  10. A Two-Stage Waste Gasification Reactor for Mars In-Situ Resource Utilization Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to design, build, and test a two-stage waste processing reactor for space applications. Our proposed technology converts waste from space missions into...

  11. Reactor pulse repeatability studies at the annular core research reactor

    Energy Technology Data Exchange (ETDEWEB)

    DePriest, K.R. [Applied Nuclear Technologies, Sandia National Laboratories, Mail Stop 1146, Post Office Box 5800, Albuquerque, NM 87185-1146 (United States); Trinh, T.Q. [Nuclear Facility Operations, Sandia National Laboratories, Mail Stop 0614, Post Office Box 5800, Albuquerque, NM 87185-1146 (United States); Luker, S. M. [Applied Nuclear Technologies, Sandia National Laboratories, Mail Stop 1146, Post Office Box 5800, Albuquerque, NM 87185-1146 (United States)

    2011-07-01

    The Annular Core Research Reactor (ACRR) at Sandia National Laboratories is a water-moderated pool-type reactor designed for testing many types of objects in the pulse and steady-state mode of operations. Personnel at Sandia began working to improve the repeatability of pulse operations for experimenters in the facility. The ACRR has a unique UO{sub 2}-BeO fuel that makes the task of producing repeatable pulses difficult with the current operating procedure. The ACRR produces a significant quantity of photoneutrons through the {sup 9}Be({gamma}, n){sup 8}Be reaction in the fuel elements. The photoneutrons are the result of the gammas produced during fission and in fission product decay, so their production is very much dependent on the reactor power history and changes throughout the day/week of experiments in the facility. Because the photoneutrons interfere with the delayed-critical measurements required for accurate pulse reactivity prediction, a new operating procedure was created. The photoneutron effects at delayed critical are minimized when using the modified procedure. In addition, the pulse element removal time is standardized for all pulse operations with the modified procedure, and this produces less variation in reactivity removal times. (authors)

  12. The TITAN reversed-field-pinch fusion reactor study

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    This paper on titan plasma engineering contains papers on the following topics: reversed-field pinch as a fusion reactor; parametric systems studies; magnetics; burning-plasma simulations; plasma transient operations; current drive; and physics issues for compact RFP reactors.

  13. A comparative study of kinetics of nuclear reactors

    Directory of Open Access Journals (Sweden)

    Obaidurrahman Khalilurrahman

    2009-01-01

    Full Text Available The paper deals with the study of reactivity initiated transients to investigate major differences in the kinetics behavior of various reactor systems under different operating conditions. The article also states guidelines to determine the safety limits on reactivity insertion rates. Three systems, light water reactors (pressurized water reactors, heavy water reactors (pressurized heavy water reactors, and fast breeder reactors are considered for the sake of analysis. The upper safe limits for reactivity insertion rate in these reactor systems are determined. The analyses of transients are performed by a point kinetics computer code, PKOK. A simple but accurate method for accounting total reactivity feedback in kinetics calculations is suggested and used. Parameters governing the kinetics behavior of the core are studied under different core states. A few guidelines are discussed to project the possible kinetics trends in the next generation reactors.

  14. Study on the Adaptability of Etheriifcation Feedstock to Reactor Type

    Institute of Scientific and Technical Information of China (English)

    Mao Junyi; Yuan Qing; Wang Lei; Huang Tao

    2016-01-01

    A reactive C5 oleifns and methanol etheriifcation kinetic model based on E-R mechanism was established and three different types of reactors including the adiabatic ifxed-bed liquid reactor, the external loop reactor and the mixed-phase reactor were constructed by Aspen Plus. The adaptability of reactive C5 oleifns to these reactors was studied and simulated using various gasoline fractions with different oleifns content. After the theoretical model was validated by the experimental data of the etheriifcation of three C5 light cut fractions from different gasoline sources in different reactors, the simulated isoamylene conversion with reactive C5 olefin contents increasing from 10% to 60% was studied in the three different types of reactors for etheriifcation with methanol, respectively. Test results show that there is an obvious adaptability of the feedstock composition to the reactor type to achieve a high conversion.

  15. Studying SNC achondrites: Looking for clues on Mars

    Science.gov (United States)

    Moyano-Cambero, C. E.; Trigo-Rodríguez, J. M.; Mestres, N.; Chennaoui Aoudjehane, N.; Madiedo, J. M.

    2013-05-01

    We characterize here the main minerals forming four SNC achondrites (Zagami, Nakhla, Dar al Gani 735 and Tissint), studied with a petrographic microscope and a Raman spectrometer. Our goal is to obtain information on the physico-chemical processes that participated in their formation and delivery to Earth. We are also studying the ability of some minerals forming the different groups to retain Mars atmospheric gases during the post-shock stages in order to sample Mars' atmospheric evolution.

  16. Mars Design Reference Architecture 5.0 Study: Executive Summary

    Science.gov (United States)

    Drake, Bret G.

    2008-01-01

    The NASA Mars Design Reference Architecture 5.0 Study seeks to update its long term goals and objective for human exploration missions; flight and surface systems for human missions and supporting infrastructure; operational concept for human and robotic exploration of Mars; key challenges including risk and cost drivers; and, its development schedule options. It additionally seeks to assess strategic linkages between lunar and Mars strategies and develop and understanding of methods for reducing the cost/risk of human Mars missions through investment in research, technology development, and synergy with other exploration plans. Recommendations are made regarding conjunction class (long-stay) missions which are seen as providing the best balance of cost, risk, and performance. Additionally, this study reviews entry, descent, and landing challenges; in-space transportation systems; launch vehicle and Orion assessments; risk and risk mitigation; key driving requirements and challenges; and, lunar linkages.

  17. Geological Study of Gale Crater on Mars

    Science.gov (United States)

    Le Deit, L.; Hauber, E.; Fueten, F.; Pondrelli, M.; Rossi, A.; Mangold, N.; Jaumann, R.

    2011-12-01

    Gale is an impact crater of 150 km in diameter, formed at Late Noachian/Early Hesperian located close to the dichotomy boundary and to the Medusae Fossae Formation. This crater is partially filled by a crescent-shaped mound of layered deposits up to 5 km thick and 6000 km2 in area, for which several origins have been proposed including volcanic, eolian, and fluviatile and lacustrine processes, precipitation as spring deposits, and a combination of several origins. The past presence of water is attested by the occurrence of many channels carved into the deposits and the crater rim, and of phyllosilicates and sulfates located in the lowest part of the deposits. Hence, Gale crater is a site of high interest to understand the evolution of the geochemical and climatic environment of the region through time, and may have had favorable conditions for supporting life in the past. This will be studied in situ by Curiosity (Mars Science Laboratory) from August 2012. In order to better constrain the history of Gale and the origin of its deposits, a geologic map of Gale crater based on the analysis of the orbital data CTX (~ 6 m/pixel) and HiRISE (25-32 cm/pixel) was produced. The geometry of the layered deposits was measured from HiRISE DEM. The geological units and landforms were defined according to their location, physical characteristics, albedo, erosion patterns, and mineralogical composition. Five main units were identified within the mound of layered deposits, which are interpreted as mainly airfall deposits including aeolian dunes. North of the mound, linear lobate features and a fan-shaped feature might have resulted from mass-wasting processes (i.e., landslides, debris flows, or viscous flows). The crater fill units correspond to deposits located on the rims and on the floor of the crater. They are incised by many valleys and superposed by sinuous ridges, interpreted as fluvial channels and inverted channels respectively. These crater fill units are interpreted as

  18. Raman Spectroscopy Applied to Mars Water Cycle Studies

    Science.gov (United States)

    Nikolakakos, G.; Whiteway, J. A.

    2014-12-01

    One of the key findings during the Phoenix and Mars Science Laboratory landed Mars missions has been the detection of perchlorate, a highly deliquescent salt. Perchlorates are of great interest on Mars due to their high affinity for water vapour as well as their ability to greatly depress the freezing point of water when in solution. This has intriguing biological implications as resulting brines could potentially provide a habitable environment for living organisms. Additionally, it has been speculated that these salts may play a significant role in influencing the hydrological cycle on Mars. In order to experimentally study brine formation on Mars and assess the feasibility of a future landed detection tool, a stand-off Raman spectroscopy instrument and environmental simulation chamber have been developed at York University. A sample of magnesium perchlorate has been subjected to the water vapour pressure, background pressure and temperatures found at polar Martian latitudes. Results indicate that at a water vapour pressure of ~20 Pa, Raman spectroscopy is able to detect the onset of brine formation and provide an estimate of the quantity of water taken up by the sample. At the lower water vapour pressures typically found on Mars ( ~1 Pa), it appears that slower dynamics inhibit the onset of water uptake over relevant time scales. The experimental setup and current results will be presented.

  19. Fusion reactor blanket/shield design study

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.L.; Clemmer, R.G.; Harkness, S.D.

    1979-07-01

    A joint study of tokamak reactor first-wall/blanket/shield technology was conducted by Argonne National Laboratory (ANL) and McDonnell Douglas Astronautics Company (MDAC). The objectives of this program were the identification of key technological limitations for various tritium-breeding-blanket design concepts, establishment of a basis for assessment and comparison of the design features of each concept, and development of optimized blanket designs. The approach used involved a review of previously proposed blanket designs, analysis of critical technological problems and design features associated with each of the blanket concepts, and a detailed evaluation of the most tractable design concepts. Tritium-breeding-blanket concepts were evaluated according to the proposed coolant. The ANL effort concentrated on evaluation of lithium- and water-cooled blanket designs while the MDAC effort focused on helium- and molten salt-cooled designs. A joint effort was undertaken to provide a consistent set of materials property data used for analysis of all blanket concepts. Generalized nuclear analysis of the tritium breeding performance, an analysis of tritium breeding requirements, and a first-wall stress analysis were conducted as part of the study. The impact of coolant selection on the mechanical design of a tokamak reactor was evaluated. Reference blanket designs utilizing the four candidate coolants are presented.

  20. A Sunphotometer for Mars Atmosphere Studies

    Science.gov (United States)

    Strawa, A. W.; Velante, M.; Colaprete, A.; Papadopoulos, P.

    2005-12-01

    The interaction between the sun's energy and Martian dust is recognized as one of the biggest driving forces for climate on Mars, yet not enough is known about the physical and optical properties of this dust or its spatial and temporal variation. A better understanding of the interaction between Mars dust and its weather and climate is required for manned exploration. Recognizing this, we are developing an instrument concept that would enable dedicated measurements to characterize Mars' atmosphere and dust than has been possible in the past. The instrument is based on the sunphotometer concept, integrating concepts that produce an instrument with no moving parts. Consequently, it would be small, light weight, and consume little electrical power. Sunphotometer's are commonly used on the Earth's surface, as well as on aircraft, to determine the solar energy attenuated by gases and aerosol particles in the atmosphere. Typically, these instruments track the sun to measure the direct solar attenuation. Our concept uses a combination of unique optics and a detector array to eliminate the moving parts and make the instrument much smaller, compact, and reliable. Data products would include downwelling flux, gas and aerosol optical depth at multiple-wavelengths, gas phase constituent column density, and aerosol size distribution. One of the desirable features of this concept is that the techniques exist that would enable the instrument to be self-calibrating throughout the year. This means that as dust begins to deposit on the instrument window, or the electronics or sensor array degrade, the instrument could be periodically recalibrated in situ. Thus it would provide invaluable data for long-term modeling efforts. This system would also be able to compensate for deployment on non-level surfaces. This instrument would have applicability to the Discovery and Mars Exploration class Missions. The instrument would be a valuable component in the exploration of any planetary

  1. 火星表面核反应堆电源方案研究%Scheme Research of Mars Surface Nuclear Reactor Power

    Institute of Scientific and Technical Information of China (English)

    姚成志; 胡古; 赵守智; 解家春; 郭键; 高剑

    2016-01-01

    As the nearest neighbor of earth,Mars has always been the first choice for space exploration and development of human beings.Landing on Mars,establishing a base and developing and utilizing resource are the primary goal of Mars exploration,but the establishment of Mars base needs to solve the issue of power supply first.The nuclear reactor power has the advantages of high power,long service life and environ-mental tolerance ability,and it is an ideal energy solution option for Mars base and other deep space exploration missions.A brief analysis of the current status of energy that can be used for a Mars base was carried out.The overall scheme of 40 kWe nuclear reactor power for Mars surface was given.Finally,the power scheme was analyzed and demon-strated from the aspects of reactor physics,critical safety,shielding,thermal and struc-ture.The results show that the nuclear reactor power scheme is reasonable and feasible. It can meet the requirements of safety and lifetime.%火星作为地球的近邻,一直是人类进行深空探测和开发的首选目标。登陆火星、建立火星基地并开发利用火星资源首先需解决电力供给问题,核反应堆电源具有功率大、寿命长、环境适应性强等优点,是火星基地及其他深空探测任务的理想能源。通过分析目前可用于火星基地的能源情况,针对性地提出了40 kWe 火星表面核反应堆电源的总体方案,并从物理、安全、屏蔽、热工以及结构方面对电源方案进行了分析和论证。结果表明:该电源方案合理可行,能满足安全和寿期要求。

  2. HELIAS stellarator reactor studies and related European technology studies

    Energy Technology Data Exchange (ETDEWEB)

    Grieger, G. (Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany)); Nuehrenberg, J. (Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany)); Renner, H. (Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany)); Sapper, J. (Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany)); Wobig, H. (Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany))

    1994-08-01

    Research on stellarators has been carried out in Europe since the early years of the fusion programme. Early studies of this reactor concept were done at the Culham Laboratory of the UK Atomic Energy Authority. Such classical stellarators, however, have poor reactor prospects in spite of the significant advantage of not needing a large toroidal plasma current. It seemed to be just this large toroidal plasma current which has led to intrinsic deficiencies with respect to reactor potential of the tokamak. Expecting that these deficiencies would disappear for a concept without such a current, the Institut fuer Plasmaphysik developed, in a roll-back fashion, i.e. by starting from reactor considerations, the concept of the helical axis advanced stellarator (HELIAS). The results achieved look very promising indeed. Since tokamaks and stellarators show many similarities, there appeared no need as yet for a new stand-alone stellarator reactor study. The work was rather concentrated on the few but decisive differences between the two concepts and on evaluation of their relative importance. Studies on the coil system, the stress distribution in the supporting material, the space needed for an efficient blanket system, the properties of the exhaust system, etc. have been done. Applying contemporary scaling laws, it turns out that although the aspect ratio of such advanced stellarators is larger than that of tokamaks, the plasma volume is about the same. The magnetic energy needed for plasma confinement is considerably lower and the mass utilization tends to be larger than for comparable tokamaks. It also follows that a number of reactor components needed for tokamak operation (e.g. current drive, feedback stabilization, disruption prevention) are not needed in stellarators, making this type of reactor and its operation simpler. Such results would have a large influence on selection of the final concept and the further evolution of the fusion programme.

  3. Atmospheric distribution of methane on Mars: A model study

    Science.gov (United States)

    Viscardy, Sébastien; Daerden, Frank; Neary, Lori

    2016-10-01

    In the past decade, the detection of methane (CH4) in the atmosphere of Mars has been reported several times. These observations have strongly drawn the attention of the scientific community and triggered a renewed interest in Mars as their implications for the geochemical or biological activities are remarkable. However, given that methane is expected to have a photochemical lifetime of several centuries, the relatively fast loss rates of methane estimated from Earth-based measurements remain unexplained. Although this gave rise to objections against the validity of those observations, recent in situ measurements confirmed that methane is being occasionally released into the atmosphere from an unknown source (possibly from the ground). Additionally, ExoMars/TGO was launched to Mars in March 2016. NOMAD, one of the instruments onboard TGO, will provide the first global detailed observations of methane on Mars. It is in this context that we present a model study of the behavior of methane plumes.A general circulation model for the atmosphere of Mars is applied to simulate surface emission of methane and to investigate its vertical distribution during the first weeks after the release. Such surface emissions were suggested to explain observations of methane. Previous GCM simulations focused on the horizontal evolution of the methane, but the present study focuses on the three-dimensional dispersion of methane throughout the atmosphere after the surface release. It is found that a highly nonuniform vertical distribution, including distinct vertical layers, can appear throughout the atmosphere during the first weeks after the emission. This is explained by the global circulation patterns in the atmosphere at the time of the emission. Large Hadley cells transport the methane rapidly to other locations over the planet, and methane will be stretched out in layers along the general circulation streamlines at heights corresponding to strong zonal jets.This result changes

  4. Experimental devices in the osiris reactor to study effects of radiations on fusion reactor materials

    Science.gov (United States)

    Lefevre, F.; Thevenot, G.

    1986-11-01

    Within the framework of the Technology Research Program on controlled fusion initiated by the European Communities, the Services des Piles de Saclay (SPS) of Commissariat à l'Energie Atomique (CEA) have been requested to perform some necessary experiments to study the irradiation behaviour of materials which are possible candidates for controlled fusion reactors. This paper describes the devices, generally adapted from a standard model "The COLIBRI", which allow one to carry out, in the OSIRIS reactor, irradiations on the three great families of fusion reactor materials: - lithium containing materials of breeding blanket for in-situ tritium production, - protection materials, and - structural materials.

  5. Experimental devices in the OSIRIS reactor to study effects of radiations on fusion reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    Lefevre, F.; Thevenot, G.

    Within the framework of the Technology Research Program on controlled fusion initiated by the European Communities, the Services des Piles de Saclay (SPS) of Commissariat a l'Energie Atomique (CEA) have been requested to perform some necessary experiments to study the irradiation behaviour of materials which are possible candidates for controlled fusion reactors. This paper describes the devices, generally adapted from a standard model The COLIBRI, which allow one to carry out, in the OSIRIS reactor, irradiations on the three great families of fusion reactor materials: Lithium containing materials of breeding blanket for in-situ tritium production, protection materials, and structural materials.

  6. Emotions and Habitability study in Moon Mars Analogue.

    Science.gov (United States)

    Mertens, Alexandre; Lia Schlacht, Irene

    Euro Moon Mars mission have been conducted by students and field researchers in the Mars Desert Research Station (MDRS) a habitat installed by the Mars Society (MS) in the Utah desert. The campaign was supported by ILEWG International Lunar Exploration Working Group, ESTEC, NASA Ames, and partners. It investigated human aspects of isolation in a Mars analogue base. The project is in line with the ILEWG which coordinates several MDRS missions, and contributes to the preparation of future Mars sample return missions. The objective is to study and improve the habitat dynamics in a closed and small environment. Investigation cover different fields as emotional, sociological and psychological aspects and a food study but also habitability aspects. The study has been conducted by asking to the crew members to perform task and fill in questionnaires before, during and after the simulation. Video recovering, pictures and heart rate counting will also be used. One of the main study subject, conducted by Bernard Rimé, concerns the sharing of emotions in an isolated environ-e ment. Another is "Mars Habitability Experiment", which responsible is Irene Schlacht, will try to determine whether humans need variability of stimuli such as it happens in the natural environment -e.g. seasonal changing -to gain efficiency, reliability and well-being. This study have been conducted from February 19 to April 19 on two crews presenting different aspects that could lead to various behaviours. The first crew is made of people from different countries that don't know each other very well. On the opposite, the second crew members have the same cultural background -they come from the same country, university -and they know each other for at least six months. This allow studying how the extreme conditions of the isolation affect the crew efficiency, creativity and sanity according to its homogeneity. Report on the science and technical results, and implications for Earth-Mars comparative stud-ies

  7. Study on secondary shutdown systems in Tehran research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jalali, H.R.; Fadaei, A.H., E-mail: Fadaei_amir@aut.ac.ir; Gharib, M.

    2015-09-15

    Highlights: • A study was undertaken to summarize the techniques for secondary shutdown systems (SSS). • Neutronic calculation performed for proposed systems as SSS. • Dumping the heavy water stored in the reflector vessel is capable to shut down reactor. • Neutronic and transient calculation was done for validating the selected SSS. • All calculation shown that this system has advantages in safety and neutron economy. - Abstract: One important safety aspect of any research reactor is the ability to shut down the reactor. Usually, research reactors, currently in operation, have a single shutdown system based on the simultaneous insertion of the all control rods into the reactor core through gravity. Nevertheless, the International Atomic Energy Agency currently recommends use of two shutdown systems which are fully independent from each other to guarantee secure shutdown when one of them fails. This work presents an investigative study into secondary shutdown systems, which will be an important safety component in the research reactor and will provide another alternative way to shut down the reactor emergently. As part of this project, a study was undertaken to summarize the techniques that are currently used at world-wide research reactors for recognizing available techniques to consider in research reactors. Removal of the reflector, removal of the fuels, change in critical shape of reactor core and insertion of neutron absorber between the core and reflector are selected as possible techniques in mentioned function. In the next step, a comparison is performed for these methods from neutronic aspects. Then, chosen method is studied from the transient behavior point of view. Tehran research reactor which is a 5 MW open-pool reactor selected as a case study and all calculations are carried out for it. It has 5 control rods which serve the purpose of both reactivity control and shutdown of reactor under abnormal condition. Results indicated that heavy

  8. Mars Aeronomy Explorer (MAX): Study Employing Distributed Micro-Spacecraft

    Science.gov (United States)

    Shotwell, Robert F.; Gray, Andrew A.; Illsley, Peter M.; Johnson, M.; Sherwood, Robert L.; Vozoff, M.; Ziemer, John K.

    2005-01-01

    An overview of a Mars Aeronomy Explorer (MAX) mission design study performed at NASA's Jet Propulsion Laboratory is presented herein. The mission design consists of ten micro-spacecraft orbiters launched on a Delta IV to Mars polar orbit to determine the spatial, diurnal and seasonal variation of the constituents of the Martian upper atmosphere and ionosphere over the course of one Martian year. The spacecraft are designed to allow penetration of the upper atmosphere to at least 90 km. This property coupled with orbit precession will yield knowledge of the nature of the solar wind interaction with Mars, the influence of the Mars crustal magnetic field on ionospheric processes, and the measurement of present thermal and nonthermal escape rates of atmospheric constituents. The mission design incorporates alternative design paradigms that are more appropriate for-and in some cases motivate-distributed micro-spacecraft. These design paradigms are not defined by a simple set of rules, but rather a way of thinking about the function of instruments, mission reliability/risk, and cost in a systemic framework.

  9. A Study of Reactor Neutrino Monitoring at Experimental Fast Reactor JOYO

    CERN Document Server

    Furuta, H; Hara, T; Haruna, T; Ishihara, N; Ishitsuka, M; Ito, C; Katsumata, M; Kawasaki, T; Konno, T; Kuze, M; Maeda, J; Matsubara, T; Miyata, H; Nagasaka, Y; Nitta, K; Sakamoto, Y; Suekane, F; Sumiyoshi, T; Tabata, H; Takamatsu, M; Tamura, N

    2011-01-01

    We carried out a study of neutrino detection at the experimental fast reactor JOYO using a 0.76 tons gadolinium loaded liquid scintillator detector. The detector was set up on the ground level at 24.3m from the JOYO reactor core of 140MW thermal power. The measured neutrino event rate from reactor on-off comparison was 1.11\\pm1.24(stat.)\\pm0.46(syst.)events/day. Although the statistical significance of the measurement was not enough, the background in such a compact detector at the ground level was studied in detail and MC simulation was found to describe the data well. A study for improvement of the detector for future such experiments is also shown.

  10. Strategies to Improve the Accuracy of Mars-GRAM Sensitivity Studies at Large Optical Depths

    Science.gov (United States)

    Justh, Hilary L.; Justus, Carl G.; Badger, Andrew M.

    2010-01-01

    The poster provides an overview of techniques to improve the Mars Global Reference Atmospheric Model (Mars-GRAM) sensitivity. It has been discovered during the Mars Science Laboratory (MSL) site selection process that the Mars Global Reference Atmospheric Model (Mars-GRAM) when used for sensitivity studies for TES MapYear = 0 and large optical depth values such as tau = 3 is less than realistic. A preliminary fix has been made to Mars-GRAM by adding a density factor value that was determined for tau = 0.3, 1 and 3.

  11. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, S., E-mail: hamann@inp-greifswald.de; Röpcke, J. [INP-Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Börner, K.; Burlacov, I.; Spies, H.-J. [TU Bergakademie Freiberg, Institute of Materials Engineering, Gustav-Zeuner-Str. 5, 09599 Freiberg (Germany); Strämke, M.; Strämke, S. [ELTRO GmbH, Arnold-Sommerfeld-Ring 3, 52499 Baesweiler (Germany)

    2015-12-15

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH{sub 4}, C{sub 2}H{sub 2}, HCN, and NH{sub 3}). With the help of OES, the rotational temperature of the screen plasma could be determined.

  12. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

    Science.gov (United States)

    Hamann, S.; Börner, K.; Burlacov, I.; Spies, H.-J.; Strämke, M.; Strämke, S.; Röpcke, J.

    2015-12-01

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH4, C2H2, HCN, and NH3). With the help of OES, the rotational temperature of the screen plasma could be determined.

  13. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen.

    Science.gov (United States)

    Hamann, S; Börner, K; Burlacov, I; Spies, H-J; Strämke, M; Strämke, S; Röpcke, J

    2015-12-01

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH4, C2H2, HCN, and NH3). With the help of OES, the rotational temperature of the screen plasma could be determined.

  14. NGNP Reactor Coolant Chemistry Control Study

    Energy Technology Data Exchange (ETDEWEB)

    Brian Castle

    2010-11-01

    The main focus of this paper is to identify the most desirable ranges of impurity levels in the primary coolant to optimize component life in the primary circuit of the Next Generation Nuclear Plant (NGNP), which will either be a prismatic block or pebble bed reactor.

  15. Parametric design study of tandem mirror fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, G.A.

    1977-05-27

    The parametric design study of the tandem mirror reactor (TMR) is described. The results of this study illustrate the variation of reactor characteristics with changes in the independent design parameters, reveal the set of design parameters which minimizes the cost of the reactor, and show the sensitivity of the optimized design to physics and technological uncertainties. The total direct capital cost of an optimized 1000 MWe TMR is estimated to be $1300/kWe. The direct capital cost of a 2000 MWe plant is less than $1000/kWe.

  16. Reactor

    Science.gov (United States)

    Evans, Robert M.

    1976-10-05

    1. A neutronic reactor having a moderator, coolant tubes traversing the moderator from an inlet end to an outlet end, bodies of material fissionable by neutrons of thermal energy disposed within the coolant tubes, and means for circulating water through said coolant tubes characterized by the improved construction wherein the coolant tubes are constructed of aluminum having an outer diameter of 1.729 inches and a wall thickness of 0.059 inch, and the means for circulating a liquid coolant through the tubes includes a source of water at a pressure of approximately 350 pounds per square inch connected to the inlet end of the tubes, and said construction including a pressure reducing orifice disposed at the inlet ends of the tubes reducing the pressure of the water by approximately 150 pounds per square inch.

  17. Human Mars Entry, Descent, and Landing Architecture Study Overview

    Science.gov (United States)

    Cianciolo, Alicia D.; Polsgrove, Tara T.

    2016-01-01

    The Entry, Descent, and Landing (EDL) Architecture Study is a multi-NASA center activity to analyze candidate EDL systems as they apply to human Mars landing in the context of the Evolvable Mars Campaign. The study, led by the Space Technology Mission Directorate (STMD), is performed in conjunction with the NASA's Science Mission Directorate and the Human Architecture Team, sponsored by NASA's Human Exploration and Operations Mission Directorate. The primary objective is to prioritize future STMD EDL technology investments by (1) generating Phase A-level designs for selected concepts to deliver 20 t human class payloads, (2) developing a parameterized mass model for each concept capable of examining payloads between 5 and 40 t, and (3) evaluating integrated system performance using trajectory simulations. This paper summarizes the initial study results.

  18. A Study on the Kinetic Characteristics of Transmutation Process Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Chang Hyun; You, Young Woo; Cho, Jae seon; Huh, Chang Wook; Kim, Doh Hyung [Seoul National University, Seoul (Korea, Republic of)

    1997-07-01

    The purpose of this study is to examine the transient heat transfer characteristics of liquid mental as the coolant used in accelerator-driven transmutation process reactor which is related the disposal of high-level radioactive nuclide. At current stage, the accelerator-driven transmutation process is investigated as the most appropriate method among many transmutation process methods. In this study, previous research works are investigated especially about the thermal hydraulics and kinetic behavior of coolant material including heat transfer of coolant in transmutation process reactor. A study on the heat transfer characteristics of liquid metal is performed based on the thermal hydraulic kinetic characteristics of liquid metal reactor which uses liquid metal coolant. Based on this study, the most appropriate material for the coolant of transmutation reactor will be recommended. 53 refs., 15 tabs., 33 figs. (author)

  19. A Simple Parallel Photochemical Reactor for Photodecomposition Studies

    Science.gov (United States)

    Xiaobo Chen; Halasz, Sarah M.; Giles, Eric C.; Mankus, Jessica V.; Johnson, Joseph C.; Burda, Clemens

    2006-01-01

    A simple and useful parallel photochemical reactor intended to study the photodecomposition of dyes using semiconductor photocatalysis is presented. The photochemical reactions are followed through time-dependent changes in the ground-state absorption spectra of the dyes.

  20. Economic Development Benefits of the Mars Hill Wind Farm, Wind Powering America Rural Economic Development, Case Study (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2009-06-01

    This case study summarizes the economic development benefits of the Mars Hill Wind Farm to the community of Mars Hill, Maine. The Mars Hill Wind Farm is New England's first utility-scale wind farm.

  1. Sensitivity and Uncertainty Study for Thermal Molten Salt Reactors

    Science.gov (United States)

    Bidaud, Adrien; Ivanona, Tatiana; Mastrangelo, Victor; Kodeli, Ivo

    2006-04-01

    The Thermal Molten Salt Reactor (TMSR) using the thorium cycle can achieve the GEN IV objectives of economy, safety, non-proliferation and durability. Its low production of higher actinides, coupled with its breeding capabilities - even with a thermal spectrum - are very valuable characteristics for an innovative reactor. Furthermore, the thorium cycle is more flexible than the uranium cycle since only a small fissile inventory (reactor. The potential of these reactors is currently being extensively studied at the CNRS and EdF /1,2/. A simplified chemical reprocessing is envisaged compared to that used for the former Molten Salt Breeder Reactor (MSBR). The MSBR concept was developed at Oak Ridge National Laboratory (ORNL) in the 1970's based on the Molten Salt Reactor Experiment (MSRE). The main goals of our current studies are to achieve a reactor concept that enables breeding, improved safety and having chemical reprocessing needs reduced and simplified as much as reasonably possible. The neutronic properties of the new TMSR concept are presented in this paper. As the temperature coefficient is close to zero, we will see that the moderation ratio cannot be chosen to simultaneously achieve a high breeding ratio, long graphite lifetime and low uranium inventory. It is clear that any safety margin taken due to uncertainty in the nuclear data will significantly reduce the capability of this concept, thus a sensitivity analysis is vital to propose measurements which would allow to reduce at present high uncertainties in the design parameters of this reactor. Two methodologies, one based on OECD/NEA deterministic codes and one on IPPE (Obninsk) stochastic code, are compared for keff sensitivity analysis. The uncertainty analysis of keff using covariance matrices available in evaluated files has been performed. Furthermore, a comparison of temperature coefficient sensitivity profiles is presented for the most important reactions. These results are used to review the

  2. Space reactor assessment and validation study

    Science.gov (United States)

    Gedeon, Stephen; Morey, Dennis

    The present difficulties experienced by the United States in launching payloads into space has suggested a number of problems which are associated with the handling of hazardous materials in spacecraft. The question has arisen as to the safety of launching highly radioactive material such as plutonium-238, related to the possibility of its dispersion into the atmosphere during a launch vehicle explosion. An alternative is the use of a small nuclear reactor which is not started until it is in space and contains little or no radioactivity at launch. A first order assessment of six small reactor concepts with power levels up to 100 MWe was performed. Both the nuclear feasibility of these concepts to operate at their rated power levels between 7 and 10 years and the capability of these concepts to remain subcritical both before and during launch and also in the case of water immersion during a potential launch failure or abort were investigated.

  3. Advanced Burner Reactor Preliminary NEPA Data Study.

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, L. L.; Cahalan, J. E.; Deitrich, L. W.; Fanning, T. H.; Grandy, C.; Kellogg, R.; Kim, T. K.; Yang, W. S.; Nuclear Engineering Division

    2007-10-15

    The Global Nuclear Energy Partnership (GNEP) is a new nuclear fuel cycle paradigm with the goals of expanding the use of nuclear power both domestically and internationally, addressing nuclear waste management concerns, and promoting nonproliferation. A key aspect of this program is fast reactor transmutation, in which transuranics recovered from light water reactor spent fuel are to be recycled to create fast reactor transmutation fuels. The benefits of these fuels are to be demonstrated in an Advanced Burner Reactor (ABR), which will provide a representative environment for recycle fuel testing, safety testing, and modern fast reactor design and safeguard features. Because the GNEP programs will require facilities which may have an impact upon the environment within the meaning of the National Environmental Policy Act of 1969 (NEPA), preparation of a Programmatic Environmental Impact Statement (PEIS) for GNEP is being undertaken by Tetra Tech, Inc. The PEIS will include a section on the ABR. In support of the PEIS, the Nuclear Engineering Division of Argonne National Laboratory has been asked to provide a description of the ABR alternative, including graphics, plus estimates of construction and operations data for an ABR plant. The compilation of this information is presented in the remainder of this report. Currently, DOE has started the process of engaging industry on the design of an Advanced Burner Reactor. Therefore, there is no specific, current, vendor-produced ABR design that could be used for this PEIS datacall package. In addition, candidate sites for the ABR vary widely as to available water, geography, etc. Therefore, ANL has based its estimates for construction and operations data largely on generalization of available information from existing plants and from the environmental report assembled for the Clinch River Breeder Reactor Plant (CRBRP) design [CRBRP, 1977]. The CRBRP environmental report was chosen as a resource because it thoroughly

  4. Studies on Nitrogen Oxides Removal Using Plasma Assisted Catalytic Reactor

    Institute of Scientific and Technical Information of China (English)

    V. Ravi; Young Sun Mok; B. S. Rajanikanth; Ho-Chul Kang

    2003-01-01

    An electric discharge plasma reactor combined with a catalytic reactor was studied for removing nitrogen oxides. To understand the combined process thoroughly, discharge plasma and catalytic process were separately studied first, and then the two processes were combined for the study. The plasma reactor was able to oxidize NO to NO2 well although the oxidation rate decreased with temperature. The plasma reactor alone did not reduce the NOx (NO+NO2)level effectively, but the increase in the ratio of NO2 to NO as a result of plasma discharge led to the enhancement of NOx removal efficiency even at lower temperatures over the catalyst surface (V2O5-WOa/TiO2). At a gas temperature of 100℃, the NOx removal efficiency obtained using the combined plasma catalytic process was 88% for an energy input of 36 eV/molecule or 30 J/1.

  5. Human Mars Entry, Descent and Landing Architectures Study Overview

    Science.gov (United States)

    Polsgrove, Tara T.; Dwyer Cianciolo, Alicia

    2016-01-01

    Landing humans on Mars will require entry, descent and landing (EDL) capability beyond the current state of the art. Nearly twenty times more delivered payload and an order of magnitude improvement in precision landing capability will be necessary. Several EDL technologies capable of meeting the human class payload delivery requirements are being considered. The EDL technologies considered include low lift-to-drag vehicles like Hypersonic Inflatable Aerodynamic Decelerators (HIAD), Adaptable Deployable Entry and Placement Technology (ADEPT), and mid range lift-to-drag vehicles like rigid aeroshell configurations. To better assess EDL technology options and sensitivities to future human mission design variations, a series of design studies has been conducted. The design studies incorporate EDL technologies with conceptual payload arrangements defined by the Evolvable Mars Campaign to evaluate the integrated system with higher fidelity than have been performed to date. This paper describes the results of the design studies for a lander design using the HIAD, ADEPT and rigid shell entry technologies and includes system and subsystem design details including mass and power estimates. This paper will review the point design for three entry configurations capable of delivering a 20 t human class payload to the surface of Mars.

  6. Reactor Physics Scoping and Characterization Study on Implementation of TRIGA Fuel in the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jennifer Lyons; Wade R. Marcum; Mark D. DeHart; Sean R. Morrell

    2014-01-01

    The Advanced Test Reactor (ATR), under the Reduced Enrichment for Research and Test Reactors (RERTR) Program and the Global Threat Reduction Initiative (GTRI), is conducting feasibility studies for the conversion of its fuel from a highly enriched uranium (HEU) composition to a low enriched uranium (LEU) composition. These studies have considered a wide variety of LEU plate-type fuels to replace the current HEU fuel. Continuing to investigate potential alternatives to the present HEU fuel form, this study presents a preliminary analysis of TRIGA® fuel within the current ATR fuel envelopes and compares it to the functional requirements delineated by the Naval Reactors Program, which includes: greater than 4.8E+14 fissions/s/g of 235U, a fast to thermal neutron flux ratio that is less than 5% deviation of its current value, a constant cycle power within the corner lobes, and an operational cycle length of 56 days at 120 MW. Other parameters outside those put forth by the Naval Reactors Program which are investigated herein include axial and radial power profiles, effective delayed neutron fraction, and mean neutron generation time.

  7. Alignment and resolution studies of a MARS scanner

    CERN Document Server

    Butler, A P; Bell, S T; Chelkov, G; Demichev, M; Gongadze, A; Kotov, S; Kozhevnikov, D; Kruchonak, U; Potrap, I; Smolyanskiy, P; Zhemchugov, A

    2015-01-01

    The MARS scanner is designed for the x-ray spectroscopic study of samples with the aid of computer tomography methods. Computer tomography allows the reconstruction of slices of an investigated sample using a set of shadow projections obtained for different angles. Projections in the MARS scanner are produced using a cone x-ray beam geometry. Correct reconstruction in this scheme requires precise knowledge of several geometrical parameters of a tomograph, such as displacement of a rotation axis, x-ray source position with respect to a camera, and camera inclinations. Use of inaccurate parameters leads to a poor sample reconstruction. Non-ideal positioning of camera, x-ray source and cylindrical rotating frame (gantry) itself on which these parts are located, leads to the need for tomograph alignment. In this note we describe the alignment procedure that was used to get different geometrical corrections for the reconstruction. Also, several different estimations of the final spatial resolution for reconstructe...

  8. Mars Atmospheric Conversion to Methane and Water: An Engineering Model of the Sabatier Reactor with Characterization of Ru/Al2O3 for Long Duration Use on Mars

    Science.gov (United States)

    Meier, Anne J.; Shah, Malay; Petersen, Elspeth; Hintze, Paul; Muscatello, Tony

    2017-01-01

    The Atmospheric Processing Module (APM) is a Mars In-Situ Resource Utilization (ISRU) technology designed to demonstrate conversion of the Martian atmosphere into methane and water. The Martian atmosphere consists of approximately 95 carbon dioxide (CO2) and residual argon and nitrogen. APM utilizes cryocoolers for CO2 acquisition from a simulated Martian atmosphere and pressure. The captured CO2 is sublimated and pressurized as a feedstock into the Sabatier reactor, which converts CO2 and hydrogen to methane and water. The Sabatier reaction occurs over a packed bed reactor filled with Ru/Al2O3 pellets. The long duration use of the APM system and catalyst was investigated for future scaling and failure limits. Failure of the catalyst was detected by gas chromatography and temperature sensors on the system. Following this, characterization and experimentation with the catalyst was carried out with analysis including x-ray photoelectron spectroscopy and scanning electron microscopy with elemental dispersive spectroscopy. This paper will discuss results of the catalyst performance, the overall APM Sabatier approach, as well as intrinsic catalyst considerations of the Sabatier reactor performance incorporated into a chemical model.

  9. Conceptual Study for development of a low power research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Park, C.; Kim, H. S.; Park, J. H.; Chae, H. T.; Lee, B. C. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-07-01

    Even though the nuclear society is again facing with difficult situations after Fukusima accident, some countries still continues to consider nuclear power as one option of national energy sources and to introduce nuclear energy. As a research reactor has been regarded as a step-stone to establish infrastructures for the nuclear power development program, some countries that have plan to introduce the nuclear power energy are considering to construct a research reactor. Particularly, a low power research reactor whose main purpose is basic researches on the nuclear technology and education/training would be of interest to developing countries when taking the economy and level of science and technology into consideration. And many low power research reactors at operation are obsolescent and their numbers are decreasing. Hence, some concepts on a low power research reactor are being studied for the future needs. This paper presents the conceptual study on the basic requirements and the preliminary design features of a low power research reactor.

  10. Desalination of seawater with nuclear power reactors in cogeneration; Desalacion de agua de mar con reactores nucleares de potencia en cogeneracion

    Energy Technology Data Exchange (ETDEWEB)

    Flores E, R.M

    2004-07-01

    The growing demand for energy and hydraulic resources for satisfy the domestic, industrial, agricultural activities, etc. has wakened up the interest to carry out concerning investigations to study the diverse technologies guided to increase the available hydraulic resources, as well as to the search of alternatives of electric power generation, economic and socially profitable. In this sense the possible use of the nuclear energy is examined in cogeneration to obtain electricity and drinkable water for desalination of seawater. The technologies are analysed involved in the nuclear cogeneration (desalination technology, nuclear and desalination-nuclear joining) available in the world. At the same time it is exemplified the coupling of a nuclear reactor and a process of hybrid desalination that today in day the adult offers and economic advantages. Finally, the nuclear desalination is presented as a technical and economically viable solution in regions where necessities of drinkable water are had for the urban, agricultural consumption and industrial in great scale and that for local situations it is possible to satisfy it desalinating seawater. (Author)

  11. Joule-Heated Molten Regolith Electrolysis Reactor Concepts for Oxygen and Metals Production on the Moon and Mars

    Science.gov (United States)

    Sibille, Laurent; Dominques, Jesus A.

    2012-01-01

    The maturation of Molten Regolith Electrolysis (MRE) as a viable technology for oxygen and metals production on explored planets relies on the realization of the self-heating mode for the reactor. Joule heat generated during regolith electrolysis creates thermal energy that should be able to maintain the molten phase (similar to electrolytic Hall-Heroult process for aluminum production). Self-heating via Joule heating offers many advantages: (1) The regolith itself is the crucible material, it protects the vessel walls (2) Simplifies the engineering of the reactor (3) Reduces power consumption (no external heating) (4) Extends the longevity of the reactor. Predictive modeling is a tool chosen to perform dimensional analysis of a self-heating reactor: (1) Multiphysics modeling (COMSOL) was selected for Joule heat generation and heat transfer (2) Objective is to identify critical dimensions for first reactor prototype.

  12. Mars-GRAM: Increasing the Precision of Sensitivity Studies at Large Optical Depths

    Science.gov (United States)

    Justh, Hilary L.; Justus, C. G.; Badger, Andrew M.

    2010-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM's perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). It has been discovered during the Mars Science Laboratory (MSL) site selection process that Mars-GRAM, when used for sensitivity studies for MapYear=0 and large optical depth values such as tau=3, is less than realistic. A comparison study between Mars atmospheric density estimates from Mars-GRAM and measurements by Mars Global Surveyor (MGS) has been undertaken for locations of varying latitudes, Ls, and LTST on Mars. The preliminary results from this study have validated the Thermal Emission Spectrometer (TES) limb data. From the surface to 80 km altitude, Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM). MGCM results that were used for Mars-GRAM with MapYear=0 were from a MGCM run with a fixed value of tau=3 for the entire year at all locations. This has resulted in an imprecise atmospheric density at all altitudes. To solve this pressure-density problem, density factor values were determined for tau=.3, 1 and 3 that will adjust the input values of MGCM MapYear 0 pressure and density to achieve a better match of Mars-GRAM MapYear 0 with TES observations for MapYears 1 and 2 at comparable dust loading. The addition of these density factors to Mars-GRAM will improve the results of the sensitivity studies done for large optical depths.

  13. Comparative study of the Martian suprathermal electron depletions based on Mars Global Surveyor, Mars Express, and Mars Atmosphere and Volatile EvolutioN mission observations

    Science.gov (United States)

    Steckiewicz, M.; Garnier, P.; André, N.; Mitchell, D. L.; Andersson, L.; Penou, E.; Beth, A.; Fedorov, A.; Sauvaud, J.-A.; Mazelle, C.; Brain, D. A.; Espley, J. R.; McFadden, J.; Halekas, J. S.; Larson, D. E.; Lillis, R. J.; Luhmann, J. G.; Soobiah, Y.; Jakosky, B. M.

    2017-01-01

    Nightside suprathermal electron depletions have been observed at Mars by three spacecraft to date: Mars Global Surveyor, Mars Express, and the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. This spatial and temporal diversity of measurements allows us to propose here a comprehensive view of the Martian electron depletions through the first multispacecraft study of the phenomenon. We have analyzed data recorded by the three spacecraft from 1999 to 2015 in order to better understand the distribution of the electron depletions and their creation mechanisms. Three simple criteria adapted to each mission have been implemented to identify more than 134,500 electron depletions observed between 125 and 900 km altitude. The geographical distribution maps of the electron depletions detected by the three spacecraft confirm the strong link existing between electron depletions and crustal magnetic field at altitudes greater than 170 km. At these altitudes, the distribution of electron depletions is strongly different in the two hemispheres, with a far greater chance to observe an electron depletion in the Southern Hemisphere, where the strongest crustal magnetic sources are located. However, the unique MAVEN observations reveal that below a transition region near 160-170 km altitude the distribution of electron depletions is the same in both hemispheres, with no particular dependence on crustal magnetic fields. This result supports the suggestion made by previous studies that these low-altitudes events are produced through electron absorption by atmospheric CO2.

  14. Simulation of A Main Steam Line Break Accident Using the Coupled 'System Thermal-Hydraulics, 3D reactor Kinetics, and Hot Channel' Analysis Capability of MARS 3.0

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jae Jun; Chung, Bub Dong

    2005-09-15

    For realistic analysis of thermal-hydraulics (T-H) transients in light water reactors, KAERI has developed the best-estimate T-H system code, MARS. The code has been improved from the consolidated version of the RELAP5/MOD3 and COBRA-TF codes. Then, the MARS code was coupled with a three-dimensional (3-D) reactor kinetics code, MASTER. This coupled calculation feature, in conjunction with the existing hot channel analysis capabilities of the MARS and MASTER codes, allows for more realistic simulations of nuclear system transients. In this work, a main steam line break (MSLB) accident is simulated using the coupled 'system T-H, 3-D reactor kinetics, and hot channel analysis' feature of the MARS code. Two coupled calculations are performed for demonstration. First, a coupled calculation of the 'system T-H and 3-D reactor kinetics' with a refined core T-H nodalization is carried out to obtain global core power and local departure from nucleate boiling (DNB) ratio (DNBR) behaviors. Next, for a more accurate DNBR prediction, another coupled calculation with subchannel meshes for the hot channels is performed. The results of the coupled calculations are very reasonable and consistent so that these can be used to remove the excessive conservatism in the conventional safety analysis.

  15. Studying the Mars atmosphere using a SOIR Instrument

    Science.gov (United States)

    Drummond, R.; Vandaele, A.; Daerden, F.; Neefs, E.; Mahieux, A.; Wilquet, V.; Montmessin, F.; Bertaux, J.; McConnell, J. C.; Kaminski, J. W.

    2009-05-01

    SOIR (Solar Occultation InfraRed spectrometer) is currently part of the SPICAV/SOIR instrument on board the Venus Express orbiter (VEX). SOIR, an Echelle infrared spectrometer using an acousto-optic tunable filter (AOTF) for the order selection, is probing the atmosphere by solar occultation, operating between 2.2 and 4.3 μm, with a resolution of 0.15 cm-1. This spectral range is suitable for the detection of several key components of planetary atmospheres, including H2O and its isotopologue HDO, CH4 and other trace species. The SOIR instrument was designed to have a minimum of moving parts, to be light and compact in order to fit on top of the SPICAV instrument. The AOTF allows a narrow range of wavelengths to pass, according to the radio frequency applied to the TeO2 crystal; this selects the order. The advantage of the AOTF is that different orders can be observed quickly and easily during one occultation. To obtain a compact optical scheme, a Littrow configuration was implemented in which the usual collimating and imaging lenses are merged into a single off-axis parabolic mirror. The light is diffracted on the echelle grating, where orders overlap and addition occurs, and finally is recorded by the detector. The detector is 320x256 pixels and is cooled to 88K during an occultation measurement, to maximise the signal to noise ratio. SOIR on VEX has been in orbit around Venus since April 2006, allowing us to characterise the instrument and study its performance. These data have allowed the engineering team to devise several instrumental improvements. The next step in further improving the readiness for Martian atmospheric studies comes in close collaboration with the Mars Atmospheric Modelling group at BIRA-IASB. A General Circulation Model is used to simulate the Martian atmosphere. Currently work is underway with SPICAM data to verify the GCM inputs and outputs. Later the GCM output will be used as feedback for instrumental design of both an improved version

  16. Quantitative studies of volcanic processes on Mars using data from the Mars Global Surveyor

    Science.gov (United States)

    Bishop, Louise Jane

    Volcanic processes on Mars were investigated using topographic profiles derived with the help of IDL software from data collected by the Mars Orbiter Laser Altimeter (MOLA) on the Mars Global Surveyor Mission (MGS) in 1997-2001 and images obtained by the MGS Mars Orbiter Camera (MOC) and by the earlier Viking mission. Thickness and slope values for lava flows at both Elysium Mons and Alba Patera made it possible to compute flow emplacement times and effusion rates using the flow growth model proposed by C. R. J. Kilburn and R. M. C Lopes in 1990. Geological mapping of the Elysium volcanic region showed that Elysium Mons was emplaced as a result of a single shift in vent position on top of an older volcanic edifice, here termed the Ancient Volcanic Edifice (AVE). This implies that there have been substantial variations in both position and time for the magma supply. Calculations suggest that the flows at Alba Patera were emplaced more quickly than those at Elysium Mons, possibly owing to differences in fissure width and lava composition. There is evidence for both aa and pahoehoe on the summit areas of Elysium Mons and Alba Patera. The presence of aa is consistent with the view that long lava flows on Mars are emplaced quickly. Pahoehoe flows imply slow emplacement, and their inferred presence on Mars provides support for the theory that long terrestrial lavas are often emplaced as sheets of inflated pahoehoe. MOC image analysis indicated that late-stage explosive activity has occurred at several Martian volcanoes where it was previously undetected, contrary to the prevalent view that Martian volcanism evolves from explosive to effusive activity. To resolve the many ambiguities inherent in morphological data and imagery the need remains for ground truthing by experienced observers and detailed geochemical analyses in situ or by means of a sample return mission

  17. Simulation Studies of Bipedal Walking on the Moon and Mars

    Science.gov (United States)

    Yamada, Shin; Ohshima, Hiroshi; Yamaguchi, Tomofumi; Narukawa, Terumasa; Takahashi, Masaki; Hase, Kimitaka; Liu, Meigen; Mukai, Chiaki

    In order to walk upright on the Moon or Mars without falling, a specific walking strategy to account for altered gravitational conditions must be verified. We have therefore been studying changes in the kinematics of walking at different gravitational loads using a body weight suspension system. Our simulation consisted of three gravitational conditions: 1 g (Earth); 1/3 g (Mars); and 1/6 g (the Moon). Surface EMG recordings were taken from the leg muscles of subjects walking on a treadmill. Cadence, stance phase duration, and step length were calculated from the walking velocity and steps. Subsequent experiments revealed that muscle activity and the duration of the double support phase decreased as simulated gravity was reduced. These changes are apparently caused not only by the direct effects of unloading but also by kinematic adaptations to the same. It can be said that humans walk slowly with a shortened stride and elongated stance phase in order to adjust to low gravitational conditions. One major limitation of our study that may have affected walking stability was the fact that the suspension system was fixed to an immovable frame. We have begun further studies using a newer movable body weight suspension system to achieve more realistic simulations.

  18. On use of ZPR research reactors and associated instrumentation and measurement methods for reactor physics studies

    Energy Technology Data Exchange (ETDEWEB)

    Chauvin, J.P. [CEA,DEN, DER, SPEX, Experimental Physics Service, Cadarache, F-13108 St-Paul-Lez-Durance (France); Blaise, P. [CEA, DEN, DER, SPEX Experimental Programs Laboratory, Cadarache, F-13108 St-Paul-Lez-Durance (France); Lyoussi, A. [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-Lez-Durance (France)

    2015-07-01

    The French atomic and alternative energies -CEA- is strongly involved in research and development programs concerning the use of nuclear energy as a clean and reliable source of energy and consequently is working on the present and future generation of reactors on various topics such as ageing plant management, optimization of the plutonium stockpile, waste management and innovative systems exploration. Core physics studies are an essential part of this comprehensive R and D effort. In particular, the Zero Power Reactor (ZPR) of CEA: EOLE, MINERVE and MASURCA play an important role in the validation of neutron (as well photon) physics calculation tools (codes and nuclear data). The experimental programs defined in the CEA's ZPR facilities aim at improving the calculation routes by reducing the uncertainties of the experimental databases. They also provide accurate data on innovative systems in terms of new materials (moderating and decoupling materials) and new concepts (ADS, ABWR, new MTR (e.g. JHR), GENIV) involving new fuels, absorbers and coolant materials. Conducting such interesting experimental R and D programs is based on determining and measuring main parameters of phenomena of interest to qualify calculation tools and nuclear data 'libraries'. Determining these parameters relies on the use of numerous and different experimental techniques using specific and appropriate instrumentation and detection tools. Main ZPR experimental programs at CEA, their objectives and challenges will be presented and discussed. Future development and perspectives regarding ZPR reactors and associated programs will be also presented. (authors)

  19. Parametric study of the Incompletely Stirred Reactor modeling

    Energy Technology Data Exchange (ETDEWEB)

    Mobini, K. [Department of Mechanical Engineering, Shahid Rajaee University, Lavizan, Tehran (Iran); Bilger, R.W. [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, Sydney (Australia)

    2009-09-15

    The Incompletely Stirred Reactor (ISR) is a generalization of the widely-used Perfectly Stirred Reactor (PSR) model and allows for incomplete mixing within the reactor. Its formulation is based on the Conditional Moment Closure (CMC) method. This model is applicable to nonpremixed combustion with strong recirculation such as in a gas turbine combustor primary zone. The model uses the simplifying assumptions that the conditionally-averaged reactive-scalar concentrations are independent of position in the reactor: this results in ordinary differential equations in mixture fraction space. The simplicity of the model permits the use of very complex chemical mechanisms. The effects of the detailed chemistry can be found while still including the effects of micromixing. A parametric study is performed here on an ISR for combustion of methane at overall stoichiometric conditions to investigate the sensitivity of the model to different parameters. The focus here is on emissions of nitric oxide and carbon monoxide. It is shown that the most important parameters in the ISR model are reactor residence time, the chemical mechanism and the core-averaged Probability Density Function (PDF). Using several different shapes for the core-averaged PDF, it is shown that use of a bimodal PDF with a low minimum at stoichiometric mixture fraction and a large variance leads to lower nitric oxide formation. The 'rich-plus-lean' mixing or staged combustion strategy for combustion is thus supported. (author)

  20. Plasma boundaries at Mars: a 3-D simulation study

    Directory of Open Access Journals (Sweden)

    A. Bößwetter

    2004-12-01

    Full Text Available The interaction of the solar wind with the ionosphere of planet Mars is studied using a three-dimensional hybrid model. Mars has only a weak intrinsic magnetic field, and consequently its ionosphere is directly affected by the solar wind. The gyroradii of the solar wind protons are in the range of several hundred kilometers and therefore comparable with the characteristic scales of the interaction region. Different boundaries emerge from the interaction of the solar wind with the continuously produced ionospheric heavy-ion plasma, which could be identified as a bow shock (BS, ion composition boundary (ICB and magnetic pile up boundary (MPB, where the latter both turn out to coincide. The simulation results regarding the shape and position of these boundaries are in good agreement with the measurements made by Phobos-2 and MGS spacecraft. It is shown that the positions of these boundaries depend essentially on the ionospheric production rate, the solar wind ram pressure, and the often unconsidered electron temperature of the ionospheric heavy ion plasma. Other consequences are rays of planetary plasma in the tail and heavy ion plasma clouds, which are stripped off from the dayside ICB region by some instability.

    Key words. Magnetospheric physics (solar wind interactions with unmagnetized bodies – Space plasma physics (discontinuities; numerical simulation studies

  1. Studying the effects of dynamical parameters on reactor core temperature

    Directory of Open Access Journals (Sweden)

    R Khodabakhsh

    2015-01-01

    Full Text Available In order to increase productivity, reduce depreciation, and avoid possible accidents in a system such as fuel rods' melting and overpressure, control of temperature changes in the reactor core is an important factor. There are several methods for solving and analysing the stability of point kinetics equations. In most previous analyses, the effects of various factors on the temperature of the reactor core have been ignored. In this work, the effects of various dynamical parameters on the temperature of the reactor core and stability of the system in the presence of temperature feedback reactivity with external reactivity step, ramp and sinusoidal for six groups of delayed neutrons were studied using the method of Lyapunov exponent. The results proved to be in good agreement with other works

  2. Moessbauer study of EUROFER and VVER steel reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmann, E., E-mail: kuzmann@ludens.elte.hu [Eoetvoes University, Laboratory of Nuclear Chemistry, Institute of Chemistry (Hungary); Horvath, A. [Hungarian Academy of Sciences, Centre for Energy Research (Hungary); Alves, L.; Silva, J. F.; Gomes, U.; Souza, C. [Universidade Federal do Rio Grande do Norte (University) (Brazil); Homonnay, Z. [Eoetvoes University, Laboratory of Nuclear Chemistry, Institute of Chemistry (Hungary)

    2013-04-15

    {sup 57}Fe Moessbauer spectroscopy and X-ray diffractometry were used to study EUROFER or VVER ferritic reactor steels mechanically alloyed with TaC or NbC. Significant changes were found in the Moessbauer spectra and in the corresponding hyperfine field distributions between the ball milled pure steel and that alloyed with TaC or NbC. Spectral differences were also found in the case of use of same carbides with different origin, too. The observed spectral changes as an effect of ball milling of the reactor material steels with carbides can be associated with change in short range order of the constituents of steel.

  3. Planetary Simulation Chambers bring Mars to laboratory studies

    Energy Technology Data Exchange (ETDEWEB)

    Mateo-Marti, E.

    2016-07-01

    Although space missions provide fundamental and unique knowledge for planetary exploration, they are always costly and extremely time-consuming. Due to the obvious technical and economical limitations of in-situ planetary exploration, laboratory simulations are among the most feasible research options for making advances in planetary exploration. Therefore, laboratory simulations of planetary environments are a necessary and complementary option to expensive space missions. Simulation chambers are economical, more versatile, and allow for a higher number of experiments than space missions. Laboratory-based facilities are able to mimic the conditions found in the atmospheres and on the surfaces of a majority of planetary objects. Number of relevant applications in Mars planetary exploration will be described in order to provide an understanding about the potential and flexibility of planetary simulation chambers systems: mainly, stability and presence of certain minerals on Mars surface; and microorganisms potential habitability under planetary environmental conditions would be studied. Therefore, simulation chambers will be a promising tools and necessary platform to design future planetary space mission and to validate in-situ measurements from orbital or rover observations. (Author)

  4. Astrobiology through the ages of Mars: the study of terrestrial analogues to understand the habitability of Mars.

    Science.gov (United States)

    Fairén, Alberto G; Davila, Alfonso F; Lim, Darlene; Bramall, Nathan; Bonaccorsi, Rosalba; Zavaleta, Jhony; Uceda, Esther R; Stoker, Carol; Wierzchos, Jacek; Dohm, James M; Amils, Ricardo; Andersen, Dale; McKay, Christopher P

    2010-10-01

    Mars has undergone three main climatic stages throughout its geological history, beginning with a water-rich epoch, followed by a cold and semi-arid era, and transitioning into present-day arid and very cold desert conditions. These global climatic eras also represent three different stages of planetary habitability: an early, potentially habitable stage when the basic requisites for life as we know it were present (liquid water and energy); an intermediate extreme stage, when liquid solutions became scarce or very challenging for life; and the most recent stage during which conditions on the surface have been largely uninhabitable, except perhaps in some isolated niches. Our understanding of the evolution of Mars is now sufficient to assign specific terrestrial environments to each of these periods. Through the study of Mars terrestrial analogues, we have assessed and constrained the habitability conditions for each of these stages, the geochemistry of the surface, and the likelihood for the preservation of organic and inorganic biosignatures. The study of these analog environments provides important information to better understand past and current mission results as well as to support the design and selection of instruments and the planning for future exploratory missions to Mars.

  5. Kartini Research Reactor prospective studies for neutron scattering application

    Energy Technology Data Exchange (ETDEWEB)

    Widarto [Yogyakarta Nuclear Research Center, BATAN (Indonesia)

    1999-10-01

    The Kartini Research Reactor (KRR) is located in Yogyakarta Nuclear Research Center, Yogyakarta - Indonesia. The reactor is operated for 100 kW thermal power used for research, experiments and training of nuclear technology. There are 4 beam ports and 1 column thermal are available at the reactor. Those beam ports have thermal neutron flux around 10{sup 7} n/cm{sup 2}s each other and used for sub critical assembly, neutron radiography studies and Neutron Activation Analysis (NAA). Design of neutron collimator has been done for piercing radial beam port and the calculation result of collimated neutron flux is around 10{sup 9} n/cm{sup 2}s. This paper describes experiment facilities and parameters of the Kartini research reactor, and further more the prospective studies for neutron scattering application. The purpose of this paper is to optimize in utilization of the beam ports facilities and enhance the manpower specialty. The special characteristic of the beam ports and preliminary studies, pre activities regarding with neutron scattering studies for KKR is presented. (author)

  6. Magnetic enzyme reactors for isolation and study of heterogeneous glycoproteins

    Energy Technology Data Exchange (ETDEWEB)

    Korecka, Lucie [Department of Analytical Chemistry, University of Pardubice, Namesti Cs. Legii 565, 532 10 Pardubice (Czech Republic)]. E-mail: lucie.korecka@upce.cz; Jezova, Jana [Department of Analytical Chemistry, University of Pardubice, Namesti Cs. Legii 565, 532 10 Pardubice (Czech Republic); Bilkova, Zuzana [Department of Biological and Biochemical Sciences, University of Pardubice, Namesti Cs. Legii 565, 532 10 Pardubice (Czech Republic); Benes, Milan [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovskeho Namesti 2, 162 06 Prague (Czech Republic); Horak, Daniel [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovskeho Namesti 2, 162 06 Prague (Czech Republic); Hradcova, Olga [Department of Biological and Biochemical Sciences, University of Pardubice, Namesti Cs. Legii 565, 532 10 Pardubice (Czech Republic); Slovakova, Marcela [Department of Biological and Biochemical Sciences, University of Pardubice, Namesti Cs. Legii 565, 532 10 Pardubice (Czech Republic); Laboratoire Physicochimie Curie, UMR 168 CNRS/Institute Curie, Paris Cedex 05 (France); Viovy, Jean-Louis [Laboratoire Physicochimie Curie, UMR 168 CNRS/Institute Curie, Paris Cedex 05 (France)

    2005-05-15

    The newly developed magnetic micro- and nanoparticles with defined hydrophobicity and porosity were used for the preparation of magnetic enzyme reactors. Magnetic particles with immobilized proteolytic enzymes trypsin, chymotrypsin and papain and with enzyme neuraminidase were used to study the structure of heterogeneous glycoproteins. Factors such as the type of carrier, immobilization procedure, operational and storage stability, and experimental conditions were optimized.

  7. Numerical study of the effects of lamp configuration and reactor wall roughness in an open channel water disinfection UV reactor.

    Science.gov (United States)

    Sultan, Tipu

    2016-07-01

    This article describes the assessment of a numerical procedure used to determine the UV lamp configuration and surface roughness effects on an open channel water disinfection UV reactor. The performance of the open channel water disinfection UV reactor was numerically analyzed on the basis of the performance indictor reduction equivalent dose (RED). The RED values were calculated as a function of the Reynolds number to monitor the performance. The flow through the open channel UV reactor was modelled using a k-ε model with scalable wall function, a discrete ordinate (DO) model for fluence rate calculation, a volume of fluid (VOF) model to locate the unknown free surface, a discrete phase model (DPM) to track the pathogen transport, and a modified law of the wall to incorporate the reactor wall roughness effects. The performance analysis was carried out using commercial CFD software (ANSYS Fluent 15.0). Four case studies were analyzed based on open channel UV reactor type (horizontal and vertical) and lamp configuration (parallel and staggered). The results show that lamp configuration can play an important role in the performance of an open channel water disinfection UV reactor. The effects of the reactor wall roughness were Reynolds number dependent. The proposed methodology is useful for performance optimization of an open channel water disinfection UV reactor.

  8. Preliminary Study of Lead-Oxide Cooled Fast Reactor with Natural Uranium as an Input Fuel with Reactor Shuffling Strategy

    Science.gov (United States)

    Mahmudah, Rida SN; Su’ud, Zaki

    2017-01-01

    A preliminary study of lead-oxide cooled fast reactor with natural uranium as an input fuel using reactor shuffling strategy has been conducted. In this study, reactor core is divided into four zone with the same volume, each zone use different uranium enrichment. The enrichment number is estimated so that in the end of reactor’s operation, we only need to add natural uranium as the fresh input fuel. This study used UN-PuN as the fuel and lead oxide as the coolant. Several parameter studies have been conducted to determine the most suitable input condition. It is confirmed in this study that with fuel : cladding : coolant ratio of 53 : 10 : 37, and uranium enrichment in the first to the fourth zone of 0%, 6.25%, 7.5% and 8%, respectively, the reactor can operate as long as 20 years of operation with terminal k-eff of 1.0004.

  9. Yale High Energy Physics Research: Precision Studies of Reactor Antineutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Heeger, Karsten M. [Yale Univ., New Haven, CT (United States)

    2014-09-13

    This report presents experimental research at the intensity frontier of particle physics with particular focus on the study of reactor antineutrinos and the precision measurement of neutrino oscillations. The experimental neutrino physics group of Professor Heeger and Senior Scientist Band at Yale University has had leading responsibilities in the construction and operation of the Daya Bay Reactor Antineutrino Experiment and made critical contributions to the discovery of non-zero$\\theta_{13}$. Heeger and Band led the Daya Bay detector management team and are now overseeing the operations of the antineutrino detectors. Postdoctoral researchers and students in this group have made leading contributions to the Daya Bay analysis including the prediction of the reactor antineutrino flux and spectrum, the analysis of the oscillation signal, and the precision determination of the target mass yielding unprecedented precision in the relative detector uncertainty. Heeger's group is now leading an R\\&D effort towards a short-baseline oscillation experiment, called PROSPECT, at a US research reactor and the development of antineutrino detectors with advanced background discrimination.

  10. A comparative study of S/MAR prediction tools

    Directory of Open Access Journals (Sweden)

    Koentges Georgy

    2007-03-01

    Full Text Available Abstract Background S/MARs are regions of the DNA that are attached to the nuclear matrix. These regions are known to affect substantially the expression of genes. The computer prediction of S/MARs is a highly significant task which could contribute to our understanding of chromatin organisation in eukaryotic cells, the number and distribution of boundary elements, and the understanding of gene regulation in eukaryotic cells. However, while a number of S/MAR predictors have been proposed, their accuracy has so far not come under scrutiny. Results We have selected S/MARs with sufficient experimental evidence and used these to evaluate existing methods of S/MAR prediction. Our main results are: 1. all existing methods have little predictive power, 2. a simple rule based on AT-percentage is generally competitive with other methods, 3. in practice, the different methods will usually identify different sub-sequences as S/MARs, 4. more research on the H-Rule would be valuable. Conclusion A new insight is needed to design a method which will predict S/MARs well. Our data, including the control data, has been deposited as additional material and this may help later researchers test new predictors.

  11. Improving Mars-GRAM: Increasing the Accuracy of Sensitivity Studies at Large Optical Depths

    Science.gov (United States)

    Justh, Hilary L.; Justus, C. G.; Badger, Andrew M.

    2010-01-01

    Extensively utilized for numerous mission applications, the Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model. In a Monte-Carlo mode, Mars-GRAM's perturbation modeling capability is used to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). Mars-GRAM has been found to be inexact when used during the Mars Science Laboratory (MSL) site selection process for sensitivity studies for MapYear=0 and large optical depth values such as tau=3. Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM) from the surface to 80 km altitude. Mars-GRAM with the MapYear parameter set to 0 utilizes results from a MGCM run with a fixed value of tau=3 at all locations for the entire year. Imprecise atmospheric density and pressure at all altitudes is a consequence of this use of MGCM with tau=3. Density factor values have been determined for tau=0.3, 1 and 3 as a preliminary fix to this pressure-density problem. These factors adjust the input values of MGCM MapYear 0 pressure and density to achieve a better match of Mars-GRAM MapYear 0 with Thermal Emission Spectrometer (TES) observations for MapYears 1 and 2 at comparable dust loading. These density factors are fixed values for all latitudes and Ls and are included in Mars-GRAM Release 1.3. Work currently being done, to derive better multipliers by including variations with latitude and/or Ls by comparison of MapYear 0 output directly against TES limb data, will be highlighted in the presentation. The TES limb data utilized in this process has been validated by a comparison study between Mars atmospheric density estimates from Mars-GRAM and measurements by Mars Global Surveyor (MGS). This comparison study was undertaken for locations on Mars of varying latitudes, Ls, and LTST. The more precise density factors will be included in Mars-GRAM 2005 Release 1.4 and thus improve the results of future sensitivity studies done for large

  12. Study of counter current flow limitation model of MARS-KS and SPACE codes under Dukler's air/water flooding test conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Woong; Kim, Min Gil; Lee, Jeong Ik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Bang, Young Seok [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-10-15

    In particular, CCFL(the counter current flow limitation) occurs in components such as hot leg, downcomer annulus and steam generator inlet plenum during LOCA which is possible to have flows in two opposite directions. Therefore, CCFL is one of the thermal-hydraulic models which has significant effect on the reactor safety analysis code performance. In this study, the CCFL model will be evaluated with MARS-KS based on two-phase two-field governing equations and SPACE code based on two-phase three-field governing equations. This study will be conducted by comparing MARS-KS code which is being used for evaluating the safety of a Korean Nuclear Power Plant and SPACE code which is currently under assessment for evaluating the safety of the designed nuclear power plant. In this study, comparison of the results of liquid upflow and liquid downflow rate for different gas flow rate from two code to the famous Dukler's CCFL experimental data are presented. This study will be helpful to understand the difference between system analysis codes with different governing equations, models and correlations, and further improving the accuracy of system analysis codes. In the nuclear reactor system, CCFL is an important phenomenon for evaluating the safety of nuclear reactors. This is because CCFL phenomenon can limit injection of ECCS water when CCFL occurs in components such as hot leg, downcomer annulus or steam generator inlet plenum during LOCA which is possible to flow in two opposite directions. Therefore, CCFL is one of the thermal-hydraulic models which has significant effect on the reactor safety analysis code performance. In this study, the CCFL model was evaluated with MARS-KS and SPACE codes for studying the difference between system analysis codes with different governing equations, models and correlations. This study was conducted by comparing MARS-KS and SPACE code results of liquid upflow and liquid downflow rate for different gas flow rate to the famous Dukler

  13. Numerical study of the effects of surface roughness on water disinfection UV reactor.

    Science.gov (United States)

    Sultan, Tipu; Ahmad, Sarfraz; Cho, Jinsoo

    2016-04-01

    UV reactors are an emerging choice as a big barrier against the pathogens present in drinking water. However, the precise role of reactor's wall roughness for cross flow ultraviolet (CF-UV) and axial flow ultraviolet (AF-UV) water disinfection reactors are unknown. In this paper, the influences of reactor's wall roughness were investigated with a view to identify their role on the performance factors namely dose distribution and reduction equivalent dose (RED). Herein, the relative effects of reactor's wall roughness on the performance of CF-UV and AF-UV reactors were also highlighted. This numerical study is a first step towards the comprehensive analysis of the effects of reactor's wall roughness for UV reactor. A numerical analysis was performed using ANSYS Fluent 15 academic version. The reactor's wall roughness has a significant effect on the RED. We found that the increase in RED is Reynolds number dependent (at lower value of turbulent Reynolds number the effects are remarkable). The effects of reactor's roughness were more pronounced for AF-UV reactor. The simulation results suggest that the study of reactor's wall roughness provides valuable insight to fully understand the effects of reactor's wall roughness and its impact on the flow behavior and other features of CF-UV and AF-UV water disinfection reactors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Mars ISRU for Production of Mission Critical Consumables - Options, Recent Studies, and Current State of the Art

    Science.gov (United States)

    Sanders, G. B.; Paz, A.; Oryshchyn, L.; Araghi, K.; Muscatello, A.; Linne, D.; Kleinhenz, J.; Peters, T.

    2015-01-01

    In 1978, a ground breaking paper titled, "Feasibility of Rocket Propellant Production on Mars" by Ash, Dowler, and Varsi discussed how ascent propellants could be manufactured on the Mars surface from carbon dioxide collected from the atmosphere to reduce launch mass. Since then, the concept of making mission critical consumables such as propellants, fuel cell reactants, and life support consumables from local resources, commonly known as In-Situ Resource Utilization (ISRU), for robotic and human missions to Mars has been studied many times. In the late 1990's, NASA initiated a series of Mars Human Design Reference Missions (DRMs), the first of which was released in 1997. These studies primarily focused on evaluating the impact of making propellants on Mars for crew ascent to Mars orbit, but creating large caches of life support consumables (water & oxygen) as a backup for regenerative life support systems for long-duration surface stays (>500 days) was also considered in Mars DRM 3.0. Until science data from the Mars Odyssey orbiter and subsequent robotic missions revealed that water may be widely accessable across the surface of Mars, prior Mars ISRU studies were limited to processing Mars atmospheric resources (carbon dioxide, nitrogen, argon, oxygen, and water vapor). In December 2007, NASA completed the Mars Human Design Reference Architecture (DRA) 5.0 study which considered water on Mars as a potential resource for the first time in a human mission architecture. While knowledge of both water resources on Mars and the hardware required to excavate and extract the water were very preliminary, the study concluded that a significant reduction in mass and significant enhancements to the mission architecture were possible if Mars water resources were utilized. Two subsequent Mars ISRU studies aimed at reexamining ISRU technologies, processing options, and advancements in the state-of-the-art since 2007 and to better understand the volume and packaging associated

  15. Strategies to Improve the Accuracy of Mars-GRAM Sensitivity Studies at Large Optical Depths

    Science.gov (United States)

    Justh, Hilary L.; Justus, Carl G.; Badger, Andrew M.

    2009-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM s perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). It has been discovered during the Mars Science Laboratory (MSL) site selection process that Mars-GRAM when used for sensitivity studies for MapYear=0 and large optical depth values such as tau=3 is less than realistic. A comparison study between Mars atmospheric density estimates from Mars- GRAM and measurements by Mars Global Surveyor (MGS) has been undertaken for locations of varying latitudes, Ls, and LTST on Mars. The preliminary results from this study have validated the Thermal Emission Spectrometer (TES) limb data. From the surface to 80 km altitude, Mars- GRAM is based on the NASA Ames Mars General Circulation Model (MGCM). MGCM results that were used for Mars-GRAM with MapYear=0 were from a MGCM run with a fixed value of tau=3 for the entire year at all locations. Unrealistic energy absorption by uniform atmospheric dust leads to an unrealistic thermal energy balance on the polar caps. The outcome is an inaccurate cycle of condensation/sublimation of the polar caps and, as a consequence, an inaccurate cycle of total atmospheric mass and global-average surface pressure. Under an assumption of unchanged temperature profile and hydrostatic equilibrium, a given percentage change in surface pressure would produce a corresponding percentage change in density at all altitudes. Consequently, the final result of a change in surface pressure is an imprecise atmospheric density at all altitudes. To solve this pressure-density problem, a density factor value was determined for tau=.3, 1 and 3 that will adjust the input values of MGCM MapYear 0 pressure and density to achieve a better match of Mars-GRAM MapYear=0 with MapYears 1 and 2 MGCM output

  16. Study the Expression of marA Gene in Ciprofloxacin and Tetracycline Resistant Mutants of Esherichia coli.

    Science.gov (United States)

    Pourahmad Jaktaji, Razieh; Ebadi, Rayhaneh

    2013-01-01

    MarA activates two membrane dependent mechanisms of resistance to different antibiotics, such as ciprofloxacin and tetracycline, including promotion of outflux and inhibition of influx of antibiotics. Thus, MarA causes multiple antibiotic resistance phenotype. The activation of these mechanisms needs overexpression of marA. This could happen through mutation in marR. Thus, the aim of this study was to measure marA expression in ciprofloxacin resistant E. coli gyrA mutants and clones with or without marR mutation. For this purpose, real time PCR was used to measure relative expression of marA in above mutants and clones. Results showed that two clones, C14 and C17 overexpressed marA. It is concluded that the level of marA expression is important for activation of above mechanisms.

  17. Study of Natural Convection Passive Cooling System for Nuclear Reactors

    Science.gov (United States)

    Abdillah, Habibi; Saputra, Geby; Novitrian; Permana, Sidik

    2017-07-01

    Fukushima nuclear reactor accident occurred due to the reactor cooling pumps and followed by all emergencies cooling systems could not work. Therefore, the system which has a passive safety system that rely on natural laws such as natural convection passive cooling system. In natural convection, the cooling material can flow due to the different density of the material due to the temperature difference. To analyze such investigation, a simple apparatus was set up and explains the study of natural convection in a vertical closed-loop system. It was set up that, in the closed loop, there is a heater at the bottom which is representing heat source system from the reactor core and cooler at the top which is showing the cooling system performance in room temperature to make a temperature difference for convection process. The study aims to find some loop configurations and some natural convection performances that can produce an optimum flow of cooling process. The study was done and focused on experimental approach and simulation. The obtained results are showing and analyzing in temperature profile data and the speed of coolant flow at some point on the closed-loop system.

  18. Systems study of tokamak fusion--fission reactors

    Energy Technology Data Exchange (ETDEWEB)

    Tenney, F.H.; Bathke, C.G.; Price, W.G. Jr.; Bohlke, W.H.; Mills, R.G.; Johnson, E.F.; Todd, A.M.M.; Buchanan, C.H.; Gralnick, S.L.

    1978-11-01

    This publication reports the results of a two to three year effort at a systematic analysis of a wide variety of tokamak-driven fissioning blanket reactors, i.e., fusion--fission hybrids. It addresses the quantitative problems of determining the economically most desirable mix of the two products: electric power and fissionable fuel and shows how the price of electric power can be minimized when subject to a variety of constraints. An attempt has been made to avoid restricting assumptions, and the result is an optimizing algorithm that operates in a six-dimensional parameter space. Comparisons are made on sets of as many as 100,000 distinct machine models, and the principal results of the study have been derived from the examination of several hundred thousand possible reactor configurations.

  19. Study on core design for reduced-moderation water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Okubo, Tsutomu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-12-01

    The Reduced-Moderation Water Reactor (RMWR) is a water-cooled reactor with the harder neutron spectrum comparing with the LWR, resulting from low neutron moderation due to reduced water volume fraction. Based on the difference from the spectrum from the LWR, the conversion from U-238 to Pu-239 is promoted and the new cores preferable to effective utilization of uranium resource can be possible Design study of the RMWR core started in 1997 and new four core concepts (three BWR cores and one PWR core) are recently evaluated in terms of control rod worths, plutonium multiple recycle, high burnup and void coefficient. Comparative evaluations show needed incorporation of control rod programming and simplified PUREX process as well as development of new fuel cans for high burnup of 100 GW-d/t. Final choice of design specifications will be made at the next step aiming at realization of the RMWR. (T. Tanaka)

  20. Propulsion engineering study for small-scale Mars missions

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, J.

    1995-09-12

    Rocket propulsion options for small-scale Mars missions are presented and compared, particularly for the terminal landing maneuver and for sample return. Mars landing has a low propulsive {Delta}v requirement on a {approximately}1-minute time scale, but at a high acceleration. High thrust/weight liquid rocket technologies, or advanced pulse-capable solids, developed during the past decade for missile defense, are therefore more appropriate for small Mars landers than are conventional space propulsion technologies. The advanced liquid systems are characterize by compact lightweight thrusters having high chamber pressures and short lifetimes. Blowdown or regulated pressure-fed operation can satisfy the Mars landing requirement, but hardware mass can be reduced by using pumps. Aggressive terminal landing propulsion designs can enable post-landing hop maneuvers for some surface mobility. The Mars sample return mission requires a small high performance launcher having either solid motors or miniature pump-fed engines. Terminal propulsion for 100 kg Mars landers is within the realm of flight-proven thruster designs, but custom tankage is desirable. Landers on a 10 kg scale also are feasible, using technology that has been demonstrated but not previously flown in space. The number of sources and the selection of components are extremely limited on this smallest scale, so some customized hardware is required. A key characteristic of kilogram-scale propulsion is that gas jets are much lighter than liquid thrusters for reaction control. The mass and volume of tanks for inert gas can be eliminated by systems which generate gas as needed from a liquid or a solid, but these have virtually no space flight history. Mars return propulsion is a major engineering challenge; earth launch is the only previously-solved propulsion problem requiring similar or greater performance.

  1. Updating Mars-GRAM to Increase the Accuracy of Sensitivity Studies at Large Optical Depths

    Science.gov (United States)

    Justh, Hiliary L.; Justus, C. G.; Badger, Andrew M.

    2010-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM s perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). During the Mars Science Laboratory (MSL) site selection process, it was discovered that Mars-GRAM, when used for sensitivity studies for MapYear=0 and large optical depth values such as tau=3, is less than realistic. From the surface to 80 km altitude, Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM). MGCM results that were used for Mars-GRAM with MapYear set to 0 were from a MGCM run with a fixed value of tau=3 for the entire year at all locations. This has resulted in an imprecise atmospheric density at all altitudes. As a preliminary fix to this pressure-density problem, density factor values were determined for tau=0.3, 1 and 3 that will adjust the input values of MGCM MapYear 0 pressure and density to achieve a better match of Mars-GRAM MapYear 0 with Thermal Emission Spectrometer (TES) observations for MapYears 1 and 2 at comparable dust loading. Currently, these density factors are fixed values for all latitudes and Ls. Results will be presented from work being done to derive better multipliers by including variation with latitude and/or Ls by comparison of MapYear 0 output directly against TES limb data. The addition of these more precise density factors to Mars-GRAM 2005 Release 1.4 will improve the results of the sensitivity studies done for large optical depths.

  2. A design study of reactor core optimization for direct nuclear heat-to-electricity conversion in a space power reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Hidekazu; Takahashi, Makoto; Shimoda, Hiroshi; Takeoka, Satoshi [Kyoto Univ. (Japan); Nakagawa, Masayuki; Kugo, Teruhiko

    1998-01-01

    To propose a new design concept of a nuclear reactor used in the space, research has been conducted on the conceptual design of a new nuclear reactor on the basis of the following three main concepts: (1) Thermionic generation by thermionic fuel elements (TFE), (2) reactivity control by rotary reflector, and (3) reactor cooling by liquid metal. The outcomes of the research are: (1) A calculation algorithm was derived for obtaining convergent conditions by repeating nuclear characteristic calculation and thermal flow characteristic calculation for the space nuclear reactor. (2) Use of this algorithm and the parametric study established that a space nuclear reactor using 97% enriched uranium nitride as the fuel and lithium as the coolant and having a core with a radius of about 25 cm, a height of about 50 cm and a generation efficiency of about 7% can probably be operated continuously for at least more than ten years at 100 kW only by reactivity control by rotary reflector. (3) A new CAD/CAE system was developed to assist design work to optimize the core characteristics of the space nuclear reactor comprehensively. It is composed of the integrated design support system VINDS using virtual reality and the distributed system WINDS to collaboratively support design work using Internet. (N.H.)

  3. Study on Modeling Technology in Digital Reactor System

    Institute of Scientific and Technical Information of China (English)

    刘晓平; 罗月童; 童莉莉

    2004-01-01

    Modeling is the kernel part of a digital reactor system. As an extensible platform for reactor conceptual design, it is very important to study modeling technology and develop some kind of tools to speed up preparation of all classical computing models. This paper introduces the background of the project and basic conception of digital reactor. MCAM is taken as an example for modeling and its related technologies used are given. It is an interface program for MCNP geometry model developed by FDS team (ASIPP & HUT), and designed to run on windows system. MCAM aims at utilizing CAD technology to facilitate creation of MCNP geometry model. There have been two ways for MCAM to utilize CAD technology:(1) Making use of user interface technology in aid of generation of MCNP geometry model;(2) Making use of existing 3D CAD model to accelerate creation of MCNP geometry model. This paper gives an overview of MCAM's major function. At last, several examples are given to demonstrate MCAM's various capabilities.

  4. Flow Reactor Studies with Nanosecond Pulsed Discharges at Atmospheric Pressure and Higher

    Science.gov (United States)

    2013-10-01

    Image of Discharge Reactor with Viewport Inlet Cap • Modular plasma discharge reactor can be interchanged with redesigned pressure shell to perform...Flow Reactor Studies with Nanosecond Pulsed Discharges at Atmospheric Pressure and Higher Nicholas Tsolas, Kuni Togai and Richard Yetter...Department of Mechanical and Nuclear Engineering The Pennsylvania State University University Park, PA, 16801 Fourth Annual Review Meeting of the

  5. Water on Mars: A status report and suggestions for further study

    Science.gov (United States)

    Rummel, John; McKay, Christopher P.

    2016-07-01

    The most recent MEPAG review of Mars Special Regions (Rummel et al., 2014) contained the following statement, "Mars' average atmospheric pressure allows for liquid water when it exceeds that of the triple point of water, and at lower altitudes (e.g., Hellas and Argyre Basins) that is commonly the case. Higher temperatures and/or insolation may allow melting or condensation over limited areas for short time periods." Nonetheless, the US National Academies - European Science Foundation review of the MEPAG report disagreed with a preliminary statement regarding the potential for snow fallen on Mars to melt, and thus stated that, "The review committee asserts that pure liquid water simply cannot exist on Mars because the atmosphere is too dry to allow it. The partial pressure of atmospheric water vapor is typically less than 1 Pa near the surface of Mars, whereas the partial pressure of water vapor at the triple point of water is about 600 Pa." This paper will address the discrepancies between what the MEPAG paper actually asserted, and the validity of the arguments in each report and in the literature for and against liquid water on Mars - whether salty or pure (as the Mars-driven snow). Refs: Committee to Review the MEPAG Report on Mars Special Regions; Space Studies Board; The [US] National Academies of Sciences, Engineering, and Medicine; European Space Sciences Committee; European Science Foundation. (2015). Review of the MEPAG Report on Mars Special Regions. National Academy Press, Washington, DC. Rummel, J. D., Beaty, D. W., Jones, M. A., Bakermans, C., Barlow, N. G., Boston, P. J., ... & Wray, J. J. (2014). A New Analysis of Mars "Special Regions": Findings of the Second MEPAG Special Regions Science Analysis Group (SR-SAG2). Astrobiology, 14, 887-968.

  6. The study meeting report on the undermoderated spectrum reactor

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Nobuya; Ochiai, Masaaki [eds.

    1998-09-01

    The interest to the high converter or in the breeder is rising as the research and the development of the light water-type nuclear reactor in future. A study session about the undermoderated spectrum reactor of the Japan Atomic Energy Research Institute (JAERI) sponsorship was held in March, 1998 4, on the 5th. This report is the contents of the study session. The study session began with the basis lecture to entitle to be `The expectations to the undermoderated core study` almost. Next, the review of the high conversion-type core study about PWR and BWR was reported. As the undermoderated spectrum MOX core study, the latest situation of (1) the development of the supercritical pressure water reactor, (2) the development of RBWR, (3) the development of the advanced fuel cycle by BWR and (4) the development of the pressurized water-type breeder were reported from the university and the maker. As also the study present situation and the plan in future in JAERI, there was an explanation about the design study of the undermoderated spectrum core and the actinide research facility. The panel discussion lastly, to entitle to be `Undermoderated MOX core research and development of the future and the technical issues` was done. There was an opinion about the way of carrying forward concerned research and development, the acceptability of the society, the view of the future, the cooperation of the electric power or the desire to JAERI and there was wide inquiry replying. The 9 of the presented papers are indexed individually. (J.P.N.)

  7. RBS and NRA studies in Zr-alloy reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    Laursen, T. (Queen' s Univ., Kingston, ON (Canada)); Palmer, G.R. (Queen' s Univ., Kingston, ON (Canada)); Elmoselhi, M.B. (Ontario Hydro Research, Toronto, ON (Canada)); Leger, M. (Ontario Hydro Research, Toronto, ON (Canada)); Shek, G. (Ontario Hydro Research, Toronto, ON (Canada)); Warr, B.D. (Ontario Hydro Research, Toronto, ON (Canada)); Hood, G.M. (AECL, Chalk River, ON (Canada)); Tapping, R.L. (AECL, Chalk River, ON (Canada))

    1993-06-01

    Rutherford backscattering and nuclear reaction analysis have been used to address a range of materials science problems associated with the Zr-alloy pressure tubes used in the Canadian CANDU (CANada Deuterium Uranium) nuclear reactors. Pressure-tube corrosion in D[sub 2]O, resulting in oxidation and deuterium ingress, is studied by measuring oxygen and deuterium concentration vs depth profiles. Hydrogen embrittlement, caused by D diffusion and formation of deuterided regions, is studied by D profiling. Irradiation creep of pressure tubes involves Zr self-diffusion. Studies of substitutional diffusion of Hf in Zr-alloys using RBS have allowed diffusion coefficients to be measured and probable diffusion mechanisms identified. (orig.)

  8. Study on the License Requirements for the SRO/RO of the Kijang Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Subeom; Shin, Taemyung [Korea Nat. University of Transportation, Seoul (Korea, Republic of); Chae, H. T.; Ahn, G. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, S. J.; Gam, S. C. [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2016-10-15

    The purpose of the study is to propose an appropriate regulatory position for the Kijang reactor operator license requirement by the review of the applicability and compatibility of HANARO SRO/RO license holders for Kijang reactor operation. As the area using radioactive isotope became gradually enlarged both inside and outside of the country, the Kijang research reactor is planned and now under construction next to the HANARO research reactor now being operated in Taejon. In this paper, therefore, an establishment of revised operator license system is discussed for the new research reactor. The design and operation characteristics of the two (HANARO and Kijang) reactors are concluded to be very similar to each other, however, there still exist slight differences in some minor portions. It is recommendable to allow an independent license for each reactor if two reactors of the same power level have recognizable differences in the design and operation characteristics.

  9. Emotional energy, work self-efficacy, and perceived similarity during the Mars 520 study

    OpenAIRE

    Šolcová, I. (Iva); Gushin, V. (1); Vinokhodova, A.; Lukavský, J. (Jiří)

    2013-01-01

    The objective of the present research was to study the dynamics of changes in emotional energy, work self-efficacy, and perceived similarity in the crew of the Mars 520 experimental study that simulated traveling to Mars, orbiting it, landing, and returning to Earth. The study comprised six volunteers, all men, between 27–38 yr of age. During the simulation, measures of emotional energy, work self-efficacy, and perceived similarity were repeated every month. Emotional energy, work self-effica...

  10. Oak Ridge Tokamak experimental power reactor study scoping report

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, M.

    1977-03-01

    This report presents the scoping studies performed as the initial part of the program to produce a conceptual design for a Tokamak Experimental Power Reactor (EPR). The EPR as considered in this study is to employ all systems necessary for significant electric power production at continuous high duty cycle operation; it is presently scheduled to be the final technological step before a Demonstration Reactor Plant (Demo). The scoping study tasks begin with an exploration and identification of principal problem areas and then concentrate on consideration and evaluation of alternate design choices for each of the following major systems: Plasma Engineering and Physics, Nuclear, Electromagnetics, Neutral Beam Injection, and Tritium Handling. In addition, consideration has been given to the integration of these systems and requirements arising out of their incorporation into an EPR. One intent of this study is to document the paths explored in search of the appropriate EPR characteristics. To satisfy this intent, the explorations are presented in chart form outlining possible options in key areas with extensive supporting footnotes. An important result of the scoping study has been the development and definition of an EPR reference design to serve as (1) a common focus for the continuing design study and (2) a guide for associated development programs. In addition, the study has identified research and development requirements essential to facilitate the successful conceptual design, construction, and operation of an EPR.

  11. Hydrodynamic Studies on a Trickle Bed Reactor for Foaming Liquids

    Directory of Open Access Journals (Sweden)

    Ajay Bansal

    2010-10-01

    Full Text Available Hydrodynamic studies of trickle bed reactors (TBRs are essential for the design and prediction of their performance. The hydrodynamic characteristics involving pressure drop and dynamic liquid saturation are greatly affected by the physical properties of the liquids. In the present study experiments have been carried out in a concurrent downflow air - liquid trickle bed reactor to investigate the dynamic liquid saturation and pressure drop for the water (non-foaming and 3% polyethylene glycol and 4% polyethylene glycol foaming liquids in the gas continuous regime (GCF and foaming pulsing regime (FP. In the GCF regime the dynamic liquid saturation was found to increase with increase in liquid flow rate for non-foaming and foaming liquids. While for 3% and 4% polyethylene glycol solutions the severe foaming was observed in the high interaction regime and the regime is referred to as foaming pulsing (FP regime. The decrease in dynamic liquid saturation followed by a sharp rise in the pressure drop was observed during transition from gas GCF to FP regime. However in the FP regime, a dip in the dynamic liquid saturation was observed. The pressure drop for foaming liquids is observed to be manifolds higher compared to non-foaming liquid in the GCF regime. ©2010 BCREC UNDIP. All rights reserved(Received: 16th January 2010, Revised: 10th February 2010, Accepted: 21st Feberuary 2010[How to Cite: R. Gupta, A. Bansal. (2010. Hydrodynamic Studies on a Trickle Bed Reactor for Foaming Liquids. Bulletin of Chemical Reaction Engineering & Catalysis, 5 (1: 31-37. doi:10.9767/bcrec.5.1.775.31-37][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.5.1.775.31-37 ][Cited by: Scopus 1 |

  12. Hydrodynamic Studies on a Trickle Bed Reactor for Foaming Liquids

    Directory of Open Access Journals (Sweden)

    Renu Gupta

    2010-10-01

    Full Text Available Hydrodynamic studies of trickle bed reactors (TBRs are essential for the design and prediction of their performance. The hydrodynamic characteristics involving pressure drop and dynamic liquid saturation are greatly affected by the physical properties of the liquids. In the present study experiments have been carried out in a concurrent downflow air - liquid trickle bed reactor to investigate the dynamic liquid saturation and pressure drop for the water (non-foaming and 3% polyethylene glycol and 4% polyethylene glycol foaming liquids in the gas continuous regime (GCF and foaming pulsing regime (FP. In the GCF regime the dynamic liquid saturation was found to increase with increase in liquid flow rate for non-foaming and foaming liquids. While for 3% and 4% polyethylene glycol solutions the severe foaming was observed in the high interaction regime and the regime is referred to as foaming pulsing (FP regime. The decrease in dynamic liquid saturation followed by a sharp rise in the pressure drop was observed during transition from gas GCF to FP regime. However in the FP regime, a dip in the dynamic liquid saturation was observed. The pressure drop for foaming liquids is observed to be manifolds higher compared to non-foaming liquid in the GCF regime. ©2010 BCREC UNDIP. All rights reserved(Received: 16th January 2010, Revised: 10th February 2010, Accepted: 21st Feberuary 2010[How to Cite: R. Gupta, A. Bansal. (2010. Hydrodynamic Studies on a Trickle Bed Reactor for Foaming Liquids. Bulletin of Chemical Reaction Engineering & Catalysis, 5 (1: 31-37. doi:10.9767/bcrec.5.1.7127.31-37][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.5.1.7127.31-37 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/7127][Cited by: Scopus 1 | ] 

  13. Joint KAERI/VAEC pre-possibility study on a new research reactor for Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    Park, Cheol; Lee, B. C.; Chae, H. T.; Kim, H.; Lee, C. S.; Choi, C. O.; Jun, B. J. [KAERI, Taejon (Korea, Republic of); Vien, Luong Ba; Dien, Nguyen Nhi [Vietnam Atomic Energy Commission, Hanoi (Viet Nam)

    2004-05-01

    Based on the agreement on the technical cooperation for nuclear technology between Korea and Vietnam, a KAERI/VAEC joint study on the pre-possibility of a new research reactor for Vietnam has been carried out in the research reactor area from Nov. 2003 to May 2004. In this report, the results of the pre-possibility study on a new research reactor are described. The report presents the necessity of a new research reactor in Vietnam, and the desired performance requirements of the new research reactor if necessary. The major design characteristics of some existing research reactors and those under planning were also reviewed and the main characteristics which should be considered in selecting a new multipurpose research reactor for Vietnam were drawn. Some recommendations on the considerations for the next step of the feasibility study such as the project formulation, manpower requirements and international co-operation were also briefly touched upon.

  14. Conceptual design study of a scyllac fusion test reactor

    Energy Technology Data Exchange (ETDEWEB)

    Thomassen, K.I. (comp.)

    1975-07-01

    The report describes a conceptual design study of a fusion test reactor based on the Scyllac toroidal theta-pinch approach to fusion. It is not the first attempt to describe the physics and technology required for demonstrating scientific feasibility of the approach, but it is the most complete design in the sense that the physics necessary to achieve the device goals is extrapolated from experimentally tested MHD theories of toroidal systems,and it uses technological systems whose engineering performance has been carefully calculated to ensure that they meet the machine requirements.

  15. Transverse flow reactor studies of the dynamics of radical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Macdonald, R.G. [Argonne National Laboratory, IL (United States)

    1993-12-01

    Radical reactions are in important in combustion chemistry; however, little state-specific information is available for these reactions. A new apparatus has been constructed to measure the dynamics of radical reactions. The unique feature of this apparatus is a transverse flow reactor in which an atom or radical of known concentration will be produced by pulsed laser photolysis of an appropriate precursor molecule. The time dependence of individual quantum states or products and/or reactants will be followed by rapid infrared laser absorption spectroscopy. The reaction H + O{sub 2} {yields} OH + O will be studied.

  16. Neutronic study of a nuclear reactor of fused salts; Estudio neutronico de un reactor nuclear de sales fundidas

    Energy Technology Data Exchange (ETDEWEB)

    Garcia B, F. B.; Francois L, J. L., E-mail: faviolabelen@gmail.com [UNAM, Facultad de Ingenieria, Departamento de Sistemas Energeticos, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2012-10-15

    The reactors of fused salts called Molten Salt Reactor have presented a resurgence of interest in the last decade, due to they have a versatility in particular to operate, either with a thermal or fast neutrons spectrum. The most active development was by the middle of 1950 and principles of 1970 in the Oak Ridge National Laboratory. In this work some developed models are presented particularly and studied with the help of the MCNPX code, for the development of the neutronic study of this reactor, starting of proposed models and from a simple and homogeneous geometry until other more complex models and approximate to more real cases. In particular the geometry conditions and criticality of each model were analyzed, the isotopic balance, as well as the concentrations of the salts and different assigned fuel types. (Author)

  17. Studies of fragileness in steels of vessels of BWR reactors; Estudios de fragilizacion en aceros de vasija de reactores BWR

    Energy Technology Data Exchange (ETDEWEB)

    Robles, E.F.; Balcazar, M.; Alpizar, A.M.; Calderon, B.E. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    The structural materials with those that are manufactured the pressure vessels of the BWR reactors, suffer degradation in its mechanical properties mainly to the damage taken place by the fast neutrons (E > 1 MeV) coming from the reactor core. Its are experimentally studied those mechanisms of neutron damage in this material type, by means of the irradiation of steel vessel in experimental reactors to age them quickly. Alternatively it is simulated the neutron damage by means of irradiation of steel with heavy ions. In this work those are shown first results of the damage induced by irradiation from a similar steel to the vessel of a BWR reactor. The irradiation was carried out with fast neutrons (E > 1 MeV, fluence of 1.45 x 10{sup 18} n/cm{sup 2}) in the TRIGA MARK lll reactor and separately with Ni{sup +3} ions in a Tandetrom accelerator, E = 4.8 MeV and range of the ionic flow of 0.1 to 53 iones/A{sup 2}. (Author)

  18. Aging study of boiling water reactor high pressure injection systems

    Energy Technology Data Exchange (ETDEWEB)

    Conley, D.A.; Edson, J.L.; Fineman, C.F. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)

    1995-03-01

    The purpose of high pressure injection systems is to maintain an adequate coolant level in reactor pressure vessels, so that the fuel cladding temperature does not exceed 1,200{degrees}C (2,200{degrees}F), and to permit plant shutdown during a variety of design basis loss-of-coolant accidents. This report presents the results of a study on aging performed for high pressure injection systems of boiling water reactor plants in the United States. The purpose of the study was to identify and evaluate the effects of aging and the effectiveness of testing and maintenance in detecting and mitigating aging degradation. Guidelines from the United States Nuclear Regulatory Commission`s Nuclear Plant Aging Research Program were used in performing the aging study. Review and analysis of the failures reported in databases such as Nuclear Power Experience, Licensee Event Reports, and the Nuclear Plant Reliability Data System, along with plant-specific maintenance records databases, are included in this report to provide the information required to identify aging stressors, failure modes, and failure causes. Several probabilistic risk assessments were reviewed to identify risk-significant components in high pressure injection systems. Testing, maintenance, specific safety issues, and codes and standards are also discussed.

  19. Feasibility study on small modular reactors for modern microgrids

    Energy Technology Data Exchange (ETDEWEB)

    Islam, R.; Gabbar, H.A., E-mail: hossam.gabbar@uoit.ca [Univ. of Ontario Inst. of Technology, Faculty of Energy Systems and Nuclear Science, Oshawa, Ontario (Canada)

    2013-07-01

    Microgrid is a solution of conventional power grid problem and offer sustainable decentralized power system. Microgrid with modern distributed energy resources (DER) could play an important role to alleviate dependency on the main electricity grid. Distributed energy resource comprises wind turbine, solar photovoltaic, diesel generator, gas engine, micro turbine, fuel cells, etc.Due to the gap between typical loads and supply within microgrid, larger scale energy generation could provide a possible solution to balance power demand and supply. Feasibility study of Small Nuclear Power Plant, such as Small Modular reactor (SMR), within microgrids could be achieved via different cases. To achieve the target, a comprehensive feasibility study is conducted on microgrid with SMR through electricity generation profiles, geographical and environmental assessment, as well as cost analysis using simulation practices and data analysis.Also potency of SMRs is analyzed. Parameters and Key Performance Indicators (KPIs) could be analyzed to achieve feasible solution of microgrids with small modular reactor (SMR) to improve the overall microgrid performance.The study shows that SMR could be a feasible solution if microgrid parameters are selected properly. (author)

  20. Astrobiology in the Field: Studying Mars by Analogue Expeditions on Earth

    Science.gov (United States)

    Conrad, Pamela G.

    2011-01-01

    We will present a strategy for how one prepares to engage in fieldwork on another planets by practicing in analogous environments on the Earth, including at Mono Lake. As an example, we will address the problem of how to study the habitability of an environment when you have no idea what kind of life might be there to exploit it. This will all be related to the upcoming launch of the Mars Science Laboratory to Mars in late November this year.

  1. A brief history of design studies on innovative nuclear reactors

    Science.gov (United States)

    Sekimoto, Hiroshi

    2014-09-01

    In a short period after the success of CP1, many types of nuclear reactors were proposed and investigated. However, soon only a small number of reactors were selected for practical use. Around 1970, only LWRs with small number of CANDUs were operated in the western world, and FBRs were under development. It was about the time when Apollo moon landing was accomplished. However, at the same time, the future of human being was widely considered pessimistic and Limits to Growth was published. In the end of 1970's the TMI accident occurred and many nuclear reactor contracts were cancelled in USA and any more contracts had not been concluded until recent years. From the reflection of this accident, many Inherent Safe Reactors (ISRs) were proposed, though none of them were constructed. A common idea of ISRs is smallness of their size. Tokyo Institute of Technology (TokyoTech) held a symposium on small reactors, SR/TIT, in 1991, where many types of small ISRs were presented. Recently small reactors attract interest again. The most ideas employed in these reactors were the same discussed in SR/TIT. In 1980's the radioactive wastes from fuel cycle became a severe problem around the world. In TokyoTech, this issue was discussed mainly from the viewpoint of nuclear transmutations. The neutron economy became inevitable for these innovative nuclear reactors especially small long-life reactors and transmutation reactors.

  2. A brief history of design studies on innovative nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Sekimoto, Hiroshi, E-mail: hsekimot@gmail.com [Emeritus Professor, Tokyo Institute of Technology (Japan)

    2014-09-30

    In a short period after the success of CP1, many types of nuclear reactors were proposed and investigated. However, soon only a small number of reactors were selected for practical use. Around 1970, only LWRs with small number of CANDUs were operated in the western world, and FBRs were under development. It was about the time when Apollo moon landing was accomplished. However, at the same time, the future of human being was widely considered pessimistic and Limits to Growth was published. In the end of 1970’s the TMI accident occurred and many nuclear reactor contracts were cancelled in USA and any more contracts had not been concluded until recent years. From the reflection of this accident, many Inherent Safe Reactors (ISRs) were proposed, though none of them were constructed. A common idea of ISRs is smallness of their size. Tokyo Institute of Technology (TokyoTech) held a symposium on small reactors, SR/TIT, in 1991, where many types of small ISRs were presented. Recently small reactors attract interest again. The most ideas employed in these reactors were the same discussed in SR/TIT. In 1980’s the radioactive wastes from fuel cycle became a severe problem around the world. In TokyoTech, this issue was discussed mainly from the viewpoint of nuclear transmutations. The neutron economy became inevitable for these innovative nuclear reactors especially small long-life reactors and transmutation reactors.

  3. Study for improvement of performance of the test and research reactors

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, Fumio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1999-03-01

    Current utilization needs for the test and research reactors become more advanced and diversified along with the advance of nuclear science and technology. Besides, the requested safety for the research and test reactors grows strictly every year as well as a case of the power reactors. Under this circumstance, every effort to improve reactor performance including its safety is necessary to be sustained for allowing more effective utilization of the test and research reactors as experimental apparatus for advanced researches. In this study, the following three themes i.e., JMTR high-performance fuel element, evaluation method of fast neutron irradiation dose in the JMTR, evaluation method of performance of siphon break valve as core covering system for water-cooled test and research reactors, were investigated respectively from the views of improvement of core performance as a neutron source, utilization performance as an experimental apparatus, and safety as a reactor plant. (author)

  4. Airborne Radar Study of Mars Analogs in the Southwestern United States

    Science.gov (United States)

    Greeley, R.; Doggett, T. C.; Davies, A. G.; Baker, V.; Dohm, J.; Ferre, P. A.; Hinnell, A.; Rucker, D.; Roden, J.; Stough, T.

    2003-01-01

    The search for surface and near-surface liquid water on Mars is a central part of current and planned future exploration, which include radar sounders on Mars Express and MRO and proposed synthetic aperture radar (SAR) imagers. In order to penetrate sand and dust cover, these systems are proposed for longer wavelengths (e.g, from [2]: 24 cm / L-band and 74 cm / P-band) than those considered optimal for the detection of soil moisture (6 cm / C-band). However, there has been some success in detecting soil moisture at longer wavelengths. Given the size and mass constraints for Mars missions, the optimization of radar instrument parameters for meeting science objectives, such as searching for liquid water, is essential. In this on-going study, we are using repeat coverage of Mars analog sites with multifrequency (C, L and P band) airborne radar and ground truth soil sample data to assess the detectability of soil moisture.

  5. Pressurized-water reactor internals aging degradation study. Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Luk, K.H. [Oak Ridge National Lab., TN (United States)

    1993-09-01

    This report documents the results of a Phase I study on the effects of aging degradations on pr internals. Primary stressers for internals an generated by the primary coolant flow in the they include unsteady hydrodynamic forces and pump-generated pressure pulsations. Other stressors are applied loads, manufacturing processes, impurities in the coolant and exposures to fast neutron fluxes. A survey of reported aging-related failure information indicates that fatigue, stress corrosion cracking (SCC) and mechanical wear are the three major aging-related degradation mechanisms for PWR internals. Significant reported failures include thermal shield flow-induced vibration problems, SCC in guide tube support pins and core support structure bolts, fatigue-induced core baffle water-jet impingement problems and excess wear in flux thimbles. Many of the reported problems have been resolved by accepted engineering practices. Uncertainties remain in the assessment of long-term neutron irradiation effects and environmental factors in high-cycle fatigue failures. Reactor internals are examined by visual inspections and the technique is access limited. Improved inspection methods, especially one with an early failure detection capability, can enhance the safety and efficiency of reactor operations.

  6. Boiling-Water Reactor internals aging degradation study. Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Luk, K.H. [Oak Ridge National Lab., TN (United States)

    1993-09-01

    This report documents the results of an aging assessment study for boiling water reactor (BWR) internals. Major stressors for BWR internals are related to unsteady hydrodynamic forces generated by the primary coolant flow in the reactor vessel. Welding and cold-working, dissolved oxygen and impurities in the coolant, applied loads and exposures to fast neutron fluxes are other important stressors. Based on results of a component failure information survey, stress corrosion cracking (SCC) and fatigue are identified as the two major aging-related degradation mechanisms for BWR internals. Significant reported failures include SCC in jet-pump holddown beams, in-core neutron flux monitor dry tubes and core spray spargers. Fatigue failures were detected in feedwater spargers. The implementation of a plant Hydrogen Water Chemistry (HWC) program is considered as a promising method for controlling SCC problems in BWR. More operating data are needed to evaluate its effectiveness for internal components. Long-term fast neutron irradiation effects and high-cycle fatigue in a corrosive environment are uncertainty factors in the aging assessment process. BWR internals are examined by visual inspections and the method is access limited. The presence of a large water gap and an absence of ex-core neutron flux monitors may handicap the use of advanced inspection methods, such as neutron noise vibration measurements, for BWR.

  7. Study of the Total Electron Content in Mars ionosphere from MARSIS data set

    Science.gov (United States)

    Bergeot, Nicolas; Witasse, Olivier; Kofman, Wlodek; Grima, Cyril; Mouginot, Jeremie; Peter, Kerstin; Pätzold, Martin; Dehant, Véronique

    2016-04-01

    Centimeter level accuracy on the signal delay will be required on X-band radio link for future Mars landers such as InSIGHT, aiming at better determining the interior structure of Mars. One of the main error sources in the estimated signal delay is directly linked to the Total Electron Content (TEC) values at Earth and Mars ionosphere level. While the Earth ionosphere is now well modeled and monitored at regional and global scales, this is not the case concerning the Mars' upper atmosphere. The present paper aims at establishing the basis to model the climatological behavior of the TEC on a global scale in the Mars' ionosphere. For that we analyzed ˜8.5 years of data (mid-2005 to 2014) of the vertical Total Electron Content (vTEC) expressed in TEC units (1 TECu = 1016e-.m-2) from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) radar. Our study takes advantage of the double data set of EUV solar index and Mars vTEC data to develop an empirical Model of Mars Ionosphere (MoMo). The finality of this model is to predict the vTEC at a given latitude, solar zenith angle and season taking only F10.7P solar index as input. To minimize the differences during the least-square adjustment between the modeled and observed vTEC, we considered (1) a 4th-order polynomial function to describe the vTEC diurnal behavior (2) a discretization with respect to Mars seasons (depending on Ls) and (3) two latitudinal sectors (North and South hemispheres). The mean of the differences between the model and the observations is 0.00±0.07 TECu with an error of the model around 0.1 TECu depending on the Solar Zenith Angle (SZA), season and hemisphere of interest (e.g. rms 0.12 TECu for SZA equal to 50°±5° in the Northern hemisphere during the spring season). Additionally, comparison with 250 Mars Express radio occultation data shows differences with MoMo predictions of 0.02±0.06 TECu for solar zenith angles below 50 degrees. Using the model we (1) highlighted

  8. Pico de Orizaba as an analogue to study planetary ecosynthesis on Mars

    Science.gov (United States)

    Navarro-González, R.

    2010-03-01

    Studies of Mars by spacecrafts, landers and rovers have indicated that it was once a wetter, more habitable world than the cold desert planet of today. If water was once stable as a liquid on the surface and flowed in such vast quantities, then the atmosphere must have been denser and the climate warmer in the past. The same processes that led to the origin of life on Earth may have occurred simultaneously on Mars, and living organisms may have colonized the planet. It is unclear how or when Mars lost its thicker atmosphere and as a result lost its habitable environment. The Viking landers of the mid-1970s carried experiments designed to detect the presence of extant life and showed the martian soil to be lifeless on the surface. Future space missions will continue to explore if there was or still is life on Mars, perhaps in the subsurface. However, if there is no life on Mars, there is an opportunity to explore the potential for survival and biological evolution for terrestrial life beyond their place of origin, and do planetary ecosynthesis on Mars, a process of making the planet habitable for terrestrial organisms. The evidence that Mars was once habitable is important for planetary ecosynthesis as it provides a proof in principle that Mars can support a habitable state on timescales that, while short over the age of the solar system, are long in human terms. Artificial greenhouse gases, such as perfluorocarbons, appear to be the best method for warming Mars and increase its atmospheric density so that liquid water becomes stable. The process of introducing terrestrial ecosystems to Mars can be compared with a descent down a high mountain. Each drop in elevation results in a warmer, wetter climate and more diverse biological community. This is shown in Pico de Orizaba which is located at 19.03°N, 97.27°W and rises 5,636 meters above sea level. It is the highest mountain in Mexico, the third highest in the tropics after Mount Kilimanjaro (5,892) in Tanzania and

  9. A large-scale validation study of the Medication Adherence Rating Scale (MARS).

    Science.gov (United States)

    Fialko, Laura; Garety, Philippa A; Kuipers, Elizabeth; Dunn, Graham; Bebbington, Paul E; Fowler, David; Freeman, Daniel

    2008-03-01

    Adherence to medication is an important predictor of illness course and outcome in psychosis. The Medication Adherence Rating Scale (MARS) is a ten-item self-report measure of medication adherence in psychosis [Thompson, K., Kulkarni, J., Sergejew, A.A., 2000. Reliability and validity of a new Medication Adherence Rating Scale (MARS) for the psychoses. Schizophrenia Research. 42. 241-247]. Although initial results suggested that the scale has good reliability and validity, the development sample was small. The current study aimed to establish the psychometric properties of the MARS in a sample over four times larger. The scale was administered to 277 individuals with psychosis, along with measures of insight and psychopathology. Medication adherence was independently rated by each individual's keyworker. Results showed the internal consistency of the MARS to be lower than in the original sample, though adequate. MARS total score correlated weakly with keyworker-rated adherence, hence concurrent validity of the scale appeared only moderate to weak. The three factor structure of the MARS was replicated. Examination of the factor scores suggested that the factor 1 total score, which corresponds to the Medication Adherence Questionnaire [Morisky,D.E., Green,L.W. and Levine,D.M., 1986. Concurrent and predictive validity of a self-reported measure of medication adherence. Medical Care. 24, 67-74] may be a preferable measure of medication adherence behaviour to the total scale score.

  10. Radiation Hydrodynamic Parameter Study of Inertial Fusion Energy Reactor Chambers

    Science.gov (United States)

    Sacks, Ryan; Moses, Gregory

    2014-10-01

    Inertial fusion energy reactors present great promise for the future as they are capable of providing baseline power with no carbon footprint. Simulation work regarding the chamber response and first wall insult is performed with the 1-D radiation hydrodynamics code BUCKY. Simulation with differing chamber parameters are implemented to study the effect of gas fill, gas mixtures and chamber radii. Xenon and argon gases are of particular interest as shielding for the first wall due to their high opacity values and ready availability. Mixing of the two gases is an attempt to engineer a gas cocktail to provide the maximum amount of shielding with the least amount of cost. A parameter study of different chamber radii shows a consistent relationship with that of first wall temperature (~1/r2) and overpressure (~1/r3). This work is performed under collaboration with Lawrence Livermore National Laboratory.

  11. A study on the fault diagnostic techniques for reactor internal structures using neutron noise analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Ryong; Jeong, Seong Ho; Park, Jin Ho; Park, Jin Suk [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-08-01

    The unfavorable phenomena, such as flow induced vibration and aging process in reactor internals, cause degradation of structural integrity and may result in loosing some mechanical binding components which might impact other equipments and components or cause flow blockage. Since these malfunctions and potential failures change reactor noise signal, it is necessary to analyze reactor noise signal for early fault diagnosis in the point of few of safety and plant economics. The objectives of this study are to establish fault diagnostic and TS(thermal shield), and to develop a data acquisition and signal processing software system. In the first year of this study, an analysis technique for the reactor internal vibration using the reactor noise was proposed. With the technique proposed and the reactor noise signals (ex-core neutron and acceleration), the dynamic characteristics of Ulchin-1 reactor internals were obtained, and compared with those of Tricastin-1 which is the prototype of Ulchin-1. In the second year, a PC-based expert system for reactor internals fault diagnosis is developed, which included data acquisition, signal processing, feature extraction function, and represented diagnostic knowledge by the IF-THEN rule. To know the effect of the faults, the reactor internals of Ulchin-1 is modeled using FEM and simulated with an artificial defect given in the hold-down spring. Trend in the dynamic characteristics of reactor internals is also observed during one fuel cycle to know the effect of boron concentration. 100 figs, 7 tabs, 18 refs. (Author).

  12. Glacial and Periglacial Chemical Weathering on Mars: New Results and New Questions from Field Analog Studies and Mars Remote Sensing

    Science.gov (United States)

    Horgan, B.; Scudder, N.; Rutledge, A.; Ackiss, S.

    2016-09-01

    Ice has been a powerful physical weather agent on Mars through geologic time, however, it is less well understood how much chemical weathering ice has caused on Mars, and how the mode of alteration has changed with the climate over time.

  13. Mars Pathfinder

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    First of NASA's Discovery missions. Launched in December 1996 and arrived at Mars on 4 July 1997. Mainly intended as a technology demonstration mission. Used airbags to cushion the landing on Mars. The Carl Sagan Memorial station returned images of an ancient flood plain in Ares Vallis. The 10 kg Sojourner rover used an x-ray spectrometer to study the composition of rocks and travelled about 100 ...

  14. Magnetic Fustion Reactor Design Studies Program final report, 1 July 1986--30 September 1986

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1986-09-30

    This report presents progress reported during the period, 7/1/86 - 9/30/86 for the Technical Support Services (TSS) for the Magnetic Fusion Reactor Design Studies Program. Tasks reported include: systems studies work plan, normalization of reactor design studies, interpretation of design study activities, research and development plan, conference support, and reports generated.

  15. Study of reactor plant disturbed cooling condition modes caused by the VVER reactor secondary circuit

    Directory of Open Access Journals (Sweden)

    V.I. Belozerov

    2016-12-01

    Based on the RELAP-5, TRAC, and TRACE software codes, reactor plant cooling condition malfunction modes caused by the VVER-1000 secondary circuit were simulated and investigated. Experimental data on the mode with the turbine-generator stop valve closing are presented. The obtained dependences made it possible to determine the maximum values of pressure and temperature in the circulation circuit as well as estimate the Minimum Critical Heat Flux Ratio (MCHFR. It has been found that, if any of the initial events occurs, safety systems are activated according to the set points; transient processes are stabilized in time; and the Critical Heat Flux (CHF limit is provided. Therefore, in the event of emergency associated with the considered modes, the reactor plant safety will be ensured.

  16. Exploring Mars

    Science.gov (United States)

    Breuil, Stéphanie

    2016-04-01

    Mars is our neighbour planet and has always fascinated humans as it has been seen as a potential abode for life. Knowledge about Mars is huge and was constructed step by step through numerous missions. It could be difficult to describe these missions, the associated technology, the results, the questions they raise, that's why an activity is proposed, that directly interests students. Their production is presented in the poster. Step 1: The main Mars feature and the first Mars explorations using telescope are presented to students. It should be really interesting to present "Mars Canals" from Percival Lowell as it should also warn students against flawed interpretation. Moreover, this study has raised the big question about extra-terrestrial life on Mars for the first time. Using Google Mars is then a good way to show the huge knowledge we have on the planet and to introduce modern missions. Step 2: Students have to choose and describe one of the Mars mission from ESA and NASA. They should work in pairs. Web sites from ESA and NASA are available and the teacher makes sure the main missions will be studied. Step 3: Students have to collect different pieces of information about the mission - When? Which technology? What were the main results? What type of questions does it raise? They prepare an oral presentation in the form they want (role play, academic presentation, using a poster, PowerPoint). They also have to produce playing cards about the mission that could be put on a timeline. Step 4: As a conclusion, the different cards concerning different missions are mixed. Groups of students receive cards and they have to put them on a timeline as fast as possible. It is also possible to play the game "timeline".

  17. Reactor Technology Options Study for Near-Term Deployment of GNEP Grid-Appropriate Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ingersoll, Daniel T [ORNL; Poore III, Willis P [ORNL

    2007-09-01

    World energy demand is projected to significantly increase over the coming decades. The International Energy Agency projects that electricity demand will increase 50% by 2015 and double by 2030, with most of the increase coming in developing countries as they experience double-digit rates of economic growth and seek to improve their standards of living. Energy is the necessary driver for human development, and the demand for energy in these countries will be met using whatever production technologies are available. Recognizing this inevitable energy demand and its implications for the United States, the U.S. National Security Strategy has proposed the Global Nuclear Energy Partnership (GNEP) to work with other nations to develop and deploy advanced nuclear recycling and reactor technologies. This initiative will help provide reliable, emission-free energy with less of the waste burden of older technologies and without making available separated plutonium that could be used by rogue states or terrorists for nuclear weapons. These new technologies will make possible a dramatic expansion of safe, clean nuclear energy to help meet the growing global energy demand. In other words, GNEP seeks to create an international regime to support large-scale growth in the worldwide use of nuclear energy without increasing the risk of nuclear weapon proliferation. This global expansion of nuclear power is strategically important to the United States for several reasons, including the following: (1) National security, by reducing the competition and potential for conflict over increasingly scarce fossil energy resources; (2) Economic security, by helping maintain stable prices for nonrenewable resources such as oil, gas, and coal; (3) Environmental security, by replacing or off-setting large-scale burning of greenhouse gas-emitting fuels for electricity production; and (4) Regaining technical leadership, through deployment of innovative U.S. technology-based reactors. Fully meeting

  18. A study of reactor monitoring method with neural network

    Energy Technology Data Exchange (ETDEWEB)

    Nabeshima, Kunihiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    The purpose of this study is to investigate the methodology of Nuclear Power Plant (NPP) monitoring with neural networks, which create the plant models by the learning of the past normal operation patterns. The concept of this method is to detect the symptom of small anomalies by monitoring the deviations between the process signals measured from an actual plant and corresponding output signals from the neural network model, which might not be equal if the abnormal operational patterns are presented to the input of the neural network. Auto-associative network, which has same output as inputs, can detect an kind of anomaly condition by using normal operation data only. The monitoring tests of the feedforward neural network with adaptive learning were performed using the PWR plant simulator by which many kinds of anomaly conditions can be easily simulated. The adaptively trained feedforward network could follow the actual plant dynamics and the changes of plant condition, and then find most of the anomalies much earlier than the conventional alarm system during steady state and transient operations. Then the off-line and on-line test results during one year operation at the actual NPP (PWR) showed that the neural network could detect several small anomalies which the operators or the conventional alarm system didn't noticed. Furthermore, the sensitivity analysis suggests that the plant models by neural networks are appropriate. Finally, the simulation results show that the recurrent neural network with feedback connections could successfully model the slow behavior of the reactor dynamics without adaptive learning. Therefore, the recurrent neural network with adaptive learning will be the best choice for the actual reactor monitoring system. (author)

  19. Preliminary design study of the Tandem Mirror Reactor (TMR)

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R.W.; Barr, W.L.; Carlson, G.A.

    1978-07-15

    This report describes work done in Fiscal Year 1977 by the Fusion Reactor Studies Group of LLL on the conceptual design of a 1000-MW(e) Tandem Mirror Reactor (TMR). The high Q (defined as the ratio of fusion power to injection power) predicted for the TMR (approximately 5) reduces the recirculating power to a nondominant problem and results in an attractive mirror fusion power plant. The fusion plasma of the TMR is contained in the 100-m-long central cell where the magnetic field strength is a modest 2 T. The blanket for neutron energy recovery and tritium breeding is cylindrical and, along with the solenoidal magnet, is divided into 3-m-long modules to facilitate maintenance. The central cell is fueled (but not heated) by the injection of low-energy neutral beams near its ends. Thus, the central cell is simple and of low technology. The end-cell plasmas must be of high density and high energy in order to plug and heat (via the electrons) the central-cell plasma. The present conceptual design uses 1.2-MeV neutral-beam injection for the end plugs and a cryogenic-aluminum, Yin-Yang magnet that produces an incremental field of about 1 T over a field of 16 T produced by a pair of Nb/sub 3/Sn superconducting solenoids. Important design problems remain in both the neutral-beam injector and in the end-plug magnet. Also remaining are important physics questions such as alpha-beam particle transport and end-plug stability. These questions are discussed at length in the report and suggestions for future work are given.

  20. Total absorption spectroscopy study of $^{92}$Rb decay: a major contributor to reactor antineutrino flux

    CERN Document Server

    Zakari-Issoufou, A -A; Porta, A; Algora, A; Tain, J L; Valencia, E; Rice, S; Bui, V M; Cormon, S; Estienne, M; Agramunt, J; Äystö, J; Bowry, M; Briz, J A; Caballero-Folch, R; Cano-Ott, D; Cucoanes, A; Elomaa, V -V; Eronen, T; Estévez, E; Farrelly, G F; Garcia, A R; Gelletly, W; Gomez-Hornillos, M B; Gorlychev, V; Hakala, J; Jokinen, A; Jordan, M D; Kankainen, A; Karvonen, P; Kolhinen, V S; Kondev, F G; Martinez, T; Mendoza, E; Molina, F; Moore, I; Perez, A; Podolyák, Zs; Penttilä, H; Regan, P H; Reponen, M; Rissanen, J; Rubio, B; Shiba, T; Sonzogni, A A; Weber, C

    2015-01-01

    The antineutrino spectra measured in recent experiments at reactors are inconsistent with calculations based on the conversion of integral beta spectra recorded at the ILL reactor. $^{92}$Rb makes the dominant contribution to the reactor spectrum in the 5-8 MeV range but its decay properties are in question. We have studied $^{92}$Rb decay with total absorption spectroscopy. Previously unobserved beta feeding was seen in the 4.5-5.5 region and the GS to GS feeding was found to be 87.5(25)%. The impact on the reactor antineutrino spectra calculated with the summation method is shown and discussed.

  1. Total Absorption Spectroscopy Study of 92Rb Decay: A Major Contributor to Reactor Antineutrino Spectrum Shape

    Science.gov (United States)

    Zakari-Issoufou, A.-A.; Fallot, M.; Porta, A.; Algora, A.; Tain, J. L.; Valencia, E.; Rice, S.; Bui, V. M.; Cormon, S.; Estienne, M.; Agramunt, J.; ńystö, J.; Bowry, M.; Briz, J. A.; Caballero-Folch, R.; Cano-Ott, D.; Cucoanes, A.; Elomaa, V.-V.; Eronen, T.; Estévez, E.; Farrelly, G. F.; Garcia, A. R.; Gelletly, W.; Gomez-Hornillos, M. B.; Gorlychev, V.; Hakala, J.; Jokinen, A.; Jordan, M. D.; Kankainen, A.; Karvonen, P.; Kolhinen, V. S.; Kondev, F. G.; Martinez, T.; Mendoza, E.; Molina, F.; Moore, I.; Perez-Cerdán, A. B.; Podolyák, Zs.; Penttilä, H.; Regan, P. H.; Reponen, M.; Rissanen, J.; Rubio, B.; Shiba, T.; Sonzogni, A. A.; Weber, C.

    2015-09-01

    The antineutrino spectra measured in recent experiments at reactors are inconsistent with calculations based on the conversion of integral beta spectra recorded at the ILL reactor. 92Rb makes the dominant contribution to the reactor antineutrino spectrum in the 5-8 MeV range but its decay properties are in question. We have studied 92Rb decay with total absorption spectroscopy. Previously unobserved beta feeding was seen in the 4.5-5.5 region and the GS to GS feeding was found to be 87.5(25)%. The impact on the reactor antineutrino spectra calculated with the summation method is shown and discussed.

  2. Preliminary study on aerobic granular biomass formation with aerobic continuous flow reactor

    Science.gov (United States)

    Yulianto, Andik; Soewondo, Prayatni; Handajani, Marissa; Ariesyady, Herto Dwi

    2017-03-01

    A paradigm shift in waste processing is done to obtain additional benefits from treated wastewater. By using the appropriate processing, wastewater can be turned into a resource. The use of aerobic granular biomass (AGB) can be used for such purposes, particularly for the processing of nutrients in wastewater. During this time, the use of AGB for processing nutrients more reactors based on a Sequencing Batch Reactor (SBR). Studies on the use of SBR Reactor for AGB demonstrate satisfactory performance in both formation and use. SBR reactor with AGB also has been applied on a full scale. However, the use use of SBR reactor still posses some problems, such as the need for additional buffer tank and the change of operation mode from conventional activated sludge to SBR. This gives room for further reactor research with the use of a different type, one of which is a continuous reactor. The purpose of this study is to compare AGB formation using continuous reactor and SBR with same operation parameter. Operation parameter are Organic Loading Rate (OLR) set to 2,5 Kg COD/m3.day with acetate as substrate, aeration rate 3 L/min, and microorganism from Hospital WWTP as microbial source. SBR use two column reactor with volumes 2 m3, and continuous reactor uses continuous airlift reactor, with two compartments and working volume of 5 L. Results from preliminary research shows that although the optimum results are not yet obtained, AGB can be formed on the continuous reactor. When compared with AGB generated by SBR, then the characteristics of granular diameter showed similarities, while the sedimentation rate and Sludge Volume Index (SVI) characteristics showed lower yields.

  3. Study of phyllosilicates and carbonates from the Capri Chasma region of Valles Marineris on Mars based on Mars Reconnaissance Orbiter-Compact Reconnaissance Imaging Spectrometer for Mars (MRO-CRISM) observations

    Science.gov (United States)

    Jain, Nirmala; Chauhan, Prakash

    2015-04-01

    Spectral reflectance data from the MRO-CRISM (Mars Reconnaissance Orbiter-Compact Reconnaissance Imaging Spectrometer for Mars) of Capri Chasma, a large canyon within Valles Marineris on Mars, have been studied. Results of this analysis reveal the presence of minerals, such as, phyllosilicates (illite, smectite (montmorillonite)) and carbonates (ankerite and manganocalcite). These minerals hint of the aqueous history of Noachian time on Mars. Phyllosilicates are products of chemical weathering of igneous rocks, whereas carbonates could have formed from local aqueous alteration of olivine and other igneous minerals. Four different locations within the Capri Chasma region were studied for spectral reflectance based mineral detection. The study area also shows the spectral signatures of iron-bearing minerals, e.g. olivine with carbonate, indicating partial weathering of parent rocks primarily rich in ferrous mineral. The present study shows that the minerals of Capri Chasma are characterized by the presence of prominent spectral absorption features at 2.31 μm, 2.33 μm, 2.22 μm, 2.48 μm and 2.52 μm wavelength regions, indicating the existence of hydrous minerals, i.e., carbonates and phyllosilicates. The occurrence of carbonates and phyllosilicates in the study area suggests the presence of alkaline environment during the period of their formation. Results of the study are important to understand the formation processes of these mineral assemblages on Mars, which may help in understanding the evolutionary history of the planet.

  4. High-Temperature Water-Gas Shift Membrane Reactor Study

    Energy Technology Data Exchange (ETDEWEB)

    Ciocco, M.V.; Iyoha, O.; Enick, R.M.; Killmeyer, R.P.

    2007-06-01

    NETL’s Office of Research and Development is exploring the integration of membrane reactors into coal gasification plants as a way of increasing efficiency and reducing costs. Water-Gas Shift Reaction experiments were conducted in membrane reactors at conditions similar to those encountered at the outlet of a coal gasifier. The changes in reactant conversion and product selectivity due to the removal of hydrogen via the membrane reactor were quantified. Research was conducted to determine the influence of residence time and H2S on CO conversion in both Pd and Pd80wt%Cu membrane reactors. Effects of the hydrogen sulfide-to-hydrogen ratio on palladium and a palladium-copper alloy at high-temperature were also investigated. These results were compared to thermodynamic calculations for the stability of palladium sulfides.

  5. A study on naphtha catalytic reforming reactor simulation and analysis

    OpenAIRE

    Liang, Ke-min; Guo, Hai-Yan; Pan, Shi-Wei

    2005-01-01

    A naphtha catalytic reforming unit with four reactors in series is analyzed. A physical model is proposed to describe the catalytic reforming radial flow reactor. Kinetics and thermodynamics equations are selected to describe the naphtha catalytic reforming reactions characteristics based on idealizing the complex naphtha mixture by representing the paraffin, naphthene, and aromatic groups by single compounds. The simulation results based above models agree very well with actual operation uni...

  6. A study on naphtha catalytic reforming reactor simulation and analysis.

    Science.gov (United States)

    Liang, Ke-min; Guo, Hai-yan; Pan, Shi-wei

    2005-06-01

    A naphtha catalytic reforming unit with four reactors in series is analyzed. A physical model is proposed to describe the catalytic reforming radial flow reactor. Kinetics and thermodynamics equations are selected to describe the naphtha catalytic reforming reactions characteristics based on idealizing the complex naphtha mixture by representing the paraffin, naphthene, and aromatic groups by single compounds. The simulation results based above models agree very well with actual operation unit data.

  7. Study and Analysis on Naphtha Catalytic Reforming Reactor Simulation

    Institute of Scientific and Technical Information of China (English)

    Liang Ke min; Song Yongji; Pan Shiwei

    2004-01-01

    A naphtha catalytic reforming unit with four reactors connected in series is analyzed. A physical model is proposed to describe the catalytic reforming radial flow reactor. Kinetics and thermodynamics equations are selected to describe the naphtha catalytic reforming reaction characteristics based on idealizing the complex naphtha mixture to represent the paraffin, naphthene, and aromatic groups with individual compounds. The simulation results based on above models agree very well with actual operating data of process unit.

  8. A study on naphtha catalytic reforming reactor simulation and analysis

    Institute of Scientific and Technical Information of China (English)

    LIANG Ke-min; GUO Hai-yan; PAN Shi-wei

    2005-01-01

    A naphtha catalytic reforming unit with four reactors in series is analyzed. A physical model is proposed to describe the catalytic reforming radial flow reactor. Kinetics and thermodynamics equations are selected to describe the naphtha catalytic reforming reactions characteristics based on idealizing the complex naphtha mixture by representing the paraffin, naphthene, and aromatic groups by single compounds. The simulation results based above models agree very well with actual operation unit data.

  9. The Mars-500 crew in daily life activities: An ethological study

    Science.gov (United States)

    Tafforin, Carole

    2013-10-01

    A Mars mission is a new challenge for scientific investigators in the space field. What would be the behavioral profile of an interplanetary crew with long-duration social isolation and spatial restriction? The current study addresses this question with the first ethological data from the Mars-500 experiment. It took place in Moscow, Russia from June 3, 2010 to November 4, 2011. It was designed to simulate the living and working conditions of an isolated and confined crew over 250 days for reaching Mars, 30 days for Mars orbiting with Mars landing and 240 days for returning to Earth. The Mars-500 crew was composed of three Russians, two Europeans and one Chinese. The Mars-500 facilities comprised four hermetically sealed, interconnected modules and a Martian surface module. We applied the ethological method based on observation, description and quantification of the individual and inter-individual behaviors in terms of personal actions, visual interactions, object interactions, body interactions, facial expressions and collateral acts. These events were scored on the Observer XT® software, from video recordings made every two weeks at breakfast time inside the habitat module. We found the following results: a diminishing collective time from the first phase corresponding to the 250-day trip to Mars to the second phase corresponding to the 240-day return to Earth; 35-day cycles then 70-day cycles of high duration of personal actions within these phases; periodic oscillations of duration of inter-personal actions; decreasing then increasing occurrences of facial expressions with temporal points of decrements, around day 159 and day 355, after 6 months and one year of simulation; increasing occurrences of collateral acts over the full 520-day journey. We discuss the findings with regard to a Mars mission scenario. Time has a major impact on the behavioral profile, as shown by indicators of physical and psychological states of fatigue, stress, well being and good

  10. Experimental and computational studies on the natural circulation characteristics of a small- and medium-sized reactor, REX-10

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Byeong Il

    2012-02-15

    The rapid economic development in many countries has led to a growing need for energy. To meet the demand, the nuclear power generation is emerging as a viable alternative because it emits much smaller amount of carbon dioxide as compared to conventional fossil fuel plant produces high power density energy. Because of the latter attractiveness, many large-sized nuclear reactors ({approx}1000 MWe/unit) for electricity generation have been constructed around the world. Recently, small- and medium-sized nuclear reactors (SMRs) receive attention because of its effective adaptability to diversified energy demands. Several attractiveness of the SMR is worth to report here. First, the SMR is a viable alternative for the developing countries that have inferior electricity grids. Second, the SMR may effectively prevent the Large-Break Loss of Coolant Accident (LBLOCA) as it adopts the integral-type reactor. Finally, the SMR is used for various applications - desalination, district heating, small-scale power generation, ship propulsion, to mention a few. These attractiveness provides reasonable justification to construct the SMRs such as SMART, IRIS, CAREM, and KLT-40S. As such, the Regional Energy Research Institute for Next Generation (RERI) has been developing a SMR for regional energy supply, REX-10 since 2005. The REX-10 is the integral-type reactor and relies on natural circulation to improve passive safety. In this study, the natural circulation behavior and capability of the REX-10 is investigated experimentally as well as numerically. To evaluate the thermal-hydraulics of the REX-10, two experimental facilities . RTF and NACTER . were designed and fabricated using the scaling laws proposed by Ishii et al. Both experimental facilities consist of main components of the core, heat exchanger, hot legs, pressurizer, and chillers; however, both experimental facilities have different heat exchanger systems because two types of the heat exchanger are being considered. To

  11. A fuel management study and cycle nuclear design for PW reactors

    Energy Technology Data Exchange (ETDEWEB)

    Minguez, E.; Ahnert, C.; Aragones, J. M.; Corella, M. R.

    1975-07-01

    A reference reactor was chosen to do a general study involving Fuel Management Evaluations of several cycles, and Design Calculations of cycles already performed, according to a calculation scheme set up in the Reactor Technology Division of the J.E.N., using some computer codes acquired to foreign sources and other ones developed in the J.E.N. (Author) 5 refs.

  12. A novel reverse flow reactor coupling endothermic and exothermic reactions: an experimental study

    NARCIS (Netherlands)

    van Sint Annaland, M.; Nijssen, R.C.

    2002-01-01

    A new reactor concept is studied for highly endothermic heterogeneously catalysed gas phase reactions at high temperatures with rapid but reversible catalyst deactivation. The reactor concept aims to achieve an indirect coupling of energy necessary for endothermic reactions and energy released by

  13. Mars Science Laboratory Launch-Arrival Space Study: A Pork Chop Plot Analysis

    Science.gov (United States)

    Cianciolo, Alicia Dwyer; Powell, Richard; Lockwood, Mary Kae

    2006-01-01

    Launch-Arrival, or "pork chop", plot analysis can provide mission designers with valuable information and insight into a specific launch and arrival space selected for a mission. The study begins with the array of entry states for each pair of selected Earth launch and Mars arrival dates, and nominal entry, descent and landing trajectories are simulated for each pair. Parameters of interest, such as maximum heat rate, are plotted in launch-arrival space. The plots help to quickly identify launch and arrival regions that are not feasible under current constraints or technology and also provide information as to what technologies may need to be developed to reach a desired region. This paper provides a discussion of the development, application, and results of a pork chop plot analysis to the Mars Science Laboratory mission. This technique is easily applicable to other missions at Mars and other destinations.

  14. Neutron beam studies for a medical therapy reactor.

    Science.gov (United States)

    Neuman, W A

    1990-01-01

    A conceptual design of a Medical Therapy Reactor (MTR) for neutron capture therapy (NCT) has been performed at the Idaho National Engineering Laboratory (INEL). The initial emphasis of the conceptual design was toward the treatment of glioblastoma multiforme and other presently incurable cancers. The design goal of the facility is to provide routine patient treatments both in brief time intervals (approximately 10 minutes) and inexpensively. The conceptual study has shown this goal to be achievable by locating an MTR at a major medical facility. This paper addresses the next step in the conceptual design process: a guide to the optimization of the epithermal-neutron filter and collimator assembly for the treatment of brain tumors. The current scope includes the sensitivity of the treatment beam to variations in filter length, gamma shield length, and collimator lengths as well as exit beam aperture size. The study shows the areas which can provide the greatest latitude in improving beam intensity and quality. Suggestions are given for future areas of optimization of beam filtering and collimation.

  15. Moessbauer In Situ Studies of the Surface of Mars

    Energy Technology Data Exchange (ETDEWEB)

    Klingelhoefer, G., E-mail: klingel@mail.uni-mainz.de [Johannes Gutenberg Universitaet, Inst. Anorganische and Analytische Chemie (Germany)

    2004-11-15

    For the first time in history, a Moessbauer spectrometer was placed on the surface of another planet. Our miniaturized Moessbauer spectrometer MIMOS II is part of the instrument payload of NASA's twin Mars Exploration Rovers (MER) 'Spirit' and 'Opportunity', which in January 2004 successfully landed at the Gusev crater and the Meridiani Planum landing sites, respectively. MIMOS II determines the Fe-bearing mineralogy of Martian soils and rocks at the Rovers' respective landing sites. The main goals of this planetary twin mission are to: (1) identify hydrologic, hydrothermal, and other processes that have operated and affected materials at the landing sites; (2) identify and investigate the rocks and soils at both landing sites, as there is a possible chance that they may preserve evidence of ancient environmental conditions and possible prebiotic or biotic activities. With MIMOS II, besides other minerals the Fe silicate olivine has been identified in both soil and rocks at both landing sites. At the Meridiani site the Fe sulfate jarosite has been identified by MIMOS II which is definitive mineralogical proof of the presence of water at this site in the past.

  16. Experimental study of lunar and SNC (Mars) magmas

    Science.gov (United States)

    Rutherford, Malcolm J.

    1994-01-01

    The overall objectives of this research were to evaluate the role of C-O-S-Cl degassing processes in explaining vesiculation, oxidation state and fire-fountaining of lunar magmas by analysis of individual lunar glass spherules, and by experimental determination of equilibrium abundances and diffusion rates of C, S and Cl melt species in lunar glass compositions; and to determine possible primitive SNC magma compositions and the mineralogy of the mantle from which they were derived, and to evaluate P, T, XH2O etc. conditions at which they crystallize to form the SNC meteorites. After funding for one year, a project on the A15 volcanic green glass has been completed to the point of writing a first manuscript. Carbon-oxygen species C-O and CO2 are below detection limits (20 ppm) in these glasses, but there is up to 500 ppm S with concentrations both increasing and decreasing toward the spherule margins. Calculations and modeling indicate that C species could have been present in the volcanic gases, however. In a second project, experiments with low PH2O have resulted in refined estimates of the early intercumulus melt composition in the Chassigny meteorite which is generally accepted as a sample from Mars.

  17. High temperature gas-cooled reactor: gas turbine application study

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-01

    The high-temperature capability of the High-Temperature Gas-Cooled Reactor (HTGR) is a distinguishing characteristic which has long been recognized as significant both within the US and within foreign nuclear energy programs. This high-temperature capability of the HTGR concept leads to increased efficiency in conventional applications and, in addition, makes possible a number of unique applications in both electrical generation and industrial process heat. In particular, coupling the HTGR nuclear heat source to the Brayton (gas turbine) Cycle offers significant potential benefits to operating utilities. This HTGR-GT Application Study documents the effort to evaluate the appropriateness of the HTGR-GT as an HTGR Lead Project. The scope of this effort included evaluation of the HTGR-GT technology, evaluation of potential HTGR-GT markets, assessment of the economics of commercial HTGR-GT plants, and evaluation of the program and expenditures necessary to establish HTGR-GT technology through the completion of the Lead Project.

  18. Plasma engineering studies for Tennessee Tokamak (TENTOK) fusion power reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, K.E.; Lacatski, J.T.; Miller, J.B.; Bryan, W.E.; King, P.W.; Santoro, R.T.; Uckan, N.A.; Shannon, T.E.

    1984-02-01

    This paper summarizes the results of the plasma engineering and systems analysis studies for the Tennessee Tokamak (TENTOK) fusion power reactor. TENTOK is a 3000-MW(t) central station power plant that uses deuterium-tritium fuel in a D-shaped tokamak plasma configuration with a double-null poloidal divertor. The major parameters are R/sub 0/ = 6.4 m, a = 1.6 m, sigma (elongation) = 1.65, (n) = 1.5 x 10/sup 20/ m/sup -3/, (T) = 15 keV, (..beta..) = 6%, B/sub T/ (on-axis) = 5.6 T, I/sub p/ = 8.5 MA, and wall loading = 3 MW/m/sup 2/. Detailed analyses are performed in the areas of (1) transport simulation using the one-and-one-half-dimensional (1-1/2-D) WHIST transport code, (2) equilibrium/poloidal field coil systems, (3) neutral beam and radiofrequency (rf) heating, and (4) pellet fueling. In addition, impurity control systems, diagnostics and controls, and possible microwave plasma preheating and steady-state current drive options are also considered. Some of the major features of TENTOK include rf heating in the ion cyclotron range of frequencies, superconducting equilibrium field coils outside the superconducting toroidal field coils, a double-null poloidal divertor for impurity control and alpha ash removal, and rf-assisted plasma preheating and current startup.

  19. Downer reactor: From fundamental study to industrial application

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Y.; Wu, C.N.; Zhu, J.X.; Wei, F.; Jin, Y. [Tsinghua University, Beijing (China). Dept. of Chemical Engineering

    2008-04-15

    Downer reactor, in which gas and solids move downward co-currently, has unique features such as the plug-flow reactor performance and relatively uniform flow structure compared to other gas-solids fluidized bed reactors, e.g., bubbling bed, turbulent bed and riser. Downer is therefore acknowledged as a novel multiphase flow reactor with great potential in high-severity operated processes, such as the high temperature, ultra-short contact time reactions with the intermediates as the desired products. Typical process developments in industry have directed to (1) the new-generation refinery process for cracking of heavier feedstock to gasoline and light olefins (e.g., propylene) as by-products; and (2) coal pyrolysis in hydrogen plasma which opens up a direct means for producing acetylene, i.e., a new route to synthesize chemicals from a clean coal utilization process. This paper gives a comprehensive review on the development of fundamental research on downer reactors as well as the particular industrial demonstrations for the fluid catalytic cracking (FCC) of heavy oils and coal pyrolysis in thermal plasma.

  20. Experimental and numerical study of the mars pathfinder vehicle; Etude experimentale et numerique sur le mars pathfinder

    Energy Technology Data Exchange (ETDEWEB)

    Bur, R.; Benay, R.; Chanetz, B.; Galli, A.; Pot, T. [Office National d' Etudes et de Recherches Aerospatiales (ONERA), Dept. Fundamental and Experimental Aerodynamics, 92 - Chatillon (France); Hollis, B.; Moss, J. [Aerothermodynamics Branch, NASA Langley Research Center Hampton, Virginia (United States)

    2002-07-01

    An experimental and numerical study on the Mars Pathfinder aero-shell vehicle has been carried out in the framework of an agreement between ONERA and NASA. The experimental work was performed in the ONERA R5Ch hypersonic wind tunnel. Flow-field visualizations and heat-flux measurements along the model have been obtained. Numerical simulations have been performed at ONERA with the RANS solver NASCA and at NASA with a DSMC code. The flow-field structure is correctly reproduced by both computations. The location of the bow shock is well predicted, as well as the expansion waves emanating from the end of the fore-body cone. Both computations also predict the same extension of the separation bubble in the base flow region of the model. Measured and calculated heat-flux distributions along the model have been compared. Both computations give similar results, excepted on the prediction of the heat-flux level on the after-body cone. But computations over-predict the measured heat-flux values on the fore-body and the sting of the model: the value of the stagnation point is overestimated of 28% and the averaged sting level of 35%. (authors)

  1. Detoxification of tar water by anaerobic treatment in an UASB reactor - A study of the degradation of phenolic compounds in a combined denitrifying and anaerobic UASB reactor

    Energy Technology Data Exchange (ETDEWEB)

    Skibsted Mogensen, A.; Schmidt, J.E.; Ahring, B.K. [Technical Univ., Dept. of Environmental Science and Engineering, Lyngby (Denmark)

    1998-08-01

    The digestion of pyrolysis condensate (PC) in two combined anaerobic and denitrifying upflow anaerobic sludge blanket (UASB) reactors was studied. A COD removal of 80% was achieved with an influent concentration of 1.43% PC{sub pH}. When the reactor was fed with 100% PC during a period of 10 days good reactor operation was observed. Despite less than one retention time of operation, the results indicated clearly, that PC could be used as substrate in the biogas process, even in very high concentrations. A combined anaerobic and denitrifying UASB reactor was successfully digesting 5.5% of wet oxidised PC, but further loading increments deteriorated the anaerobic digestion process. The detoxification of PC was studied by determining the degradation of phenols during reactor operation and the toxicity of PC was decreased more than 77 times witnessed through decreased inhibition of the nitrification process. Phenol, methyl and dimethyl phenols along with methoxyphenols were shown to be degraded within the reactor systems. Degradation rates for phenol and substituted phenols were determined by the reactor experiment indicating that the biomass was selective towards the substrates. Maximum growth rates and half saturation constants for phenol, 4-Methylphenol and 2-Methoxy-4-methylphenol were determined in batch experiments. The degradation rates of phenols determined in batches were significantly higher compared to degradation rates observed in the reactor systems digesting pyrolysis condensate. Determination of the population of methanogens revealed, that Methanosarcina was found only in one reactor, while Methanobacterium and Methanosaeta were found in reactors and inoculum. A UASB reactor was designed for the treatment of pyrolysis condensate at the gasification plant at Harbooere, Denmark. (au) 35 refs.

  2. Background Studies for the MINER Coherent Neutrino Scattering Reactor Experiment

    CERN Document Server

    Agnolet, G; Barker, D; Beck, R; Carroll, T J; Cesar, J; Cushman, P; Dent, J B; De Rijck, S; Dutta, B; Flanagan, W; Fritts, M; Gao, Y; Harris, H R; Hays, C C; Iyer, V; Jastram, A; Kadribasic, F; Kennedy, A; Kubik, A; Ogawa, I; Lang, K; Mahapatra, R; Mandic, V; Martin, R D; Mast, N; McDeavitt, S; Mirabolfathi, N; Mohanty, B; Nakajima, K; Newhouse, J; Newstead, J L; Phan, D; Proga, M; Roberts, A; Rogachev, G; Salazar, R; Sander, J; Senapati, K; Shimada, M; Strigari, L; Tamagawa, Y; Teizer, W; Vermaak, J I C; Villano, A N; Walker, J; Webb, B; Wetzel, Z; Yadavalli, S A

    2016-01-01

    The proposed Mitchell Institute Neutrino Experiment at Reactor (MINER) experiment at the Nuclear Science Center at Texas A&M University will search for coherent elastic neutrino-nucleus scattering within close proximity (about 2 meters) of a 1 MW TRIGA nuclear reactor core using low threshold, cryogenic germanium and silicon detectors. Given the Standard Model cross section of the scattering process and the proposed experimental proximity to the reactor, as many as 5 to 20 events/kg/day are expected. We discuss the status of preliminary measurements to characterize the main backgrounds for the proposed experiment. Both in situ measurements at the experimental site and simulations using the MCNP and GEANT4 codes are described. A strategy for monitoring backgrounds during data taking is briefly discussed.

  3. A study on future nuclear reactor technology and development strategy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. Y.; Kim, S. H.; Sohn, D. S.; Suk, S. D.; Zee, S. K.; Yang, M. H.; Kim, H. J.; Park, W. S

    2000-12-01

    Development of nuclear reactor and fuel cycle technology for future is essential to meet the current issues such as enhancement of nuclear power reactor safety, economically competitive with gas turbine power generation, less production of radioactive waste, proliferation resistant fuel cycle, and public acceptance in consideration of lack of energy resources in the nuclear countries worldwide as well as in Korea. This report deals with as follows, 1) Review the world energy demand and supply perspective and analyse nature of energy and sustainable development to set-up nuclear policy in Korea 2) Recaptitulate the current long term nuclear R and D activities 3) Review nuclear R and D activities and programs of USA, Japan, France, Russia, international organizations such as IAEA, OECD/NEA 4) Recommend development directions of nuclear reactors and fuels.

  4. System Study: Reactor Core Isolation Cooling 1998–2012

    Energy Technology Data Exchange (ETDEWEB)

    T. E. Wierman

    2013-10-01

    This report presents an unreliability evaluation of the reactor core isolation cooling (RCIC) system at 31 U.S. commercial boiling water reactors. Demand, run hours, and failure data from fiscal year 1998 through 2012 for selected components were obtained from the Equipment Performance and Information Exchange (EPIX). The unreliability results are trended for the most recent 10 year period while yearly estimates for system unreliability are provided for the entire active period. No statistically significant increasing trend was identified in the HPCI results. Statistically significant decreasing trends were identified for RCIC start-only and 8-hour trends.

  5. System Study: Reactor Core Isolation Cooling 1998-2014

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, John Alton [Idaho National Lab. (INL), Idaho Falls, ID (United States). Risk Assessment and Management Services Dept.

    2015-12-01

    This report presents an unreliability evaluation of the reactor core isolation cooling (RCIC) system at 31 U.S. commercial boiling water reactors. Demand, run hours, and failure data from fiscal year 1998 through 2014 for selected components were obtained from the Institute of Nuclear Power Operations (INPO) Consolidated Events Database (ICES). The unreliability results are trended for the most recent 10 year period, while yearly estimates for system unreliability are provided for the entire active period. No statistically significant trends were identified in the RCIC results.

  6. System Study: Reactor Core Isolation Cooling 1998–2013

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, John Alton [Idaho National Lab. (INL), Idaho Falls, ID (United States). Risk Assessment and Management Services Dept.

    2015-01-31

    This report presents an unreliability evaluation of the reactor core isolation cooling (RCIC) system at 31 U.S. commercial boiling water reactors. Demand, run hours, and failure data from fiscal year 1998 through 2013 for selected components were obtained from the Institute of Nuclear Power Operations (INPO) Consolidated Events Database (ICES). The unreliability results are trended for the most recent 10-year period, while yearly estimates for system unreliability are provided for the entire active period. No statistically significant trends were identified in the RCIC results.

  7. A combined SEM, CV and EIS study of multi-layered porous ceramic reactors for flue gas purification

    DEFF Research Database (Denmark)

    He, Zeming; Andersen, Kjeld Bøhm; Nygaard, Frederik Berg;

    2013-01-01

    The effect of sintering temperature of 12-layered porous ceramic reactors (comprising 5 cells) was studied using scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The difference in microstructures of the reactors was evaluated by SEM...

  8. A study on nonlinear behavior of reactor containment structures during ultimate accident condition(I)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sun Hoon; Kim, Young Jin; Park, Joo Yeon [Youngdong Univ., Yeongdong (Korea, Republic of)] (and others)

    2003-03-15

    In this study, the following scope and contents are established for first year's study of determining ultimate pressure capacity of CANDU-type reactor containment. State-of-arts on the prediction of the ultimate pressure capacity of prestressed concrete reactor containment. Comparative study on structural characteristics and analysis model of CANDU-type reactor containment. State-of-arts on evaluation method of the ultimate pressure capacity of prestressed concrete reactor containment. Enhancement of evaluation method of the ultimate pressure capacity for PWR containment structure. In order to determine a realistic lower bound of a typical reactor containment structural capacity for internal pressure, modelling techniques and analytical investigation to predict its non-linear behavior up to ultimate capacity are required. Especially, the in-depth evaluation of modeling technique and analysis procedure for determining ultimate pressure capacity of CANDU-type reactor containment is required. Therefore, modelling techniques and analytical investigation to predict its non-linear behavior up to ultimate pressure capacity of CANDU-type reactor containment for internal pressure will be suggested in this study.

  9. A photochemical reactor for studies of atmospheric chemistry

    DEFF Research Database (Denmark)

    Nilsson, Elna Johanna Kristina; Eskebjerg, Carsten; Johnson, Matthew Stanley

    2009-01-01

    flanges, surrounded by UV-A, UV-C and broadband sun lamps in a temperature-controlled housing. The combination of a quartz vessel and UV-C lamps allows higher concentrations of O(1D) and OH than can be generated by similar chambers. The reactor is able to produce radical concentrations of ca. 8 1011 cm 3...

  10. Study of fast reactor safety test facilities. Preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Bell, G.I.; Boudreau, J.E.; McLaughlin, T.; Palmer, R.G.; Starkovich, V.; Stein, W.E.; Stevenson, M.G.; Yarnell, Y.L.

    1975-05-01

    Included are sections dealing with the following topics: (1) perspective and philosophy of fast reactor safety analysis; (2) status of accident analysis and experimental needs; (3) experiment and facility definitions; (4) existing in-pile facilities; (5) new facility options; and (6) data acquisition methods. (DG)

  11. Statistical parametric study of non-parallel inductive reactors

    Energy Technology Data Exchange (ETDEWEB)

    Keiter, E.R.; Kushner, M.J. [Univ. of Illinois, Urbana, IL (United States). Dept. of Electrical and Computer Engineering

    1997-12-31

    Parameterization of new plasma processing is a very time consuming process. By combining statistical techniques with computer simulation, one can construct a numerical design of experiment (NDOE), which minimizes the time required for the investigation. Here the authors present the results of such an NDOE, applied to a generic non-parallel inductively coupled reactor, as there has recently been interest in inductive reactors with a dome shaped quartz top. They use a statistical design of experiment software too, Echip{copyright}, to construct the experiment and then perform the experiment with the Hybrid Plasma Equipment Model (HPEM). Echip{copyright} is also used in the post-experiment analysis. The goal is to determine functional relationships between ion and neutral flux uniformity to the wafer and geometrical parameters such as focus ring height, reactor height, and reactor radius. Additionally, they consider several non-geometrical variables such as substrate bias and pressure. By combining numerical modeling with statistics software they have been able to determine optimal parameters sets for different gas systems. Of the geometric parameters, focus ring height appears to have the strongest correlation with the ion and neutral flux uniformity. Correlation becomes worse at higher pressures for most parameters.

  12. Positron Annihilation Studies of VVER Type Reactor Steels

    OpenAIRE

    Brauer, G.

    1995-01-01

    A summary of recent positron annihilation work on Russian VVER type reactor steels is presented. Thereby, special attention is paid to the outline of basic processes that might help to understand the positron behaviour in this class of industrial material. The idea of positron trapping by irradiation-induced precipitates, which are probably carbides, is discussed in detail.

  13. [Study on hydrogen autotrophic denitrification of bio-ceramic reactor].

    Science.gov (United States)

    Chen, Dan; Wang, Hong-Yu; Song, Min; Yang, Kai; Liu, Chen

    2013-10-01

    Nitrate wastewater is processed in a bio-ceramic reactor based on hydrogen autotrophic denitrification. The implementation procedure of biological denitrification by hydrogen autotrophic denitrification was investigated. The effects of hydraulic retention time, influent nitrate load, influent pH, temperature and the amount of hydrogen were assessed throughout this trial. The results showed that the removal rate of NO-(3) -N was 94. 54% and 97. 47% when the hydraulic retention time was 24 h and 48 h, respectively. When the hydraulic retention time was in the range of 5-16 h, the removal rate gradually dropped with the shortening of the hydraulic retention time. When the influent NO-(3) -N concentration was low, with the increase in the influent NO-(3) -N concentration, the degradation rate also increased. The denitrification was inhibited when the NO-(3) -N concentration was higher than 110 mg.L-1. Neutral and alkaline environment was more suitable for the reactor. The reactor showed a wide range of temperature adaptation and the optimum temperature of the reactor was from 25 to 30 degrees C. When hydrogen was in short supply, the effect of denitrification was significantly reduced. These results indicated the specificity of hydrogen utilization by the denitrifying bacteria. The effluent nitrite nitrogen concentration was maintained at low levels during the operation.

  14. High flux isotope reactor cold source preconceptual design study report

    Energy Technology Data Exchange (ETDEWEB)

    Selby, D.L.; Bucholz, J.A.; Burnette, S.E. [and others

    1995-12-01

    In February 1995, the deputy director of Oak Ridge National Laboratory (ORNL) formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced Neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. The anticipated cold source will consist of a cryogenic LH{sub 2} moderator plug, a cryogenic pump system, a refrigerator that uses helium gas as a refrigerant, a heat exchanger to interface the refrigerant with the hydrogen loop, liquid hydrogen transfer lines, a gas handling system that includes vacuum lines, and an instrumentation and control system to provide constant system status monitoring and to maintain system stability. The scope of this project includes the development, design, safety analysis, procurement/fabrication, testing, and installation of all of the components necessary to produce a working cold source within an existing HFIR beam tube. This project will also include those activities necessary to transport the cold neutron beam to the front face of the present HFIR beam room. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and research and development (R and D), (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the preconceptual phase and establishes the concept feasibility. The information presented includes the project scope, the preliminary design requirements, the preliminary cost and schedule, the preliminary performance data, and an outline of the various plans for completing the project.

  15. A STUDY ON MEMBRANE PROCESS WITH γ-ALUMINA MEMBRANE REACTOR FOR ETHYLBENZENE DEHYDROGENATION TO STYRENE

    Institute of Scientific and Technical Information of China (English)

    Chen Qingling; Xu Zhongqiang

    2001-01-01

    The membrane reaction of ethylbenzene(EB) dehydrogenation to styrene(ST) has been studied by using K2O/Fe2O3 industrial catalyst and γ-alumina ceramic membrane developed by our institute. In comparison with the packed bed reactor (that is, plug flow reactor, abbr. PFR) in industrial practice, the yield of styrene was increased by 5%~10% in the membrane reactor. Furthermore, mathematical modeling of membrane reaction has been studied to display the principle of optimal match between the catalytic activity and the membrane permeability.

  16. Feasibility study of a single, elliptical heliocentric Earth-Mars trajectory

    Science.gov (United States)

    Blake, M.; Fulgham, K.; Westrup, S.

    1989-01-01

    The initial intent of this design project was to evaluate the existence and feasibility of a single elliptical heliocentric Earth/Mars trajectory. This trajectory was constrained to encounter Mars twice in its orbit, within a time interval of 15 to 180 Earth days between encounters. The single ellipse restriction was soon found to be prohibitive for reasons shown later. Therefore, the approach taken in the design of the round-trip mission to Mars was to construct single-leg trajectories which connected two planets on two prescribed dates. Three methods of trajectory design were developed. Method 1 is an eclectic approach and employs Gaussian Orbit Determination (Method 1A) and Lambert-Euler Preliminary Orbit Determination (Method 1B) in conjunction with each other. Method 2 is an additional version of Lambert's Solution to orbit determination, and both a coplanar and a noncoplanar solution were developed within Method 2. In each of these methods, the fundamental variables are two position vectors and the time between the position vectors. In all methods, the motion was considered Keplerian motion and the reference frame origin was located at the sun. Perturbative effects were not considered in Method 1. The feasibility study of round-trip Earth/Mars trajectories maintains generality by considering only heliocentric trajectory parameters and planetary approach conditions. The coordinates and velocity components of the planets, for the standard epoch J2000, were computed from an approximate set of osculating elements by the procedure outlined in an ephemeris of coordinates.

  17. Mirror Advanced Reactor Study (MARS). Final report. Volume 1-B. Commercial fusion electric plant

    Energy Technology Data Exchange (ETDEWEB)

    Donohue, M.L.; Price, M.E. (eds.)

    1984-07-01

    Volume 1-B contains the following chapters: (1) blanket and reflector; (2) central cell shield; (3) central cell structure; (4) heat transport and energy conversion; (5) tritium systems; (6) cryogenics; (7) maintenance; (8) safety; (9) radioactivity, activation, and waste disposal; (10) instrumentation and control; (11) balance of plant; (12) plant startup and operation; (13) plant availability; (14) plant construction; and (15) economic analysis.

  18. Mirror Advanced Reactor Study (MARS). Final report. Volume 1-A. Commercial fusion electric plant

    Energy Technology Data Exchange (ETDEWEB)

    Donohue, M.L.; Price, M.E. (eds.)

    1984-07-01

    Volume 1-A contains the following chapters: (1) plasma engineering, (2) magnets, (3) ecr heating systems, (4) anchor ion-cyclotron resonance heating system, (5) sloshing ion neutral beam, (6) end cell structure, (7) end plasma technology, (8) fueling, (9) startup ion cyclotron resonant heating systems, and (10) end cell radiation analysis. (MOW)

  19. Computational Fluid Dynamics Study of Channel Geometric Effect for Fischer-Tropsch Microchannel Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Na, Jonggeol; Jung, Ikhwan; Kshetrimayum, Krishnadash S.; Park, Seongho; Park, Chansaem; Han, Chonghun [Seoul National University, Seoul (Korea, Republic of)

    2014-12-15

    Driven by both environmental and economic reasons, the development of small to medium scale GTL(gas-to-liquid) process for offshore applications and for utilizing other stranded or associated gas has recently been studied increasingly. Microchannel GTL reactors have been preferred over the conventional GTL reactors for such applications, due to its compactness, and additional advantages of small heat and mass transfer distance desired for high heat transfer performance and reactor conversion. In this work, multi-microchannel reactor was simulated by using commercial CFD code, ANSYS FLUENT, to study the geometric effect of the microchannels on the heat transfer phenomena. A heat generation curve was first calculated by modeling a Fischer-Tropsch reaction in a single-microchannel reactor model using Matlab-ASPEN integration platform. The calculated heat generation curve was implemented to the CFD model. Four design variables based on the microchannel geometry namely coolant channel width, coolant channel height, coolant channel to process channel distance, and coolant channel to coolant channel distance, were selected for calculating three dependent variables namely, heat flux, maximum temperature of coolant channel, and maximum temperature of process channel. The simulation results were visualized to understand the effects of the design variables on the dependent variables. Heat flux and maximum temperature of cooling channel and process channel were found to be increasing when coolant channel width and height were decreased. Coolant channel to process channel distance was found to have no effect on the heat transfer phenomena. Finally, total heat flux was found to be increasing and maximum coolant channel temperature to be decreasing when coolant channel to coolant channel distance was decreased. Using the qualitative trend revealed from the present study, an appropriate process channel and coolant channel geometry along with the distance between the adjacent

  20. An experimental study of a VVER reactor's steam generator model operating in the condensing mode

    Science.gov (United States)

    Morozov, A. V.; Remizov, O. V.

    2012-05-01

    Results obtained from an experimental study of a VVER reactor's steam generator model operating in the condensing mode are presented. The obtained empirical dependence for calculating the power of heat exchangers operating in the steam condensation mode is presented.

  1. Capital cost: pressurized water reactor plant. Commercial electric power cost studies

    Energy Technology Data Exchange (ETDEWEB)

    1977-06-01

    The investment cost study for the 1139 MW(e) pressurized water reactor (PWR) central station power plant consists of two volumes. This volume contains the drawings, equipment list and site description.

  2. Report of the APS Neutrino Study Reactor Working Group

    Energy Technology Data Exchange (ETDEWEB)

    Abouzaid, E.; Anderson, K.; Barenboim, G.; Berger, B.; Blucher, E.; Bolton, T.; Choubey, S.; Conrad, J.; Formaggio, J.; Freedman, S.; Finely, D.; Fisher, P.; Fujikawa, B.; Gai, M.; Goodman, M.; de Goueva, A.; Hadley, N.; Hahn, R.; Horton-Smith, G.; Kadel, R.; Kayser, B.; Heeger, K.; Klein, J.; Learned, J.; Lindner, M.; Link, J.; Luk, K.-B.; McKeown, R.; Mocioiu, I.; Mohapatra, R.; Naples, D.; Peng, J.; Petcov, S.; Pilcher, J.; Rapidis, P.; Reyna, D.; Shaevitz, M.; Shrock, R.; Stanton, N.; Stefanski, R.; Yamamoto, R.; Worcester, M.

    2004-10-28

    The worldwide program to understand neutrino oscillations and determine the neutrino mixing parameters, CP violating effects, and mass hierarchy will require a broad combination of measurements. The group believes that a key element of this future neutrino program is a multi-detector neutrino experiment (with baselines of {approx} 200 m and {approx} 1.5 km) with a sensitivity of sin{sup 2} 2{theta}{sub 13} = 0.01. In addition to oscillation physics, the reactor experiment may provide interesting measurements of sin{sup 2} {theta}{sub W} at Q{sup 2} = 0, neutrino couplings, magnetic moments, and mixing with sterile neutrino states. {theta}{sub 13} is one of the twenty-six parameters of the standard model, the best model of electroweak interactions for energies below 100 GeV and, as such, is worthy of a precision measurement independent of other considerations. A reactor experiment of the proposed sensitivity will allow a measurement of {theta}{sub 13} with no ambiguities and significantly better precision than any other proposed experiment, or will set limits indicating the scale of future experiments required to make progress. Figure 1 shows a comparison of the sensitivity of reactor experiments of different scales with accelerator experiments for setting limits on sin{sup 2} 2{theta}{sub 13} if the mixing angle is very small, or for making a measurement of sin{sup 2} 2{theta}{sub 13} if the angle is observable. A reactor experiment with a 1% precision may also resolve the degeneracy in the {theta}{sub 23} parameter when combined with long-baseline accelerator experiments. In combination with long-baseline measurements, a reactor experiment may give early indications of CP violation and the mass hierarchy. The combination of the T2K and Nova long-baseline experiments will be able to make significant measurements of these effects if sin{sup 2} 2{theta}{sub 13} > 0.05 and with enhanced beam rates can improve their reach to the sin{sup 2} 2{theta}{sub 13} > 0.02 level

  3. Common-Cause Failure Analysis for Reactor Protection System Reliability Studies

    Energy Technology Data Exchange (ETDEWEB)

    Gentillon, C.; Rasmuson, D.; Eide, S.; Wierman, T.

    1999-08-01

    Analyses were performed of the safety-related performance of the reactor protection system (RPS) at U.S. Westinghouse and General Electric commercial reactors during the period 1984 through 1995. RPS operational data from these reactors were collected from the Nuclear Plant Reliability Data System (NPRDS) and Licensee Event Reports (LER). The common-cause failure (CCF) modeling in the fault trees developed for these studies and the analysis and use of common-cause failure data were sophisticated, state-of-the-art efforts. The overall CCF effort helped to test and expand the limits of the U.S. Nuclear Regulatory Commission's CCF methodology.

  4. Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hogerton, John

    1964-01-01

    This pamphlet describes how reactors work; discusses reactor design; describes research, teaching, and materials testing reactors; production reactors; reactors for electric power generation; reactors for supply heat; reactors for propulsion; reactors for space; reactor safety; and reactors of tomorrow. The appendix discusses characteristics of U.S. civilian power reactor concepts and lists some of the U.S. reactor power projects, with location, type, capacity, owner, and startup date.

  5. Experimental and analytical study on thermal hydraulics in reduced-moderation water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Akimoto, Hajime; Araya, Fumimasa; Ohnuki, Akira; Yoshida, Hiroyuki; Kureta, Masatoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-06-01

    Study and development of reduced-moderation spectrum water reactor proceeds as a option of the future type reactor in Japan Atomic Energy Research Institute (JAERI). The reduced-moderation spectrum in which a neutron has higher energy than the conventional water reactors is achieved by decreasing moderator-to-fuel ratio in the lattice core of the reactor. Conversion ratio in the reduced-moderation water reactor can be more than 1.0. High burnup and long term cycle operation of the reactor are expected. A type of heavy water cooled PWR and three types of BWR are discussed as follows; For the PWR, (1) critical heat flux experiments in hexagonal tight lattice core, (2) evaluation of cooling limit at a nominal power operation, and (3) analysis of rewetting cooling behavior at loss of coolant accident following with large scale pipe rupture. For the BWR, analyses of cooling limit at a nominal power operation of, (1) no blanket BWR, (2) long term cycle operation BWR, and (3) high conversion ratio BWR. The experiments and the analyses proved that the basic thermal hydraulic characteristics of these reduced-moderation water reactors satisfy the essential points of the safety requirements. (Suetake, M.)

  6. Outcrop-Scale Hyperspectral Studies of a Lacustrine-Volcanic Mars Analog: Examination with a Mars 2020-like Instrument Suite

    Science.gov (United States)

    Martin, P.; Ehlmann, B. L.; Blaney, D. L.; Bhartia, R.; Allwood, A.

    2015-12-01

    Using the recently developed Ultra Compact Imaging Spectrometer (UCIS) (0.4-2.5 μm) to generate outcrop-scale infrared images and compositional maps, a Mars-relevant field site near China Ranch in the Mojave Desert has been surveyed and sampled to analyze the synergies between instruments in the Mars 2020 rover instrument suite. The site is broadly comprised of large lacustrine gypsum beds with fine-grained gypsiferous mudstones and interbedded volcanic ashes deposited in the Pleistocene, with a carbonate unit atop the outcrop. Alteration products such as clays and iron oxides are pervasive throughout the sequence. Mineralogical mapping of the outcrop was performed using UCIS. As the 2020 rover will have an onboard multispectral camera and IR point spectrometer, Mastcam-Z and SuperCam, this process of spectral analysis leading to the selection of sites for more detailed investigation is similar to the process by which samples will be selected for increased scrutiny during the 2020 mission. The infrared image is resampled (spatially and spectrally) to the resolutions of Mastcam-Z and SuperCam to simulate data from the Mars 2020 rover. Hand samples were gathered in the field (guided by the prior infrared compositional mapping), capturing samples of spectral and mineralogical variance in the scene. After collection, a limited number of specimens were chosen for more detailed analysis. The hand samples are currently being analyzed using JPL prototypes of the Mars 2020 arm-mounted contact instruments, specifically PIXL (Planetary Instrument for X-ray Lithochemistry) and SHERLOC (Scanning Habitable Environments with Raman & Luminescence). The geologic story as told by the Mars 2020 instrument data will be analyzed and compared to the full suite of data collected by hyperspectral imaging and terrestrial techniques (e.g. XRD) applied to the collected hand samples. This work will shed light on the potential uses and synergies of the Mars 2020 instrument suite, especially

  7. Experimental Study of a Photocatalytic Reactor for Trace Formaldehyde Removal

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-min; LIAN Zhi-wei; YE Xiao-jiang; SHANG-GUAN Wen-feng

    2005-01-01

    Formaldehyde is the key contaminant influencing building occupants' health in indoor environment. In order to reduce occupants' exposures to formaldehyde, a newly designed photocatalytic reactor was applied in a dynamic HVAC(heating, ventilation and air conditioning) system. The experiments were carried out for the removal of formaldehyde present in air at low parts per million (ppm) concentrations.The initial formaldehyde concentrations were set as1.59 ppm and 0.27 ppm respectively, based on the formaldehyde levels in the polluted places. Experimental results show that the photocatalytic reactor is effective on formaldehyde photodegradation, causes a low pressure drop, and does not make the second pollution of ozone. The kinetic analysis indicates that the kinetics for oxidation processes can be fitted well by a pseudo-first-order kinetic model deduced from Langmuir - Hinshelwood (L-H) model.

  8. Study for Reactor Monitoring using Anti-neutrino Detection in the Neos experiment

    Energy Technology Data Exchange (ETDEWEB)

    Han, Bo Young; Sun, Gwang Min [KAERI, Daejeon (Korea, Republic of); Jeon, Eun Ju [ISB, Daejeon (Korea, Republic of); and others

    2016-05-15

    In this study we describe a feasibility study of reactor monitoring using antineutrino detection in the Neutrino Experiment for Oscillation at Short baseline (NEOS) at Hanbit power plant. Recently, in the perspective of nonproliferation issues and misuse of nuclear energy as a fast-growing nuclear energy industry, the application of anti-neutrino measurement has been proposed and the feasibility studies has been carried out as a novel technology for monitoring the burning process of nuclear power reactor. The NEOS detector with 1000 L Gd-doped liquid scintillator was installed in tendon gallery at Hanbit power station unit 5 and has been collecting close to 2000 IBD events per day with the signal to noise ratio of ∼ 20. As a preliminary result, we demonstrate the possibility of monitoring nuclear power reactor with the IBD counting rate during reactor power ON, ramping up, and OFF.

  9. Water-moderated reactor fuel cladding reliability study

    OpenAIRE

    Бакутяк, Елена Викторовна; Пелых, Сергей Николаевич

    2014-01-01

    Considering the fuel element, averaged by fuel assembly (FA) of water-moderated reactor with the power of 1000 MW (VVER-1000), the number of fuel elements with the greatest cladding failure probability after 4 operation years at Khmelnitsky NPP-2 (KNPP-2) is found. This will allow to calculate the fuel cladding failure probability and determine the most likely cladding damages, which will enable to improve the performance and economic indexes of VVER.The novelty of the paper lies in calculati...

  10. Studies on modelling of bubble driven flows in chemical reactors

    Energy Technology Data Exchange (ETDEWEB)

    Grevskott, Sverre

    1997-12-31

    Multiphase reactors are widely used in the process industry, especially in the petrochemical industry. They very often are characterized by very good thermal control and high heat transfer coefficients against heating and cooling surfaces. This thesis first reviews recent advances in bubble column modelling, focusing on the fundamental flow equations, drag forces, transversal forces and added mass forces. The mathematical equations for the bubble column reactor are developed, using an Eulerian description for the continuous and dispersed phase in tensor notation. Conservation equations for mass, momentum, energy and chemical species are given, and the k-{epsilon} and Rice-Geary models for turbulence are described. The different algebraic solvers used in the model are described, as are relaxation procedures. Simulation results are presented and compared with experimental values. Attention is focused on the modelling of void fractions and gas velocities in the column. The energy conservation equation has been included in the bubble column model in order to model temperature distributions in a heated reactor. The conservation equation of chemical species has been included to simulate absorption of CO{sub 2}. Simulated axial and radial mass fraction profiles for CO{sub 2} in the gas phase are compared with measured values. Simulations of the dynamic behaviour of the column are also presented. 189 refs., 124 figs., 1 tab.

  11. 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: sqjxv3@mst.edu; Alajo, A.B., E-mail: alajoa@mst.edu

    2017-04-01

    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.

  12. Recent neutronics developments for reactor safety studies with SIMMER code at KIT

    Science.gov (United States)

    Rineiski, A.; Marchetti, M.; Andriolo, L.; Gabrielli, F.

    2017-01-01

    The SIMMER family of codes is applied for safety studies of sodium fast reactors and reactors of other types. Both neutronics and fluid-dynamics parts of SIMMER are under development. In the paper new neutronics capabilities are presented. In particular developments for neutron transport solvers and a new technique for taking into account thermal expansion effects are described. These new capabilities facilitate 3D simulations and improve accuracy of modelling for the initiation transient phase during a hypothetical severe accident.

  13. Study on Thermal-Hydraulic Behavior of an Integral Type Reactor under Heaving Condition

    OpenAIRE

    2014-01-01

    A self-developed program was used to study the thermal-hydraulic behavior of an integral type reactor under heaving condition. Comparison of calculated results with the data of experiments performed on a natural circulation loop designed with reference to an integral type reactor of Tsinghua University in inclination, heaving, and rolling motions was carried out. Characteristics of natural circulation in heaving motion and effect of motion parameters on natural circulation were investigated. ...

  14. Multidimensional MHD Model Studies of the Ionospheres of Venus and Mars

    Science.gov (United States)

    Nagy, Andrew

    1998-01-01

    Continuing efforts have been made towards an increased understanding of the solar wind interaction and ionospheric processes at Venus and Mars. This work centered on a systematic development of a new generation of three dimensional magnetohydrodynamic (MHD) numerical code, which models the interaction processes of the solar wind with non-magnetic planets, such as Venus and Mars. We have also worked on a number of different, more specific and discrete studies, as various opportunities arose. We have developed new numerical codes for magnetospheric and cometary studies. As a first step in this process we built an axisymmetric model in which the solar wind interacts with a hard, perfectly conducting sphere. Even that model provided, in certain respects, significant improvements over previous ones.

  15. Study on the safety and on international developments of small modular reactors (SMR). Final report; Studie zur Sicherheit und zu internationalen Entwicklungen von Small Modular Reactors (SMR). Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, Sebastian; Kruessenberg, Anne; Schaffrath, Andreas; Zipper, Reinhard

    2015-05-15

    This report documents the work and results of the project RS1521 Study of Safety and International Development of Small Modular Reactors (SMR). The aims of this study can be summarized as - setting-up of a sound overview on SMR, - identification of essential issues of reactor safety research and future R and D projects, - identification of needs for adaption of system codes of GRS used in reactor safety research. The sound overview consists of the descriptions of in total 69 SMR (Small and Medium Sized Rector) concepts (32 light water reactors (LWR), 22 liquid metal cooled reactors (LMR), 2 heavy water reactors, 9 gas cooled reactors (GCR) and 4 molten salt reactors (MSR)). It provides information about the core, the cooling circuits and the safety systems. The quality of the given specifications depends on their availability and public accessibility. Using the safety requirements for nuclear power plants and the fundamental safety functions, the safety relevant issues of the described SMR concepts were identified. The systems and measures used in the safety requirements were summarized in table form. Finally it was evaluated whether these systems and measures can be already simulated with the nuclear simulation chain of GRS and where further code development and validation is necessary. The results of this study can be summarized as follows: Many of the current SMR concepts are based on integral design. Here the main components like steam generators, intermediate heat exchangers or - in case of forced convection core cooling - main cooling pumps are located within the reactor pressure vessel. Most of the SMR fulfil highest safety standards and their safety concepts are mainly based on passive safety systems. The safety of theses reactors is achieved indefinitely without energy supply or additional measures of the operators. Since SMR's aim is not only to produce electricity but also couple them with chemical or physical process plants, the safety aspects of

  16. Reactor physics studies in the GCFR phase-II critical assembly

    Energy Technology Data Exchange (ETDEWEB)

    Pond, R B [ed.

    1976-09-01

    The reactor physics studies performed in the gas cooled fast reactor (GCFR) mockup on ZPR-9 are covered. This critical assembly, designated Phase II in the GCFR program, had a single zone PuO/sub 2/-UO/sub 2/ core composition and UO/sub 2/ radial and axial blankets. The assembly was built both with and without radial and axial stainless steel reflectors. The program included the following measurements: small-sample reactivity worths of reactor constituent materials (including helium); /sup 238/U Doppler effect; uranium and plutonium reaction rate distributions; thorium, uranium, and plutonium ..cap alpha.. and reactor kinetics. Analysis of the measurements used ENDF/B-IV nuclear data; anisotropic diffusion coefficients were used to account for neutron streaming effects. Comparison of measurements and calculations to GCFR Phase I are also made.

  17. Biological production of ethanol from coal. Task 4 report, Continuous reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    1992-10-01

    The production of ethanol from synthesis gas by the anaerobic bacterium C. ljungdahlii has been demonstrated in continuous stirred tank reactors (CSTRs), CSTRs with cell recycle and trickle bed reactors. Various liquid media were utilized in these studies including basal medium, basal media with 1/2 B-vitamins and no yeast extract and a medium specifically designed for the growth of C. ljungdahlii in the CSTR. Ethanol production was successful in each of the three reactor types, although trickle bed operation with C. ljungdahlii was not as good as with the stirred tank reactors. Operation in the CSTR with cell recycle was particularly promising, producing 47 g/L ethanol with only minor concentrations of the by-product acetate.

  18. MITR-III: Upgrade and relicensing studies for the MIT Research Reactor. Second annual report

    Energy Technology Data Exchange (ETDEWEB)

    Trosman, H.G. [ed.; Lanning, D.D.; Harling, O.K.

    1994-08-01

    The current operating license of the MIT research reactor will expire on May 7, 1996 or possibly a few years later if the US Nuclear Regulatory Commission agrees that the license period can start with the date of initial reactor operation. Driven by the imminent expiration of the operating license, a team of nuclear engineering staff and students have begun a study of the future options for the MIT Research Reactor. These options have included the range from a major rebuilding of the reactor to its decommissioning. This document reports the results of a two year intensive activity which has been supported by a $148,000 grant from the USDOE contract Number DEFG0293ER75859, approximately $100,000 of internal MIT funds and Nuclear Engineering Department graduate student fellowships as well as assistance from international visiting scientists and engineers.

  19. Microstructural studies of carbides in MAR-M247 nickel-based superalloy

    Science.gov (United States)

    Szczotok, A.; Rodak, K.

    2012-05-01

    Carbides play an important role in the strengthening of microstructures of nickel-based superalloys. Grain boundary carbides prevent or retard grain-boundary sliding and make the grain boundary stronger. Carbides can also tie up certain elements that would otherwise promote phase instability during service. Various types of carbides are possible in the microstructure of nickel-based superalloys, depending on the superalloy composition and processing. In this paper, scanning electron and scanning transmission electron microscopy studies of carbides occurring in the microstructure of polycrystalline MAR-M247 nickel-based superalloy were carried out. In the present work, MC and M23C6 carbides in the MAR-M247 microstructure were examined.

  20. Human Mars EDL Pathfinder Study: Assessment of Technology Development Gaps and Mitigations

    Science.gov (United States)

    Lillard, Randolph; Olejniczak, Joe; Polsgrove, Tara; Cianciolo, Alice Dwyer; Munk, Michelle; Whetsel, Charles; Drake, Bret

    2017-01-01

    This paper presents the results of a NASA initiated Agency-wide assessment to better characterize the risks and potential mitigation approaches associated with landing human class Entry, Descent, and Landing (EDL) systems on Mars. Due to the criticality and long-lead nature of advancing EDL techniques, it is necessary to determine an appropriate strategy to improve the capability to land large payloads. A key focus of this study was to understand the key EDL risks and with a focus on determining what "must" be tested at Mars. This process identified the various risks and potential risk mitigation strategies along with the key near term technology development efforts required and in what environment those technology demonstrations were best suited. The study identified key risks along with advantages to each entry technology. In addition, it was identified that provided the EDL concept of operations (con ops) minimized large scale transition events, there was no technology requirement for a Mars pre-cursor demonstration. Instead, NASA should take a direct path to a human-scale lander.

  1. Mars topography investigated through the wavelet leaders method: A multidimensional study of its fractal structure

    Science.gov (United States)

    Deliège, Adrien; Kleyntssens, Thomas; Nicolay, Samuel

    2017-02-01

    This work examines the scaling properties of Mars topography through a wavelet-based formalism. We conduct exhaustive one-dimensional (both longitudinal and latitudinal) and two-dimensional studies based on Mars Orbiter Laser Altimeter (MOLA) data using the multifractal formalism called Wavelet Leaders Method (WLM). This approach shows that a scale break occurs at approximately 15 km, giving two scaling regimes in both 1D and 2D cases. At small scales, these topographic profiles mostly display a monofractal behavior while a switch to multifractality is observed in several areas at larger scales. The scaling exponents extracted from this framework tend to be greater at small scales. In the 1D context, these observations are in agreement with previous works and thus suggest that the WLM is well-suited for examining scaling properties of topographic fields. Moreover, the 2D analysis is the first such complete study to our knowledge. It gives both a local and global insight on the scaling regimes of the surface of Mars and allows to exhibit the link between the scaling exponents and several famous features of the Martian topography. These results may be used as a solid basis for further investigations of the scaling laws of the Red planet and show that the WLM could be used to perform systematic analyses of the surface roughness of other celestial bodies.

  2. Mars Topography Investigated Through the Wavelet Leaders Method: a Multidimensional Study of its Fractal Structure

    Science.gov (United States)

    Deliège, Adrien; Kleyntssens, Thomas; Nicolay, Samuel

    2016-04-01

    This work examines the scaling properties of Mars topography through a wavelet-based formalism. We conduct exhaustive one-dimensional (both longitudinal and latitudinal) and two-dimensional studies based on Mars Orbiter Laser Altimeter (MOLA) data using the multifractal formalism called Wavelet Leaders Method (WLM). This approach shows that a scale break occurs at approximately 15 km, giving two scaling regimes in both 1D and 2D cases. At small scales, these topographic profiles mostly display a monofractal behavior while a switch to multifractality is observed in several areas at larger scales. The scaling exponents extracted from this framework tend to be greater at small scales. In the 1D context, these observations are in agreement with previous works and thus suggest that the WLM is well-suited for examining scaling properties of topographic fields. Moreover, the 2D analysis is the first such complete study to our knowledge. It gives both a local and global insight on the scaling regimes of the surface of Mars and allows to exhibit the link between the scaling exponents and several famous features of the Martian topography. These results may be used as a solid basis for further investigations of the scaling laws of the Red planet and show that the WLM could be used to perform systematic analyses of the surface roughness of other celestial bodies.

  3. Study of lower hybrid current drive for the demonstration reactor

    Energy Technology Data Exchange (ETDEWEB)

    Molavi-Choobini, Ali Asghar [Dept. of Physics, Faculty of Engineering, Islamic Azad University, Shahr-e-kord Branch, Shahr-e-kord (Iran, Islamic Republic of); Naghidokht, Ahmed [Dept. of Physics, Urmia University, Urmia (Iran, Islamic Republic of); Karami, Zahra [Dept. of Engineering, Islamic Azad University, Zanjan Branch, Zanjan (Iran, Islamic Republic of)

    2016-06-15

    Steady-state operation of a fusion power plant requires external current drive to minimize the power requirements, and a high fraction of bootstrap current is required. One of the external sources for current drive is lower hybrid current drive, which has been widely applied in many tokamaks. Here, using lower hybrid simulation code, we calculate electron distribution function, electron currents and phase velocity changes for two options of demonstration reactor at the launched lower hybrid wave frequency 5 GHz. Two plasma scenarios pertaining to two different demonstration reactor options, known as pulsed (Option 1) and steady-state (Option 2) models, have been analyzed. We perceive that electron currents have major peaks near the edge of plasma for both options but with higher efficiency for Option 1, although we have access to wider, more peripheral regions for Option 2. Regarding the electron distribution function, major perturbations are at positive velocities for both options for flux surface 16 and at negative velocities for both options for flux surface 64.

  4. Results of theoretical and experimental studies of hydrodynamics of circulation loops in circulating fluidized bed reactors and systems with interconnected reactors

    Science.gov (United States)

    Ryabov, G. A.; Folomeev, O. M.; Sankin, D. A.; Melnikov, D. A.

    2015-02-01

    Problems of the calculation of circulation loops in circulating fluidized bed reactors and systems with interconnected reactors (polygeneration systems for the production of electricity, heat, and useful products and chemical cycles of combustion and gasification of solid fuels)are considered. A method has been developed for the calculation of circulation loop of fuel particles with respect to boilers with circulating fluidized bed (CFB) and systems with interconnected reactors with fluidized bed (FB) and CFB. New dependences for the connection between the fluidizing agent flow (air, gas, and steam) and performance of reactors and for the whole system (solids flow rate, furnace and cyclone pressure drops, and bed level in the riser) are important elements of this method. Experimental studies of hydrodynamics of circulation loops on the aerodynamic unit have been conducted. Experimental values of pressure drop of the horizontal part of the L-valve, which satisfy the calculated dependence, have been obtained.

  5. A comparative study of the attenuation of reactor thermal neutrons in different types of concrete

    Energy Technology Data Exchange (ETDEWEB)

    Bashiter, I.I. [Zagazig Univ. (Egypt). Dept. of Physics; El-Sayed Abdo, A.; Makarious, A.S. [Atomic Energy Authority, Cairo (Egypt). Nuclear Research Centre

    1996-05-20

    This study was carried out to assess the distribution of thermal neutrons emitted directly from the core of the ET-RR-1 reactor in ordinary concrete, ilmenite concrete and ilmenite-limonite concrete shields. Measurements were carried out by using a direct beam and a cadmium filtered beam of reactor neutrons. The neutron dose distributions were measured using Li{sub 2}B{sub 4}O{sub 7}:Mn thermoluminescent dosimeters. The data obtained show that ilmenite concrete is better for slow and thermal neutron attenuation than both ordinary and ilmenite-limonite concrete. Also it was concluded that thermal neutrons emitted directly from the reactor core are highly absorbed within the first few centimeters of each type of concrete. The thickness of ilmenite concrete required to attenuate the doses of neutrons to a certain value along the beam axis for a direct reactor beam estimated to be about 75 and 57% of the shield thickness made from ordinary and ilmenite-limonite concretes, respectively. Empirical formulae were derived to calculate the neutron dose distribution in ordinary, ilmenite and ilmenite-limonite concrete shields both along and perpendicular to the beam axis for both the direct reactor neutrons and the reactor thermal neutrons. (author).

  6. Gamma ray spectrometer for future Mars mission: design concept and simulation study

    Science.gov (United States)

    Goyal, S. K.; Banerjee, D.; Vadawale, S.; Panda, Dipak K.; Patel, A. R.; Patinge, A.; Ladiya, T.; Sarbadhikari, A. B.

    2016-07-01

    One of the basic keys to understand the evolution and formation of any planet is the knowledge of the elemental composition of its surface. Gamma spectroscopy on Mars orbiter provides a unique opportunity to measure the elemental composition of its surface, with an atmosphere thin enough to allow detection of gamma rays produced from the near surface rock and soil materials. We are developing gamma ray spectrometer using High Purity Germanium (HPGe) detector for future Mars orbiter mission. The scientific objective of the instrument is to map the naturally occurring radioactive elements (Th, U, and K) and other major elements (Fe, Mg, Cl, Al, Si, S, Mg, Cl) over the entire Martian surface with a spatial resolution of better than 250 km. Gamma ray spectrometer will also have Anti - Coincidence Shield (ACS) detector for background subtraction from the surrounding material. This paper gives the details of the GEANT4 simulation, carried out to study the design requirements for a gamma ray spectrometer for a future Mars orbiter mission. This includes the selection of the size of HPGe detector, selection of the detector material and thickness for the ACS detector, and attenuation of gamma rays in the Martian atmosphere. Generation of gamma rays from the Martian surface due to Galactic Cosmic Rays (GCR) particles' interaction has also been simulated. Preliminary results from the standard off the shelf detector are also presented here.

  7. A Wind Tunnel Study on the Mars Pathfinder (MPF) Lander Descent Pressure Sensor

    Science.gov (United States)

    Soriano, J. Francisco; Coquilla, Rachael V.; Wilson, Gregory R.; Seiff, Alvin; Rivell, Tomas

    2001-01-01

    The primary focus of this study was to determine the accuracy of the Mars Pathfinder lander local pressure readings in accordance with the actual ambient atmospheric pressures of Mars during parachute descent. In order to obtain good measurements, the plane of the lander pressure sensor opening should ideally be situated so that it is parallel to the freestream. However, due to two unfavorable conditions, the sensor was positioned in locations where correction factors are required. One of these disadvantages is due to the fact that the parachute attachment point rotated the lander's center of gravity forcing the location of the pressure sensor opening to be off tangent to the freestream. The second and most troublesome factor was that the lander descends with slight oscillations that could vary the amplitude of the sensor readings. In order to accurately map the correction factors required at each sensor position, an experiment simulating the lander descent was conducted in the Martian Surface Wind Tunnel at NASA Ames Research Center. Using a 115 scale model at Earth ambient pressures, the test settings provided the necessary Reynolds number conditions in which the actual lander was possibly subjected to during the descent. In the analysis and results of this experiment, the readings from the lander sensor were converted to the form of pressure coefficients. With a contour map of pressure coefficients at each lander oscillatory position, this report will provide a guideline to determine the correction factors required for the Mars Pathfinder lander descent pressure sensor readings.

  8. The Mar Piccolo of Taranto: an interesting marine ecosystem for the environmental problems studies.

    Science.gov (United States)

    Cardellicchio, Nicola; Annicchiarico, Cristina; Di Leo, Antonella; Giandomenico, Santina; Spada, Lucia

    2016-07-01

    The National Project RITMARE (la Ricerca ITaliana per il MARE-Italian Research for the sea) started from 1 January 2012. It is one of the national research programs funded by the Italian Ministry of University and Research. RITMARE is coordinated by the National Research Council (CNR) and involves an integrated effort of most of the scientific community working on marine and maritime issues. Within the project, different marine study areas of strategic importance for the Mediterranean have been identified: Among these, the coastal area of Taranto (Ionian Sea, Southern Italy) was chosen for its different industry settlements and the relative impact on the marine environment. In particular, the research has been concentrated on the Mar Piccolo of Taranto, a complex marine ecosystem model important in terms of ecological, social, and economic activities for the presence also of extensive mussel farms. The site has been selected also because the Mar Piccolo area is a characteristic "on field" laboratory suitable to investigate release and diffusion mechanisms of contaminants, evaluate chemical-ecological risks towards the marine ecosystem and human health, and suggest and test potential remediation strategies for contaminated sediments. In this context, within the project RITMARE, a task force of researchers has contributed to elaboration a functioning conceptual model with a multidisciplinary approach useful to identify anthropogenic forcings, its impacts, and solutions of environmental remediation. This paper describes in brief some of the environmental issues related to the Mar Piccolo basin.

  9. A jet-stirred reactor for transient studies of char gasification

    Energy Technology Data Exchange (ETDEWEB)

    Calo, J.M.; Suuberg, E.M.; Hradil, G.; Perkins, M.T.; Lilly, W.D.

    1986-01-01

    For some time now in our laboratory we have been using well-mixed, ''gradientless'' reactors to study the dynamics of gas-carbon reactions. In the past we have used a mechanically-stirred, Berty-type reactor to examine the kinetics of carbon dioxide and steam gasification of chars. More recently, we have been involved in investigating the behavior of ''active sites'' in certain carbonaceous chars. As a result of the requirements of this work, we were led to the development of a jet-stirred, ''gradientless'' reactor. The current paper describes the design, development and application of this reactor to char gasification studies. The research project for which the reactor was developed is concerned with the study of the nature and behavior of ''active sites'' in the gasification of chars produced from synthesized model compounds, primarily those of the phenol-formaldehyde family of resins. One of the tasks defined for this project was to conduct transient kinetic studies on the gasification of these model compound chars, for both unlabelled and /sup 13/C-labelled resins. Due to the requirements of the expense of the labelled resins we were led to a design that minimized the relatively large sample requirements of the existing autoclave reactor. Once the necessity for developing a new reactor was realized, it was decided to employ jet-mixing in order to avoid some of the potential complexities of mechanical mixing under the particular operating conditions dictated by the nature of the reaction system. 6 refs., 8 figs., 1 tab.

  10. Pratt & Whitney ESCORT derivative for mars surface power

    Science.gov (United States)

    Feller, Gerald J.; Joyner, Russell

    1999-01-01

    The purpose of this paper is to address the applicability of a common reactor system design from the Pratt & Whitney ESCORT nuclear thermal rocket engine concept to support current NASA mars surface-based power requirements. The ESCORT is a bimodal engine capable of supporting a wide range of propulsive thermal and vehicle electrical power requirements. The ESCORT engine is powered by a fast-spectrum beryllium-reflected CERMET-fueled nuclear reactor. In addition to an expander cycle propulsive mode, the ESCORT is capable of operating in an electrical power mode. In this mode, the reactor is used to heat a mixture of helium and xenon to drive a closed-loop Brayton cycle in order to generate electrical energy. Recent Design Reference Mission requirements (DRM) from NASA Johnson Space Center and NASA Lewis Research Center studies in 1997 and 1998 have detailed upgraded requirements for potential mars transfer missions. The current NASA DRM requires a nuclear thermal propulsion system capable of delivering total mission requirements of 200170 N (45000 lbf) thrust and 50 kWe of spacecraft electrical power. Additionally, these requirements detailed a surface power system capable of providing approximately 160 kW of electrical energy over an approximate 10 year period within a given weight and volume envelope. Current NASA studies use a SP-100 reactor (0.8 MT) and a NERVA derivative (1.6 MT) as baseline systems. A mobile power cart of approximate dimensions 1.7 m×4.5 m×4.4 m has been conceptualized to transport the reactor power system on the Mars Surface. The 63.25 cm diameter and 80.25 cm height of the ESCORT and its 1.3 MT of weight fit well within the current weight and volume target range of the NASA DRM requirements. The modifications required to the ESCORT reactor system to support this upgraded electrical power requirements along with operation in the Martian atmospheric conditions are addressed in this paper. Sufficient excess reactivity and burnup capability

  11. A comparative study of sequencing batch reactor and moving-bed sequencing batch reactor for piggery wastewater treatment

    Directory of Open Access Journals (Sweden)

    Kwannate Sombatsompop

    2011-06-01

    Full Text Available This research aims to comparatively study the efficiency of piggery wastewater treatment by the moving-bed sequencing batch reactor (moving-bed SBR system with held medium, and the conventional sequencing batch reactor (SBR system, by varying the organic load from 0.59 to 2.36 kgCOD/m3.d. The COD treatment efficiency of the SBR and moving-bed SBR was higher than 60% at an organic load of 0.59 kgCOD/m3.d and higher than 80% at the organic loads of 1.18-2.36 kgCOD/m3.d. The BOD removal efficiency was greater than 90% at high organic loads of 1.18-2.36 kgCOD/m3.d. The moving-bed SBR gave TKN removal efficiency of 86-93%, whereas the SBR system exhibited the removal efficiency of 75-87% at all organic loads. The amount of effluent suspended solids for SBR systems exceeded the piggery wastewater limit of 200 mg/L at the organic load of 2.36 kgCOD/m3.d while that for the moving-bed SBR system did not. When the organic load was increased, the moving-bed SBR system yielded better treatment efficiency than that of the SBR system. The wastewater treated by the moving-bed SBR system met the criteria of wastewater standard for pig farms at all organic loads, while that treated by the SBR system was not satisfactory at a high organic load of 2.36 kgCOD/m3.d.

  12. Study of fuel assemblies for the nuclear reactor GFR; Estudio de ensambles de combustible para el reactor nuclear GFR

    Energy Technology Data Exchange (ETDEWEB)

    Reyes R, R.; Martin del Campo M, C.; Francois L, J. L. [UNAM, Facultad de Ingenieria, Departamento de Sistemas Energeticos, Paseo Cuauhnahuac 8532, Jiutepec, Morelos 62550 (Mexico)]. e-mail: ricarera@yahoo.com.mx

    2008-07-01

    In the present work the criticality calculations for two models of fuel assembly were realized to study the nuclear reactor cooled by gas (Gas Fast Reactor) of IV Generation. Model 1 is an assembly with hexagonal adjustment of fuel rods with reflector in the axial ends higher and lower, the coolant flows between the rods. Model 2 is an hexagonal assembly type block with spheres dispersion and cylindrical channels for where the coolant with reflector in the axial ends also flows. The materials selected for each component of the assemblies, should be resistant to the radiation of fast neutrons and high operation temperatures, for what in both models the following materials were chosen: a mixture of uranium carbide more plutonium for the fuel; a mixture of silicon carbide in different theoretical density percentages for structures and shieldings; helium gas like coolant and a zirconium carbide mixture like reflector, which fulfill the restrictions of being resistant to the high operation temperatures and means of irradiation. General considerations were taken, which are common parameters to both types of assemblies, like size and materials used in the different parts of each model of assembly. The criticality calculations were obtained with the help of the MCNPx code, based on the Monte Carlo method. It was realized a validation of the atomic density data of each component of the assemblies, to have the certainty of the proportionate values that they were introduced of correct way in the code. The results show that model 1 makes better use of the fissile material in a assembly that has the same dimensions externally. That is to say, that from the only considered viewpoint, the neutron one, model 1 is better than model 2. (Author)

  13. Prestressed concrete reactor vessel thermal cylinder model study

    Energy Technology Data Exchange (ETDEWEB)

    Callahan, J.P.; Canonico, D.A.; Richardson, M.; Corum, J.M.; Dodge, W.G.; Robinson, G.C.; Whitman, G.D.

    1977-05-04

    The thermal cylinder experiment was designed both to provide information for evaluating the capability of analytical methods to predict the time-dependent stress-strain behavior of a /sup 1///sub 6/-scale model of the barrel section of a single-cavity prestressed concrete reactor vessel and to demonstrate the structural behavior under design and off-design thermal conditions. The model was a thick-walled cylinder having a height of 1.22 m, a thickness of 0.46 m, and an outer diameter of 2.06 m. It was prestressed both axially and circumferentially and subjected to 4.83 MPa internal pressure together with a thermal crossfall imposed by heating the inner surface to 338.8 K and cooling the outer surface to 297.1 K. The initial 460 days of testing were divided into time periods that simulated prestressing, heatup, reactor operation, and shutdown. At the conclusion of the simulated operating period, the model was repressurized and subjected to localized heating at 505.4 K for 84 days to produce an off-design hot-spot condition. Comparisons of experimental data with calculated values obtained using the SAFE-CRACK finite-element computer program showed that the program was capable of predicting time-dependent behavior in a vessel subjected to normal operating conditions, but that it was unable to accurately predict the behavior during off-design hot-spot heating. Readings made using a neutron and gamma-ray backscattering moisture probe showed little, if any, migration of moisture in the concrete cross section. Destructive examination indicated that the model maintained its basic structural integrity during localized hot-spot heating.

  14. Multiphysics Modeling for Dimensional Analysis of a Self-Heated Molten Regolith Electrolysis Reactor for Oxygen and Metals Production on the Moon and Mars

    Science.gov (United States)

    Dominguez, Jesus A.; Sibille, Laurent

    2010-01-01

    The technology of direct electrolysis of molten lunar regolith to produce oxygen and molten metal alloys has progressed greatly in the last few years. The development of long-lasting inert anodes and cathode designs as well as techniques for the removal of molten products from the reactor has been demonstrated. The containment of chemically aggressive oxide and metal melts is very difficult at the operating temperatures ca 1600 C. Containing the molten oxides in a regolith shell can solve this technical issue and can be achieved by designing a self-heating reactor in which the electrolytic currents generate enough Joule heat to create a molten bath. In a first phase, a thermal analysis model was built to study the formation of a melt of lunar basaltic regolith irradiated by a focused solar beam This mode of heating was selected because it relies on radiative heat transfer, which is the dominant mode of transfer of energy in melts at 1600 C. Knowing and setting the Gaussian-type heat flux from the concentrated solar beam and the phase and temperature dependent thermal properties, the model predicts the dimensions and temperature profile of the melt. A validation of the model is presented in this paper through the experimental formation of a spherical cap melt realized by others. The Orbitec/PSI experimental setup uses an 3.6-cm diameter concentrated solar beam to create a hemispheric melt in a bed of lunar regolith simulant contained in a large pot. Upon cooling, the dimensions of the vitrified melt are measured to validate the thermal model. In a second phase, the model is augmented by multiphysics components to compute the passage of electrical currents between electrodes inserted in the molten regolith. The current through the melt generates Joule heating due to the high resistivity of the medium and this energy is transferred into the melt by conduction, convection and primarily by radiation. The model faces challenges in two major areas, the change of phase as

  15. Raman spectroscopy in the study of hydrothermal cave minerals: Implications for research on Mars

    Science.gov (United States)

    Gázquez, Fernando; Rull, Fernando; Calaforra, José-María; Martínez-Frías, Jesús; Sanz, Aurelio; Audra, Philippe

    2013-04-01

    Regarding that the ExoMars mission of the ESA, scheduled for launch in 2018 will be equipped with a Raman spectrometer, investigations by Raman spectroscopy on Earth's minerals are essential to interpret data coming from this further mission to Mars. Among terrestrial minerals, cave minerals represent an opportunity to better understand the genesis of Martian minerals and the evolution of Mars itself, in particular by studying minerals formed in hydrothermal conditions, as well as those generated due to hydrothermal alteration of previous materials. The absence of solar radiation, practically constant temperature at daily and seasonal scale and the presence of liquid water are some of the attractions which make caves interesting for Martian research. In the present work, we have studied a great variety of cave minerals from hypogenic/thermal mine-caves like the Giant Geode of Pulpí (south-eastern Spain), the caves of the Naica mine (northern Mexico), the caves of the San Giovanni Mountain (Sardinia, Italy) and Baume Galinière Cave (south-eastern France). Carbonate, sulphate, sulphurs and polymetallic oxyhydroxides are the most common minerals found in these cavities. Among them, it is worth noting the presence of several minerals of the jarosite group and gypsum, since these minerals have been recently discovered on the Mars surface. Both of them are hydrated minerals, which genetic mechanisms are linked to the presence of liquid water. In the case of jarosite minerals, identification of species like argentojarosite and plumbojarosite confers worth to the Raman technique against other methodologies, like XRD by which the characterization of the jarosite group minerals is difficult. As a consequence of the recent discovery of Ca-rich sulphates (probably gypsum) on the surface of Mars, attention has been focused on the terrestrial gypsiferous formations. The gypsum samples from the Giant Geode of Pulpí and the caves of the Naica mine, which are subject of this

  16. Study on the selection of nuclear fuel type for a hybrid power extraction reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Dong Han; Park, Won Suk [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-11-01

    The development of a subcritical transmutation reactor concept is emerging for reducing the amounts of actinides and long-lived nuclides in the spent fuel from nuclear power plants. This technology may make contribution to reduce the human risks associated with constructing radio-waste disposal facilities. One of the important issues for the design of the reactor is the selection of a suitable nuclear fuel type. Choosing the best nuclear fuel type for the reactor may not be easy since there exist several criteria associated with neutronic aspects, thermal performance, safety problem, cost problem, radiation damage in the reactor, etc. The best option should be chosen based on the maximization of our needs in this situation. This study presents a logical decision model for this issue using an analytic hierarchy process (AHP). Hierarchy is a representation of a system to study the functional relations of its components and its impact on the entire system. The study shows first how to construct hierarchy representing their relations and then measure the individual element's impact to the entire system for a quantitative decision making. Current four fuel types; metal, oxide, molten salt, and nitride, were selected and analyzed based on several characteristics with respect to overall comparison. Based on the decision model developed, the study concludes that the metal fuel type is the best choice for the transmutation reactor. The proposed approach is intended to help people be rational and logical in making decisions such complex task. 13 refs., 16 figs., 16 tabs. (Author)

  17. Study on the selection of nuclear fuel type for a hybrid power extration reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, D. H.; Park, W. S. [KAERI, Taejon (Korea, Republic of)

    1999-05-01

    In order to solve the problem related to long-lived radioactive nuclides in spent fuel, development of a subcritical transmutation reactor concept is emerging. One of the important issues for the design of the reactor may be the selection of a suitable nuclear fuel type. This study presents a logical decision model for this issue using an analytic hierachy process (AHP). Hierarchy is a representation of a system to study the functional relations of its components and its impact on the entire system. The study shows first how to construct hierachy representing their relations and then measure the individual element's impact to the entire system for a quantitative decision making. Current four fuel types; metal, oxide, molten salt, and nitride, were selected and analyzed based on several characteristics with respect to overall comparison. Based on the decision model, the study concludes that the metal fuel type is the best choice for the transmutation reactor.

  18. Theoretical study for ICRF sustained LHD type p-{sup 11}B reactor

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Tsuguhiro (ed.)

    2003-04-01

    This is a summary of the workshop on 'Theoretical Study for ICRF Sustained LHD Type p-{sup 11}B Reactor' held in National Institute for Fusion Science (NIFS) on July 25, 2002. In the workshop, study of LHD type D-{sup 3}He reactor is also reported. A review concerning the advanced nuclear fusion fuels is also attached. This review was reported at the workshop of last year. The development of the p-{sup 11}B reactor research which uses the LHD magnetic field configuration has been briefly summarized in section 1. In section 2, an integrated report on advanced nuclear fusion fuels is given. Ignition conditions in a D-{sup 3}He helical reactor are summarized in section 3. 0-dimensional particle and power balance equations are solved numerically assuming the ISS95 confinement law including a confinement factor ({gamma}{sub HH}). It is shown that high average beta plasma confinement, a large confinement factor ({gamma}{sub HH} > 3) and the hot ion mode (T{sub i}/T{sub e} > 1.4) are necessary to achieve the ignition of the D-{sup 3}He helical reactor. Characteristics of ICRF sustained p-{sup 11}B reactor are analyzed in section 4. The nuclear fusion reaction rate < {sigma}{upsilon} > is derived assuming a quasilinear plateau distribution function (QPDF) for protons, and an ignition condition of p-{sup 11}B reactor is shown to be possible. The 3 of the presented papers are indexed individually. (J.P.N.)

  19. The Monitored Atherosclerosis Regression Study (MARS). Design, methods and baseline results.

    Science.gov (United States)

    Cashin-Hemphill, L; Kramsch, D M; Azen, S P; DeMets, D; DeBoer, L W; Hwang, I; Vailas, L; Hirsch, L J; Mack, W J; DeBoer, L

    1992-10-23

    The Monitored Atherosclerosis Regression Study (MARS) was designed to evaluate the effect of cholesterol lowering by monotherapy with an HMG-CoA reductase inhibitor on progression/regression of atherosclerosis in subjects with angiographically documented coronary artery disease. The purpose of this paper is to present the design, methods, and baseline results of MARS. MARS is a prospective, randomized, double-blind, placebo-controlled trial with baseline, 2-year, and 4-year coronary angiography as well as carotid, brachial, and popliteal ultrasonography. Outpatient clinics at the University of Southern California School of Medicine and the University of Wisconsin School of Medicine. Two hundred seventy participants of both sexes were recruited directly from the cardiac catheterization laboratory or by chart review of patients having undergone cardiac catheterization in the past. Subjects were considered eligible if they had angiographically demonstrable atherosclerosis in 2 or more coronary artery segments, unaltered by angioplasty, with at least 1 lesion > or = 50% but or = 500 mg/dL; premenopausal females; uncontrolled hypertension; diabetes mellitus; untreated thyroid disease; liver dysfunction; renal insufficiency; congestive heart failure; major arrhythmia; left ventricular conduction defects; or any life-threatening disease. Subjects were placed on a low-fat, low-cholesterol diet and either 40 mg b.i.d. lovastatin (Mevacor) or placebo. Randomization was stratified by sex, smoking status, and TC. Per-subject average change in %S as determined by quantitative coronary angiography (QCA) is the primary angiographic endpoint. Secondary endpoints are: categorical analyses of the proportion of subjects with progression; human panel reading of coronary angiograms; and change in minimum lumen diameter (MLD) in mm by QCA. Carotid, brachial, and popliteal ultrasonography is also being performed. The subjects randomized into MARS are 91.5% male with an age range of 37 to

  20. Experimental study on thermal stratification in a reactor hot plenum of a Japanese demonstration LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Tomonari [Central Research Inst. of Electric Power Industry, Abiko, Chiba (Japan). Abiko Research Lab.; Yamamoto, K.; Takakuwa, M.; Kajiwara, H.; Watanabe, O.; Akamatsu, K.

    1997-12-31

    Thermal stratification which occurs in a reactor hot plenum after reactor trip has been regarded as one of the most serious phenomena in the thermal-hydraulics of LMFBR. Using a 1/8th scale water model, an experimental study has been conducted to estimate the thermal stratification for a Japanese demonstration LMFBR (DFBR). In the present study, reactor trip was simulated by changing the core outlet temperature with maintaining a constant flow rate. Temperature distribution was measured during the transient and detailed phenomena have been acquired in the study. A severe density interface on structural integrity occurs in a hot plenum under the thermal stratification. Experimental results for temperature gradient and rising speed of the density interface were estimated based on a similarity rule so that an actual condition in the DFBR could be fully discerned. (author)

  1. On the study of catalytic membrane reactor for water detritiation: Modeling approach

    Energy Technology Data Exchange (ETDEWEB)

    Liger, Karine, E-mail: karine.liger@cea.fr [CEA, DEN, DTN/SMTA/LIPC Cadarache, Saint Paul-lez-Durance F-13108 (France); Mascarade, Jérémy [CEA, DEN, DTN/SMTA/LIPC Cadarache, Saint Paul-lez-Durance F-13108 (France); Joulia, Xavier; Meyer, Xuan-Mi [Université de Toulouse, INPT, UPS, Laboratoire de Génie Chimique, 4, Allée Emile Monso, Toulouse F-31030 (France); CNRS, Laboratoire de Génie Chimique, Toulouse F-31030 (France); Troulay, Michèle; Perrais, Christophe [CEA, DEN, DTN/SMTA/LIPC Cadarache, Saint Paul-lez-Durance F-13108 (France)

    2016-11-01

    Highlights: • Experimental results for the conversion of tritiated water (using deuterium as a simulant of tritium) by means of a catalytic membrane reactor in view of tritium recovery. • Phenomenological 2D model to represent catalytic membrane reactor behavior including the determination of the compositions of gaseous effluents. • Good agreement between the simulation results and experimental measurements performed on the dedicated facility. • Explanation of the unexpected behavior of the catalytic membrane reactor by the modeling results and in particular the gas composition estimation. - Abstract: In the framework of tritium recovery from tritiated water, efficiency of packed bed membrane reactors have been successfully demonstrated. Thanks to protium isotope swamping, tritium bonded water can be recovered under the valuable Q{sub 2} form (Q = H, D or T) by means of isotope exchange reactions occurring on catalyst surface. The use of permselective Pd-based membrane allows withdrawal of reactions products all along the reactor, and thus limits reverse reaction rate to the benefit of the direct one (shift effect). The reactions kinetics, which are still little known or unknown, are generally assumed to be largely greater than the permeation ones so that thermodynamic equilibriums of isotope exchange reactions are generally assumed. This paper proposes a new phenomenological 2D model to represent catalytic membrane reactor behavior with the determination of gas effluents compositions. A good agreement was obtained between the simulation results and experimental measurements performed on a dedicated facility. Furthermore, the gas composition estimation permits to interpret unexpected behavior of the catalytic membrane reactor. In the next future, further sensitivity analysis will be performed to determine the limits of the model and a kinetics study will be conducted to assess the thermodynamic equilibrium of reactions.

  2. A Study on Conceptual Design of Fischer-Tropsch Reactors in GTL Applications

    Directory of Open Access Journals (Sweden)

    Shin Jae Sun

    2016-01-01

    Full Text Available GTL (Gas-to-liquid process is becoming an attractive technology which can produce liquid petroleum products using natural gas. As a part of preliminary design of GTL-FPSO application, process simulation analysis for conceptual design and optimization of reformers and F-T reactors are performed in GTL-FPSO applications by implementing the user made subroutine programs of kinetic equations into PRO/II PROVISION simulator. As for the F-T reactors, Plug Flow Reactor (PFR model is used with detailed kinetics equations over two different Fe based catalysts (Fe-Cu-K and K/Fe-Cu-Al. Dry reformer is also studied with Plug Flow Reactor (PFR model. In this study, simulation results are compared with available experimental data and found well agreed with experimental data for both reformer and FT reactor. The Peng-Robinson equation of state is also used to calculate the vapor phase non-idealities and vapor-liquid equilibrium. The optimum operating conditions and process simulation analysis are also presented.

  3. Study of carbon dioxide gas treatment based on equations of kinetics in plasma discharge reactor

    Science.gov (United States)

    Abedi-Varaki, Mehdi

    2017-08-01

    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.

  4. The role of mass spectrometry to study the Oklo-Bangombé natural reactors.

    Science.gov (United States)

    De Laeter, J R; Hidaka, H

    2007-01-01

    The discovery of the existence of chain reactions at the Oklo natural reactors in Gabon, Central Africa in 1972 was a triumph for the accuracy of mass spectrometric measurements, in that a 0.5% anomaly in the (235)U/(238)U ratio of certain U ore samples indicated a depletion in (235)U. Mass spectrometric techniques thereafter played a dominant role in determining the nuclear parameters of the reactor zones themselves, and in deciphering the geochemical characteristics of various elements in the U-rich ore and in the surrounding rock strata. The variations in the isotopic composition of a large number of elements, caused by a combination of nuclear fission, neutron capture and radioactive decay, provide a powerful tool for investigating this unique geological environment. Mass spectrometry can be used to measure the present-day elemental and isotopic abundances of numerous elements, so as to decipher the past history of the reactors and examine the retentivity/mobility of these elements. Many of the fission products have a radioactive decay history that have been used to date the age and duration of the reactor zones, and to provide insight into their nuclear and geochemical behavior as a function of time. The Oklo fission reactors and their near neighbor at Bangombé, some 30 km to the south-east of Oklo, are unique in that not only did they become critical some 2 x 10(9) years ago, but also the deposits have been preserved over this period of geological time. The long-term geochemical behavior of actinides and fission products have been extensively studied by a variety of mass spectrometric techniques over the past 30 years to provide us with significant information on the mobility/retentivity of this material in a natural geological repository. The Oklo-Bangombé natural reactors are therefore geological analogs that can be evaluated in terms of possible radioactive waste containment sites. As more reactor zones were discovered, it was realized that they could be

  5. Progress Toward a New/Modern Nonhydrostatic Mars General Circulation Model: Adapting MPAS-A to Study the Atmosphere of Mars

    Science.gov (United States)

    Tyler, Daniel; Barnes, Jeffrey R.

    2016-10-01

    As the database of observations of the Martian atmosphere grows to considerable size and depth, atmospheric modeling becomes more constrained. Improved models and modeling techniques are needed to maintain the scientifically productive interaction between the two specialities. We have begun a process of adapting the nonhydrostatic state-of-the-art atmospheric model for prediction across scales (MPAS-A) to study the atmosphere of Mars. Useful descriptions and references can be found at ( https://mpas-dev.github.io/ ). The key features of this model are: 1) it is global and nonhydrostatic, 2) in its basic configuration it has isotropic spatial resolution that is not hindered by a 'pole problem' as are many GCMs, 3) it is designed to be and is typically run with regions of refined resolution (allowing for true mesoscale simulations, without nest boundary issues, while being forced globally in a fully consistent fashion). Initial testing of the model under Mars conditions has been performed: with Mars topography and surface pressure, at a spatial resolution of ~60 km, and with air temperatures relaxed to a 3-D temperature field for a moderately high dust loading at winter solstice in either hemisphere. Results are fascinatingly complex, and depict a good overall agreement with the expected zonal-mean circulation under these conditions. The model is being run on Pleiades at the NAS supercomputing facility at NASA/Ames, where tests using various numbers of processor cores reveal a near-linear scalability (the decrease in elapsed wall-clock time to the number of cores). Having completed this initial testing phase, we expect to present results where the model is being run: 1) with a simple atmospheric radiation scheme, 2) with realistic surface properties and a soil model, and 3) with a capable PBL scheme. Upon reaching that point in development, we will be able to compare and contrast results from our mission-support modeling efforts for both the Mars 2020 and Insight

  6. Isovaleraldehyde elimination by UV/TiO2 photocatalysis: comparative study of the process at different reactors configurations and scales.

    Science.gov (United States)

    Assadi, Aymen Amine; Bouzaza, Abdelkrim; Wolbert, Dominique; Petit, Philippe

    2014-10-01

    A proposal for scaling-up the photocatalytic reactors is described and applied to the coated catalytic walls with a thin layer of titanium dioxide under the near ultraviolet (UV) irradiation. In this context, the photocatalytic degradation of isovaleraldehyde in gas phase is studied. In fact, the removal capacity is compared at different continuous reactors: a photocatalytic cylindrical reactor, planar reactor, and pilot unit. Results show that laboratory results can be useful for reactor design and scale-up. The flowrate increases lead to the removal capacity increases also. For example, with pilot unit, when flowrate extends four times, the degradation rate varies from 0.14 to 0.38 g h(-1) mcat (-2). The influence of UV intensity is also studied. When this parameter increases, both degradation rate and overall mineralization are enhanced. Moreover, the effects of inlet concentration, flowrate, geometries, and size of reactors on the removal capacity are also studied.

  7. Outlet plenum flow stratification studies for the Clinch River Breeder Reactor Plant

    Energy Technology Data Exchange (ETDEWEB)

    Novendstern, E.H.; Woods, M.D.; Andreychek, T.S.; Flannigan, L.J.; Carr, J.A.

    1976-01-01

    The transient temperature behavior during a simulated reactor trip was studied in a 1/3 sector, 0.55 scale model of the reactor outlet plenum of the CRBRP. Buoyancy effects were simulated using water and salt solution. Effects of variations in Richardson Number (ratio of buoyancy/inertia forces) and Froude Number (ratio of inertia/viscous forces) were evaluated. Effects of geometrical changes of a component in the outlet plenum called the Upper Internals Structure on transient temperature response were studied; both height of the structure and leakage under this component were experimentally varied. The test results confirm that flow stratification occurs in the outlet plenum following a reactor trip. The colder, denser fluid issuing from the core assemblies during the transient fills the lower portion of the plenum while the hotter fluid is trapped in the region above the outlet nozzles.

  8. Experimental study of coal topping process in a downer reactor

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.G.; Lu, X.S.; Yao, J.X.; Lin, W.G.; Cui, L.J. [Chinese Academy of Science, Beijing (China). Inst. of Processing Engineering

    2005-02-02

    Experiments were carried out in a downer reactor integrated in a circulating fluidized bed combustor to examine the performance of the coal topping process. The effects of reaction temperature and coal particle size on the product distribution and their compositions were determined. The experimental results show that an increase in temperature will increase the yields of gas and liquid product, and the liquid yield decreases with the increase in coal particle size. The experiments exhibit an optimal condition for the liquid product. When the pyrolysis temperature is 660{sup o}C and coal particle size is less than 0.2-8 mm, the yield of light tar (hexane-soluble fraction) reaches 7.5 wt % (dry coal basis). The light tar is composed of acid groups (57.1 wt %), crude gasoline (aliphatics) (12.9 wt %), aromatics (21.4 wt %), and polar and basic groups (8.6 wt %). The experiments indicate that the coal topping process is a promising technology for partially converting coal into liquid fuels and fine chemicals.

  9. A study on the recriticality possibilities of fast reactor cores after a hypothetical core meltdown accident

    Energy Technology Data Exchange (ETDEWEB)

    Na, Byung Chan; Han, Do Hee; Kim, Young Cheol

    1997-04-01

    The preliminary and parametric sensitivity study on recriticality risk of fast reactor cores after a hypothetical total core meltdown accident was performed. Only the neutronic aspects of the accident was considered for this study, independent of the accident scenario. Estimation was made for the quantities of molten fuel which must be ejected out of the core in order to assure a sub-critical state. Diverse parameters were examined: molten pool type (homogenized or stratified), fuel temperature, conditions of the reactor core, core size (small or large), and fuel type (oxide, nitride, metal) (author). 7 refs.

  10. Study of hydrogen generation plant coupled to high temperature gas cooled reactor

    Science.gov (United States)

    Brown, Nicholas Robert

    Hydrogen generation using a high temperature nuclear reactor as a thermal driving vector is a promising future option for energy carrier production. In this scheme, the heat from the nuclear reactor drives an endothermic water-splitting plant, via coupling, through an intermediate heat exchanger. While both high temperature nuclear reactors and hydrogen generation plants have high individual degrees of development, study of the coupled plant is lacking. Particularly absent are considerations of the transient behavior of the coupled plant, as well as studies of the safety of the overall plant. The aim of this document is to contribute knowledge to the effort of nuclear hydrogen generation. In particular, this study regards identification of safety issues in the coupled plant and the transient modeling of some leading candidates for implementation in the Nuclear Hydrogen Initiative (NHI). The Sulfur Iodine (SI) and Hybrid Sulfur (HyS) cycles are considered as candidate hydrogen generation schemes. Several thermodynamically derived chemical reaction chamber models are coupled to a well-known reference design of a high temperature nuclear reactor. These chemical reaction chamber models have several dimensions of validation, including detailed steady state flowsheets, integrated loop test data, and bench scale chemical kinetics. Eight unique case studies are performed based on a thorough literature review of possible events. The case studies are: (1) feed flow failure from one section of the chemical plant to another, (2) product flow failure (recycle) within the chemical plant, (3) rupture or explosion within the chemical plant, (4) nuclear reactor helium inlet overcooling due to a process holding tank failure, (5) helium inlet overcooling as an anticipated transient without SCRAM, (6) total failure of the chemical plant, (7) parametric study of the temperature in an individual reaction chamber, and (8) control rod insertion in the nuclear reactor. Various parametric

  11. A Boiling-Potassium Fluoride Reactor for an Artificial-Gravity NEP Vehicle

    Science.gov (United States)

    Sorensen, Kirk; Juhasz, Albert

    2007-01-01

    Several years ago a rotating manned spacecraft employing nuclear-electric propulsion was examined for Mars exploration. The reactor and its power conversion system essentially served as the counter-mass to an inflatable manned module. A solid-core boiling potassium reactor based on the MPRE concept of the 1960s was baselined in that study. This paper proposes the use of a liquid-fluoride reactor, employing direct boiling of potassium in the core, as a means to overcome some of the residual issues with the MPRE reactor concept. Several other improvements to the rotating Mars vehicle are proposed as well, such as Canfield joints to enable the electric engines to track the inertial thrust vector during rotation, and innovative "cold-ion" engine technologies to improve engine performance.

  12. Micro-structural study and Rietveld analysis of fast reactor fuels: U-Mo fuels

    Science.gov (United States)

    Chakraborty, S.; Choudhuri, G.; Banerjee, J.; Agarwal, Renu; Khan, K. B.; Kumar, Arun

    2015-12-01

    U-Mo alloys are the candidate fuels for both research reactors and fast breeder reactors. In-reactor performance of the fuel depends on the microstructural stability and thermal properties of the fuel. To improve the fuel performance, alloying elements viz. Zr, Mo, Nb, Ti and fissium are added in the fuel. The first reactor fuels are normally prepared by injection casting. The objective of this work is to compare microstructure, phase-fields and hardness of as-cast four different U-Mo alloy (2, 5, 10 and 33 at.% Mo) fuels with the equilibrium microstructure of the alloys. Scanning electron microscope with energy dispersive spectrometer and optical microscope have been used to characterize the morphology of the as-cast and annealed alloys. The monoclinic α'' phase in as-cast U-10 at.% Mo alloy has been characterized through Rietveld analysis. A comparison of metallographic and Rietveld analysis of as-cast (dendritic microstructure) and annealed U-33 at.% Mo alloy, corresponding to intermetallic compound, has been reported here for the first time. This study will provide in depth understanding of microstructural and phase evolution of U-Mo alloys as fast reactor fuel.

  13. Design study of lead bismuth cooled fast reactors and capability of natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Oktamuliani, Sri, E-mail: srioktamuliani@ymail.com; Su’ud, Zaki, E-mail: szaki@fi.itb.ac.id [Nuclear and Reactor Physics Laboratory, FMIPA, ITB, Physics Buildings, Jl. Ganesha 10, Bandung 40132 (Indonesia)

    2015-09-30

    A preliminary study designs SPINNOR (Small Power Reactor, Indonesia, No On-Site Refueling) liquid metal Pb-Bi cooled fast reactors, fuel (U, Pu)N, 150 MWth have been performed. Neutronic calculation uses SRAC which is designed cylindrical core 2D (R-Z) 90 × 135 cm, on the core fuel composed of heterogeneous with percentage difference of PuN 10, 12, 13% and the result of calculation is effective neutron multiplication 1.0488. Power density distribution of the output SRAC is generated for thermal hydraulic calculation using Delphi based on Pascal language that have been developed. The research designed a reactor that is capable of natural circulation at inlet temperature 300 °C with variation of total mass flow rate. Total mass flow rate affect pressure drop and temperature outlet of the reactor core. The greater the total mass flow rate, the smaller the outlet temperature, but increase the pressure drop so that the chimney needed more higher to achieve natural circulation or condition of the system does not require a pump. Optimization of the total mass flow rate produces optimal reactor design on the total mass flow rate of 5000 kg/s with outlet temperature 524,843 °C but require a chimney of 6,69 meters.

  14. Automated disposable small scale reactor for high throughput bioprocess development: a proof of concept study.

    Science.gov (United States)

    Bareither, Rachel; Bargh, Neil; Oakeshott, Robert; Watts, Kathryn; Pollard, David

    2013-12-01

    The acceleration of bioprocess development for biologics and vaccines can be enabled by automated high throughput technologies. This will alleviate the significant resource burden from the multi-factorial statistical experimentation required for controlling product quality attributes of complex biologics. Recent technology advances have improved clone evaluation and screening, but have struggled to combine the scale down criteria required for both high cell density cell culture and microbial processes, with sufficient automation and disposable technologies to accelerate process development. This article describes the proof of concept evaluations of an automated disposable small scale reactor for high throughput upstream process development. Characterization studies established the small scale stirred tank disposable 250 mL reactor as similar to those of lab and pilot scale. The reactor generated equivalent process performance for industrial biologics processes for therapeutic protein and monoclonal antibody production using CHO cell culture, Pichia pastoris and E. coli. This included similar growth, cell viability, product titer, and product quality. The technology was shown to be robust across multiple runs and met the requirements for the ability to run high cell density processes (>400 g/L wet cell weight) with exponential feeds and sophisticated event triggered processes. Combining this reactor into an automated array of reactors will ultimately be part of a high throughput process development strategy. This will combine upstream, small scale purification with rapid analytics that will dramatically shorten timelines and costs of developing biological processes.

  15. Analytical Study of High Concentration PCB Paint at the Heavy Water Components Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lowry, N.J.

    1998-10-21

    This report provides results of an analytical study of high concentration PCB paint in a shutdown nuclear test reactor located at the US Department of Energy's Savannah River Site (SRS). The study was designed to obtain data relevant for an evaluation of potential hazards associated with the use of and exposure to such paints.

  16. A Numerical Study of Possible Water Distribution in the Subsurface of Mars

    Science.gov (United States)

    Travis, B.

    2003-12-01

    Many studies of surface features on Mars conclude that large quantities of water were released across the Martian surface early in Mars' history, and that water may have continued to play a role at various times throughout that planet's history in shaping its surface, even into the present time. At present, water is found in the polar caps, but a considerable inventory may reside in the subsurface, as permafrost, and perhaps liquid water beneath. Recent analyses of thermal neutrons (Feldman et al, 2003) indicate a large region of shallow, high water content in the topsoil. But is there substantial water at depth? Clifford (1993) presented an argument for a global Martian water cycle, with basal melting at polar cap bases providing liquid water that infiltrates the subsurface and slowly migrates to the equatorial region, where it can exit through the dessicated surface and then return to the poles via atmospheric transport. Total water inventory and transit time through a Martian hydrologic cycle are still very uncertain. Numerical modeling can be useful in refining qualitative ideas, providing sensitivities, and bringing together into one dynamically consistent quantitative process various kinds of information. A 3-D numerical model of porous flow and transport, previously developed to study possible modes of hydrothermal circulation beneath permafrost under Martian conditions (Travis, Rosenberg, & Cuzzi, 2003) has been extended to include unsaturated conditions and vapor transport. It is applied to estimate possible subsurface water and permafrost distributions on Mars for a range of postulated water inventories. Travel times through a hydrologic cycle can be predicted as well.

  17. A study on the regulatory approach of safety issues for Korean next generation reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Keun Seon; Choi, Jeong Tae; Kim, In Joon [Sunmoon Univ., Asan (Korea, Republic of); Lee, Sang Hoon [Korea Association of Nuclear Technology, Taejon (Korea, Republic of); Kang, Gee Sik [Korea Power Engineering Co., Inc., Seoul (Korea, Republic of); Kim, Han Gon [Korea Electric Power Corporation, Seoul (Korea, Republic of); Park, Jae Uk; Kim, Yun Il; Yang, Soo Hyeong [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1997-10-15

    The project aims to provide the regulatory direction of major technical issues related to the quantitative criteria for probabilistic risk analysis, establishment of containment performance criteria, design of additional water source for long-term corium cooling of core debris, protection against common mode failure of digital I and C system, criteria for safety-related operator action, quantitative reliability targets, classification of plant conditions and acceptance criteria and development of graded QA. These issues are parts of major technical issues resulted from the safety regulation R and D on the next generation reactor. Regulatory directions to be applied to the Korea Next Generation Reactors in this study are developed by analyzing the state-of-the-art of the development of local and foreign regulatory requirements, research trends, and the design features and safety goals of advanced reactors.

  18. Study for identification of control rod drops in PWR reactors at any burnup step

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Thiago J.; Martinez, Aquilino S.; Medeiros, Jose A.C.C.; Goncalves, Alessandro C., E-mail: tsouza@nuclear.ufrj.br, E-mail: aquilino@lmp.ufrj.br, E-mail: canedo@lmp.ufrj.br, E-mail: alessandro@nuclear.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Nuclear; Palma, Daniel A.P., E-mail: dapalma@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    The control rod drop event in PWR reactors induces an unsafe operating condition. Therefore, in a scenario of a control rod drop is important to quickly identify the rod to minimize undesirable effects. The objective of this work is to develop an on-line method for identification of control rod drop in PWR reactors. The method consists on the construction of a tool that is based on the ex-core detector responses. Therefore, it is proposed to recognize patterns in the neutron ex-core detectors responses and thus to identify on-line a control rod drop in the core during the reactor operation. The results of the study, as well as the behavior of the detector responses, demonstrated the feasibility of this method. (author)

  19. Conceptual study of reactor control and shutdown rod drive mechanism of a SFR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Han; Kim, Jong Bum

    2012-09-15

    The conceptual design of a prototype SFR (sodium cooled Fast Reactor) of 150MWe capacity was began in 2012 through the Korea national long term R and D project by KAERI. This report describes the design concepts of a control rod drive mechanism for plant control system and a passive shutdown rod drive mechanism for reactor protection system of a SFR. The performance requirements and preliminary design values of the core power control rod drive mechanism are determined based on the KALIMER 600 and PRISM design concepts. As for the scram rod drive mechanism, several types of passive shutdown systems are introduced, several candidate design concepts are proposed and the reactor shutdown rod drive mechanism is described shortly. This report also performs the parametric design studies for the electromagnet component of the passive shutdown device. Its design feasibility is investigated for a given design installation constraint, and the necessary items for design improvements to meet the design requirements are suggested.

  20. The study of aeroball system for measuring 3D neutron flux distribution in reactor core

    Institute of Scientific and Technical Information of China (English)

    LuoZheng-Pei; LiFu; 等

    1997-01-01

    Aeroball system is attractive in several aspects because it can easily transport the map of neutron flux distribution to be measured from incore to outside of a reactor vessel.However,before the aeroball system is put to practical use in the heating reactor.there are four topics that have to be further studied.They are the stability of the activated positions,enhancement of signal/noise(S/N)ratio,distributed control and data-acquisition system and on-lin nbeutron flux distribution reconstruction.Besides describing the rasons for them,this paper gives out the theory,concept and solution about the first two topics and it is helptul to give the possibility to enhance the reactor-power.

  1. Experimental Studies of NGNP Reactor Cavity Cooling System With Water

    Energy Technology Data Exchange (ETDEWEB)

    Corradini, Michael; Anderson, Mark; Hassan, Yassin; Tokuhiro, Akira

    2013-01-16

    This project will investigate the flow behavior that can occur in the reactor cavity cooling system (RCCS) with water coolant under the passive cooling-mode of operation. The team will conduct separate-effects tests and develop associated scaling analyses, and provide system-level phenomenological and computational models that describe key flow phenomena during RCCS operation, from forced to natural circulation, single-phase flow and two-phase flow and flashing. The project consists of the following tasks: Task 1. Conduct separate-effects, single-phase flow experiments and develop scaling analyses for comparison to system-level computational modeling for the RCCS standpipe design. A transition from forced to natural convection cooling occurs in the standpipe under accident conditions. These tests will measure global flow behavior and local flow velocities, as well as develop instrumentation for use in larger scale tests, thereby providing proper flow distribution among standpipes for decay heat removal. Task 2. Conduct separate-effects experiments for the RCCS standpipe design as two-phase flashing occurs and flow develops. As natural circulation cooling continues without an ultimate heat sink, water within the system will heat to temperatures approaching saturation , at which point two-phase flashing and flow will begin. The focus is to develop a phenomenological model from these tests that will describe the flashing and flow stability phenomena. In addition, one could determine the efficiency of phase separation in the RCCS storage tank as the two-phase flashing phenomena ensues and the storage tank vents the steam produced. Task 3. Develop a system-level computational model that will describe the overall RCCS behavior as it transitions from forced flow to natural circulation and eventual two-phase flow in the passive cooling-mode of operation. This modeling can then be used to test the phenomenological models developed as a function of scale.

  2. Critical review of the reactor-safety study radiological health effects model. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, D.W.; Evans, J.S.; Jacob, N.; Kase, K.R.; Maletskos, C.J.; Robertson, J.B.; Smith, D.G.

    1983-03-01

    This review of the radiological health effects models originally presented in the Reactor Safety Study (RSS) and currently used by the US Nuclear Regulatory Commission (NRC) was undertaken to assist the NRC in determining whether or not to revise the models and to aid in the revision, if undertaken. The models as presented in the RSS and as implemented in the CRAC (Calculations of Reactor Accident Consequences) Code are described and critiqued. The major elements analyzed are those concerning dosimetry, early effects, and late effects. The published comments on the models are summarized, as are the important findings since the publication of the RSS.

  3. A study of core melting phenomena in reactor severe accident of PWR

    Energy Technology Data Exchange (ETDEWEB)

    Jeun, Gyoo Dong; Park, Shane; Kim, Jong Sun; Kim, Sung Joong [Hanyang Univ., Seoul (Korea, Republic of); Kim, Jin Man [Korea Maritime Univ., Busan (Korea, Republic of)

    2001-03-15

    In the 4th year, SCDAP/RELAP5 best estimate input data obtained from the TMI-2 accident analysis were applied to the analysis of domestic nuclear power plant. Ulchin nuclear power plant unit 3, 4 were selected as reference plant and steam generator tube rupture, station blackout SCDAP/RELAP5 calculation were performed to verify the adequacy of the best estimate input parameters and the adequacy of related models. Also, System 80+ EVSE simulation was executed to study steam explosion phenomena in the reactor cavity and EVSE load test was performed on the simplified reactor cavity geometry using TRACER-II code.

  4. Mössbauer study of EUROFER and VVER steel reactor materials

    Science.gov (United States)

    Kuzmann, E.; Horváth, Á.; Alves, L.; Silva, J. F.; Gomes, U.; Souza, C.; Homonnay, Z.

    2013-04-01

    57Fe Mössbauer spectroscopy and X-ray diffractometry were used to study EUROFER or VVER ferritic reactor steels mechanically alloyed with TaC or NbC. Significant changes were found in the Mössbauer spectra and in the corresponding hyperfine field distributions between the ball milled pure steel and that alloyed with TaC or NbC. Spectral differences were also found in the case of use of same carbides with different origin, too. The observed spectral changes as an effect of ball milling of the reactor material steels with carbides can be associated with change in short range order of the constituents of steel.

  5. Cold Model Study and Commercial Test on Novel Vapor-Liquid Distributor of Hydroprocessing Reactor

    Institute of Scientific and Technical Information of China (English)

    Wang Shaobing; Zhang Zhanzhu; Wu Defei; Guo Qingming

    2007-01-01

    A novel vapor-liquid distributor was developed on the basis of sufficient study on the existing distributors applied in hydroprocessing reactors.The cold model test data showed that the fluid distribution performance of the novel vapor-liquid distributor was evidently better than the traditional one.Commercial tests of the new distributor were carried out in the 300 kt/a gas oil hydrotreating reactor at SINOPEC Changling Branch Company,showing that the new vapor-liquid distributor could improve the fluid distribution,promote the hydrotreating efficiency and lead to better performance than the traditional one.

  6. Development of a multiplexed microfluidic proteomic reactor and its application for studying protein-protein interactions.

    Science.gov (United States)

    Tian, Ruijun; Hoa, Xuyen Dai; Lambert, Jean-Philippe; Pezacki, John Paul; Veres, Teodor; Figeys, Daniel

    2011-06-01

    Mass spectrometry-based proteomics techniques have been very successful for the identification and study of protein-protein interactions. Typically, immunopurification of protein complexes is conducted, followed by protein separation by gel electrophoresis and in-gel protein digestion, and finally, mass spectrometry is performed to identify the interacting partners. However, the manual processing of the samples is time-consuming and error-prone. Here, we developed a polymer-based microfluidic proteomic reactor aimed at the parallel analysis of minute amounts of protein samples obtained from immunoprecipitation. The design of the proteomic reactor allows for the simultaneous processing of multiple samples on the same devices. Each proteomic reactor on the device consists of SCX beads packed and restricted into a 1 cm microchannel by two integrated pillar frits. The device is fabricated using a combination of low-cost hard cyclic olefin copolymer thermoplastic and elastomeric thermoplastic materials (styrene/(ethylene/butylenes)/styrene) using rapid hot-embossing replication techniques with a polymer-based stamp. Three immunopurified protein samples are simultaneously captured, reduced, alkylated, and digested on the device within 2-3 h instead of the days required for the conventional protein-protein interaction studies. The limit of detection of the microfluidic proteomic reactor was shown to be lower than 2 ng of protein. Furthermore, the application of the microfluidic proteomic reactor was demonstrated for the simultaneous processing of the interactome of the histone variant Htz1 in wild-type yeast and in a swr1Δ yeast strain compared to an untagged control using a novel three-channel microfluidic proteomic reactor.

  7. Experimental study of the stability and activity of brines on the surface of Mars

    Science.gov (United States)

    Altheide, Travis S.

    This work contributes to the understanding of liquid water stability, with an emphasis on the role that dissolved solutes may have had on liquid water formation on Mars, past and present. In chapter 2, the stability of liquid water under martian conditions is explored through experiments on ferric sulfate brines. First, it is demonstrated that such brines can be formed starting from typical martian mineralogy. Ferric sulfates are quite soluble, up to 48 wt%, and can form solutions which remain liquid down to 205 +/-1 K at the eutectic. As a result of low water activities, these solutions exhibit evaporation rates 20 times lower than pure water. The combination of a low eutectic point and low evaporation rates allow subsurface liquids to be stable at high martian latitudes, where the majority of gullies and viscous flow features are located. Thus, the characteristics of ferric sulfate brines were further investigated in chapter 3, where the viscous properties of such solutions were measured, with respect to changing temperature and concentration. Using these results, the viscosity of these solutions on the formation of gullies was considered, where calculated fluid flow velocities were found to be in accordance with some estimates from image analyses of gully formations. In chapter 4, other Mars-relevant brines were studied and characterized under martian surface conditions. Magnesium and ferrous sulfate, and magnesium and ferric chloride brines were found to stabilize water, through lower evaporation rates and freezing point depression, much like the ferric sulfate brines. For these sulfate brines, it was found that the thermodynamic process of phase change, i.e. ice formation and/or salt crystallization, can affect the kinetic process of evaporation, through very low water activities in solution. Furthermore, in chapter 5 these studies were extended to recent results from the Phoenix mission, by examining the stability of perchlorate brines under conditions

  8. Design Study of Modular Nuclear Power Plant with Small Long Life Gas Cooled Fast Reactors Utilizing MOX Fuel

    Science.gov (United States)

    Ilham, Muhammad; Su’ud, Zaki

    2017-01-01

    Growing energy needed due to increasing of the world’s population encourages development of technology and science of nuclear power plant in its safety and security. In this research, it will be explained about design study of modular fast reactor with helium gas cooling (GCFR) small long life reactor, which can be operated over 20 years. It had been conducted about neutronic design GCFR with Mixed Oxide (UO2-PuO2) fuel in range of 100-200 MWth NPPs of power and 50-60% of fuel fraction variation with cylindrical pin cell and cylindrical balance of reactor core geometry. Calculation method used SRAC-CITATION code. The obtained results are the effective multiplication factor and density value of core reactor power (with geometry optimalization) to obtain optimum design core reactor power, whereas the obtained of optimum core reactor power is 200 MWth with 55% of fuel fraction and 9-13% of percentages.

  9. Planning Considerations for a Mars Sample Receiving Facility: Summary and Interpretation of Three Design Studies

    Science.gov (United States)

    Beaty, David W.; Allen, Carlton C.; Bass, Deborah S.; Buxbaum, Karen L.; Campbell, James K.; Lindstrom, David J.; Miller, Sylvia L.; Papanastassiou, Dimitri A.

    2009-10-01

    It has been widely understood for many years that an essential component of a Mars Sample Return mission is a Sample Receiving Facility (SRF). The purpose of such a facility would be to take delivery of the flight hardware that lands on Earth, open the spacecraft and extract the sample container and samples, and conduct an agreed-upon test protocol, while ensuring strict containment and contamination control of the samples while in the SRF. Any samples that are found to be non-hazardous (or are rendered non-hazardous by sterilization) would then be transferred to long-term curation. Although the general concept of an SRF is relatively straightforward, there has been considerable discussion about implementation planning. The Mars Exploration Program carried out an analysis of the attributes of an SRF to establish its scope, including minimum size and functionality, budgetary requirements (capital cost, operating costs, cost profile), and development schedule. The approach was to arrange for three independent design studies, each led by an architectural design firm, and compare the results. While there were many design elements in common identified by each study team, there were significant differences in the way human operators were to interact with the systems. In aggregate, the design studies provided insight into the attributes of a future SRF and the complex factors to consider for future programmatic planning.

  10. Planning considerations for a Mars Sample Receiving Facility: summary and interpretation of three design studies.

    Science.gov (United States)

    Beaty, David W; Allen, Carlton C; Bass, Deborah S; Buxbaum, Karen L; Campbell, James K; Lindstrom, David J; Miller, Sylvia L; Papanastassiou, Dimitri A

    2009-10-01

    It has been widely understood for many years that an essential component of a Mars Sample Return mission is a Sample Receiving Facility (SRF). The purpose of such a facility would be to take delivery of the flight hardware that lands on Earth, open the spacecraft and extract the sample container and samples, and conduct an agreed-upon test protocol, while ensuring strict containment and contamination control of the samples while in the SRF. Any samples that are found to be non-hazardous (or are rendered non-hazardous by sterilization) would then be transferred to long-term curation. Although the general concept of an SRF is relatively straightforward, there has been considerable discussion about implementation planning. The Mars Exploration Program carried out an analysis of the attributes of an SRF to establish its scope, including minimum size and functionality, budgetary requirements (capital cost, operating costs, cost profile), and development schedule. The approach was to arrange for three independent design studies, each led by an architectural design firm, and compare the results. While there were many design elements in common identified by each study team, there were significant differences in the way human operators were to interact with the systems. In aggregate, the design studies provided insight into the attributes of a future SRF and the complex factors to consider for future programmatic planning.

  11. AFM Studies of Lunar Soils and Application to the Mars 2001 Mission

    Science.gov (United States)

    Weitz, C. M.; Anderson, M. S.; Marshall, J.

    1999-01-01

    The upcoming Mars 01 mission will carry an Atomic Force Microscope (AFM) as part of the Mars Environmental Compatibility Assessment (MECA) instrument. By operating in a tapping mode, the AFM is capable of sub-nanometer resolution in three dimensions and can distinguish between substances of different compositions by employing phase contrast imaging. To prepare for the Mars 01 mission, we are testing the AFM on a lunar soil to determine its ability to define particle shapes and sizes and grain-surface textures. The test materials are from the Apollo 17 soil 79221, which is a mixture of agglutinates, impact and volcanic beads, and mare and highland rock and mineral fragments. The majority of the lunar soil particles are less than 100 microns in size, comparable to the sizes estimated for martian dust. We have used the AFM to examine several different soil particles at various resolutions. The instrument has demonstrated the ability to identify parallel ridges characteristic of twinning on a 150 micron plagioclase feldspar particle. Extremely small (10-100 nanometer) adhering particles are visible on the surface of the feldspar grain, and they appear elongate with smooth surfaces. Phase contrast imaging of the nanometer particles shows several compositions to be present. When the AFM was applied to a 100 micron glass spherule, it was possible to define an extremely smooth surface; this is in clear contrast to results from a basalt fragment which exhibited a rough surface texture. Also visible on the surface of the glass spherule were chains of 100 nanometer and smaller impact melt droplets. For the '01 Mars mission, the AFM is intended to define the size and shape distributions of soil particles, in combination with the NMCA optical microscope system and images from the Robot Arm Camera (RAC). These three data sets will provide a means of assessing potentially hazardous soil and dust properties. The study that we have conducted on the lunar soils now suggests that the

  12. Inertial Fusion Energy reactor design studies: Prometheus-L, Prometheus-H. Volume 2, Final report

    Energy Technology Data Exchange (ETDEWEB)

    Waganer, L.M.; Driemeyer, D.E.; Lee, V.D.

    1992-03-01

    This report contains a review of design studies for Inertial Confinement reactor. This second of three volumes discussions is some detail the following: Objectives, requirements, and assumptions; rationale for design option selection; key technical issues and R&D requirements; and conceptual design selection and description.

  13. Oklo: The fossil nuclear reactors. Physics study - Translation of chapters 6, 13 and conclusions

    Energy Technology Data Exchange (ETDEWEB)

    Naudet, R. [CEA, Paris (France)

    1996-09-01

    Three parts of the 1991 book `Oklo: reacteurs nucleaires fossiles. Etude physique` have been translated in this report. The chapters bear the titles `Study of criticality`(45 p.), `Some problems with the overall functioning of the reactor zones`(45 p.) and `Conclusions` (15 p.), respectively.

  14. A Catalytically Active Membrane Reactor for Fast, Highly Exothermic, Heterogeneous Gas Reactions. A Pilot Plant Study

    NARCIS (Netherlands)

    Veldsink, Jan W.; Versteeg, Geert F.; Swaaij, Wim P.M. van

    1995-01-01

    Membrane reactors have been frequently studied because of their ability to combine chemical activity and separation properties into one device. Due to their thermal stability and mechanical strength, ceramic membranes are preferred over polymeric ones, but small transmembrane fluxes obstruct a wides

  15. Space radiation studies at the White Sands Missile Range Fast Burst Reactor

    Science.gov (United States)

    Delapaz, A.

    1972-01-01

    The operation of the White Sands Missile Range Fast Burst Reactor is discussed. Space radiation studies in radiobiology, dosimetry, and transient radiation effects on electronic systems and components are described. Proposed modifications to increase the capability of the facility are discussed.

  16. Novel swirl-flow reactor for kinetic studies of semiconductor photocatalysis

    NARCIS (Netherlands)

    Ray, A.K; Beenackers, A.A C M

    1997-01-01

    A new two-phase swirl-flow monolithic-type reactor was designed to study the kinetics of heterogeneous photocatalytic processes on immobilized semiconductor catalysts. True kinetic rate constants for destruction of a textile dye were measured as a function of wavelength of light intensity and angle

  17. A model based on equations of kinetics to study nitrogen dioxide behavior within a plasma discharge reactor.

    Science.gov (United States)

    Abedi-Varaki, Mehdi; Ganjovi, Alireza; Shojaei, Fahimeh; Hassani, Zahra

    2015-01-01

    In this work, a zero-dimensional kinetics model is used to study the temporal behavior of different species such as charged particles, radicals and excited states inside a Dielectric Barrier Discharge plasma reactor. It is shown that, the reactor significantly reduces the concentration of nitrogen monoxide as an environmental pollutant. After a drastic increase, a decrease in the concentration of the NO2 molecules inside the reactor is seen. Nitrogen monoxide molecules with a very low concentration are produced inside the reactor and its quick conversion to other products is proved. The obtained results are compared with the existing experimental and simulation findings, whenever possible.

  18. 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

    2016-01-01

    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 locat...

  19. The minimum area requirements (MAR) for giant panda: an empirical study.

    Science.gov (United States)

    Qing, Jing; Yang, Zhisong; He, Ke; Zhang, Zejun; Gu, Xiaodong; Yang, Xuyu; Zhang, Wen; Yang, Biao; Qi, Dunwu; Dai, Qiang

    2016-12-08

    Habitat fragmentation can reduce population viability, especially for area-sensitive species. The Minimum Area Requirements (MAR) of a population is the area required for the population's long-term persistence. In this study, the response of occupancy probability of giant pandas against habitat patch size was studied in five of the six mountain ranges inhabited by giant panda, which cover over 78% of the global distribution of giant panda habitat. The probability of giant panda occurrence was positively associated with habitat patch area, and the observed increase in occupancy probability with patch size was higher than that due to passive sampling alone. These results suggest that the giant panda is an area-sensitive species. The MAR for giant panda was estimated to be 114.7 km(2) based on analysis of its occupancy probability. Giant panda habitats appear more fragmented in the three southern mountain ranges, while they are large and more continuous in the other two. Establishing corridors among habitat patches can mitigate habitat fragmentation, but expanding habitat patch sizes is necessary in mountain ranges where fragmentation is most intensive.

  20. ACS experiment for atmospheric studies on "ExoMars-2016" Orbiter

    Science.gov (United States)

    Korablev, O. I.; Montmessin, F.; Fedorova, A. A.; Ignatiev, N. I.; Shakun, A. V.; Trokhimovskiy, A. V.; Grigoriev, A. V.; Anufreichik, K. A.; Kozlova, T. O.

    2015-12-01

    ACS is a set of spectrometers for atmospheric studies (Atmospheric Chemistry Suite). It is one of the Russian instruments for the Trace Gas Orbiter (TGO) of the Russian-European "ExoMars" program. The purpose of the experiment is to study the Martian atmosphere by means of two observations regimes: sensitive trace gases measurements in solar occultations and by monitoring the atmospheric state during nadir observations. The experiment will allow us to approach global problems of Mars research such as current volcanism, and the modern climate status and its evolution. Also, the experiment is intended to solve the mystery of methane presence in the Martian atmosphere. Spectrometers of the ACS set cover the spectral range from the near IR-range (0.7 μm) to the thermal IR-range (17 μm) with spectral resolution λ/Δλ reaching 50000. The ACS instrument consists of three independent IR spectrometers and an electronics module, all integrated in a single unit with common mechanical, electrical and thermal interfaces. The article gives an overview of scientific tasks and presents the concept of the experiment.

  1. Exploring Stochastic Sampling in Nuclear Data Uncertainties Assessment for Reactor Physics Applications and Validation Studies

    Directory of Open Access Journals (Sweden)

    Alexander Vasiliev

    2016-12-01

    Full Text Available The quantification of uncertainties of various calculation results, caused by the uncertainties associated with the input nuclear data, is a common task in nuclear reactor physics applications. Modern computation resources and improved knowledge on nuclear data allow nowadays to significantly advance the capabilities for practical investigations. Stochastic sampling is the method which has received recently a high momentum for its use and exploration in the domain of reactor design and safety analysis. An application of a stochastic sampling based tool towards nuclear reactor dosimetry studies is considered in the given paper with certain exemplary test evaluations. The stochastic sampling not only allows the input nuclear data uncertainties propagation through the calculations, but also an associated correlation analysis performance with no additional computation costs and for any parameters of interest can be done. Thus, an example of assessment of the Pearson correlation coefficients for several models, used in practical validation studies, is shown here. As a next step, the analysis of the obtained information is proposed for discussion, with focus on the systems similarities assessment. The benefits of the employed method and tools with respect to practical reactor dosimetry studies are consequently outlined.

  2. A study on the irradiation embrittlement and recovery characteristics of light water reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Se Hwan; Hong, Jun Hwa; Lee, Bong Sang; Oh, Jong Myung; Song, Sook Hyang; Milan, Brumovsky [NRI Czech (Czech Republic)

    1999-03-01

    The neutron irradiation embrittlement phenomenon of light water RPV steels greatly affects the life span for safe operation of a reactor. Reliable evaluation and prediction of the embrittlement of RPV steels, especially of aged reactors, are of importance to the safe operation of a reactor. In addition, the thermal recovery of embrittled RPV has been recognized as an option for life extension. This study aimed to tracer/refine available technologies for embrittlement characterization and prediction, to prepare relevant materials for several domestic RPV steels of the embrittlement and recovery, and to find out possible remedy for steel property betterment. Small specimen test techniques, magnetic measurement techniques, and the Meechan and Brinkmann's recovery curve analysis method were examined/applied as the evaluation techniques. Results revealed a high irradiation sensitivity in YG 3 RPV steel. Further extended study may be urgently needed. Both the small specimen test technique for the direct determination of fracture toughness, and the magnetic measurement technique for embrittlement evaluation appeared to be continued for the technical improvement and data base preparation. Manufacturing process relevant to the heat treatment appeared to be improved in lowering the irradiation sensitivity of the steel. Further study is needed especially in applying the present techniques to the new structural materials under new irradiation environment of advanced reactors. (author)

  3. A comparative study between control strategies for a solar sailcraft in an Earth-Mars transfer

    Science.gov (United States)

    Mainenti-Lopes, I.; Souza, L. C. Gadelha; De Sousa, Fabiano. L.

    2016-10-01

    The goal of this work was a comparative study of solar sail trajectory optimization using different control strategies. Solar sailcraft is propulsion system with great interest in space engineering, since it uses solar radiation to propulsion. So there is no need for propellant to be used, thus it can remains active throughout the entire transfer maneuver. This type of propulsion system opens the possibility to reduce the cost of exploration missions in the solar system. In its simplest configuration, a Flat Solar Sail (FSS) consists of a large and thin structure generally composed by a film fixed to flexible rods. The performance of these vehicles depends largely on the sails attitude relative to the Sun. Using a FSS as propulsion, an Earth-Mars transfer optimization problem was tackled by the algorithms GEOreal1 and GEOreal2 (Generalized Extremal Optimization with real codification). Those algorithms are Evolutionary Algorithms (AE) based on the theory of Self-Organized Criticality. They were used to optimize the FSS attitude angle so it could reach Mars orbit in minimum time. It was considered that the FSS could perform up to ten attitude maneuvers during orbital transfer. Moreover, the time between maneuvers can be different. So, the algorithms had to optimize an objective function with 20 design variables. The results obtained in this work were compared with previously results that considered constant values of time between maneuvers.

  4. SEM morphological studies of carbonates and the search for ancient life on Mars

    Science.gov (United States)

    D'Elia, M.; Blanco, A.; Galiano, A.; Orofino, V.; Fonti, S.; Mancarella, F.; Guido, A.; Russo, F.; Mastandrea, A.

    2017-04-01

    Next space missions will investigate the possibility of extinct or extant life on Mars. Studying the infrared spectral modifications, induced by thermal processing on different carbonate samples (recent shells and fossils of different ages), we developed a method able to discriminate biogenic carbonates from their abiogenic counterparts. The method has been successfully applied to microbialites, i.e. bio-induced carbonates deposits, and particularly to stromatolites, the laminated fabric of microbialites, some of which can be ascribed to among the oldest traces of biological activity known on Earth. These results are of valuable importance since such carbonates are linked to primitive living organisms that can be considered as good analogues for putative Martian life forms. Considering that the microstructures of biogenic carbonate are different from those of abiogenic origin, we investigated the micromorphology of shells, skeletal grains and microbialites at different scale with a scanning electron microscope. The results show that this line of research may provide an alternative and complementary approach to other techniques developed in the past by our group to distinguish biotic from abiotic carbonates. In this paper, we present some results that can be of valuable interest since they demonstrate the utility for a database of images concerning the structures and textures of relevant carbonate minerals. Such data may be useful for the analysis of Martian samples, coming from sample return missions or investigated by future in situ explorations, aimed to characterize the near-subsurface of Mars in search for past or present life.

  5. Study of the thermal decomposition of petrochemical sludge in a pilot plant reactor

    OpenAIRE

    Conesa Ferrer, Juan Antonio; Moltó Berenguer, Julia; Ariza, José; Ariza, María; García Barneto, Agustín

    2014-01-01

    The pyrolysis of a sludge produced in the waste water treatment plant of an oil refinery was studied in a pilot plant reactor provided with a system for condensation of semivolatile matter. The study comprises experiments at 350, 400, 470 and 530 °C in nitrogen atmosphere. Analysis of all the products obtained (gases, liquids and chars) are presented, with a thermogravimetric study of the char produced and analysis of main components of the liquid. In the temperature range studied, the compos...

  6. Autonomous Control of Space Nuclear Reactors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Nuclear reactors to support future lunar and Mars robotic and manned missions impose new and innovative technological requirements for their control and protection...

  7. A Study on the Optimal Position for the Secondary Neutron Source in Pressurized Water Reactors

    Directory of Open Access Journals (Sweden)

    Jungwon Sun

    2016-12-01

    Full Text Available This paper presents a new and efficient scheme to determine the optimal neutron source position in a model near-equilibrium pressurized water reactor, which is based on the OPR1000 Hanul Unit 3 Cycle 7 configuration. The proposed scheme particularly assigns importance of source positions according to the local adjoint flux distribution. In this research, detailed pin-by-pin reactor adjoint fluxes are determined by using the Monte Carlo KENO-VI code from solutions of the reactor homogeneous critical adjoint transport equations. The adjoint fluxes at each allowable source position are subsequently ranked to yield four candidate positions with the four highest adjoint fluxes. The study next simulates ex-core detector responses using the Monte Carlo MAVRIC code by assuming a neutron source is installed in one of the four candidate positions. The calculation is repeated for all positions. These detector responses are later converted into an inverse count rate ratio curve for each candidate source position. The study confirms that the optimal source position is the one with very high adjoint fluxes and detector responses, which is interestingly the original source position in the OPR1000 core, as it yields an inverse count rate ratio curve closest to the traditional 1/M line. The current work also clearly demonstrates that the proposed adjoint flux-based approach can be used to efficiently determine the optimal geometry for a neutron source and a detector in a modern pressurized water reactor core.

  8. Theoretical Study of Palladium Membrane Reactor Performance During Propane Dehydrogenation Using CFD Method

    Directory of Open Access Journals (Sweden)

    Kamran Ghasemzadeh

    2017-04-01

    Full Text Available This study presents a 2D-axisymmetric computational fluid dynamic (CFD model to investigate the performance Pd membrane reactor (MR during propane dehydrogenation process for hydrogen production. The proposed CFD model provided the local information of temperature and component concentration for the driving force analysis. After investigation of mesh independency of CFD model, the validation of CFD model results was carried out by other modeling data and a good agreement between CFD model results and theoretical data was achieved. Indeed, in the present model, a tubular reactor with length of 150 mm was considered, in which the Pt-Sn-K/Al2O3 as catalyst were filled in reaction zone. Hence, the effects of the important operating parameter (reaction temperature on the performances of membrane reactor (MR were studied in terms of propane conversion and hydrogen yield. The CFD results showed that the suggested MR system during propane dehydrogenation reaction presents higher performance with respect to once obtained in the conventional reactor (CR. In particular, by applying Pd membrane, was found that propane conversion can be increased from 41% to 49%. Moreover, the highest value of propane conversion (X = 91% was reached in case of Pd-Ag MR. It was also established that the feed flow rate of the MR is to be the one of the most important factors defining efficiency of the propane dehydrogenation process.

  9. SiO2 aerosol nanoparticle reactor for occupational health and safety studies.

    Science.gov (United States)

    Ostraat, Michele L; Swain, Keith A; Krajewski, James J

    2008-06-01

    Important questions are emerging about potential occupational safety, toxicological, and ecotoxicological effects and occupational inhalation exposure risks to engineered aerosol nanoparticles. Although multiple avenues are available to synthesize nanoparticles, few tools are accessible to industrial hygienists and inhalation toxicologists to produce well-characterized aerosols of known aerosol size distribution and particle number concentration that are stable, simple, and robust to operate. This article describes a SiO(2) aerosol nanoparticle reactor that has been developed as a tool for the study of the safety, health, and environmental consequences of exposure to nanoparticle synthesis and processing. The SiO(2) aerosol nanoparticle reactor is capable of stable, long-term synthesis of amorphous SiO(2) aerosol nanoparticles from d(50) = 10-70 nm at particle concentrations approximately 10(4)-10(7)particles/cm(3) that does not produce halogen-containing byproducts and does not require daily monitoring of the particle size distribution. This reactor is designed to produce a well-characterized aerosol to enable subsequent testing with a continuous, stable supply of aerosol nanoparticles (i) to facilitate inhalation toxicology studies, (ii) to measure explosion characteristics of aerosol nanoparticles, (iii) to determine the barrier efficacy for respirator filtration, bag house exhaust, and personal protective garment media challenged with diverse aerosol nanoparticles, and (iv) to develop airborne monitoring technologies for verifying workplace safety protocols. This article details reactor design, synthesis parameters, and instruments available to characterize the resulting aerosol nanoparticle size distributions.

  10. An experimental study of hypervapotron structure in external reactor vessel cooling

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yufeng; Zhang, Ming [State Nuclear Power Technology R& D Center (Beijing), Beijing (China); Hou, Fangxin [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing (China); Gao, Tianfang [State Nuclear Power Technology R& D Center (Beijing), Beijing (China); Chen, Peipei, E-mail: chenpeipei@snptc.com.cn [State Power Investment Group Corporation, Beijing (China)

    2016-07-15

    Highlights: • Experiments are performed to study the application of hypervapotron in ERVC design. • CHF experiments on two surfaces are conducted under different flow conditions. • Hypervapotron improves CHF performance by 40–60% compared with smooth surface. • Visualization shows fin structure removes vapor mushroom for better liquid supply. - Abstract: In vessel retention (IVR) is one of the key strategies for many advanced LWR designs to mitigate postulated severe accidents. The success of IVR substantially relies on external reactor vessel cooling (ERVC) by which the decay heat is removed from the melt core in the reactor vessel lower head. The main challenge of IVR is to provide an adequate safety margin of ERVC against critical heat flux (CHF) of subcooled flow boiling in the reactor lower head flow channel. Due to uncertainties in corium melt pool configuration, large CHF margin of ERVC is usually required by regulatory authorities to demonstrate reliability of severe accident mitigation methods. Various CHF enhancement designs have been proposed and studied in literature. In this paper, an experimental study of hypervapotron structure as a novel design to improve CHF performance of ERVC is conducted. Hypervapotron is chosen as one of the potential engineering options for International Thermonuclear Experimental Reactor (ITER) program as a divertor structure to remove highly intense heat from fusion chamber. This study is to conduct CHF experiments at typical PWR ERVC working conditions. The CHF experiments are performed in a 30 mm by 61 mm rectangular flow channel with a 200 mm long heated surface along the flow direction. Both smooth and hypervapotron surface are tested at various inclination angles of the test section to simulate various positions of the reactor lower head. The hypervapotron is found to have a 40–60% CHF improvement compared with the smooth surface. The high speed visualization indicates that hypervapotron is able to

  11. Study of Pu consumption in Advanced Light Water Reactors. Evaluation of GE Advanced Boiling Water Reactor plants

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-13

    Timely disposal of the weapons plutonium is of paramount importance to permanently safeguarding this material. GE`s 1300 MWe Advanced Boiling Water Reactor (ABWR) has been designed to utilize fill] core loading of mixed uranium-plutonium oxide fuel. Because of its large core size, a single ABWR reactor is capable of disposing 100 metric tons of plutonium within 15 years of project inception in the spiking mode. The same amount of material could be disposed of in 25 years after the start of the project as spent fuel, again using a single reactor, while operating at 75 percent capacity factor. In either case, the design permits reuse of the stored spent fuel assemblies for electrical energy generation for the remaining life of the plant for another 40 years. Up to 40 percent of the initial plutonium can also be completely destroyed using ABWRS, without reprocessing, either by utilizing six ABWRs over 25 years or by expanding the disposition time to 60 years, the design life of the plants and using two ABWRS. More complete destruction would require the development and testing of a plutonium-base fuel with a non-fertile matrix for an ABWR or use of an Advanced Liquid Metal Reactor (ALMR). The ABWR, in addition, is fully capable of meeting the tritium target production goals with already developed target technology.

  12. Study on the properties of the fuel compact for High Temperature Gas-cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chung-yong; Lee, Sung-yong; Choi, Min-young; Lee, Seung-jae; Jo, Young-ho [KEPCO Nuclear Fuel, Daejeon (Korea, Republic of); Lee, Young-woo; Cho, Moon-sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    High Temperature Gas-cooled Reactors (HTGR), one of the Gen-IV reactors, have been using the fuel element which is manufactured by the graphite matrix, surrounding Tristructural-isotropic (TRISO)-coated Uranium particles. Factors with these characteristics effecting on the matrix of fuel compact are chosen and their impacts on the properties are studied. The fuel elements are considered with two types of concepts for HTGR, which are the block type reactor and the pebble bed reactor. In this paper, the cylinder-formed fuel element for the block type reactor is focused on, which consists of the large part of graphite matrix. One of the most important properties of the graphite matrix is the mechanical strength with the high reliability because the graphite matrix should be enabled to protect the TRISO particles from the irradiation environment and the impact from the outside. In this study, the three kinds of candidate graphites and the two kinds of candidate binder (Phenol and Polyvinyl butyral) were chosen and mixed with each other, formed and heated to measure mechanical properties. The objective of this research is to optimize the materials and composition of the mixture and the forming process by evaluating the mechanical properties before/after carbonization and heat treatment. From the mechanical test results, the mechanical properties of graphite pellets was related to the various conditions such as the contents and kinds of binder, the kinds of graphite and the heat treatments. In the result of the compressive strength and Vicker's hardness, the 10 wt% phenol binder added R+S graphite pellet was relatively higher mechanical properties than other pellets. The contents of Phenol binder, the kinds of graphite powder and the temperature of carbonization and heat treatment are considered important factors for the properties. To optimize the mechanical properties of fuel elements, the role of binders and the properties of graphites will be investigated as

  13. Nuclear Thermal Rocket/Vehicle Characteristics And Sensitivity Trades For NASA's Mars Design Reference Architecture (DRA) 5.0 Study

    Science.gov (United States)

    Borowski, Stanley K.; McCurdy, David R.; Packard, Thomas W.

    2009-01-01

    This paper summarizes Phase I and II analysis results from NASA's recent Mars DRA 5.0 study which re-examined mission, payload and transportation system requirements for a human Mars landing mission in the post-2030 timeframe. Nuclear thermal rocket (NTR) propulsion was again identified as the preferred in-space transportation system over chemical/aerobrake because of its higher specific impulse (I(sub sp)) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit (IMLEO) which is important for reducing the number of Ares-V heavy lift launches and overall mission cost. DRA 5.0 features a long surface stay (approximately 500 days) split mission using separate cargo and crewed Mars transfer vehicles (MTVs). All vehicles utilize a common core propulsion stage with three 25 klbf composite fuel NERVA-derived NTR engines (T(sub ex) approximately 2650 - 2700 K, p(sub ch) approximately 1000 psia, epsilon approximately 300:1, I(sub sp) approximately 900 - 910 s, engine thrust-toweight ratio approximately 3.43) to perform all primary mission maneuvers. Two cargo flights, utilizing 1-way minimum energy trajectories, pre-deploy a cargo lander to the surface and a habitat lander into a 24-hour elliptical Mars parking orbit where it remains until the arrival of the crewed MTV during the next mission opportunity (approximately 26 months later). The cargo payload elements aerocapture (AC) into Mars orbit and are enclosed within a large triconicshaped aeroshell which functions as payload shroud during launch, then as an aerobrake and thermal protection system during Mars orbit capture and subsequent entry, descent and landing (EDL) on Mars. The all propulsive crewed MTV is a 0-gE vehicle design that utilizes a fast conjunction trajectory that allows approximately 6-7 month 1-way transit times to and from Mars. Four 12.5 kW(sub e) per 125 square meter rectangular photovoltaic arrays provide the crewed MTV with

  14. Novel high-temperature reactors for in situ studies of three-way catalysts using turbo-XAS.

    Science.gov (United States)

    Guilera, Gemma; Gorges, Bernard; Pascarelli, Sakura; Vitoux, Hugo; Newton, Mark A; Prestipino, Carmelo; Nagai, Yasutaka; Hara, Naoyuki

    2009-09-01

    Two novel high-temperature reactors for in situ X-ray absorption spectroscopy (XAS) measurements in fluorescence are presented, each of them being optimized for a particular purpose. The powerful combination of these reactors with the turbo-XAS technique used in a dispersive-XAS beamline permits the study of commercial three-way catalysts under realistic gas composition and temporal conditions.

  15. Techniques in Gas-Phase Thermolyses. Part 6. Pulse Pyrolysis: Gas Kinetic Studies in an Inductively Heated Flow Reactor

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Bo, P.; Carlsen, Lars

    1985-01-01

    A prototype of an inductively heated flow reactor for gas kinetic studies is presented. The applicability of the system, which is based on a direct coupling between the reactor and the ion source of a mass spectrometer, is illustrated by investigations of a series of simple bond fission reactions...

  16. Mars @ ASDC

    Science.gov (United States)

    Carraro, Francesco

    "Mars @ ASDC" is a project born with the goal of using the new web technologies to assist researches involved in the study of Mars. This project employs Mars map and javascript APIs provided by Google to visualize data acquired by space missions on the planet. So far, visualization of tracks acquired by MARSIS and regions observed by VIRTIS-Rosetta has been implemented. The main reason for the creation of this kind of tool is the difficulty in handling hundreds or thousands of acquisitions, like the ones from MARSIS, and the consequent difficulty in finding observations related to a particular region. This led to the development of a tool which allows to search for acquisitions either by defining the region of interest through a set of geometrical parameters or by manually selecting the region on the map through a few mouse clicks The system allows the visualization of tracks (acquired by MARSIS) or regions (acquired by VIRTIS-Rosetta) which intersect the user defined region. MARSIS tracks can be visualized both in Mercator and polar projections while the regions observed by VIRTIS can presently be visualized only in Mercator projection. The Mercator projection is the standard map provided by Google. The polar projections are provided by NASA and have been developed to be used in combination with APIs provided by Google The whole project has been developed following the "open source" philosophy: the client-side code which handles the functioning of the web page is written in javascript; the server-side code which executes the searches for tracks or regions is written in PHP and the DB which undergoes the system is MySQL.

  17. Experimental Study on the Hydrodynamics and Mass Transfer Characteristics of Airlift Loop Reactors(ALR)

    Institute of Scientific and Technical Information of China (English)

    Tang Lixin; Han Pingfang; Lu Xiaoping

    2007-01-01

    The promoting effect of ultrasonic wave on the hydrodynamics and mass transfer characteristics of the airlift loop reactor was studied. The effect of the airlift reactor and ultrasonic wave on the reactor's gas holdup, liquid circulation velocity, mixing time and overall volumetric mass transfer coefficient respectively with and without the presence of ultrasonic wave is empathetically examined and compared. The experiment has proven that the incorporation of ultrasonic wave has no effect on the gas holdup but has the tendency to gradually decrease the liquid circulation velocity and increase the overall volumetric mass transfer coefficient; the effect on the mixing time is relatively complex. At low gas velocity, low powered ultrasonic wave promotes the radial mixing of fluid; with the increase of ultrasonic power, ultrasonic vibration obstructs the radial mixing of fluid. Therefore, there exists an optimal ultrasonic power. Moreover, the effect of ultrasonic wave on the mixing time gradually decreases with the increase of the superficial gas velocity. Correlations were also proposed for the hydrodynamics and mass transfer characteristics of the reactor.

  18. Design Study of Small Pb-Bi Cooled Modified Candle Reactors

    Science.gov (United States)

    Su'ud, Zaki; Sekimoto, H.

    2010-06-01

    In this study application of modified CANDLE burnup scheme based long life Pb-Bi Cooled Fast Reactors for small long life reactors with natural Uranium as Fuel Cycle Input has been performed. The reactor cores are subdivided into several parts with the same volume in the axial directions. The natural uranium is initially put in region 1, after one cycle of 10 years of burn-up it is shifted to region 2, and 10 years after that it is shifted to region 3. This concept is applied to all regions, i.e. shifted the core of I'th region into I+1 region after the end of 10 years burn-up cycle. The first region 1 is filled by fresh natural uranium fuel. Compared to the previous works, in a smaller reactor core the criticality need to be considered more carefully especially at the beginning of life. As an optimized design, a core of 85 cm radius and 150 cm height with 300 MWt power are selected. This core can be operated 10 years without refueling or fuel shuffling. The average discharge burn-up is 350 GWd/ton HM.

  19. A Study on Comparison of HANARO and KIJANG Research Reactor in Nuclear Safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Juang; Lee, Sung Ho; Kim, Hyun-Jo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    As one of major national projects for nuclear science and engineering in Korea, the KIJANG Research Reactor(KJRR) project was commenced in order to develop the core research reactor(RR) technologies for strengthening the competitiveness of the RR export and also to stabilize the supply of key radioisotopes for medical and industrial applications. This paper is about applying IAEA safeguards at new nuclear facility (KJRR). The beginning of this project is comparing of HANARO and KIJANG research reactor in nuclear safeguards for nuclear material accountancy method. As mentioned before, research reactor is basically item counting facility. In Fig 1, first two processes are belonging to item counting. But last two processes are for bulk handling. So KIJANG RR would be treated item counting facility as well as bulk handling facility by fission moly production facility. For this reason, nuclear material accountancy method for KJRR is not easy compared to existing one. This paper accounted for solution of KJRR nuclear material accountancy briefly. Future study on the suitable nuclear material accountancy method for mixed facility between item counting facility and bulk handling facility will be conducted more specifically.

  20. Radar studies of the planets. [radar measurements of lunar surface, Mars, Mercury, and Venus

    Science.gov (United States)

    Ingalls, R. P.; Pettengill, G. H.; Rogers, A. E. E.; Sebring, P. B. (Editor); Shapiro, I. I.

    1974-01-01

    The radar measurements phase of the lunar studies involving reflectivity and topographic mapping of the visible lunar surface was ended in December 1972, but studies of the data and production of maps have continued. This work was supported by Manned Spacecraft Center, Houston. Topographic mapping of the equatorial regions of Mars has been carried out during the period of each opposition since that of 1967. The method comprised extended precise traveling time measurements to a small area centered on the subradar point. As measurements continued, planetary motions caused this point to sweep out extensive areas in both latitude and longitude permitting the development of a fairly extensive topographical map in the equatorial region. Radar observations of Mercury and Venus have also been made over the past few years. Refinements of planetary motions, reflectivity maps and determinations of rotation rates have resulted.

  1. Numerical Study of Thermal Hydraulics for Secondary side of Steam Generator by CUPID/MARS Coupled Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Ryong; Yoon, Han Young [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    As a thermal-hydraulic behavior in the secondary side of steam generator such as two-phase boiling flow, flow-induce vibration of U-tubes is quite complicated, the importance to numerically investigate the flow behavior has been arisen. Recently, multi-scale analyses have been developed to take into account the primary side as well. In this study, the coupled CUPID and MARS code was used for the simulation of boiler side of the PWR steam generator. Calculation results are compared with the existing code quantitatively. Coupled CUPID/MARS code was applied for the simulation of the steam generator. The primary side of the steam generator and other RCS was simulated by MARS and the secondary side was calculated by CUPID with porous media approach.

  2. Experimental and computational studies of thermal mixing in next generation nuclear reactors

    Science.gov (United States)

    Landfried, Douglas Tyler

    The Very High Temperature Reactor (VHTR) is a proposed next generation nuclear power plant. The VHTR utilizes helium as a coolant in the primary loop of the reactor. Helium traveling through the reactor mixes below the reactor in a region known as the lower plenum. In this region there exists large temperature and velocity gradients due to non-uniform heat generation in the reactor core. Due to these large gradients, concern should be given to reducing thermal striping in the lower plenum. Thermal striping is the phenomena by which temperature fluctuations in the fluid and transferred to and attenuated by surrounding structures. Thermal striping is a known cause of long term material failure. To better understand and predict thermal striping in the lower plenum two separate bodies of work have been conducted. First, an experimental facility capable of predictably recreating some aspects of flow in the lower plenum is designed according to scaling analysis of the VHTR. Namely the facility reproduces jets issuing into a crossflow past a tube bundle. Secondly, extensive studies investigate the mixing of a non-isothermal parallel round triple-jet at two jet-to-jet spacings was conducted. Experimental results were validation with an open source computational fluid dynamics package, OpenFOAMRTM. Additional care is given to understanding the implementation of the realizable k-a and Launder Gibson RSM turbulence Models in OpenFOAMRTM. In order to measure velocity and temperature in the triple-jet experiment a detailed investigation of temperature compensated hotwire anemometry is carried out with special concern being given to quantify the error with the measurements. Finally qualitative comparisons of trends in the experimental results and the computational results is conducted. A new and unexpected physical behavior was observed in the center jet as it appeared to spread unexpectedly for close spacings (S/Djet = 1.41).

  3. Results of FY 2001 feasibility studies on commercialized fast reactor cycle system phase-II

    Energy Technology Data Exchange (ETDEWEB)

    Noda, Hiroshi; Yamashita, Hidetoshi; Maeda, Fumio; Sato, Kazujiro; Ieda, Yoshiaki; Funasaka, Hideyuki [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan)

    2002-09-01

    Feasibility Studies on Commercialized Fast Reactor (FR) Cycle System Phase-II were commenced on April 1, 2001, in order to select a few promising candidate concepts for commercialization from the candidate concepts of the FR system and fuel cycle system which were screened in Phase-I, and to present an outline plan for Phase-III onward. In FY 2001, which was the first year of Phase-II, the results of Phase-I and the plan for Phase-II were evaluated as appropriate by The R and D Project Evaluation Committee. With regard to the sodium-cooled medium-scale modular reactor and lead-bismuth cooled modular reactor, economical targets are expected to be achieved. In terms of the gas-cooled reactor, the helium gas-cooled reactor (coated particle fuel type and dispersion fuel type) was screened as a candidate concept. For the reprocessing system, a feasibility of the process for the crystallization method on the advanced aqueous method was confirmed. With regard to the oxide electrowinning method, the technological feasibility of MOX electrowinning co-precipitation was confirmed. In terms of the metal electrowinning method, the possibility of system rationalization was confirmed by Pu recovery testing at liquid Cd cathode. For the fuel fabrication system, in terms of the pelletizing method, the ease of remote-controlled fabrication of low-decontamination TRU fuels was confirmed, and in terms of the vibration compaction method, the packing density is expected to be satisfied as regards the design requirement. With regard to the casting method, the operation parameters of the injection casting technology, which were satisfied to slug specification requirements, were grasped by engineering-scale testing. (author)

  4. Design of an Air-Sparged Tubular Photocatalytic Reactor for the Degradation of Methylene Blue: Mass-Transfer Limitation Studies

    Directory of Open Access Journals (Sweden)

    Ramoso Patrick

    2016-01-01

    Full Text Available An alternative process for the removal of organic pollutants in aqueous systems is photocatalysis. The challenges hindering its industrial use are electron-hole recombination and mass-transfer limitations. In order to address these problems, the objective of this study is to introduce air by sparging, and design an air-sparged photocatalytic reactor using titanium dioxide immobilized on borosilicate glass. The performance of the reactor on the removal of the model pollutant, methylene blue (MB, was evaluated and compared against the reactor operated without sparging. The effect of mass-transfer limitations on reactor performance was also investigated by regression using a Langmuir-type model equation. The sparged photocatalytic reactor was able to degrade 57% MB in 2 hours, an improvement of 40% compared to no sparging, and is comparable to similar reactors in literature, but with the advantage of using less expensive materials of construction and simpler immobilization technique. Mass-transfer limitation studies showed a good fitting of the initial reaction rate r, with r = 0.1399Q / (0.6120 + Q for the sparged operation, and Q is the volumetric flowrate of water (L/min. The model also shows that the reactor operates near the reaction-limited regime, and that the extent of mass-transfer limitation effects was reduced by the present reactor.

  5. Organics on Mars : Laboratory studies of organic material under simulated martian conditions

    NARCIS (Netherlands)

    Kate, Inge Loes ten

    2006-01-01

    The search for organic molecules and traces of life on Mars has been a major topic in planetary science for several decades, and is the future perspective of several missions to Mars. In order to determine where and what those missions should be looking for, laboratory experiments under simulated Ma

  6. Organics on Mars : Laboratory studies of organic material under simulated martian conditions

    NARCIS (Netherlands)

    Kate, Inge Loes ten

    2006-01-01

    The search for organic molecules and traces of life on Mars has been a major topic in planetary science for several decades, and is the future perspective of several missions to Mars. In order to determine where and what those missions should be looking for, laboratory experiments under simulated

  7. Organics on Mars : Laboratory studies of organic material under simulated martian conditions

    NARCIS (Netherlands)

    Kate, Inge Loes ten

    2006-01-01

    The search for organic molecules and traces of life on Mars has been a major topic in planetary science for several decades, and is the future perspective of several missions to Mars. In order to determine where and what those missions should be looking for, laboratory experiments under simulated Ma

  8. Research at ITER towards DEMO: Specific reactor diagnostic studies to be carried out on ITER

    Energy Technology Data Exchange (ETDEWEB)

    Krasilnikov, A. V.; Kaschuck, Y. A.; Vershkov, V. A.; Petrov, A. A.; Petrov, V. G.; Tugarinov, S. N. [Institution Project center ITER, Moscow (Russian Federation)

    2014-08-21

    In ITER diagnostics will operate in the very hard radiation environment of fusion reactor. Extensive technology studies are carried out during development of the ITER diagnostics and procedures of their calibration and remote handling. Results of these studies and practical application of the developed diagnostics on ITER will provide the direct input to DEMO diagnostic development. The list of DEMO measurement requirements and diagnostics will be determined during ITER experiments on the bases of ITER plasma physics results and success of particular diagnostic application in reactor-like ITER plasma. Majority of ITER diagnostic already passed the conceptual design phase and represent the state of the art in fusion plasma diagnostic development. The number of related to DEMO results of ITER diagnostic studies such as design and prototype manufacture of: neutron and γ–ray diagnostics, neutral particle analyzers, optical spectroscopy including first mirror protection and cleaning technics, reflectometry, refractometry, tritium retention measurements etc. are discussed.

  9. Research at ITER towards DEMO: Specific reactor diagnostic studies to be carried out on ITER

    Science.gov (United States)

    Krasilnikov, A. V.; Kaschuck, Y. A.; Vershkov, V. A.; Petrov, A. A.; Petrov, V. G.; Tugarinov, S. N.

    2014-08-01

    In ITER diagnostics will operate in the very hard radiation environment of fusion reactor. Extensive technology studies are carried out during development of the ITER diagnostics and procedures of their calibration and remote handling. Results of these studies and practical application of the developed diagnostics on ITER will provide the direct input to DEMO diagnostic development. The list of DEMO measurement requirements and diagnostics will be determined during ITER experiments on the bases of ITER plasma physics results and success of particular diagnostic application in reactor-like ITER plasma. Majority of ITER diagnostic already passed the conceptual design phase and represent the state of the art in fusion plasma diagnostic development. The number of related to DEMO results of ITER diagnostic studies such as design and prototype manufacture of: neutron and γ-ray diagnostics, neutral particle analyzers, optical spectroscopy including first mirror protection and cleaning technics, reflectometry, refractometry, tritium retention measurements etc. are discussed.

  10. Study of the pyrochemical treatment-recycling process of the Molten Salt Reactor fuel; Estudio de sistema de un proceso de tratamiento-reciclaje piroquimico del combustible de un reactor de sales fundidas

    Energy Technology Data Exchange (ETDEWEB)

    Boussier, H.; Heuer, D.

    2010-07-01

    The Separation Processes Studies Laboratory (Commissariat a l'energie Atomique) has made a preliminary assessment of the reprocessing system associated with Molten Salt Fast Reactor (MSFR). The scheme studied in this paper is based on the principle of reductive extraction and metal transfer that constituted the core process designed for the Molten Salt Breeder Reactor (MSBR), although the flow diagram has been adapted to the current needs of the Molten Salt Fast Reactor (MSFR).

  11. Reactor Physics Programme

    Energy Technology Data Exchange (ETDEWEB)

    De Raedt, C

    2000-07-01

    The Reactor Physics and 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 on reactor fuel. This expertise is applied within the Reactor Physics and MYRRHA Research 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. Progress and achievements in 1999 in the following areas are reported on: (1) investigations on the use of military plutonium in commercial power reactors; (2) neutron and gamma calculations performed for BR-2 and for other reactors; (3) the updating of neutron and gamma cross-section libraries; (4) the implementation of reactor codes; (6) the management of the UNIX workstations; and (6) fuel cycle studies.

  12. Studies on characteristics of fluid dynamics in the coal liquefaction reactor; Sekitan ekika hanno tonai no ryudo tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Sakawaki, K.; Nogami, Y.; Inokuchi, K. [Mitsui SRC Development Co. Ltd., Tokyo (Japan); Mochizuki, M.; Imada, K. [Nippon Steel Corp., Tokyo (Japan); Tachikawa, N.; Moki, T.; Ishikawa, I. [Japan Atomic Energy Research Institute, Tokyo (Japan)

    1996-10-28

    To design the coal liquefaction reactor of large scale plant in future, it is important to understand characteristics of fluid dynamics within the coal liquefaction reactor. In this study, to measure the fluid dynamics of liquid phase within the coal liquefaction reactor operated under high temperature and high pressure coal liquefaction condition, neutron attenuating tracer (NAT) technique, one of the tracer test methods, was applied using 1 t/d coal treating PSU. The residence time of liquid phase within the reactor can be measured by utilizing property of neutron of being absorbed by materials. The tracer was injected at the inlets of first and third reactors, and the neutron was counted at each outlet. The concentration of tracer was derived from the discrete value, to determine the residence time distribution of liquid phase. The mean residence time of liquid phase in the single first reactor and in the total three reactors were prolonged under the severe operation conditions of liquefaction. The more severe the liquefaction operation condition was, the more active the mixing of liquid phase was in the first reactor. It was found that the progress of reaction was accelerated. 2 refs., 5 figs., 1 tab.

  13. Bubble column reactor fluid dynamic study at pilot plant scale for residue and extra heavy crude oil upgrading technology

    Energy Technology Data Exchange (ETDEWEB)

    Sardella, R.; Medina, H. [Infrastructure and Upgrading Department PDVSA-Intevep (Venezuela); Zacarias, L.; Paiva, M. [Refining Department. PDVSA-Intevep (Venezuela)

    2011-07-01

    Bubble column reactors are used in several applications because of their simplicity and low cost; a new technology was developed to convert extra heavy crude oil into upgraded crude using a bubble column reactor. To design this kind of reactor, a lot of parameters like flow regime, gas hold up and dispersion coefficient have to be taken into account. This study aimed at determining the fluid dynamic behaviour of a bubble column working under Aquaconversion operating conditions. Experiments were undertaken on air-tap water and air-light oil systems under atmospheric conditions with various gas superficial velocities and liquid flowrates. Results showed that gas hold up increases with superficial gas velocity but is independent of liquid flowrate and that both systems tested work at the same flow regimes. This paper showed that under the experimental conditions used, this reactor tends to be a complete mixing reactor.

  14. Research from the NASA Twins Study and Omics in Support of Mars Missions

    Science.gov (United States)

    Kundrot, C.; Shelhamer, M.; Scott, G.

    2015-01-01

    The NASA Twins Study, NASA's first foray into integrated omic studies in humans, illustrates how an integrated omics approach can be brought to bear on the challenges to human health and performance on a Mars mission. The NASA Twins Study involves US Astronaut Scott Kelly and his identical twin brother, Mark Kelly, a retired US Astronaut. No other opportunity to study a twin pair for a prolonged period with one subject in space and one on the ground is available for the foreseeable future. A team of 10 principal investigators are conducting the Twins Study, examining a very broad range of biological functions including the genome, epigenome, transcriptome, proteome, metabolome, gut microbiome, immunological response to vaccinations, indicators of atherosclerosis, physiological fluid shifts, and cognition. A novel aspect of the study is the integrated study of molecular, physiological, cognitive, and microbiological properties. Major sample and data collection from both subjects for this study began approximately six months before Scott Kelly's one year mission on the ISS, continue while Scott Kelly is in flight and will conclude approximately six months after his return to Earth. Mark Kelly will remain on Earth during this study, in a lifestyle unconstrained by this study, thereby providing a measure of normal variation in the properties being studied. An overview of initial results and the future plans will be described as well as the technological and ethical issues raised for spaceflight studies involving omics.

  15. Mars bevares

    DEFF Research Database (Denmark)

    Hendricks, Vincent Fella; Hendricks, Elbert

    2009-01-01

    2009 er femåret for Mission Mars. I den anledning opridser de to kronikører, far og søn, hvorfor man bør lade planer om en bemandet tur til Mars forblive i skrivebordsskuffen......2009 er femåret for Mission Mars. I den anledning opridser de to kronikører, far og søn, hvorfor man bør lade planer om en bemandet tur til Mars forblive i skrivebordsskuffen...

  16. Reactor physics studies for the Advanced Fuel Cycle Initiative (AFCI) Reactor-Accelerator Coupling Experiments (RACE) Project

    Science.gov (United States)

    Stankovskiy, Evgeny Yuryevich

    In the recently completed RACE Project of the AFCI, accelerator-driven subcritical systems (ADS) experiments were conducted to develop technology of coupling accelerators to nuclear reactors. In these experiments electron accelerators induced photon-neutron reactions in heavy-metal targets to initiate fission reactions in ADS. Although the Idaho State University (ISU) RACE ADS was constructed only to develop measurement techniques for advanced experiments, many reactor kinetics experiments were conducted there. In the research reported in this dissertation, a method was developed to calculate kinetics parameters for measurement and calculation of the reactivity of ADS, a safety parameter that is necessary for control and monitoring of power production. Reactivity is measured in units of fraction of delayed versus prompt neutron from fission, a quantity that cannot be directly measured in far-subcritical reactors such as the ISU RACE configuration. A new technique is reported herein to calculate it accurately and to predict kinetic behavior of a far-subcritical ADS. Experiments conducted at ISU are first described and experimental data are presented before development of the kinetic theory used in the new computational method. Because of the complexity of the ISU ADS, the Monte-Carlo method as applied in the MCNP code is most suitable for modeling reactor kinetics. However, the standard method of calculating the delayed neutron fraction produces inaccurate values. A new method was developed and used herein to evaluate actual experiments. An advantage of this method is that its efficiency is independent of the fission yield of delayed neutrons, which makes it suitable for fuel with a minor actinide component (e.g. transmutation fuels). The implementation of this method is based on a correlated sampling technique which allows the accurate evaluation of delayed and prompt neutrons. The validity of the obtained results is indicated by good agreement between experimental

  17. Pilot Study on Harmonisation of Reactor Safety in WENRA Countries

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-03-01

    Most of the objectives, set for the Pilot Study, were met. It can be concluded that the methodology was adequate for its purpose. National requirements on selected safety issues have been systematically compared and the major gaps and differences have been identified. Convenient overviews have been provided of differences and similarities between the countries. Furthermore, the conclusions are based on a safety justification and are detailed enough to provide input to a further more detailed analysis on the national level. It was not possible, however, to provide fully verified conclusions about the implementation of the reference levels in the different countries. This has to do with the following constraints on the study: In line with the Terms of Reference, the comparison of formal requirements did not address the more detailed use of criteria and methods to verify compliance. The same requirement could be enforced differently in different regulatory systems, and hence lead to different implementation. The Pilot Study also assessed the implementation, but it was not possible to do this in sufficient detail to identify such differences. The implementation was assessed on the basis of current knowledge of the respective regulatory body, but it was not possible to provide the panels with evidence of the implementation. For these reasons, conclusions about implemented safety provisions in the different countries should be drawn with precaution. The introduction of the panel assessments greatly improved the quality and consistency of the comparison assessments. Uncertainties in the assessments are mainly connected with lack of time to make a detailed analysis in some cases. The reliability of the assessments seems to be sufficient for the objectives of the Pilot Study. The introduction of the IAEA safety standards in the study proved to be helpful and provided confidence in the scope and strictness of the reference levels. This Pilot Study has contributed to

  18. Development of an FTIR in situ reactor for real time study of surface reactions in photocatalysis

    Science.gov (United States)

    Hauchecorne, Birger

    For many years, photocatalysis has been proposed as one of the promising techniques to abate environmental pollutants. To improve the catalytic efficiency, it is vital to know the reaction mechanisms of the photocatalytic degradation. Different methods are therefore described in literature to study these mechanisms at the gaseous phase/photocatalyst interface with Fourier transform infrared (FTIR) spectroscopy as a commonly used method. The reactors described in literature and/or available on the market experience some technical and scientific difficulties. Generally, the catalyst can only be investigated after the reactions have occurred, or it is only possible to look at the changes in the gas phase concentrations while the reactions are taking place. It is thus a major challenge to develop a reactor which makes it possible to detect changes on the catalyst surface at the moment the reactions are happening. In this work, a new reactor is developed that makes it possible to study the catalytic surface at the moment the reactions occur, by means of transmission-absorption FTIR spectroscopy. Moreover, by using UV LEDs, it was possible to install the UV light inside the reactor area, so that no harmful UV light can leave the reactor, inherently making it a safer method. It was also opted to construct the reactor in a modular way, so that every part was interchangeable and could easily be replaced according to the needs of the researcher. A special screw cap is designed to hold the UV LEDs on a printed circuit board and to fit in every standard FTIR spectrometer. This study provides exciting new insights in the photocatalytic degradation mechanism of ethylene and acetaldehyde. It is for instance found that OH radicals are used as the oxidising agents to abate these pollutants. For ethylene it was proven that the molecular orbitals play an important role, resulting in the formation of both formaldehyde and formic acid as intermediates before complete mineralisation

  19. MARS: a status report

    Energy Technology Data Exchange (ETDEWEB)

    Tribble, R.E.; Gagliardi, C.A.; Liu, W. (Cyclotron Inst., Texas A and M Univ., College Station (USA))

    1991-05-01

    We are building a momentum achromat recoil spectrometer (MARS) for use with the new K500 superconducting cyclotron at Texas A and M University. MARS uses a unique optical design utilizing two dispersive planes to combine a momemtum achromat with a recoil mass spectrometer. This configuration makes MARS applicable to a broad range of nuclear reaction studies utilizing inverse kinematics. It also leads to a system that is well matched to the range of secondary particle energies that will be produced in reactions with K500 beam. MARS will have a typical mass resolution of {delta}M/M{approx equal}1/300, with an energy acceptance of {+-}9% {Delta}E/E and a geometric solid angle of up to 9 msr. A beam swinger system will alow reaction products in the angular range 0deg to 30deg to be studied. MARS will be used to study both the excited states and decay properties of very proton- and neutron-rich nuclei. MARS will also be used to provide a reaction mechanism filter to assist investigations of the dynamics of heavy ion collisions and to produce secondary radioactive beams for reaction and spectroscopic studies of particular interest for nuclear astrophysics. We briefly describe the design of MARS, give a status report on its construction and an overview of the scientific program planned for it. (orig.).

  20. Prediction Study on PCI Failure of Reactor Fuel Based on a Radial Basis Function Neural Network

    Directory of Open Access Journals (Sweden)

    Xinyu Wei

    2016-01-01

    Full Text Available Pellet-clad interaction (PCI is one of the major issues in fuel rod design and reactor core operation in water cooled reactors. The prediction of fuel rod failure by PCI is studied in this paper by the method of radial basis function neural network (RBFNN. The neural network is built through the analysis of the existing experimental data. It is concluded that it is a suitable way to reduce the calculation complexity. A self-organized RBFNN is used in our study, which can vary its structure dynamically in order to maintain the prediction accuracy. For the purpose of the appropriate network complexity and overall computational efficiency, the hidden neurons in the RBFNN can be changed online based on the neuron activity and mutual information. The presented method is tested by the experimental data from the reference, and the results demonstrate its effectiveness.

  1. Kinetic study on the effect of temperature on biogas production using a lab scale batch reactor.

    Science.gov (United States)

    Deepanraj, B; Sivasubramanian, V; Jayaraj, S

    2015-11-01

    In the present study, biogas production from food waste through anaerobic digestion was carried out in a 2l laboratory-scale batch reactor operating at different temperatures with a hydraulic retention time of 30 days. The reactors were operated with a solid concentration of 7.5% of total solids and pH 7. The food wastes used in this experiment were subjected to characterization studies before and after digestion. Modified Gompertz model and Logistic model were used for kinetic study of biogas production. The kinetic parameters, biogas yield potential of the substrate (B), the maximum biogas production rate (Rb) and the duration of lag phase (λ), coefficient of determination (R(2)) and root mean square error (RMSE) were estimated in each case. The effect of temperature on biogas production was evaluated experimentally and compared with the results of kinetic study. The results demonstrated that the reactor with operating temperature of 50°C achieved maximum cumulative biogas production of 7556ml with better biodegradation efficiency.

  2. Study of Intermetallic Nanostructures for Light-Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Niels Grobech [Univ. of California, Davis, CA (United States); Asta, Mark D. [Univ. of California, Berkeley, CA (United States); Hosemann, Peter [Univ. of California, Berkeley, CA (United States); Maloy, Stuart [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-30

    High temperature mechanical measurements were conducted to study the effect of the dynamic precipitation process of PH 13-8 Mo maraging steel. Yield stress, ultimate tensile strength, total elongation, hardness, strain rate sensitivity and activation volume were evaluated as a function of the temperature. The dynamic changes in the mechanical properties at different temperatures were evaluated and a balance between precipitation hardening and annealed softening is discussed. A comparison between hardness and yield stress and ultimate tensile strength over a temperature range from 300 to 600 °C is made. The behavior of the strain rate sensitivity was correlated with the intermetallic precipitates formed during the experiments.

  3. Are tags from Mars and descriptors from Venus? A study on the ecology of educational resource metadata

    NARCIS (Netherlands)

    Vuorikari, Riina; Sillaots, Martin; Panzavolta, Silvia; Koper, Rob

    2009-01-01

    Vuorikari, R., Sillaots, M., Panzavolta, S. & Koper, R. (2009). Are tags from Mars and descriptors from Venus? A study on the ecology of educational resource metadata. In M. Spaniol, Q. Li, R. Klamma & R. W. H. Lau (Eds.), Proceedings of the 8th International Conference Advances in Web Based Learnin

  4. 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

    2016-06-14

    one is about the demonstration of a new MSR concept using the mathematic tools. In particular, the aim of the first part is to demonstrate the suitability of the TRACE code for the similar MSR designs by using a modified version of the TRACE code to implement the simulations for the steady-state, transient and accidental conditions. The basic approach of this part is to couple the thermal-hydraulic model and the modified point-kinetic model. The equivalent thermal-hydraulic model of the MSRE was built in 1D with three loops including all the critical main components. The point-kinetic model was improved through considering the precursor drift in order to produce more practical results in terms of the delayed neutron behavior. Additionally, new working fluids, namely the molten salts, were embedded into the source code of TRACE. Most results of the simulations show good agreements with the ORNL's reports and with another recent study and the errors were predictable and in an acceptable range. Therefore, the necessary code modification of TRACE appears to be successful and the model will be refined and its functions will be extended further in order to investigate new MSR design. Another part of this thesis is to implement a preliminary study on a new concept of molten salt reactor, namely the Dual Fluid Reactor (DFR). The DFR belongs to the group of the molten salt fast reactors (MSFR) and it is recently considered to be an option of minimum-waste and inherently safe operation of the nuclear reactors in the future. The DFR is using two separately circulating fluids in the reactor core. One is the fuel salt based on the mixture of tri-chlorides of uranium and plutonium (UCl{sub 3}-PuCl{sub 3}), while another is the coolant composed of the pure lead (Pb). The current work focuses on the basic dynamic behavior of a scaled-down DFR with 500 MW thermal output (DFR-500) instead of its reference design with 3000 MW thermal output (DFR-3000). For this purpose 10 parallel

  5. Study of in-reactor creep of vanadium alloy in the HFIR RB-12J experiment

    Energy Technology Data Exchange (ETDEWEB)

    Strain, R.V.; Konicek, C.F.; Tsai, H. [Argonne National Lab., IL (United States)

    1996-10-01

    Biaxial creep specimens will be included in the HFIR RB-12J experiment to study in-reactor creep of the V-4Cr-4Ti alloy at {approx}500{degrees}C and 5 dpa. These specimens were fabricated with the 500-kg, heat (832665) material and pressurized to attain 0, 50, 100, 150, and 200 MPa mid-wall hoop stresses during the irradiation.

  6. Martian Feeling: An Analogue Study to Simulate a Round-Trip to Mars using the International Space Station

    Science.gov (United States)

    Felix, C. V.; Gini, A.

    When talking about human space exploration, Mars missions are always present. It is clear that sooner or later, humanity will take this adventure. Arguably the most important aspect to consider for the success of such an endeavour is the human element. The safety of the crew throughout a Martian mission is a top priority for all space agencies. Therefore, such a mission should not take place until all the risks have been fully understood and mitigated. A mission to Mars presents unique human and technological challenges in terms of isolation, confinement, autonomy, reliance on mission control, communication delays and adaptation to different gravity levels. Analogue environments provide the safest way to simulate these conditions, mitigate the risks and evaluate the effects of long-term space travel on the crew. Martian Feeling is one of nine analogue studies, from the Mars Analogue Path (MAP) report [1], proposed by the TP Analogue group of ISU Masters class 2010. It is an integrated analogue study which simulates the psychological, physiological and operational conditions that an international, six-person, mixed gender crew would experience on a mission to Mars. Set both onboard the International Space Station (ISS) and on Earth, the Martian Feeling study will perform a ``dress rehearsal'' of a mission to Mars. The study proposes to test both human performance and operational procedures in a cost-effective manner. Since Low Earth Orbit (LEO) is more accessible than other space-based locations, an analogue studies in LEO would provide the required level of realism to a simulated transit mission to Mars. The sustained presence of microgravity and other elements of true spaceflight are features of LEO that are neither currently feasible nor possible to study in terrestrial analogue sites. International collaboration, economics, legal and ethical issues were considered when the study was proposed. As an example of international collaboration, the ISS would

  7. Microbial ureolysis in the seawater-catalysed urine phosphorus recovery system: Kinetic study and reactor verification.

    Science.gov (United States)

    Tang, Wen-Tao; Dai, Ji; Liu, Rulong; Chen, Guang-Hao

    2015-12-15

    Our previous study has confirmed the feasibility of using seawater as an economical precipitant for urine phosphorus (P) precipitation. However, we still understand very little about the ureolysis in the Seawater-based Urine Phosphorus Recovery (SUPR) system despite its being a crucial step for urine P recovery. In this study, batch experiments were conducted to investigate the kinetics of microbial ureolysis in the seawater-urine system. Indigenous bacteria from urine and seawater exhibited relatively low ureolytic activity, but they adapted quickly to the urine-seawater mixture during batch cultivation. During cultivation, both the abundance and specific ureolysis rate of the indigenous bacteria were greatly enhanced as confirmed by a biomass-dependent Michaelis-Menten model. The period for fully ureolysis was decreased from 180 h to 2.5 h after four cycles of cultivation. Based on the successful cultivation, a lab-scale SUPR reactor was set up to verify the fast ureolysis and efficient P recovery in the SUPR system. Nearly complete urine P removal was achieved in the reactor in 6 h without adding any chemicals. Terminal Restriction Fragment Length Polymorphism (TRFLP) analysis revealed that the predominant groups of bacteria in the SUPR reactor likely originated from seawater rather than urine. Moreover, batch tests confirmed the high ureolysis rates and high phosphorus removal efficiency induced by cultivated bacteria in the SUPR reactor under seawater-to-urine mixing ratios ranging from 1:1 to 9:1. This study has proved that the enrichment of indigenous bacteria in the SUPR system can lead to sufficient ureolytic activity for phosphate precipitation, thus providing an efficient and economical method for urine P recovery.

  8. Reduced physics models in SOLPS for reactor scoping studies

    Energy Technology Data Exchange (ETDEWEB)

    Coster, D.P. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

    2016-08-15

    Heat exhaust is a challenge for ITER and becomes even more of an issue for devices beyond ITER. The main reason for this is that the power produced in the core scales as R{sup 3} while relying on standard exhaust physics results in the heat exhaust scaling as R{sup 1} (R is the major radius). ITER has used SOLPS (B2-EIRENE) to design the ITER divertor, as well as to provide a database that supports the calculations of the ITER operational parameter space. The typical run time for such SOLPS runs is of the order 3 months (for D+C+He using EIRENE to treat the neutrals kinetically with an extensive choice of atomic and molecular physics). Future devices will be expected to radiate much of the power before it crosses the separatrix, and this requires treating extrinsic impurities such as Ne, Ar, Kr and Xe - the large number of charge states puts additional pressure on SOLPS, further slowing down the code. For design work of future machines, fast models have been implemented in system codes but these are usually unavoidably restricted in the included physics. As a bridge between system studies and detailed SOLPS runs, SOLPS offers a number of possibilities to speed up the code considerably at the cost of reducing the fidelity of the physics. By employing a fluid neutral model, aggressive bundling of the charge state of impurities, and reducing the size of the grids used, the run time for one second of physics time (which is often enough for the divertor to come to a steady state) can be reduced to approximately one day. This work looks at the impact of these trade-offs in the physics by comparing key parameters for different simulation assumptions. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Core and Refueling Design Studies for the Advanced High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, David Eugene [ORNL; Ilas, Dan [ORNL; Varma, Venugopal Koikal [ORNL; Cisneros, Anselmo T [ORNL; Kelly, Ryan P [ORNL; Gehin, Jess C [ORNL

    2011-09-01

    The Advanced High Temperature Reactor (AHTR) is a design concept for a central generating station type [3400 MW(t)] fluoride-salt-cooled high-temperature reactor (FHR). The overall goal of the AHTR development program is to demonstrate the technical feasibility of FHRs as low-cost, large-size power producers while maintaining full passive safety. This report presents the current status of ongoing design studies of the core, in-vessel structures, and refueling options for the AHTR. The AHTR design remains at the notional level of maturity as important material, structural, neutronic, and hydraulic issues remain to be addressed. The present design space exploration, however, indicates that reasonable options exist for the AHTR core, primary heat transport path, and fuel cycle provided that materials and systems technologies develop as anticipated. An illustration of the current AHTR core, reactor vessel, and nearby structures is shown in Fig. ES1. The AHTR core design concept is based upon 252 hexagonal, plate fuel assemblies configured to form a roughly cylindrical core. The core has a fueled height of 5.5 m with 25 cm of reflector above and below the core. The fuel assembly hexagons are {approx}45 cm across the flats. Each fuel assembly contains 18 plates that are 23.9 cm wide and 2.55 cm thick. The reactor vessel has an exterior diameter of 10.48 m and a height of 17.7 m. A row of replaceable graphite reflector prismatic blocks surrounds the core radially. A more complete reactor configuration description is provided in Section 2 of this report. The AHTR core design space exploration was performed under a set of constraints. Only low enrichment (<20%) uranium fuel was considered. The coated particle fuel and matrix materials were derived from those being developed and demonstrated under the Department of Energy Office of Nuclear Energy (DOE-NE) advanced gas reactor program. The coated particle volumetric packing fraction was restricted to at most 40%. The pressure

  10. Study of the behavior of actinides continuously recycled in a hard spectrum reactor

    Energy Technology Data Exchange (ETDEWEB)

    Schofield, P.E.

    1980-12-01

    The behavior of actinides continuously recycled through the central region of an EBR-II type reactor was studied. Such a reactor would convert long-lived nuclear wastes to short-lived isotopes, and simultaneously produce useful power. This process is proposed as an alternative to the geological isolation of long-lived actinide wastes. A driver region of 50% U-235 enriched fuel provided a nearly-constant spectrum and flux that was extremely hard compared to standard LMFBRs. This resulted in a high fission-to-capture ratio for most isotopes. The original actinide fuel was the discharge from a LWR, cooled for two years, with 99.9% of the uranium and plutonium removed by chemical processing. Comparison was made between removal of both Pu and U and removal of only U in subsequent cycles. The latter case resulted in substantial quantities of trans-plutonics burned per cycle.

  11. Review of pressurized thermal shock studies of large scale reactor pressure vessels in Hungary

    Directory of Open Access Journals (Sweden)

    Tamás Fekete

    2016-03-01

    Full Text Available In Hungary, four nuclear power units were constructed more than 30 years ago; they are operating to this day. In every unit, VVER-440 V213-type light-water cooled, light-water moderated, ressurized water reactors are in operation. Since the mid-1980s, numerous researches in the field of Pressurized Thermal Shock (PTS analyses of Reactor Pressure Vessels (RPVs have been conducted in Hungary; in all of them, the concept of structural integrity was the basis of research and development. During this time, four large PTS studies with industrial relevance have been completed in Hungary. Each used different objectives and guides, and the analysis methodology was also changing. This paper gives a comparative review of the methodologies used in these large PTS Structural Integrity Analysis projects, presenting the latest results as well

  12. Study on Thermal-Hydraulic Behavior of an Integral Type Reactor under Heaving Condition

    Directory of Open Access Journals (Sweden)

    Beibei Feng

    2014-01-01

    Full Text Available A self-developed program was used to study the thermal-hydraulic behavior of an integral type reactor under heaving condition. Comparison of calculated results with the data of experiments performed on a natural circulation loop designed with reference to an integral type reactor of Tsinghua University in inclination, heaving, and rolling motions was carried out. Characteristics of natural circulation in heaving motion and effect of motion parameters on natural circulation were investigated. Results indicated that: (1 long-period heaving motion would lead to more significant influence than inclination and rolling motion; (2 it was an alternating force field which consisted of gravity and an additional force that decided the flow temperature and density difference of natural circulation; (3 effect of strength k and cycle T of heaving motion on flow fluctuation of natural circulation and condensate depression of heating section outlet was performed.

  13. The nuclear data, A key component for reactor studies, Overview of AREVA NP needs and applications

    Directory of Open Access Journals (Sweden)

    Ravaux Simon

    2016-01-01

    Full Text Available The quality of the nuclear data is essential for AREVA NP. Indeed, many AREVA NP activities such as reactor design, safety studies or reactor instrumentation use them as input data. So, the nuclear data can be considered as a key element for AREVA NP. REVA NP’s contribution in the improvement of the nuclear data consists in a joint effort with the CEA. It means a financing and a sharing of information which can give an orientation to the future research axis. The aim of this article is to present the industrial point of view from AREVA NP on the research on nuclear data. Several examples of collaborations with the CEA which have resulted in an improvement of the nuclear data are presented.

  14. Steam drum level control studies of a natural circulation multi loop reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rajesh; Contractor, A.D.; Srivastava, Abhishek; Lele, H.G. [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Reactor Safety Div.; Vaze, K.K. [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Reactor Design and Development Group

    2013-12-15

    The proposed heavy water moderated and light water cooled pressure tube type boiling water reactor works on natural circulation at all power levels. It has parallel inter-connected loops with 452 boiling channels in the main heat transport system configuration. These multiple (four) interconnected loops influence the steam drum level control adversely through the common reactor inlet header. Alternate design studies made earlier for efficient control of SD levels have shown favorable results. This has lead to explore further the present scheme with the compartmentalization of CRIH into four compartments catering to four loops separately. The conventional 3-element level control has been found to be working satisfactorily. The interconnections between ECCS header and inlet header compartments have also increased the safety margin for various LOCA and design basis events. The paper deals with the SD level control aspects for this novel MHT configuration which has been analyzed for various PIEs (Postulated Initiating Events) and found to be satisfactory. (orig.)

  15. Positron annihilation study of Fe-ion irradiated reactor pressure vessel model alloys

    Science.gov (United States)

    Chen, L.; Li, Z. C.; Schut, H.; Sekimura, N.

    2016-01-01

    The degradation of reactor pressure vessel steels under irradiation, which results from the hardening and embrittlement caused by a high number density of nanometer scale damage, is of increasingly crucial concern for safe nuclear power plant operation and possible reactor lifetime prolongation. In this paper, the radiation damage in model alloys with increasing chemical complexity (Fe, Fe-Cu, Fe-Cu-Si, Fe-Cu-Ni and Fe-Cu-Ni-Mn) has been studied by Positron Annihilation Doppler Broadening spectroscopy after 1.5 MeV Fe-ion implantation at room temperature or high temperature (290 oC). It is found that the room temperature irradiation generally leads to the formation of vacancy-type defects in the Fe matrix. The high temperature irradiation exhibits an additional annealing effect for the radiation damage. Besides the Cu-rich clusters observed by the positron probe, the results show formation of vacancy-Mn complexes for implantation at low temperatures.

  16. Mars Atmosphere and Volatile EvolutioN (MAVEN) mission's Red Planet program: Bridging the gap in elementary school science through climate studies of Mars

    Science.gov (United States)

    Wood, E. L.

    2012-12-01

    Although reading, writing, and math examinations are often conducted early in elementary school, science is not typically tested until 4th or 5th grade. The result is a refocus on the tested topics at the expense of the untested ones, despite that standards exist for each topic at all grades. On a national level, science instruction is relegated to a matter of a few hours per week. A 2007 Education Policy study states that elementary school students spend an average of 178 minutes a week on science while spending 500 minutes on literacy. A recent NSTA report in July of 2011 of elementary and middle school teachers confirms that teachers feel pressured to teach math and literacy at the expense of other programs. In our interaction with elementary teachers, it is also apparent that many are uncomfortable with science concepts. In order for us to successfully address the Next Generation Science Standards, teachers must be able to reconcile all of the different requirements placed on them in a given school day and in a given school environment. A unique way to combat the lack of science instruction at elementary grades is to combine literacy into an integrated science program, thereby increasing the number of science contact hours. The Red Planet: Read, Write, Explore program, developed for the MAVEN mission, is a science, art, and literacy program designed to easily fit into a typical 3rd-5th grade instructional day. Red Planet tackles climate change through Mars' geologic history and makes Mars-Earth comparisons, while encouraging students to reflect on the environmental requirements needed to keep a biological organisms (including humans) happy, healthy, and alive. The Red Planet program is currently being pilot tested at Acres Green Elementary School in Colorado.

  17. Feasibility study on simultaneous removal of sulfur and trace selenium in the MTD-FGD reactor

    Institute of Scientific and Technical Information of China (English)

    LI Yuzhong; TONG Huiling; ZHUO Yuqun; LI Yan; CHEN Changhe; XU Xuchang

    2007-01-01

    This study deals with the simultaneous removal of sulfur dioxide (SO2) and trace selenium dioxide (SeO2)from flue gas by calcium oxide (CaO) adsorption in the moderate temperature range,especially the feasibility of simultaneous removal of these two pollutants in a moderate temperature dry flue gas desulfurization (MTD-FGD) reactor.The effect of SO2 presence on selenium capture is studied through the experiments performed on a thermogravimetric analyzer (TGA) and the following conclusions can be obtained.When CaO conversion is relatively low and the reaction rate is controlled by chemical reaction kinetics,the SO2 presence does not affect selenium capture.When CaO conversion is very high and the reaction rate is controlled by product layer diffusion,the SO2 presence and the product layer diffusion resistance jointly reduce selenium capture.Through analyses of some pilot scale MTD-FGD tests,it can be concluded that in the MTD-FGD reactor,the sulfate reaction of sorbent particles is generally kinetically controlled.Therefore,it is feasible that sulfur and trace selenium can be simultaneously removed by Ca-based sorbent in the MTD-FGD reactor.

  18. Experimental and kinetic modeling study of 3-methylheptane in a jet-stirred reactor

    KAUST Repository

    Karsenty, Florent

    2012-08-16

    Improving the combustion of conventional and alternative fuels in practical applications requires the fundamental understanding of large hydrocarbon combustion chemistry. The focus of the present study is on a high-molecular-weight branched alkane, namely, 3-methylheptane, oxidized in a jet-stirred reactor. This fuel, along with 2-methylheptane, 2,5-dimethylhexane, and n-octane, are candidate surrogate components for conventional diesel fuels derived from petroleum, synthetic Fischer-Tropsch diesel and jet fuels derived from coal, natural gas, and/or biomass, and renewable diesel and jet fuels derived from the thermochemical treatment of bioderived fats and oils. This study presents new experimental results along with a low- and high-temperature chemical kinetic model for the oxidation of 3-methylheptane. The proposed model is validated against these new experimental data from a jet-stirred reactor operated at 10 atm, over the temperature range of 530-1220 K, and for equivalence ratios of 0.5, 1, and 2. Significant effort is placed on the understanding of the effects of methyl substitution on important combustion properties, such as fuel reactivity and species formation. It was found that 3-methylheptane reacts more slowly than 2-methylheptane at both low and high temperatures in the jet-stirred reactor. © 2012 American Chemical Society.

  19. Theoretical and experimental studies of fixed-bed coal gasification reactors. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, B.; Bhattacharya, A.; Salam, L.; Dudukovic, M.P.

    1983-09-01

    A laboratory fixed-bed gasification reactor was designed and built with the objective of collecting operational data for model validation and parameter estimation. The reactor consists of a 4 inch stainless steel tube filled with coal or char. Air and steam is fed at one end of the reactor and the dynamic progress of gasification in the coal or char bed is observed through thermocouples mounted at various radial and axial locations. Product gas compositions are also monitored as a function of time. Results of gasification runs using Wyoming coal are included in this report. In parallel with the experimental study, a two-dimensional model of moving bed gasifiers was developed, coded into a computer program and tested. This model was used to study the laboratory gasifier by setting the coal feed rate equal to zero. The model is based on prior work on steady state and dynamic modeling done at Washington University and published elsewhere in the literature. Comparisons are made between model predictions and experimental results. These are also included in this report. 23 references, 18 figures, 6 tables.

  20. H Reactor

    Data.gov (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...

  1. A Conceptual Study of a Supercritical CO2-Cooled Micro Modular Reactor

    Directory of Open Access Journals (Sweden)

    Hwanyeal Yu

    2015-12-01

    Full Text Available A neutronics conceptual study of a supercritical CO2-cooled micro modular reactor (MMR has been performed in this work. The suggested MMR is an extremely compact and truck-transportable nuclear reactor. The thermal power of the MMR is 36.2 MWth and it is designed to have a 20-year lifetime without refueling. A salient feature of the MMR is that all the components including the generator are integrated in a small reactor vessel. For a minimal volume and long lifetime of the MMR core, a fast neutron spectrum is utilized in this work. To enhance neutron economy and maximize the fuel volume fraction in the core, a high-density uranium mono-nitride U15N fuel is used in the fast-spectrum MMR. Unlike the conventional supercritical CO2-cooled fast reactors, a replaceable fixed absorber (RFA is introduced in a unique way to minimize the excess reactivity and the power peaking factor of the core. For a compact core design, the drum-type control absorber is adopted as the primary reactivity control mechanism. In this study, the neutronics analyses and depletions have been performed by using the continuous energy Monte Carlo Serpent code with the evaluated nuclear data file ENDF/B-VII.1 Library. The MMR core is characterized in view of several important safety parameters such as control system worth, fuel temperature coefficient (FTC and coolant void reactivity (CVR, etc. In addition, a preliminary thermal-hydraulic analysis has also been performed for the hottest channel of the Korea Advanced Institute of Science and Technology (KAIST MMR.

  2. A study of the isobutane dehydrogenation in a porous membrane catalytic reactor: design, use and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Casanave, D.

    1996-01-26

    The aim of this study was to set up and model a catalytic fixed-bed membrane reactor for the isobutane dehydrogenation. The catalyst, developed at Catalysis Research Institute (IRC), was a silicalite-supported Pt-based catalyst. Their catalytic performances (activity, selectivity, stability) where found better adapted to the membrane reactor, when compared with commercial Pt or Cr based catalysts. The kinetic study of the reaction has been performed in a differential reactor and led to the determination of a kinetic law, suitable when the catalyst is used near thermodynamic equilibrium. The mass transfer mechanisms were determined in meso-porous and microporous membranes through both permeability and gas mixtures (iC{sub 4}/H{sub 2}/N{sub 2}) separation measurements. For the meso-porous {gamma}-alumina, the mass transfer is ensured by a Knudsen diffusion mechanism which can compete with surface diffusion for condensable gas like isobutane. The resulting permselectivity H{sub 2}/iC4 of this membrane is low ({approx} 4). For the microporous zeolite membrane, molecular sieving occurs due to steric hindrance, leading to higher permselectivity {approx}14. Catalyst/membrane associations were compared in terms of isobutane dehydrogenation performances, for both types of membranes (meso-porous and microporous) and for two different reactor configurations (co-current and counter-current sweep gas flow). The best experimental results were obtained with the zeolite membrane, when sweeping the outer compartment in a co-current flow. The equilibrium displacement observed with the {gamma}-alumina membrane was lower and mainly due to a dilution effect of the reaction mixture by the sweep gas. A mathematical model was developed, which correctly describes all the experimental results obtained with the zeolite membrane, when the co-current mode is used. (Abstract Truncated)

  3. Power up-grading study for the first Egyptian research reactor

    Energy Technology Data Exchange (ETDEWEB)

    El-Sawy Temraz, H.; Ashoub, N. E-mail: nageeb@pcn.aea.sci.eg; Fathallah, A

    2001-09-01

    In the present work, power up-grading study is performed, for the first Egyptian Research Reactor (ET-RR-1), using the present fuel basket with 4x4 fuel rods, (17.5 mm pitch), and a proposed fuel basket with 5x5 fuel rods, (14.0 mm pitch), without violating the thermal hydraulic safety criteria. These safety criteria are; fuel centerline temperature (fuel melting), clad surface temperature (surface boiling), outlet coolant temperature, and maximum heat flux (critical heat flux ratio). Different thermal reactor powers (2-10 MW) and different core coolant flow rates (450, 900, 1350 m{sup 3} h{sup -1}) are considered. The thermal hydraulic analysis was performed using the subchannel code COBRA-IIIC for the estimation of temperatures, coolant velocities and critical heat flux. The neutronic calculations were performed using WIMS-D4 code with 5-group neutron cross section library. These cross sections were adapted to use in the two-dimensional (2-D) diffusion code DIXY for core calculations. The study concluded that ET-RR-1 power can be upgraded safely up to 4 MW with the present 4x4-fuel basket and with the proposed 5x5-fuel basket up to 5 MW with the present coolant flow rate (900 m{sup 3} h{sup -1}). With the two fuel arrays, the reactor power can be upgraded to 6 MW with coolant flow rate of 1350 m{sup 3} h{sup -1} without violating the safety criterion. It is also concluded that, loading the ET-RR-1 core with the proposed fuel basket (5x5) increases the excess reactivity of the reactor core than the present 4x4 fuel matrix with equal U-235 mass load and gave better fuel economy of fuel utilization.

  4. Human Factor Studies on a Mars Analogue During Crew 100b International Lunar Exploration Working Group EuroMoonMars Crew: Proposed New Approaches for Future Human Space and Interplanetary Missions.

    Science.gov (United States)

    Rai, Balwant; Kaur, Jasdeep

    2012-11-01

    Knowing the risks, costs, and complexities associated with human missions to Mars, analogue research can be a great (low-risk) tool for exploring the challenges associated with the preparation for living, operating, and undertaking research in interplanetary missions. Short-duration analogue studies, such as those being accomplished at the Mars Desert Research Station (MDRS), offer the chance to study mission operations and human factors in a simulated environment, and therefore contribute to exploration of the Moon and Mars in planned future missions. This article is based upon previously published articles, abstracts, and presentations by a series of independent authors, human factor studies performed on mars analogue station by Crew 100B. The MDRS Crew 100B performed studies over 15 days providing a unique insight into human factor issues in simulated short-duration Mars mission. In this study, 15 human factors were evaluated and analyzed by subjective and objective means, and from the summary of results it was concluded that optimum health of an individual and the crew as a whole is a necessity in order to encourage and maintain high performance and the satisfaction of project goals.

  5. TOKOPS: Tokamak Reactor Operations Study: The influence of reactor operations on the design and performance of tokamaks with solid-breeder blankets: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Conn, R.W.; Ghoniem, N.M.; Firestone, M.A. (eds.)

    1986-09-01

    Reactor system operation and procedures have a profound impact on the conception and design of power plants. These issues are studied here using a model tokamak system employing a solid-breeder blanket. The model blanket is one which has evolved from the STARFIRE and BCSS studies. The reactor parameters are similar to those characterizing near-term fusion engineering reactors such as INTOR or NET (Next European Tokamak). Plasma startup, burn analysis, and methods for operation at various levels of output power are studied. A critical, and complicating, element is found to be the self-consistent electromagnetic response of the system, including the presence of the blanket and the resulting forces and loadings. Fractional power operation, and the strategy for burn control, is found to vary depending on the scaling law for energy confinement, and an extensive study is reported. Full-power reactor operation is at a neutron wall loading pf 5 MW/m/sup 2/ and a surface heat flux of 1 MW/m/sup 2/. The blanket is a pressurized steel module with bare beryllium rods and low-activation HT-9-(9-C-) clad LiAlO/sub 2/ rods. The helium coolant pressure is 5 MPa, entering the module at 297/sup 0/C and exiting at 550/sup 0/C. The system power output is rated at 1000 MW(e). In this report, we present our findings on various operational scenarios and their impact on system design. We first start with the salient aspects of operational physics. Time-dependent analyses of the blanket and balance of plant are then presented. Separate abstracts are included for each chapter.

  6. A STUDY OF DUST AND GAS AT MARS FROM COMET C/2013 A1 (SIDING SPRING)

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, Michael S. P.; Farnham, Tony L.; Bodewits, Dennis [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Tricarico, Pasquale [Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719 (United States); Farnocchia, Davide, E-mail: msk@astro.umd.edu [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2014-09-01

    Although the nucleus of comet C/2013 A1 (Siding Spring) will safely pass Mars in 2014 October, the dust in the coma and tail will more closely approach the planet. Using a dynamical model of comet dust, we estimate the impact fluence. Based on our nominal model no impacts are expected at Mars. Relaxing our nominal model's parameters, the fluence is no greater than ∼10{sup –7} grains m{sup –2} for grain radii larger than 10 μm. Mars-orbiting spacecraft are unlikely to be impacted by large dust grains, but Mars may receive as many as ∼10{sup 7} grains, or ∼100 kg of total dust. We also estimate the flux of impacting gas molecules commonly observed in comet comae.

  7. A Study of Dust and Gas at Mars from Comet C/2013 A1 (Siding Spring)

    CERN Document Server

    Kelley, Michael S P; Bodewits, Dennis; Tricarico, Pasquale; Farnocchia, Davide

    2014-01-01

    Although the nucleus of comet C/2013 A1 (Siding Spring) will safely pass Mars in October 2014, the dust in the coma and tail will more closely approach the planet. Using a dynamical model of comet dust, we estimate the impact fluence. Based on our nominal model no impacts are expected at Mars. Relaxing our nominal model's parameters, the fluence is no greater than ~10^7 grains/m^2 for grain radii larger than 10 {\\mu}m. Mars orbiting spacecraft are unlikely to be impacted by large dust grains, but Mars may receive as many as ~10^7 grains, or ~100 kg of total dust. We also estimate the flux of impacting gas molecules commonly observed in comet comae.

  8. A Study of Dust and Gas at Mars from Comet C/2013 A1 (Siding Spring)

    Science.gov (United States)

    Kelley, Michael S. P.; Farnham, Tony L.; Bodewits, Dennis; Tricarico, Pasquale; Farnocchia, Davide

    2014-09-01

    Although the nucleus of comet C/2013 A1 (Siding Spring) will safely pass Mars in 2014 October, the dust in the coma and tail will more closely approach the planet. Using a dynamical model of comet dust, we estimate the impact fluence. Based on our nominal model no impacts are expected at Mars. Relaxing our nominal model's parameters, the fluence is no greater than ~10-7 grains m-2 for grain radii larger than 10 μm. Mars-orbiting spacecraft are unlikely to be impacted by large dust grains, but Mars may receive as many as ~107 grains, or ~100 kg of total dust. We also estimate the flux of impacting gas molecules commonly observed in comet comae.

  9. [Interior] Configuration options, habitability and architectural aspects of the transfer habitat module (THM) and the surface habitat on Mars (SHM)/ESA's AURORA human mission to Mars (HMM) study

    Science.gov (United States)

    Imhof, Barbara

    2007-02-01

    This paper discusses the findings for [Interior] configuration options, habitability and architectural aspects of a first human spacecraft to Mars. In 2003 the space architecture office LIQUIFER was invited by the European Space Agency's (ESA) AURORA Program committee to consult the scientists and engineers from the European Space and Technology Center (ESTEC) and other European industrial communities with developing the first human mission to Mars, which will take place in 2030, regarding the architectural issues of crewed habitats. The task was to develop an interior configuration for a transfer vehicle (TV) to Mars, especially a transfer habitation module (THM) and a surface habitat module (SHM) on Mars. The total travel time Earth—Mars and back for a crew of six amounts to approximately 900 days. After a 200-day-flight three crewmembers will land on Mars in the Mars excursion vehicle (MEV) and will live and work in the SHM for 30 days. For 500 days before the 200-day journey back the spacecraft continues to circle the Martian orbit for further exploration. The entire mission program is based on our present knowledge of technology. The project was compiled during a constant feedback-design process and trans-disciplinary collaboration sessions in the ESA-ESTEC concurrent design facility. Long-term human space flight sets new spatial conditions and requirements to the design concept. The guidelines were developed from relevant numbers and facts of recognized standards, interviews with astronauts/cosmonauts and from analyses about habitability, sociology, psychology and configuration concepts of earlier space stations in combination with the topics of the individual's perception and relation of space. Result of this study is the development of a prototype concept for the THM and SHM with detailed information and complete plans of the interior configuration, including mass calculations. In addition the study contains a detailed explanation of the development of

  10. Studies on supercritical water reactor fuel assemblies using the sub-channel code COBRA-EN

    Energy Technology Data Exchange (ETDEWEB)

    Ammirabile, Luca, E-mail: luca.ammirabile@ec.europa.e [European Commission, JRC, Institute for Energy, Westerduinweg 3, 1755 LE Petten (Netherlands)

    2010-10-15

    In the Generation IV International Forum (GIF) program, the supercritical water reactor (SCWR) concept is among the six innovative reactor types selected for development in the near future. In principle the higher efficiency and better economics make the SCWR concept competitive with the current reactor design. Due to different technical challenges that, however exist, fuel assembly design represents a crucial aspect for the success of this concept. In particular large density variations, low moderation, heat transfer enhancement and deterioration have a strong effect on the core design parameters. Only a few computational tools are currently able to perform sub-channel thermal-hydraulic analysis under supercritical water conditions. At JRC-IE the existing sub-channel code COBRA-EN has been improved to work above the critical pressure of water. The water properties package of the IAPWS Industrial Formulation 1997 was integrated in COBRA-EN to compute the Thermodynamic Properties of Water and Steam. New heat transfer and pressure drop correlations more indicated for the supercritical region of water have also been incorporated in the code. As part of the efforts to appraise the new code capabilities, a code assessment was carried out on the hexagonal fuel assembly of a fast supercritical water reactor. COBRA-EN was also applied in combination with the neutronic code MCNP to investigate on the use of hydride fuel in the HPLWR supercritical water fuel assembly. The results showed that COBRA-EN was able to reproduce the results of similar studies with acceptable accuracy. Future activities will focus on the validation of the code against experimental data and the implementation of new features (counter-current moderator channel, wall, and wire-wrap models).

  11. Comparative study of Thermal Hydraulic Analysis Codes for Pressurized Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yang Hoon; Jang, Mi Suk; Han, Kee Soo [Nuclear Engineering Service and Solution Co. Ltd., Daejeon (Korea, Republic of)

    2015-05-15

    Various codes are used for the thermal hydraulic analysis of nuclear reactors. The use of some codes among these is limited by user and some codes are not even open to general person. Thus, the use of alternative code is considered for some analysis. In this study, simple thermal hydraulic behaviors are analyzed using three codes to show that alternative codes are possible for the analysis of nuclear reactors. We established three models of the simple u-tube manometer using three different codes. RELAP5 (Reactor Excursion and Leak Analysis Program), SPACE (Safety and Performance Analysis CodE for nuclear power Plants), GOTHIC (Generation of Thermal Hydraulic Information for Containments) are selected for this analysis. RELAP5 is widely used codes for the analysis of system behavior of PWRs. SPACE has been developed based on RELAP5 for the analysis of system behavior of PWRs and licensing of the code is in progress. And GOTHIC code also has been widely used for the analysis of thermal hydraulic behavior in the containment system. The internal behavior of u-tube manometer was analyzed by RELAP5, SPACE and GOTHIC codes. The general transient behavior was similar among 3 codes. However, the stabilized status of the transient period analyzed by REPAP5 was different from the other codes. It would be resulted from the different physical models used in the other codes, which is specialized for the multi-phase thermal hydraulic behavior analysis.

  12. Facility Configuration Study of the High Temperature Gas-Cooled Reactor Component Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    S. L. Austad; L. E. Guillen; D. S. Ferguson; B. L. Blakely; D. M. Pace; D. Lopez; J. D. Zolynski; B. L. Cowley; V. J. Balls; E.A. Harvego, P.E.; C.W. McKnight, P.E.; R.S. Stewart; B.D. Christensen

    2008-04-01

    A test facility, referred to as the High Temperature Gas-Cooled Reactor Component Test Facility or CTF, will be sited at Idaho National Laboratory for the purposes of supporting development of high temperature gas thermal-hydraulic technologies (helium, helium-Nitrogen, CO2, etc.) as applied in heat transport and heat transfer applications in High Temperature Gas-Cooled Reactors. Such applications include, but are not limited to: primary coolant; secondary coolant; intermediate, secondary, and tertiary heat transfer; and demonstration of processes requiring high temperatures such as hydrogen production. The facility will initially support completion of the Next Generation Nuclear Plant. It will secondarily be open for use by the full range of suppliers, end-users, facilitators, government laboratories, and others in the domestic and international community supporting the development and application of High Temperature Gas-Cooled Reactor technology. This pre-conceptual facility configuration study, which forms the basis for a cost estimate to support CTF scoping and planning, accomplishes the following objectives: • Identifies pre-conceptual design requirements • Develops test loop equipment schematics and layout • Identifies space allocations for each of the facility functions, as required • Develops a pre-conceptual site layout including transportation, parking and support structures, and railway systems • Identifies pre-conceptual utility and support system needs • Establishes pre-conceptual electrical one-line drawings and schedule for development of power needs.

  13. Study of different fitness functions with safety restriction for nuclear reactor reload problem using QDPSO

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Paulo C. de, E-mail: paulocaixeta@poli.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Departamento de Engenharia Nuclear; Lima, Alan M.M. de; Schirru, Roberto, E-mail: alan@lmp.ufrj.br, E-mail: schirru@lmp.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Nuclear Reactor Reload Problem (NRRP) is a classical problem in Nuclear Engineering that has been studied for more than 40 years, which focuses on the economics and safety of the Nuclear Power Plant (NPP). This problem consists in searching for the best loading pattern of fuel assemblies (FA) in the core, aiming to determine the permutation of fuel assemblies that optimizes the uranium utilization, with fitness function evaluated according to specific criteria and methods of nuclear reactor physics, such as the maximum mean power peak and the boron concentration. In this article will be presented different methodologies to obtain a representative fitness function for NRRP, where Quantum particle Swarm optimization (QPSO) was used to determine which one gives the best array of fuel assemblies that will make the maximum EFPD (Effective Full Power Days) with the least computational effort. In this approach, as well as others in literature, was not used Burnable Poison in the simulations and the results will be compared in relation of the maximization of the cycle length considering the boron concentration yield by the reactor physics code, to make sure that the configuration is valid from a safety point of view. This paper was based on Angra 1's seventh reload cycle. (author)

  14. Preliminary Studies on Oleochemical Wastewater Treatment using Submerged Bed Biofilm Reactor (SBBR)

    Science.gov (United States)

    Ismail, Z.; Mahmood, N. A. N.; Ghafar, U. S. A.; Umor, N. A.; Muhammad, S. A. F.

    2017-06-01

    Wastewater discharge from the industry into water sources is one of the main reason for water pollution. The oleochemicals industry effluent produces high content of chemical oxygen demand (COD) with value between 6000-20,000 ppm. Effective treatment is required before wastewater effluent is discharged to environment. The aim of the study is to develop submerged bed biofilm reactor (SBBR) with packing materials in the cosmoball® carrier. Water quality such as chemical oxygen demands (COD), turbidity and pH were analysed. The result shows that the initial COD of 6000 ppm was reduced below 200 ppm. The optimum conditions for SBBR were obtained when green sponges used as packing material in cosmoball® effluent flowrate set at 100 mL/min; 1:1 ratio of cosmoball® volume to reactor volume and 1:1 ratio of active sludge (mixed culture) volume to reactor volume. Turbidity and pH were recorded with 9.0 NTU and 7.0 respectively, which indicated that SBBR is feasible as an alternative for conventional biological treatment in oleochemical industry.

  15. Numerical study on soot removal in partial oxidation of methane to syngas reactors

    Institute of Scientific and Technical Information of China (English)

    Weisheng; Wei; Tao; Zhang; Jian; Xu; Wei; Du

    2014-01-01

    The serious carbon deposition existing in catalytic partial oxidation of methane(CPOM) to syngas process is one of the key problems that impede its industrialization. In this study, 3-dimensional unsteady numerical simulations of the soot formation and oxidation in oxidation section in a heat coupling reactor were carried out by computational fluid dynamics(CFD) approach incorporating the Moss-Brookes model for soot formation. The model has been validated and proven to be in good agreement with experiment results. Effects of nozzle type,nozzle convergence angle, channel spacing, number of channels, radius/height ratio, oxygen/carbon ratio, preheat temperature and additional introduction of steam on the soot formation were simulated. Results show that the soot formation in oxidation section of the heat coupling reactor depends on both nozzle structures and operation conditions, and the soot concentration can be greatly reduced by optimization with the maximum mass fraction of soot inside the oxidation reactor from 2.28% to 0.0501%, and so that the soot mass fraction at the exit reduces from0.74% to 0.03%.

  16. The Spread of Economic Ideas among Romanian People. Case Study: Dionisie Pop Marţian

    Directory of Open Access Journals (Sweden)

    Angela ROGOJANU

    2010-12-01

    Full Text Available In the nineteenth century, the accelerating globalizationstarted to show demands that the majority of the Romanians could notunderstand. The delay in the economic development, the political-stateestablishment, the scarcity of instruction and education, the historical andgeographical context marked by hostility, all these formed the gap betweenthe "West" and "East". The renewing economic ideas penetrated hard,often deformed ... The relentless intelligence of some young peopleeducated outside the Romanian land, as Dionisie Pop Marţian (1829-1865, has started the struggle for "the economic emancipation of thenation" by promoting the ideas, the principles and the institutions on whichwas build the prosperity of the West. Seen as a "reactionary" or as a "manof progress", Marţian has delivered a heterogeneous economic outlook, amixture of liberal principles and protectionist principles. The mostsignificant "protection" supported by Marţian was the one againstignorance. The compilation made by Marţian using the works of variousauthors sustaining the "social economy" shows the dimensions of economicbackwardness - the absence of current economic terms from the lexicon.Marţian invents some economic terms, which are understandable, such as:„comerciu”(trade, „manufaptură” (manufacture, „product”, „const”,„fair price”, „banc-rupt” etc. Marţian's mission was clear: "the spreadingof economics through speaking and writing.".

  17. Study of a Multi-phase Hybrid Heat Exchanger-Reaction (HEX Reactor): Part 1 - Experimental Characterization

    Science.gov (United States)

    2014-01-01

    scalability, and mixing capability compared to more traditional shell - in- tube heat exchangers or stirred tank batch reactors. This study explores the... tube heat exchangers or stirred tank batch reactors. This study explores the hydrodynamic behavior of gas-evolving reacting flows in chevron plate heat ...thermal performance and ease of maintenance. PHEs can be easily disassembled for inspection andmaintenance (in con- trast, shell -and- tube heat

  18. Experimental and Modeling Studies of the Methane Steam Reforming Reaction at High Pressure in a Ceramic Membrane Reactor

    OpenAIRE

    Hacarlioglu, Pelin

    2007-01-01

    This dissertation describes the preparation of a novel inorganic membrane for hydrogen permeation and its application in a membrane reactor for the study of the methane steam reforming reaction. The investigations include both experimental studies of the membrane permeation mechanism and theoretical modeling of mass transfer through the membrane and simulation of the membrane reactor with 1-D and 2-D models. A hydrothermally stable and hydrogen selective membrane composed of silica and a...

  19. Study of thorium-uranium based molten salt blanket in a fusion-fission hybrid reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Jing, E-mail: zhao_jing@mail.tsinghua.edu.cn [INET, Tsinghua University, Beijing 100084 (China); Yang Yongwei; Zhou Zhiwei [INET, Tsinghua University, Beijing 100084 (China)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer A molten salt blanket has been designed for the fusion-fission hybrid reactor. Black-Right-Pointing-Pointer The use of Thorium in the molten salt fuels has been studied. Black-Right-Pointing-Pointer The molten salt was consisted of F-Li-Be and with the thickness of 40 cm. Black-Right-Pointing-Pointer The concentration of {sup 6}Li was chosen to be the natural enrichment ratio. Black-Right-Pointing-Pointer The result shows that TBR is greater than 1, M is about 15-16. - Abstract: Not only solid fuels, but also liquid fuels can be used for the fusion-fission symbiotic reactor blanket. The operational record of the molten salt reactor with F-Li-Be was very successful, so the F-Li-Be blanket was chosen for research. The molten salt has several features which are suited for the fusion-fission applications. The fuel material uranium and thorium were dissolved in the F-Li-Be molten salt. A combined program, COUPLE, was used for neutronics analysis of the molten salt blanket. Several cases have been calculated and compared. Not only the influence of the different fuels have been studied, but also the thickness of the molten salt, and the concentration of the {sup 6}Li in the molten salt. Preliminary studies indicate that when thorium-uranium-plutonium fuels were added into a F-Li-Be molten salt blanket and with a component of 71% LiF-2% BeF{sub 2}-13.5% ThF{sub 4}-8.5% UF{sub 4}-5% PuF{sub 3}, and also with the molten salt thickness of 40 cm and natural concentration of {sup 6}Li, the appropriate blanket energy multiplication factor and TBR can be obtained. The result shows that thorium-uranium molten salt can be used in the blanket of a fusion-fission symbiotic reactor. The research on the molten salt blanket must be valuable for the design of fusion-fission symbiotic reactor.

  20. Model of punctual kinetic for studies on fast reactor stability; Modelo de cinetica pontual para estudos de estabilidade de reatores rapidos

    Energy Technology Data Exchange (ETDEWEB)

    Rocamora, Francisco Dias Jr.; Rosa, Mauricio A. Pinheiro; Braz Filho, Francisco A.; Borges, Eduardo M.; Guimaraes, Lamartine

    1998-07-01

    The neutron kinetics equations are used to obtain the Zero Power Transfer Function which establishes a relationship between a reactor core reactivity perturbation and the corresponding reactor power response. This transfer function should be coupled with those obtained from the fuel element and coolant thermal-hydraulics models in order to study fast reactor stability 'in the small'. (author)

  1. Conceptual Design study of Small Long-life Gas Cooled Fast Reactor With Modified CANDLE Burn-up Scheme

    Science.gov (United States)

    Nur Asiah, A.; Su'ud, Zaki; Ferhat, A.; Sekimoto, H.

    2010-06-01

    In this paper, conceptual design study of Small Long-life Gas Cooled Fast Reactors with Natural Uranium as Fuel Cycle Input has been performed. In this study Gas Cooled Fast Reactor is slightly modified by employing modified CANDLE burn-up scheme so that it can use Natural Uranium as fuel cycle input. Due to their hard spectrum, GCFR in this study showed very good performance in converting U-238 to plutonium in order to maintain the operation condition requirement of long-life reactors. Due to the limitation of thermal hydraulic aspects, the average power density of the proposed design is selected about 70 W/cc. With such condition we got an optimal design of 325 MWt reactors which can be operated 10 years without refueling and fuel shuffling and just need natural uranium as fuel cycle input. The average discharge burn-up is about 290 GWd/ton HM.

  2. Reactor safety study. An assessment of accident risks in U. S. commercial nuclear power plants. Appendix XI. Analysis of comments on the draft WASH-1400 report. [PWR and BWR

    Energy Technology Data Exchange (ETDEWEB)

    1975-10-01

    Information is presented concerning comments on reactor safety by governmental agencies and civilian organizations; reactor safety study methodology; consequence model; probability of accident sequences; and various accident conditions.

  3. Conceptual Thermal Hydraulic Design of a 20MW Multipurpose Research Reactor (KAERI/VAEC joint study on a new research reactor for Vietnam)

    Energy Technology Data Exchange (ETDEWEB)

    Chae, Hee Taek; Seo, Chul Gyo; Park, Jong Hark; Park, Cheol [Kaeri, Daejeon (Korea, Republic of); Vinh, Le Vinh; Nghiem, Huynh Ton; Dang, Vo Doan Hai [Dalat Nuclear Research Reactor, Hanoi (Viet Nam)

    2007-08-15

    The conceptual thermal hydraulics design analyses for the 20 MW reference AHR core have been jointly performed by the KAERI and DNRI(VAEC). The preliminary core thermal hydraulic characteristics and safety margins for the AHR core were studied for various core flow rates, fuel assembly powers and core inlet temperatures. Statistical method was applied to the thermal hydraulic design of the reactor core. The MATRA{sub h} subchannel code has been applied to evaluate the thermal hydraulic performances of the AHR and the resulting thermal margins of the core under the forced convection cooling mode during a nominal power operation and the natural circulation mode during a reactor shutdown condition. In addition, typical accident analyses were carried out for a loss of flow accident by a primary pump seizure and a reactivity induced accident by a CAR rod withdrawal during a normal full power operation. The normal full power operation of the AHR was ensured with a sufficient safety margin for the onset of nucleate boiling phenomena. The AHR also had a sufficient natural circulation cooling capability to cool the core without the onset of nucleate boiling in the channel after a normal reactor shutdown and the anticipated transients. It was confirmed by the typical accident analyses that the AHR core was sufficiently protected from the loss of flow by the primary cooling pump seizure and the overpower transients by the CAR withdrawal from the MCHFR and fuel temperature points of view.

  4. Study of evaluation methods for in-vessel corium retention through external vessel cooling and safety of reactor cavity

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Hoon; Chang, Soon Heung; Choi, Tae Hoon; Kim, Hyun Sop; Yang, Soo Hyung; Kim, Soo Hyung; Kim, Seung Hop; An Hyung Taek; Jeong, Yong Hoon; Huh, Gyun Young [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1998-03-15

    Cooling methodologies for the molten corium resulted from the severe accident of the nuclear power plant is suggested as one of most important items for the safety of the NPP. In this regard, considerable experimental and analytical works have been devoted. In the 1st phase of this project, present status related to the external reactor vessel cooling for the retention of the corium in the reactor vessel and corium at the reactor cavity have been investigated and preliminary studies have been accomplished for the detail evaluation of the each cooling methodology. The preliminary studies include the analysis and detail investigation of the possible phenomena, investigation of the heat transfer correlations and preliminary evaluation of the external reactor vessel cooling using the developed computer code.

  5. Research and development studies on the seismic behaviour of the PEC fast reactor (safety analysis detailed report no. 8)

    Energy Technology Data Exchange (ETDEWEB)

    Martelli, A.; Forni, M.; Masoni, P.; Maresca, G.; Castoldi, A.; Muzzi, F. (ENEA, Rome (Italy); Ansaldo Spa, Genoa (Italy); ISMES Spa, Bergamo (Italy))

    1988-01-15

    This paper presents the main features and results of the numerical and experimental studies that were carried out by ENEA (Italian Commission for Alternative Energy Sources) for the seismic verification of the Italian PEC fast reactor test facility. More precisely, the paper focuses on the wide-ranging research and development programme that has been performed (and recently completed) on the reactor building, the reactor-block, the main vessel, the core and the shutdown system. The needs of these detailed studies are stressed and the feed-backs on the design, necessary safisfy the seismic safety requirements, are recalled. The general validity of the analyses in the framework of the research and development activities for nuclear reactor is also pointed out.

  6. High-Speed Neutron and Gamma Flux Sensor for Monitoring Surface Nuclear Reactors Project

    Data.gov (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...

  7. High-Speed Neutron and Gamma Flux Sensor for Monitoring Surface Nuclear Reactors Project

    Data.gov (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...

  8. Multiphase Explosions on Mars: Numerical Studies of Phreatomagmatic Blast Dynamics (Invited)

    Science.gov (United States)

    Dufek, J.

    2010-12-01

    Phreatomagmatic activity may have helped shape the surface of early Mars and the landforms generated in such events provides clues to both the magmatic and environmental conditions in the near surface. We study the dynamics of explosions generated by rapid steam generation in the near surface when magma intersects a source of liquid water or ice. Using an EEL multiphase model we study the thermal evolution in the source region, the pressure evolution due to phase change, and the compressible multiphase dynamics of the blast and subsequent gravity currents. This numerical model was validated on similar blast conditions through a sequence of scaled analogue experiments. Both the dilute and dense part of the granular flow are modeled and we correlate dynamics during the blast to eventual depositional features such as grain size sorting, flow runout, crater size and shape, and distribution of large clasts. In this way we correlate the pre-eruptive conditions to landform morphology that may be useful in interpreting on-going observations. We also report on the mixing of gas species in explosive events to better understand the distribution of water during and after the blast. Using microsphysical models we also assess the spatial and temporal potential for electrostatic and hydrous particle aggregation.

  9. Parametric Weight Study of Cryogenic Metallic Tanks for the ``Bimodal'' NTR Mars Vehicle Concept

    Science.gov (United States)

    Kosareo, Daniel N.; Roche, Joseph M.

    2006-01-01

    A parametric weight assessment of large cryogenic metallic tanks was conducted using the design optimization capabilities in the ANSYS ® finite element analysis code. This analysis was performed to support the sizing of a ``bimodal'' nuclear thermal rocket (NTR) Mars vehicle concept developed at the NASA Glenn Research Center. The tank design study was driven by two load conditions: an in-line, ``Shuttle-derived'' heavy-lift launch with the tanks filled and pressurized, and a burst-test pressure. The main tank structural arrangement is a state-of-the art metallic construction which uses an aluminum-lithium alloy stiffened internally with a ring and stringer framework. The tanks must carry liquid hydrogen in separate launches to orbit where all vehicle components will dock and mate. All tank designs stayed within the available mass and payload volume limits of both the in-line heavy lift and Shuttle derived launch vehicles. Weight trends were developed over a range of tank lengths with varying stiffener cross-sections and tank wall thicknesses. The object of this parametric study was to verify that the proper mass was allocated for the tanks in the overall vehicle sizing model. This paper summarizes the tank weights over a range of tank lengths.

  10. Study on Application of Grey Prediction Model in Superalloy MAR-247 Machining

    Directory of Open Access Journals (Sweden)

    Chen Shao-Hsien

    2015-01-01

    Full Text Available Superalloy MAR-247 is mainly applied in the space industry and die industry. With its characteristics of mechanical property, fatigue resistance, and high temperature corrosion resistance, therefore, it is mainly applied in machine parts of high temperature and corrosion resistance, such as turbine blades and rotor of the aeroengine and turbine assembly in the nuclear power plant. However, considering that its properties of high strength, low thermal conductivity, being difficult to soften, and work hardening may reduce the life of cutting-tool and weaken the surface accuracy, the study provided minimizing experiment occurring during milling process for superalloy material. As a statistical approach used to analyse experiment data, this study used GM(1,1 in the grey prediction model to conduct simulation and then predict and analyze its characteristics based on the experimental data, focusing on the tool life and surface accuracy. Moreover, with the superalloy machining parameters of the current effective application improved grey prediction model, it can decrease the errors, extend the tool life, and improve the prediction precision of surface accuracy.

  11. Large scale breeder reactor plant prototype mechanical pump conceptual design study

    Energy Technology Data Exchange (ETDEWEB)

    1976-07-01

    This final report is a complete conceptual design study of a mechanical pump for a large scale breeder reactor plant. The pumps are located in the cold leg side of the loops. This makes the net positive suction head available - NPSHA - low, and is, in fact, a major influencing factor in the design. Where possible, experience gained from the Clinch River Project and the FFTF is used in this study. Experience gained in the design, manufacturer, and testing of pumps in general and sodium pumps in particular is reflected in this report. The report includes estimated cost and time schedule for design, manufacture, and testing. It also includes a recommendation for development needs.

  12. Mirror fusion propulsion system: A performance comparison with alternate propulsion systems for the manned Mars Mission

    Science.gov (United States)

    Schulze, Norman R.; Carpenter, Scott A.; Deveny, Marc E.; Oconnell, T.

    1993-06-01

    The performance characteristics of several propulsion technologies applied to piloted Mars missions are compared. The characteristics that are compared are Initial Mass in Low Earth Orbit (IMLEO), mission flexibility, and flight times. The propulsion systems being compared are both demonstrated and envisioned: Chemical (or Cryogenic), Nuclear Thermal Rocket (NTR) solid core, NTR gas core, Nuclear Electric Propulsion (NEP), and a mirror fusion space propulsion system. The proposed magnetic mirror fusion reactor, known as the Mirror Fusion Propulsion System (MFPS), is described. The description is an overview of a design study that was conducted to convert a mirror reactor experiment at Lawrence Livermore National Lab (LLNL) into a viable space propulsion system. Design principles geared towards minimizing mass and maximizing power available for thrust are identified and applied to the LLNL reactor design, resulting in the MFPS. The MFPS' design evolution, reactor and fuel choices, and system configuration are described. Results of the performance comparison shows that the MFPS minimizes flight time to 60 to 90 days for flights to Mars while allowing continuous return-home capability while at Mars. Total MFPS IMLEO including propellant and payloads is kept to about 1,000 metric tons.

  13. Mirror fusion propulsion system - A performance comparison with alternate propulsion systems for the manned Mars mission

    Science.gov (United States)

    Deveny, M.; Carpenter, S.; O'Connell, T.; Schulze, N.

    1993-06-01

    The performance characteristics of several propulsion technologies applied to piloted Mars missions are compared. The characteristics that are compared are Initial Mass in Low Earth Orbit (IMLEO), mission flexibility, and flight times. The propulsion systems being compared are both demonstrated and envisioned: Chemical (or Cryogenic), Nuclear Thermal Rocket (NTR) solid core, NTR gas core, Nuclear Electric Propulsion (NEP), and a mirror fusion space propulsion system. The proposed magnetic mirror fusion reactor, known as the Mirror Fusion Propulsion System (MFPS), is described. The description is an overview of a design study that was conducted to convert a mirror reactor experiment at Lawrence Livermore National Lab (LLNL) into a viable space propulsion system. Design principles geared towards minimizing mass and maximizing power available for thrust are identified and applied to the LLNL reactor design, resulting in the MFPS. The MFPS' design evolution, reactor and fuel choices, and system configuration are described. Results of the performance comparison shows that the MFPS minimizes flight time to 60 to 90 days for flights to Mars while allowing continuous return-home capability while at Mars. Total MFPS IMLEO including propellant and payloads is kept to about 1,000 metric tons.

  14. Methanol synthesis in a countercurrent gas-solid-solid trickle flow reactor. An experimental study

    NARCIS (Netherlands)

    Kuczynski, M.; Oyevaar, M.H.; Pieters, R.T.; Westerterp, K.R.

    1987-01-01

    The synthesis of methanol from CO and H2 was executed in a gas-solid-solid trickle flow reactor. The reactor consisted of three tubular reactor sections with cooling sections in between. The catalyst was Cu on alumina, the adsorbent was a silica-alumina powder and the experimental range 498–523 K,

  15. Experimental and theoretical study of the efficiency of a three-electrode reactor for the removal of NO

    Science.gov (United States)

    Gallego, J. L.; Minotti, F.; Grondona, D.

    2014-05-01

    An experimental and theoretical study is presented on the efficiency of the removal of NO in a N2 atmosphere in a novel three-electrode reactor. This reactor combines a dielectric-barrier discharge with a corona discharge, designed to enhance streamer propagation in a relatively large region. Experimentally, the reactor has a good energy yield for the removal of NO, as compared with other discharge methods. A theoretical model is developed for the production of reactive species in the streamers by different reactions that allow to relate simple electrical measurements with the reactor efficiency. This theoretical efficiency resulted in good agreement with the experimental one, validating the model and allowing the evaluation of the contribution of different reactions involved in NO removal.

  16. Study of plutonium disposition using existing GE advanced Boiling Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    The end of the cold war and the resulting dismantlement of nuclear weapons has resulted in the need for the US to dispose of 50 to 100 metric tons of excess of plutonium in a safe and proliferation resistant manner. A number of studies, including the recently released National Academy of Sciences (NAS) study, have recommended conversion of plutonium into spent nuclear fuel with its high radiation barrier as the best means of providing permanent conversion and long-term diversion resistance to this material. The NAS study ``Management and Disposition of Excess Weapons Plutonium identified Light Water Reactor spent fuel as the most readily achievable and proven form for the disposition of excess weapons plutonium. The study also stressed the need for a US disposition program which would enhance the prospects for a timely reciprocal program agreement with Russia. This summary provides the key findings of a GE study where plutonium is converted into Mixed Oxide (MOX) fuel and a typical 1155 MWe GE Boiling Water Reactor (BWR) is utilized to convert the plutonium to spent fuel. A companion study of the Advanced BWR has recently been submitted. The MOX core design work that was conducted for the ABWR enabled GE to apply comparable fuel design concepts and consequently achieve full MOX core loading which optimize plutonium throughput for existing BWRs.

  17. Food System Trade Study for a Near-Term Mars Mission

    Science.gov (United States)

    Levri, Julie; Luna, Bernadette (Technical Monitor)

    2000-01-01

    This paper evaluates several food system options for a near-term Mars mission, based on plans for the 120-day BIO-Plex test. Food systems considered in the study are based on the International Space Station (ISS) Assembly Phase and Assembly Complete food systems. The four systems considered are: 1) ISS assembly phase food system (US portion) with individual packaging without salad production; 2) ISS assembly phase food system (US portion) with individual packaging, with salad production; 3) ISS assembly phase food system (US portion) with bulk packaging, with salad production; 4) ISS assembly complete food system (US portion) with bulk packaging with salad and refrigeration/freezing. The food system options are assessed using equivalent system mass (ESM), which evaluates each option based upon the mass, volume, power, cooling and crewtime requirements that are associated with each food system option. However, since ESM is unable to elucidate the differences in psychological benefits between the food systems, a qualitative evaluation of each option is also presented.

  18. \\title{MARS15 Simulation Studies in the CMS Detector of Some LHC Beam Accident Scenarios}

    CERN Document Server

    Bhat, Pushpalatha C; Striganov, S.I; Singh, Amandeep

    2009-01-01

    \\begin{abstract} The CMS tracker, made of silicon strips and pixels and silicon-based electronics, is vulnerable to effects of radiation exposure during the LHC operation. Of much concern is the potential for damage from a high instantaneous dose to the pixel detectors and electronics located only a few centimeters from the beam in the event of a fast accidental beam loss. One of the worst case scenarios for such a beam loss is an unintended firing of an abort kicker module, referred to as the kicker pre-fire. MARS15 simulation studies of radiation loads in CMS for the kicker pre-fire scenario are described in this paper. It is found that, in a kicker pre-fire accident, in a time span of about 100 ns, the innermost pixel layer may see a radiation dose of about 0.02 Gy \\-- equivalent to a fluence of $\\sim 6\\times 10^{7}$ MIPs/$cm^2$. No discernible damage to the pixel detectors or the electronics were seen at these levels of fluence in recent beam tests. We note that the dose is about 1000 times smaller t...

  19. Parameter Study of Plasma-Induced Atmospheric Sputtering and Heating at Mars

    Science.gov (United States)

    Williamson, Hayley N.; Johnson, Robert E.; Leblanc, Francois

    2014-11-01

    Atoms and molecules in Mars’ upper atmosphere are lost predominately through sputtering, caused by the impact of ions into the exosphere, dissociative recombination, and thermal escape. While all three processes are thought to occur on Mars, a detailed understanding must ascertain the relative importance of each process, due to time variations in pick-up and solar wind ions. In this project, using case studies of an oxygen atmosphere modeled with Direct Simulation Monte Carlo techniques, we have endeavored to categorize when the momentum transfer or thermal escape is more likely to occur. To do this, we vary the incident plasma flux and energy based on models of the interaction of the solar wind with the Martian atmosphere. We first repeat the heating and sputtering rates due to a flux of pick-up O+ examined previously (Johnson et al. 2000; Michael and Johnson 2005; Johnson et al 2013). We have used multiple examples of particle fluxes for various solar wind conditions, from steady solar wind conditions (Luhmann et al. 1992; Chaufray et al. 2007) to more extreme cases (Fang et al. 2013; Wang et al. 2014), which are thought to increase escape by several orders of magnitude. The goal is to explore the escape parameter space in preparation for the expected data from MAVEN on hot atoms and molecules in the Martian exosphere.

  20. Experimental study of thermal crisis in connection with Tokamak reactor high heat flux components

    Science.gov (United States)

    Gallo, D.; Giardina, M.; Castiglia, F.; Celata, G. P.; Mariani, A.; Zummo, G.; Cumo, M.

    2000-04-01

    The results of an experimental research on high heat flux thermal crisis in forced convective subcooled water flow, under operative conditions of interest to the thermal-hydraulic design of TOKAMAK fusion reactors, are here reported. These experiments, carried out in the framework of a collaboration between the Nuclear Engineering Department of Palermo University and the National Institute of Thermal - Fluid Dynamics of the ENEA - Casaccia (Rome), were performed on the STAF (Scambio Termico Alti Flussi) water loop and consisted, essentially, in a high speed photographic study which enabled focusing several information on bubble characteristics and flow patterns taking place during the burnout phenomenology.

  1. Thermal stability study for candidate stainless steels of GEN IV reactors

    Science.gov (United States)

    Simeg Veternikova, J.; Degmova, J.; Pekarcikova, M.; Simko, F.; Petriska, M.; Skarba, M.; Mikula, P.; Pupala, M.

    2016-11-01

    Candidate stainless steels for GEN IV reactors were investigated in term of thermal and corrosion stability at high temperatures. New austenitic steel (NF 709), austenitic ODS steel (ODS 316) and two ferritic ODS steels (MA 956 and MA 957) were exposed to around 1000 °C in inert argon atmosphere at pressure of ∼8 MPa. The steels were further studied in a light of vacancy defects presence by positron annihilation spectroscopy and their thermal resistance was confronted to classic AISI steels. The thermal strain supported a creation of oxide layers observed by scanning electron microscopy (SEM).

  2. Conceptual studies of toroidal field magnets for the tokamak experimental power reactor. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Buncher, B.R.; Chi, J.W.H.; Fernandez, R.

    1976-10-26

    This report documents the principal results of a Conceptual Design Study for the Superconducting Toroidal Field System for a Tokamak Experimental Power Reactor. Two concepts are described for peak operating fields at the windings of 8 tesla, and 12 tesla, respectively. The design and manufacturing considerations are treated in sufficient detail that cost and schedule estimates could be developed. Major uncertainties in the design are identified and their potential impact discussed, along with recommendations for the necessary research and development programs to minimize these uncertainties. The minimum dimensions of a sub-size test coil for experimental qualification of the full size design are developed and a test program is recommended.

  3. Polarized SANS study of microstructural evolution in a martensitic steel for fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Coppola, R. [ENEA-Casaccia, FIS, CP 2400, 00100 Roma (Italy); Glaettli, H. [CEA-SACLAY, SPEC and Laboratoire Leon Brillouin (CEA-CNRS), 91191 Gif-sur-Yvette (France); Valli, M. [ENEA-Bologna, FIS, V. Don Fiammelli 2, 40128 Bologna (Italy)

    2002-07-01

    The results of a polarized SANS study of a martensitic steel (MANET) developed for fusion-reactor technology are presented. The measurements were carried out to investigate Cr-redistribution phenomena in the martensitic matrix, which can play a crucial role in ductile-to-brittle transition changes under irradiation. The nuclear-magnetic interference term and the ratio of nuclear plus magnetic to nuclear SANS cross sections show that such inhomogeneities, which are present immediately after quenching and give rise to Fe-rich precipitates, dissolve even for short tempering times. (orig.)

  4. Neutronic feasibility studies for LEU conversion of the HFR Petten Reactor.

    Energy Technology Data Exchange (ETDEWEB)

    Hanan, N. A.; Deen, J. R.; Matos, J. E.

    2000-09-26

    Design and safety analyses to determine an optimum LEU fuel assembly design using U{sub 3}Si{sub 2}-Al fuel with up to 4.8 g/cm{sup 3} for conversion of the HFR Petten reactor were performed by the RERTR program in cooperation with the Joint Research Centre and NRG. Credibility of the calculational methods and models were established by comparing calculations with recent measurements by NRG for a core configuration setup for this purpose. This model and methodology were then used to study various LEU fissile loading and burnable poison options that would satisfy specific design criteria.

  5. A Conceptual Study on a Supercritical CO2-cooled KAIST Micro Modular Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yu, HwanYeal; Hartanto, Donny; Kim, Yonghee [KAIST, Daejeon (Korea, Republic of)

    2015-05-15

    Small Modular Reactors (SMRs) are nuclear reactors that are completely built in a factory and shipped to the designated site for installation. As such, the SMR is especially advantageous as a flexible and cost-effective energy source for remote and isolated areas. Furthermore, the concept requires a relatively low capital cost, which makes it attractive for developing countries with limited electricity grid. In addition, the SMR concepts also generate more interest after the Fukushima accident since it can easily be designed with a passive decay heat removal system. One of the major advantages of a water-cooled SMR is its relatively small core size. Nonetheless, in spite of its small core size, the volume and area required for its steam-cycle power conversion unit is still significant. In this study, neutronics feasibility of a fully compact and transportable KAIST micro-modular reactor (MMR) was demonstrated. Rated thermal power of the core was 36.2 MWth with total weight of about 39.6 tons. The core was loaded with 15.5 w/o uranium mono-nitride U15N fuels in order to achieve a targeted lifetime of 20 EFPYs. To achieve targeted lifetime, initial excess reactivity of the core should be quite high, around 4,707 pcm. To reduce the high excess reactivity to about 2,500 pcm, a replaceable burnable absorber was utilized in the design. As a result, the MMR has a 20-year lifetime with a relatively small burnup reactivity swing. Several important safety parameters of the KAIST MMR core were also determined in this study. The Doppler reactivity coefficients and CVRs were demonstrated to negative. Worth of the primary control drums and secondary control rod were much higher than initial excess reactivity.

  6. Light Water Reactor Sustainability Program Risk Informed Safety Margin Characterization (RISMC) Advanced Test Reactor Demonstration Case Study

    Energy Technology Data Exchange (ETDEWEB)

    Curtis Smith; David Schwieder; Cherie Phelan; Anh Bui; Paul Bayless

    2012-08-01

    Safety is central to the design, licensing, operation, and economics of Nuclear Power Plants (NPPs). Consequently, the ability to better characterize and quantify safety margin holds the key to improved decision making about LWR design, operation, and plant life extension. A systematic approach to characterization of safety margins and the subsequent margins management options represents a vital input to the licensee and regulatory analysis and decision making that will be involved. The purpose of the RISMC Pathway R&D is to support plant decisions for risk-informed margins management with the aim to improve economics, reliability, and sustain safety of current NPPs. Goals of the RISMC Pathway are twofold: (1) Develop and demonstrate a risk-assessment method coupled to safety margin quantification that can be used by NPP decision makers as part of their margin recovery strategies. (2) Create an advanced “RISMC toolkit” that enables more accurate representation of NPP safety margin. This report describes the RISMC methodology demonstration where the Advanced Test Reactor (ATR) was used as a test-bed for purposes of determining safety margins. As part of the demonstration, we describe how both the thermal-hydraulics and probabilistic safety calculations are integrated and used to quantify margin management strategies.

  7. Mars Ice Age, Simulated

    Science.gov (United States)

    2003-01-01

    December 17, 2003This simulated view shows Mars as it might have appeared during the height of a possible ice age in geologically recent time.Of all Solar System planets, Mars has the climate most like that of Earth. Both are sensitive to small changes in orbit and tilt. During a period about 2.1 million to 400,000 years ago, increased tilt of Mars' rotational axis caused increased solar heating at the poles. A new study using observations from NASA's Mars Global Surveyor and Mars Odyssey orbiters concludes that this polar warming caused mobilization of water vapor and dust into the atmosphere, and buildup of a surface deposit of ice and dust down to about 30 degrees latitude in both hemispheres. That is the equivalent of the southern Unites States or Saudi Arabia on Earth. Mars has been in an interglacial period characterized by less axial tilt for about the last 300,000 years. The ice-rich surface deposit has been degrading in the latitude zone of 30 degrees to 60 degrees as water-ice returns to the poles.In this illustration prepared for the December 18, 2003, cover of the journal Nature, the simulated surface deposit is superposed on a topography map based on altitude measurements by Global Surveyor and images from NASA's Viking orbiters of the 1970s.Mars Global Surveyor and Mars Odyssey are managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, for the NASA Office of Space Science, Washington.

  8. Study on core radius minimization for long life Pb-Bi cooled CANDLE burnup scheme based fast reactor

    Science.gov (United States)

    Afifah, Maryam; Miura, Ryosuke; Su'ud, Zaki; Takaki, Naoyuki; Sekimoto, H.

    2015-09-01

    Fast Breeder Reactor had been interested to be developed over the world because it inexhaustible source energy, one of those is CANDLE reactor which is have strategy in burn-up scheme, need not control roads for control burn-up, have a constant core characteristics during energy production and don't need fuel shuffling. The calculation was made by basic reactor analysis which use Sodium coolant geometry core parameter as a reference core to study on minimum core reactor radius of CANDLE for long life Pb-Bi cooled, also want to perform pure coolant effect comparison between LBE and sodium in a same geometry design. The result show that the minimum core radius of Lead Bismuth cooled CANDLE is 100 cm and 500 MWth thermal output. Lead-Bismuth coolant for CANDLE reactor enable to reduce much reactor size and have a better void coefficient than Sodium cooled as the most coolant for FBR, then we will have a good point in safety analysis.

  9. Modeling and Experimental Studies of Mercury Oxidation and Adsorption in a Fixed-Bed Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Buitrago, Paula A.; Morrill, Mike; Lighty, JoAnn S.; Silcox, Geoffrey D.

    2009-06-15

    This report presents experimental and modeling mercury oxidation and adsorption data. Fixed-bed and single-particle models of mercury adsorption were developed. The experimental data were obtained with two reactors: a 300-W, methane-fired, tubular, quartz-lined reactor for studying homogeneous oxidation reactions and a fixed-bed reactor, also of quartz, for studying heterogeneous reactions. The latter was attached to the exit of the former to provide realistic combustion gases. The fixed-bed reactor contained one gram of coconut-shell carbon and remained at a temperature of 150°C. All methane, air, SO2, and halogen species were introduced through the burner to produce a radical pool representative of real combustion systems. A Tekran 2537A Analyzer coupled with a wet conditioning system provided speciated mercury concentrations. At 150°C and in the absence of HCl or HBr, the mercury uptake was about 20%. The addition of 50 ppm HCl caused complete capture of all elemental and oxidized mercury species. In the absence of halogens, SO2 increased the mercury adsorption efficiency to up to 30 percent. The extent of adsorption decreased with increasing SO2 concentration when halogens were present. Increasing the HCl concentration to 100 ppm lessened the effect of SO2. The fixed-bed model incorporates Langmuir adsorption kinetics and was developed to predict adsorption of elemental mercury and the effect of multiple flue gas components. This model neglects intraparticle diffusional resistances and is only applicable to pulverized carbon sorbents. It roughly describes experimental data from the literature. The current version includes the ability to account for competitive adsorption between mercury, SO2, and NO2. The single particle model simulates in-flight sorbent capture of elemental mercury. This model was developed to include Langmuir and Freundlich isotherms, rate equations, sorbent feed rate, and

  10. Monte Carlo Simulation Study of a Differential Calorimeter Measuring the Nuclear Heating in Material Testing Reactors

    Science.gov (United States)

    Amharrak, H.; Reynard-Carette, C.; Lyoussi, A.; Carette, M.; Brun, J.; De Vita, C.; Fourmentel, D.; Villard, J.-F.; Guimbal, P.

    2016-02-01

    The nuclear heating measurements in Material Testing Reactors (MTRs) are crucial for the study of nuclear materials and fuels under irradiation. The reference measurements of this nuclear heating are especially performed by a differential calorimeter including a graphite sample material. Then these measurements are used for other materials, other geometries, or other experimental conditions in order to predict the nuclear heating and thermal conditions induced in the irradiation devices. This paper will present new simulations with MCNP Monte-Carlo transport code to determine the gamma heating profile inside the calorimeter. The whole complex geometry of the sensor has been considered. We use as an input source in the model, the photon spectra calculated in various positions of CARMEN-1 irradiation program in OSIRIS reactor. After a description of the differential calorimeter device, the MCNP modeling used for the calculations of radial profile of nuclear heating inside the calorimeter elements will be introduced. The obtained results of different simulations will be detailed and discussed in this paper. The charged particle equilibrium inside the calorimeter elements will be studied. Then we will focus on parametric studies of the various components of the calorimeter. The influence of source type will be also took into account. Moreover the influence of the material used for the sample will be described.

  11. Monte Carlo Simulation Study of a Differential Calorimeter Measuring the Nuclear Heating in Material Testing Reactors

    Directory of Open Access Journals (Sweden)

    Amharrak H.

    2016-01-01

    Full Text Available The nuclear heating measurements in Material Testing Reactors (MTRs are crucial for the study of nuclear materials and fuels under irradiation. The reference measurements of this nuclear heating are especially performed by a differential calorimeter including a graphite sample material. Then these measurements are used for other materials, other geometries, or other experimental conditions in order to predict the nuclear heating and thermal conditions induced in the irradiation devices. This paper will present new simulations with MCNP Monte-Carlo transport code to determine the gamma heating profile inside the calorimeter. The whole complex geometry of the sensor has been considered. We use as an input source in the model, the photon spectra calculated in various positions of CARMEN-1 irradiation program in OSIRIS reactor. After a description of the differential calorimeter device, the MCNP modeling used for the calculations of radial profile of nuclear heating inside the calorimeter elements will be introduced. The obtained results of different simulations will be detailed and discussed in this paper. The charged particle equilibrium inside the calorimeter elements will be studied. Then we will focus on parametric studies of the various components of the calorimeter. The influence of source type will be also took into account. Moreover the influence of the material used for the sample will be described.

  12. Experimental study of flow and heat transfer in a rotating chemical vapor deposition reactor

    Science.gov (United States)

    Wong, Sun

    An experimental model was set up to study the rotating vertical impinging chemical vapor deposition reactor. Deposition occurs only when the system has enough thermal energy. Therefore, understanding the fluid characteristic and heat transfer of the system will provide a good basis to understand the full model. Growth rate and the uniformity of the film are the two most important factors in CVD process and it is depended on the flow and thermal characteristic within the system. Optimizing the operating parameters will result in better growth rate and uniformity. Operating parameters such as inflow velocity, inflow diameter and rotational speed are used to create different design simulations. Fluid velocities and various temperatures are recorded to see the effects of the different operating parameters. Velocities are recorded by using flow meter and hot wire anemometer. Temperatures are recorded by using various thermocouples and infrared thermometer. The result should provide a quantitative basis for the prediction, design and optimization of the system and process for design and fabrication of future CVD reactors. Further assessment of the system results will be discuss in detail such as effects of buoyancy and effects of rotation. The experimental study also coupled with a numerical study for further validation of both model. Comparisons between the two models are also presented.

  13. Preliminary Study on the High Efficiency Supercritical Pressure Water-Cooled Reactor for Electricity Generation

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Yoon Yeong; Park, Jong Kyun; Cho, Bong Hyun and others

    2006-01-15

    This research has been performed to introduce a concept of supercritical pressure water cooled reactor(SCWR) in Korea The area of research includes core conceptual design, evaluation of candidate fuel, fluid systems conceptual design with mechanical consideration, preparation of safety analysis code, and construction of supercritical pressure heat transfer test facility, SPHINX, and preliminary test. As a result of the research, a set of tools for the reactor core design has been developed and the conceptual core design with solid moderator was proposed. The direct thermodynamic cycle has been studied to find a optimum design. The safety analysis code has also been adapted to supercritical pressure condition. A supercritical pressure CO2 heat transfer test facility has been constructed and preliminary test proved the facility works as expected. The result of this project will be good basis for the participation in the international collaboration under GIF GEN-IV program and next 5-year mid and long term nuclear research program of MOST. The heat transfer test loop, SPHINX, completed as a result of this project may be used for the power cycle study as well as further heat transfer study for the various geometries.

  14. The TITAN Reversed-Field Pinch fusion reactor study: Scoping phase report

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    The TITAN research program is a multi-institutional effort to determine the potential of the Reversed-Field Pinch (RFP) magnetic fusion concept as a compact, high-power-density, and ''attractive'' fusion energy system from economic (cost of electricity, COE), environmental, and operational viewpoints. In particular, a high neutron wall loading design (18 MW/m/sup 2/) has been chosen as the reference case in order to quantify the issue of engineering practicality, to determine the physics requirements and plasma operating mode, to assess significant benefits of compact systems, and to illuminate the main drawbacks. The program has been divided into two phases, each roughly one year in length: the Scoping Phase and the Design Phase. During the scoping phase, the TITAN design team has defined the parameter space for a high mass power density (MPD) RFP reactor, and explored a variety of approaches to the design of major subsystems. Two major design approaches consistent with high MPD and low COE, the lithium-vanadium blanket design and aqueous loop-in-pool design, have been selected for more detailed engineering evaluation in the design phase. The program has retained a balance in its approach to investigating high MPD systems. On the one hand, parametric investigations of both subsystems and overall system performance are carried out. On the other hand, more detailed analysis and engineering design and integration are performed, appropriate to determining the technical feasibility of the high MPD approach to RFP fusion reactors. This report describes the work of the scoping phase activities of the TITAN program. A synopsis of the principal technical findings and a brief description of the TITAN multiple-design approach is given. The individual chapters on Plasma Physics and Engineering, Parameter Systems Studies, Divertor, Reactor Engineering, and Fusion Power Core Engineering have been cataloged separately.

  15. Tertiary nitrification using moving-bed biofilm reactor: a case study in Tunisia.

    Science.gov (United States)

    Houda, Nasr; Abdelwaheb, Chatti; Asma, Ben Rajeb; Ines, Mehri; Ahmed, Landoulsi; Abdennaceur, Hassen

    2015-04-01

    In this study, the effect of operational conditions on biofilm development and nitrification in moving-bed biofilm reactor (MBBR) was investigated. The reactor was operated in a continuously fed regime during 170 days and with theoretical hydraulic retention time of 7 h, respectively. The presence of chemical oxygen demand (COD) increased the time required to form stable nitrifying. Subsequent stepwise increase of influent COD caused an increment in total polysaccharide (PS) and protein (PN) content, which was accompanied by an attachment of the biofilm, as shown by atomic force microscope (AFM). PS and PN concentrations proved to be good indicators of biomass development and attachment in MBBR system. Reactor was operated and water quality was characterized before and after treatment. Parameters including pH, 5-day biochemical oxygen demand (BOD5), total suspended solids (TSS) (COD), PN, PS, and fecal bacteria in both raw and treated wastewater were monitored during the treatment. The removal rates of ammonium-nitrogen (NH4 (+)-N), BOD5, COD, and TSS are 95, 67.5, 69.2, and 73.33 %, respectively. The average bacterial reduction between the inlet and the outlet was of the order of 5 ± 1 logarithmic units for fecal coliforms. AFM showed that distinct biofilm and extracellular polymeric substances were formed in biofilm was thicker in the 70 days than in the 30 days. These results showed that the consumption rate for each substrate increased parabolically with biofilm thickness due to the increased amount of biomass Thus, MBBR can serve as a promising technology for wastewater treatment and can be scaled up for small communities in the developing countries.

  16. Reactor Physics

    Energy Technology Data Exchange (ETDEWEB)

    Ait Abderrahim, A

    2001-04-01

    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.

  17. Mars14 Monte Carlo simulation for the shielding studies of the J-PARC 3 GeV ring.

    Science.gov (United States)

    Nakao, Noriaki; Mokhov, Nikolai; Yamamoto, Kazami; Irie, Yoshiro; Drozhdin, Alexander

    2005-01-01

    MARS14 Monte Carlo simulations were performed for collimation and shielding studies of the J-PARC 3 GeV synchrotron ring. The beam line module locations in the 348.3 m ring and the curved tunnel sections were described by the 'MAD-MARS beam line builder' tool. A 400 MeV proton beam loss distribution, calculated with the STRUCT code, was used as a 4 kW source term in the collimator region, with 1 kW source terms in the injection and extraction regions at 400 MeV and 3 GeV, respectively. Deep penetration calculations were carried out with good statistics using a newly developed three-dimensional multi-layer technique. Prompt dose-rate distributions were calculated inside and outside the concrete and soil shield up to the ground level. Using the calculation results obtained thus, an effective shielding design was made.

  18. Characterizing of a Mid-Latitude Ice-Rich Landing Site on Mars to Enable in Situ Habitability Studies

    Science.gov (United States)

    Heldmann, J.; Schurmeier, L. R.; Wilhelm, M.; Stoker, C.; McKay, C.; Davila, A.; Marinova, M.; Karcz, J.; Smith, H.

    2012-01-01

    We suggest an ice-rich landing site at 188.5E 46.16N within Amazonis Planitia as a candidate location to support a Mars lander mission equipped to study past habitability and regions capable of preserving the physical and chemical signs of life and organic matter. Studies of the ice-rich subsurface on Mars are critical for several reasons. The subsurface environment provides protection from radiation to shield organic and biologic compounds from destruction. The ice-rich substrate is also ideal for preserving organic and biologic molecules and provides a source of H2O for biologic activity. Examination of martian ground ice can test several hypotheses such as: 1) whether ground ice supports habitable conditions, 2) that ground ice can preserve and accumulate organic compounds, and 3) that ice contains biomolecules evident of past or present biological activity on Mars. This Amazonis site, located near the successful Viking Lander 2, shows indirect evidence of subsurface ice (ubiquitous defined polygonal ground, gamma ray spectrometer hydrogen signature, and numerical modeling of ice stability) and direct evidence of exposed subsurface ice. This site also provides surface conditions favorable to a safe landing including no boulders, low rock density, minimal rough topography, and few craters.

  19. A study of candidate marine target impact craters in Arabia Terra, Mars

    NARCIS (Netherlands)

    Villiers, G. de; King, D.T.; Marzen, L.J.

    2010-01-01

    Previous workers have proposed that a northern ocean existed early during Martian geologic history and the shorelines of that ocean would coincide roughly with the crustal dichotomy that divides the smooth, northern lowlands with the cratered, southern highlands. Arabia Terra is a region on Mars tha

  20. Delta and fan morphologies on Mars as climate indicators (Utrecht Studies in Geosciences 042)

    NARCIS (Netherlands)

    de Villiers, G.

    2013-01-01

    The presence, duration and quantity of water on Mars remains an important research topic in planetary science. Large valley networks, regional outflow channels, and small-scale gullies indicate the presence of water on the surface at certain points in the past. However, the climatic history and evol

  1. Lunar precursor missions for human exploration of Mars--III: studies of system reliability and maintenance

    Science.gov (United States)

    Mendell, W. W.; Heydorn, R. P.

    2004-01-01

    Discussions of future human expeditions into the solar system generally focus on whether the next explorers ought to go to the Moon or to Mars. The only mission scenario developed in any detail within NASA is an expedition to Mars with a 500-day stay at the surface. The technological capabilities and the operational experience base required for such a mission do not now exist nor has any self-consistent program plan been proposed to acquire them. In particular, the lack of an Abort-to-Earth capability implies that critical mission systems must perform reliably for 3 years or must be maintainable and repairable by the crew. As has been previously argued, a well-planned program of human exploration of the Moon would provide a context within which to develop the appropriate technologies because a lunar expedition incorporates many of the operational elements of a Mars expedition. Initial lunar expeditions can be carried out at scales consistent with the current experience base but can be expanded in any or all operational phases to produce an experience base necessary to successfully and safely conduct human exploration of Mars. Published by Elsevier Ltd.

  2. Delta and fan morphologies on Mars as climate indicators (Utrecht Studies in Geosciences 042)

    NARCIS (Netherlands)

    de Villiers, G.

    2013-01-01

    The presence, duration and quantity of water on Mars remains an important research topic in planetary science. Large valley networks, regional outflow channels, and small-scale gullies indicate the presence of water on the surface at certain points in the past. However, the climatic history and evol

  3. Measurement of the Isotopic Signatures of Water on Mars: Implications for Studying Methane

    Science.gov (United States)

    Novak, R. E.; Mumma, M. J.; Villanueva, G. L.

    2010-01-01

    The recent discovery of methane on Mars has led to much discussion concerning its origin. On Earth, the isotopic signatures of methane vary with the nature of its production. Specifically, the ratios among 12CH4, 13CH4, and 12CH3D differ for biotic and abiotic origins. On Mars, measuring these ratios would provide insights into the origins of methane and measurements of water isotopologues co-released with methane would assist in testing their chemical relationship. Since 1997, we have been measuring HDO and H2O in Mars atmosphere and comparing their ratio to that in Earth s oceans. We recently incorporated a line-by-line radiative transfer model (LBLRTM) into our analysis. Here, we present a map for [HDO]/[H2O] along the central meridian (1541W) for Ls 501. From these results, we constructed models to determine the observational conditions needed to quantify the isotopic ratios of methane in Mars atmosphere. Current ground-based instruments lack the spectral resolution and sensitivity needed to make these measurements. Measurements of the isotopologues of methane will likely require in situ sampling.

  4. Feasibility study of fuel cladding performance for application in ultra-long cycle fast reactor

    Science.gov (United States)

    Jung, Ju Ang; Kim, Seung Hyun; Shin, Sang Hun; Bang, In Cheol; Kim, Ji Hyun

    2013-09-01

    As a part of the research and development activities for long-life core sodium-cooled fast reactors, the cladding performance of the ultra-long cycle fast reactor (UCFR) is evaluated with two design power levels (1000 MWe and 100 MWe) and cladding peak temperatures (873 K and 923 K). The key design concept of the UCFR is that it is non-refueling during its 30-60 years of operation. This concept may require a maximum peak cladding temperature of 923 K and a cladding radiation damage of over 200 dpa (displacements per atom). Therefore, for the design of the UCFR, deformation due to thermal creep, irradiation creep, and swelling must be taken into consideration through quantitative evaluations. As candidate cladding materials for use in UCFRs, ferritic-martensitic (FM) steels, oxide dispersion strengthened (ODS) steels, and SiC-based composite materials are studied using deformation behavior modeling for a feasibility evaluation. The results of this study indicate that SiC is a potential UCFR cladding material, with the exception of irradiation creep due to high neutron fluence stemming from its long operating time of about 30-60 years.

  5. Laboratory Scale Study of Activated Sludge Process in Jet Loop Reactor for Waste WaterTreatment

    Directory of Open Access Journals (Sweden)

    M. S. Patil

    2014-03-01

    Full Text Available The present study was undertaken to evaluate the feasibility of Activated Sludge Process (ASP for the treatment of synthetic wastewater and to develop a simple design criteria under local conditions.A laboratory scale Compact jet loop reactor model comprising of an aeration tank and final clarifier was used for this purpose.Settled synthetic wastewater was used as influent to the aeration tank. The Chemical Oxygen Demand (COD of the influent and effluent was measured to find process efficiency at various mixed liquorvolatile suspended solids (MLVSS and hydraulic retention time (θ. The results of the studydemonstrated that an efficiency of above 95% could be obtained for COD if the ASP is operated atan MLVSS concentration of 3000 mg/L keeping an aeration time of 1 hour.In the present investigation the preliminary studies were carried out in a lab scale Jet loop reactor made of glass. Synthetic waste water having a composition of 1000 mg/L mixed with other nutrients such as Urea, Primary and secondary Potassium phosphates, Magnesium sulfate, Iron chloriderequired for the bacteria was prepared in the laboratory and reduction in COD and the increase inSuspended Solids (SSand the Sludge Volume Index (SVI were determined.

  6. Optimization and implementation study of plutonium disposition using existing CANDU Reactors. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    Since early 1994, the Department of Energy has been sponsoring studies aimed at evaluating the merits of disposing of surplus US weapons plutonium as Mixed Oxide (MOX) fuel in existing commercial Canadian Pressurized Heavy Water reactors, known as CANDU`s. The first report, submitted to DOE in July, 1994 (the 1994 Executive Summary is attached), identified practical and safe options for the consumption of 50 to 100 tons of plutonium in 25 years in some of the existing CANDU reactors operating the Bruce A generating station, on Lake Huron, about 300 km north east of Detroit. By designing the fuel and nuclear performance to operate within existing experience and operating/performance envelope, and by utilizing existing fuel fabrication and transportation facilities and methods, a low cost, low risk method for long term plutonium disposition was developed. In December, 1995, in response to evolving Mission Requirements, the DOE requested a further study of the CANDU option with emphasis on more rapid disposition of the plutonium, and retaining the early start and low risk features of the earlier work. This report is the result of that additional work.

  7. Determination of the enzyme reaction rate in a differential fixed-bed reactor: a case study

    Directory of Open Access Journals (Sweden)

    Baruque Filho E.A.

    2001-01-01

    Full Text Available The reaction rate of starch hydrolysis catalyzed by a glucoamylase covalently bound to chitin particles was measured in a Differential Fixed-Bed Reactor (DFBR. Under selected test conditions the initial reaction rate may represent biocatalyst activity. Some aspects which influence measurement of the initial reaction rate of an immobilized enzyme were studied: the amount of desorbed enzyme and its hydrolytic activity, the extent of pore blockage of the biocatalyst caused by substrate solution impurities and the internal and external diffusional mass transfer effects. The results showed that the enzyme glucoamylase was firmly bound to the support, as indicated by the very low amount of desorbed protein found in the recirculating liquid. Although this protein was very active, its contribution to the overall reaction rate was negligible. It was observed that the biocatalyst pores were susceptible to being blocked by the impurities of the starch solution. This latter effect was accumulative, increasing with the number of sequential experiments carried out. When the substrate solution was filtered before use, very reliable determinations of immobilized enzyme reaction rates could be performed in the DFBR. External and internal diffusional resistences usually play a significant role in fixed-bed reactors. However, for the experimental system studied, internal mass transfer effects were not significant, and it was possible to select an operational condition (recirculation flow rate value that minimized the external diffusional limitations.

  8. A study on neural network representation of reactor power control procedures 2

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Byung Soo; Park, Jea Chang; Kim, Young Taek; Lee, Hee Cho; Yang, Sung Uoon; Hwang, Hee Sun; Hwang, In Ah

    1998-12-01

    The major results of this study are as follows; the first is the algorithm developed through this study for computing the spline interpolation coefficients without solving the matrix equation involved. This is expected to be used in various numerical analysis problems. If this algorithm can be extended to functions of two independent variables in the future, then it could be a big help for the finite element method used in solving various boundary value problems. The second is the method developed to reduce systematically the number of output fuzzy sets for fuzzy systems representing functions of two variables. this may be considered as an indication that the neural network representation of functions has advantages over other conventional methods. The third result is an artificial neural network system developed for automating the manual procedures being used to change the reactor power level by adding boric acid or water to the reactor coolant. This along with the neural networks developed earlier can be used in nuclear power plants as an operator aid after a verification process. (author). 8 refs., 13 tabs., 5 figs.

  9. Reactor safeguards

    CERN Document Server

    Russell, Charles R

    1962-01-01

    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

  10. Reactor operation

    CERN Document Server

    Shaw, J

    2013-01-01

    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

  11. In-reactor tests of the nuclear light bulb rocket concept

    Science.gov (United States)

    Gauntt, R. O.; Slutz, S. A.; Latham, T. S.; Roman, W. C.; Rogers, R. J.

    1992-07-01

    An overview is given of the closed-cycle Gas Core Nuclear Rocket outlining scenarios for its use in short-duration Mars missions and results of Nuclear Light Bulb (NLB) tests. Isothermal and nonnuclear tests are described which confirmed the fundamental concepts behind the NLB. NLB reference-engine performance characteristics are given for hypothetical engines that could be used for manned Mars missions. Vehicle/propulsion sizing is based on a Mars mission with three trans-Mars impulse burns, capture and escape burns, and a total mission duration of 600 days. The engine would have a specific impulse of 1870 seconds, a 412-kN thrust, and a thrust/weight ratio of 1.3. Reactor tests including small-scale in-reactor tests are shown to be prerequisites for studying: (1) fluid mechanical confinement of the gaseous nuclear fuel; (2) buffer gas separation and circulation; and (3) the minimization of transparent wall-heat loading. The reactor tests are shown to be critical for establishing the feasibility of the NLB concept.

  12. Functional studies of ssDNA binding ability of MarR family protein TcaR from Staphylococcus epidermidis.

    Directory of Open Access Journals (Sweden)

    Yu-Ming Chang

    Full Text Available The negative transcription regulator of the ica locus, TcaR, regulates proteins involved in the biosynthesis of poly-N-acetylglucosamine (PNAG. Absence of TcaR increases PNAG production and promotes biofilm formation in Staphylococci. Previously, the 3D structure of TcaR in its apo form and its complex structure with several antibiotics have been analyzed. However, the detailed mechanism of multiple antibiotic resistance regulator (MarR family proteins such as TcaR is unclear and only restricted on the binding ability of double-strand DNA (dsDNA. Here we show by electrophoretic mobility shift assay (EMSA, electron microscopy (EM, circular dichroism (CD, and Biacore analysis that TcaR can interact strongly with single-stranded DNA (ssDNA, thereby identifying a new role in MarR family proteins. Moreover, we show that TcaR preferentially binds 33-mer ssDNA over double-stranded DNA and inhibits viral ssDNA replication. In contrast, such ssDNA binding properties were not observed for other MarR family protein and TetR family protein, suggesting that the results from our studies are not an artifact due to simple charge interactions between TcaR and ssDNA. Overall, these results suggest a novel role for TcaR in regulation of DNA replication. We anticipate that the results of this work will extend our understanding of MarR family protein and broaden the development of new therapeutic strategies for Staphylococci.

  13. Study of guided wave transmission through complex junction in sodium cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Elie, Q.; Le Bourdais, F.; Jezzine, K.; Baronian, V. [Non Destructive Testing Department at the French Atomic Energy Commission (CEA), Saclay, 91191 Gif sur Yvette CEDEX, (France)

    2015-07-01

    Ultrasonic guided wave techniques are seen as suitable candidates for the inspection of welded structures within sodium cooled fast reactors (SFR), as the long range propagation of guided waves without amplitude attenuation can overcome the accessibility problem due to the liquid sodium. In the context of the development of the Advanced Sodium Test Reactor for Industrial Demonstration (ASTRID), the French Atomic Commission (CEA) investigates non-destructive testing techniques based on guided wave propagation. In this work, guided wave NDT methods are applied to control the integrity of welds located in a junction-type structure welded to the main vessel. The method presented in this paper is based on the analysis of scattering matrices peculiar to each expected defect, and takes advantage of the multi-modal and dispersive characteristics of guided wave generation. In a simulation study, an algorithm developed using the CIVA software is presented. It permits selecting appropriate incident modes to optimize detection and identification of expected flawed configurations. In the second part of this paper, experimental results corresponding to a first validation step of the simulation results are presented. The goal of the experiments is to estimate the effectiveness of the incident mode selection in plates. The results show good agreement between experience and simulation. (authors)

  14. A Study of Fuel and Reactor Design for Platinum Nanoparticle Catalyzed Microreactors

    Directory of Open Access Journals (Sweden)

    Dylan McNally

    2015-01-01

    Full Text Available Typical microcombustion-based power devices entail the use of catalyst to sustain combustion in less than millimeter scale channels. This work explores the use of several other candidate fuels for ~8 nm diameter Pt particle catalyzed combustion within 800 μm channel width cordierite substrates. The results demonstrate while commercial hydrocarbon fuels such as methane, propane, butane, and ethanol can be used to sustain catalytic combustion, room temperature ignition was only observed using methanol-air mixtures. Fuels, other than methanol, required preheating at temperatures >200°C, yet repeated catalytic cycling similar to methanol-air mixtures was demonstrated. Subsequently, a new reactor design was investigated to couple with thermoelectric generators. The modified reactor design enabled ignition of methanol-air mixtures at room temperature with the ability to achieve repeat catalytic cycles. Preliminary performance studies achieved a maximum temperature difference ΔT of 55°C with a flow rate of 800 mL/min. While the temperature difference indicates a respectable potential for power generation, reduced exhaust temperature and improved thermal management could significantly enhance the eventual device performance.

  15. Studies of the Methane Steam Reforming Reaction at High Pressure in a Ceramic Membrane Reactor

    Institute of Scientific and Technical Information of China (English)

    P.Hacarlioglu; Y.Gu; S.T.Oyama

    2006-01-01

    The effects of temperature and pressure on the steam reforming of methane (CH4+H2O(→)3H2+CO) were investigated in a membrane reactor (MR)with a hydrogen permeable membrane. The studies used a novel silica-based membrane prepared by using the chemical vapor deposition (CVD) techreactor (PBR) were compared to those of the membrane reactor at various temperatures (773-923 K)and pressures (1-20 atm, 101.3-2026.5 kPa) using a commercial Ni/MgAl2O4 catalyst. The conversion of methane was improved significantly in the MR by the countercurrent removal of hydrogen at all temperatures and allowed product yields higher than the equilibrium to be obtained. Pressure had a positive effect on the hydrogen yield because of the increase in driving force for the permeance of hydrogen. The yield. The results obtained with the silica-based membrane were similar to those obtained with various other membranes as reported in the literature.

  16. Use of laser flow visualization techniques in reactor component thermal-hydraulic studies

    Energy Technology Data Exchange (ETDEWEB)

    Oras, J.J.; Kasza, K.E.

    1984-01-01

    To properly design reactor components, an understanding of the various thermal hydraulic phenomena, i.e., thermal stratification flow channeling, recirculation regions, shear layers, etc., is necessary. In the liquid metal breeder reactor program, water is commonly used to replace sodium in experimental testing to facilitate the investigations, (i.e., reduce cost and allow fluid velocity measurement or flow pattern study). After water testing, limited sodium tests can be conducted to validate the extrapolation of the water results to sodium. This paper describes a novel laser flow visualization technique being utilized at ANL together with various examples of its use and plans for further development. A 3-watt argon-ion laser, in conjunction with a cylindrical opticallens, has been used to create a thin (approx. 1-mm) intense plane of laser light for the illuminiation of various flow tracers in precisely defined regions of interest within a test article having windows. Both fluorescing dyes tuned to the wavelength of the laser light (to maximize brightness and sharpness of flow image) and small (< 0.038-mm, 0.0015-in. dia.) opaque, nearly neutrally buoyant polystyrene spheres (to ensure that the particles trace out the fluid motion) have been used as flow tracers.

  17. Experimental study of hydrodynamic and operation start of a baffled anaerobic reactor treating sewage

    Directory of Open Access Journals (Sweden)

    Ana Carolina Silveira Perico

    2009-12-01

    Full Text Available It is important to provide individual sanitation systems for sewage peri-urban communities or rural areas to minimize impacts on the environment and human health caused by sewage discharge in natura into water resources. In this context, the anaerobic digestion of effluent has been one of the main considered technologies due to easy implementation, material minimization and reduction in waste production. The objective of this work was to study a Baffled Anaerobic Reactor (BAR including its hydrodynamic characteristics, percentile of inoculum to be applied and reactor operation start. It was concluded that the flow is dispersed with 3.84% of dead spaces and that 20% of the cow manure provided best results; however, due to the high fiber content of the manure, its use is not recommended as inoculum. The BAR system, composed of four chambers, presented good performance for sewage treatment of a rural community in terms of organic substance removal (COD, turbidity and solids meeting effluent disposal standards of these parameters considering the Federal and Minas Gerais State legislation, in Brazil, even in a transient phase of operation, at temperatures below 20°C. However, the effluents from the BAR can’t be released into water bodies without other parameters such as nitrogen, phosphorus, fecal coliforms, and others are investigated to be conforming to those standards.

  18. Study on the Use of Hydride Fuel in High-Performance Light Water Reactor Concept

    Directory of Open Access Journals (Sweden)

    Haileyesus Tsige-Tamirat

    2015-01-01

    Full Text Available Hydride fuels have features which could make their use attractive in future advanced power reactors. The potential benefit of use of hydride fuel in HPLWR without introducing significant modification in the current core design concept of the high-performance light water reactor (HPLWR has been evaluated. Neutronics and thermal hydraulic analyses were performed for a single assembly model of HPLWR with oxide and hydride fuels. The hydride assembly shows higher moderation with softer neutron spectrum and slightly more uniform axial power distribution. It achieves a cycle length of 18 months with sufficient excess reactivity. At Beginning of Cycle the fuel temperature coefficient of the hydride assembly is higher whereas the moderator and void coefficients are lower. The thermal hydraulic results show that the achievable fuel temperature in the hydride assembly is well below the design limits. The potential benefits of the use of hydride fuel in the current design of the HPLWR with the achieved improvements in the core neutronics characteristics are not sufficient to justify the replacement of the oxide fuel. Therefore for a final evaluation of the use of hydride fuels in HPLWR concepts additional studies which include modification of subassembly and core layout designs are required.

  19. Models and analyses for inertial-confinement fusion-reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Bohachevsky, I.O.

    1981-05-01

    This report describes models and analyses devised at Los Alamos National Laboratory to determine the technical characteristics of different inertial confinement fusion (ICF) reactor elements required for component integration into a functional unit. We emphasize the generic properties of the different elements rather than specific designs. The topics discussed are general ICF reactor design considerations; reactor cavity phenomena, including the restoration of interpulse ambient conditions; first-wall temperature increases and material losses; reactor neutronics and hydrodynamic blanket response to neutron energy deposition; and analyses of loads and stresses in the reactor vessel walls, including remarks about the generation and propagation of very short wavelength stress waves. A discussion of analytic approaches useful in integrations and optimizations of ICF reactor systems concludes the report.

  20. Study on the Neutrino Oscillation with a Next Generation Medium-Baseline Reactor Experiment

    Directory of Open Access Journals (Sweden)

    Chang Dong Shin

    2014-01-01

    Full Text Available For over fifty years, reactor experiments have played an important role in neutrino physics, in both discoveries and precision measurements. One of the methods to verify the existence of neutrino is the observation of neutrino oscillation phenomena. Electron antineutrinos emitted from a reactor provide the measurement of the small mixing angle θ13, providing rich programs of neutrino properties, detector development, nuclear monitoring, and application. Using reactor neutrinos, future reactor neutrino experiments, more precise measurements of θ12,  Δm122, and mass hierarchy will be explored. The precise measurement of θ13 would be crucial for measuring the CP violation parameters at accelerators. Therefore, reactor neutrino physics will assist in the complete understanding of the fundamental nature and implications of neutrino masses and mixing. In this paper, we investigated several characteristics of RENO-50, which is a future medium-baseline reactor neutrino oscillation experiment, by using the GloBES simulation package.

  1. Study of plutonium disposition using the GE Advanced Boiling Water Reactor (ABWR)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-04-30

    The end of the cold war and the resulting dismantlement of nuclear weapons has resulted in the need for the U.S. to disposition 50 to 100 metric tons of excess of plutonium in parallel with a similar program in Russia. A number of studies, including the recently released National Academy of Sciences (NAS) study, have recommended conversion of plutonium into spent nuclear fuel with its high radiation barrier as the best means of providing long-term diversion resistance to this material. The NAS study {open_quotes}Management and Disposition of Excess Weapons Plutonium{close_quotes} identified light water reactor spent fuel as the most readily achievable and proven form for the disposition of excess weapons plutonium. The study also stressed the need for a U.S. disposition program which would enhance the prospects for a timely reciprocal program agreement with Russia. This summary provides the key findings of a GE study where plutonium is converted into Mixed Oxide (MOX) fuel and a 1350 MWe GE Advanced Boiling Water Reactor (ABWR) is utilized to convert the plutonium to spent fuel. The ABWR represents the integration of over 30 years of experience gained worldwide in the design, construction and operation of BWRs. It incorporates advanced features to enhance reliability and safety, minimize waste and reduce worker exposure. For example, the core is never uncovered nor is any operator action required for 72 hours after any design basis accident. Phase 1 of this study was documented in a GE report dated May 13, 1993. DOE`s Phase 1 evaluations cited the ABWR as a proven technical approach for the disposition of plutonium. This Phase 2 study addresses specific areas which the DOE authorized as appropriate for more in-depth evaluations. A separate report addresses the findings relative to the use of existing BWRs to achieve the same goal.

  2. A study on the establishment of component/equipment performance criteria considering Heavy Water Reactor characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Keun Sun; Kwon, Young Chul; Lee, Min Kyu; Lee, Yun Soo [Sunmoon Univ., Asan (Korea, Republic of); Chang, Seong Hoong; Ryo, Chang Hyun [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Kim, Soong Pyung; Hwnag, Jung Rye; Chung, Chul Kee [Chosun Univ., Gwangju (Korea, Republic of)

    2002-03-15

    Foreign and domestic technology trends, regulatory requirements, design and researches for heavy water reactors are analyzed. Safety design guides of Canada industry and regulatory documents and consultative documents of Canada regulatory agency are reviewed. Applicability of MOST guidance 16 Revision 'guidance for technical criteria of nuclear reactor facility' is reviewed. Specific performance criteria are established for components and facilities for heavy water reactor.

  3. Membrane reactor for water detritiation: a parametric study on operating parameters

    Energy Technology Data Exchange (ETDEWEB)

    Mascarade, J.; Liger, K.; Troulay, M.; Perrais, C. [CEA, DEN, DTN/STPA/LIPC, Centre de Cadarache, Saint-Paul-lez-Durance (France); Joulia, X.; Meyer, X.M. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, Toulouse (France); CNRS, Laboratoire de Genie Chimique, Toulouse (France)

    2015-03-15

    This paper presents the results of a parametric study done on a single stage finger-type packed-bed membrane reactor (PBMR) used for heavy water vapor de-deuteration. Parametric studies have been done on 3 operating parameters which are: the membrane temperature, the total feed flow rate and the feed composition through D{sub 2}O content variations. Thanks to mass spectrometer analysis of streams leaving the PBMR, speciation of deuterated species was achieved. Measurement of the amounts of each molecular component allowed the calculation of reaction quotient at the packed-bed outlet. While temperature variation mainly influences permeation efficiency, feed flow rate perturbation reveals dependence of conversion and permeation properties to contact time between catalyst and reacting mixture. The study shows that isotopic exchange reactions occurring on the catalyst particles surface are not thermodynamically balanced. Moreover, the variation of the heavy water content in the feed exhibits competition between permeation and conversion kinetics.

  4. Study and Evaluation of Innovative Fuel Handling Systems for Sodium-Cooled Fast Reactors: Fuel Handling Route Optimization

    Directory of Open Access Journals (Sweden)

    Franck Dechelette

    2014-01-01

    Full Text Available The research for technological improvement and innovation in sodium-cooled fast reactor is a matter of concern in fuel handling systems in a view to perform a better load factor of the reactor thanks to a quicker fuelling/defueling process. An optimized fuel handling route will also limit its investment cost. In that field, CEA has engaged some innovation study either of complete FHR or on the optimization of some specific components. This paper presents the study of three SFR fuel handling route fully described and compared to a reference FHR option. In those three FHR, two use a gas corridor to transfer spent and fresh fuel assembly and the third uses two casks with a sodium pot to evacuate and load an assembly in parallel. All of them are designed for the ASTRID reactor (1500 MWth but can be extrapolated to power reactors and are compatible with the mutualisation of one FHS coupled with two reactors. These three concepts are then intercompared and evaluated with the reference FHR according to four criteria: performances, risk assessment, investment cost, and qualification time. This analysis reveals that the “mixed way” FHR presents interesting solutions mainly in terms of design simplicity and time reduction. Therefore its study will be pursued for ASTRID as an alternative option.

  5. Mars Sample Transfer Testbed (MSTT) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The task will assess the requirements for a testbed to study the retrieval of a Mars sample cache from the Martian surface, or from a Mars caching rover, and...

  6. Design Study for a Low-Enriched Uranium Core for the High Flux Isotope Reactor, Annual report for FY 2009

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, David [ORNL; Freels, James D [ORNL; Ilas, Germina [ORNL; Miller, James Henry [ORNL; Primm, Trent [ORNL; Sease, John D [ORNL; Guida, Tracey [University of Pittsburgh; Jolly, Brian C [ORNL

    2010-02-01

    This report documents progress made during FY 2009 in studies of converting the High Flux Isotope Reactor (HFIR) from high enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum alloy. With axial and radial grading of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in reactor performance from the current level. Results of selected benchmark studies imply that calculations of LEU performance are accurate. Studies are reported of the application of a silicon coating to surrogates for spheres of uranium-molybdenum alloy. A discussion of difficulties with preparing a fuel specification for the uranium-molybdenum alloy is provided. A description of the progress in developing a finite element thermal hydraulics model of the LEU core is provided.

  7. Reactor Neutrinos

    OpenAIRE

    Soo-Bong Kim; Thierry Lasserre; Yifang Wang

    2013-01-01

    We review the status and the results of reactor neutrino experiments. Short-baseline experiments have provided the measurement of the reactor neutrino spectrum, and their interest has been recently revived by the discovery of the reactor antineutrino anomaly, a discrepancy between the reactor neutrino flux state of the art prediction and the measurements at baselines shorter than one kilometer. Middle and long-baseline oscillation experiments at Daya Bay, Double Chooz, and RENO provided very ...

  8. BOILING REACTORS

    Science.gov (United States)

    Untermyer, S.

    1962-04-10

    A boiling reactor having a reactivity which is reduced by an increase in the volume of vaporized coolant therein is described. In this system unvaporized liquid coolant is extracted from the reactor, heat is extracted therefrom, and it is returned to the reactor as sub-cooled liquid coolant. This reduces a portion of the coolant which includes vaporized coolant within the core assembly thereby enhancing the power output of the assembly and rendering the reactor substantially self-regulating. (AEC)

  9. EXPERIMENTAL STUDY OF LOCAL HYDRODYNAMICS AND MASS EXCHANGE PROCESSES OF COOLANT IN FUEL ASSEMBLIES OF PRESSURIZED WATER REACTORS

    Directory of Open Access Journals (Sweden)

    S. M. Dmitriev

    2016-01-01

    Full Text Available The results of experimental studies of local hydrodynamics and mass exchange of coolant flow behind spacer and mixing grids of different structural versions that were developed for fuel assemblies of domestic and foreign nuclear reactors are presented in the article. In order to carry out the study the models of the following fuel assemblies have been fabricated: FA for VVER and VBER, FA-KVADRAT for PWR-reactor and FA for KLT-40C reactor. All the models have been fabricated with a full geometrical similarity with full-scale fuel assemblies. The study was carried out by simulating the flow of coolant in a core by air on an aerodynamic test rig. In order to measure local hydrodynamic characteristics of coolant flow five-channel Pitot probes were used that enable to measure the velocity vector in a point by its three components. The tracerpropane method was used for studying mass transfer processes. Flow hydrodynamics was studied by measuring cross-section velocities of coolant flow and coolant rates according to the model cells. The investigation of mass exchange processes consisted of a study of concentration distribution for tracer in experimental model, in determination of attenuation lengths of mass transfer processes behind mixing grids, in calculating of inter-cellar mass exchange coefficient. The database on coolant flow in fuel assemblies for different types of reactors had been accumulated that formed the basis of the engineering substantiation of reactor cores designs. The recommendations on choice of optimal versions of mixing grids have been taken into consideration by implementers of the JSC “OKBM Afrikantov” when creating commissioned fuel assemblies. The results of the study are used for verification of CFD-codes and CFD programs of detailed cell-by-cell calculation of reactor cores in order to decrease conservatism for substantiation of thermal-mechanical reliability.

  10. Feasibility study on nuclear core design for soluble boron free small modular reactor

    Science.gov (United States)

    Rabir, Mohamad Hairie; Hah, Chang Joo; Ju, Cho Sung

    2015-04-01

    A feasibility study on nuclear core design of soluble boron free (SBF) core for small size (150MWth) small modular reactor (SMR) was investigated. The purpose of this study was to design a once through cycle SMR core, where it can be used to supply electricity to a remote isolated area. PWR fuel assembly design with 17×17 arrangement, with 264 fuel rods per assembly was adopted as the basis design. The computer code CASMO-3/MASTER was used for the search of SBF core and fuel assembly analysis for SMR design. A low critical boron concentration (CBC) below 200 ppm core with 4.7 years once through cycle length was achieved using 57 fuel assemblies having 170 cm of active height. Core reactivity controlled using mainly 512 number of 4 wt% and 960 12 wt% Gd rods.

  11. Feasibility study on nuclear core design for soluble boron free small modular reactor

    Energy Technology Data Exchange (ETDEWEB)

    Rabir, Mohamad Hairie, E-mail: m-hairie@nuclearmalaysia.gov.my; Hah, Chang Joo; Ju, Cho Sung [Department of NPP Engineering, KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

    2015-04-29

    A feasibility study on nuclear core design of soluble boron free (SBF) core for small size (150MWth) small modular reactor (SMR) was investigated. The purpose of this study was to design a once through cycle SMR core, where it can be used to supply electricity to a remote isolated area. PWR fuel assembly design with 17×17 arrangement, with 264 fuel rods per assembly was adopted as the basis design. The computer code CASMO-3/MASTER was used for the search of SBF core and fuel assembly analysis for SMR design. A low critical boron concentration (CBC) below 200 ppm core with 4.7 years once through cycle length was achieved using 57 fuel assemblies having 170 cm of active height. Core reactivity controlled using mainly 512 number of 4 wt% and 960 12 wt% Gd rods.

  12. Experimental Study of Interfacial Friction in NaBH{sub 4} Solution in Microchannel Dehydrogenation Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seok Hyun; Hwang, Sueng Sik; Lee, Hee Joon [Kookmin Univ., Seoul (Korea, Republic of)

    2014-02-15

    Sodium borohydride (NaBH{sub 4}) is considered as a secure metal hydride for hydrogen storage and supply. In this study, the interfacial friction of two-phase flow in the dehydrogenation of aqueous NaBH{sub 4} solution in a microchannel with a hydraulic diameter of 461 μm is investigated for designing a dehydrogenation chemical reactor flow passage. Because hydrogen gas is generated by the hydrolysis of NaBH{sub 4} in the presence of a ruthenium catalyst, two different flow phases (aqueous NaBH{sub 4} solution and hydrogen gas) exist in the channel. For experimental studies, a microchannel was fabricated on a silicon wafer substrate, and 100-nm ruthenium catalyst was deposited on three sides of the channel surface. A bubbly flow pattern was observed. The experimental results indicate that the two-phase multiplier increases linearly with the void fraction, which depends on the initial concentration, reaction rate, and flow residence time.

  13. Human life support during interplanetary travel and domicile. III - Mars expedition system trade study

    Science.gov (United States)

    Seshan, P. K.; Ferrall, Joseph F.; Rohatgi, Naresh K.

    1991-01-01

    Several alternative configurations of life-support systems (LSSs) for a Mars missions are compared analytically on a quantitative basis in terms of weight, volume, and power. A baseline technology set is utilized for the illustrations of systems including totally open loop, carbon dioxide removal only, partially closed loop, and totally closed loop. The analytical model takes advantage of a modular, top-down hierarchical breakdown of LSS subsystems into functional elements that represent individual processing technologies. The open-loop systems are not competitive in terms of weight for both long-duration orbiters and short-duration lander vehicles, and power demands are lowest with the open loop and highest with the closed loop. The closed-loop system can reduce vehicle weight by over 70,000 lbs and thereby overcome the power penalty of 1600 W; the closed-loop variety is championed as the preferred system for a Mars expedition.

  14. Study of a fuel assembly for the nuclear reactor of IV generation cooled with supercritical water; Estudio de un ensamble de combustible para el reactor nuclear de generacion IV enfriado con agua supercritica

    Energy Technology Data Exchange (ETDEWEB)

    Barragan M, A.; Martin del Campo M, C.; Francois L, J. L. [UNAM, Facultad de Ingenieria, Departamento de Sistemas Energeticos, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Espinosa P, G., E-mail: albrm29@yahoo.com [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Area de Ingenieria en Recursos Energeticos, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (MX)

    2011-11-15

    In this work a neutron study is presented about a square assembly design of double line of fuel rods, with moderator box to the center of the arrangement, for a nuclear reactor cooled with supercritical water (SCWR). The SCWR reactor was chosen by the characteristics of its design, mainly because is based in light water reactors (PWR and BWR), and the operational experience that has of them allow to use models and similar programs to simulate the fuel and the nucleus of this type of reactors. To develop the necessary models and to carry out the design and analysis of the SCWR reactor, the neutron codes MCNPX and Helios were used. The reason of using both codes, is because the code MCNPX used thoroughly in the neutron simulation of these reactors, it has been our reference code to analyze the results obtained with the Helios code which results are more efficient because its calculation times are minors. In the nucleus design the same parameters for both codes were considered. The results show that the design with Helios is a viable option to simulate these reactors since their values of the neutrons multiplication factor are very similar to those obtained with MCNPX. On the other hand, it could be corroborated that the CASMO-4 code is inadequate to simulate the fuel to the temperature conditions and water pressure in the SCWR. (Author)

  15. Study of the radiotoxicity of actinides recycling in boiling water reactors fuel

    Energy Technology Data Exchange (ETDEWEB)

    Francois, J.L. [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532, Jiutepec, Mor., 62550 (Mexico)], E-mail: juan.luis.francois@gmail.com; Guzman, J.R. [Division de Ciencias Basicas e Ingenieria, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186 Col. Vicentina, Mexico, D.F., 09340 (Mexico)], E-mail: maestro_juan_rafael@hotmail.com; Martin-del-Campo, C. [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532, Jiutepec, Mor., 62550 (Mexico)], E-mail: cecilia.martin.del.campo@gmail.com

    2009-10-15

    In this paper the production and destruction, as well as the radiotoxicity of plutonium and minor actinides (MA) obtained from the multi-recycling of boiling water reactors (BWR) fuel are analyzed. A BWR MOX fuel assembly, with uranium (from enrichment tails), plutonium and minor actinides is designed and studied using the HELIOS code. The actinides mass and the radiotoxicity of the spent fuel are compared with those of the once-through or direct cycle. Other type of fuel assembly is also analyzed: an assembly with enriched uranium and minor actinides; without plutonium. For this study, the fuel remains in the reactor for four cycles, where each cycle is 18 months length, with a discharge burnup of 48 MWd/kg. After this time, the fuel is placed in the spent fuel pool to be cooled during 5 years. Afterwards, the fuel is recycled for the next fuel cycle; 2 years are considered for recycle and fuel fabrication. Two recycles are taken into account in this study. Regarding radiotoxicity, results show that in the period from the spent fuel discharge until 1000 years, the highest reduction in the radiotoxicity related to the direct cycle is obtained with a fuel composed of MA and enriched uranium. However, in the period after few thousands of years, the lowest radiotoxicity is obtained using the fuel with plutonium and MA. The reduction in the radiotoxicity of the spent fuel after one or two recycling in a BWR is however very small for the studied MOX assemblies, reaching a maximum reduction factor of 2.

  16. Optimization of hydrodynamic cavitations reactor efficiency for biodiesel production by response surface methods (Case study: Sunflower oil

    Directory of Open Access Journals (Sweden)

    H Javadikia

    2017-05-01

    Full Text Available Introduction Biofuels are considered as one of the largest sources of renewable fuels or replacement of fossil fuels. Combustion of plant-based fuels is the indirect use of solar energy. Biofuels significantly have less pollution than other fossil fuels and can easily generate from residual plant material. Waste and residues of foods and wastewater can also be a good source for biofuel production. Transesterification method (one of biodiesel production methods is the most common forms to produce mono-alkyl esters from vegetable oil and animal fats. The procedure aims are reduction the oil viscosity during the reaction between triglycerides and alcohol in the presence of a catalyst or without it. In this study, the method of transesterification with alkaline catalysts is used that it is the most common and most commercial biodiesel production method. In this study, configurations of made hydrodynamic cavitation reactor were studied to measure biodiesel fuel quality and enhanced device performance with optimum condition. The Design Expert software and response surface methodology were used to get this purpose. Materials and Methods Transesterification method was used in this study. The procedure aims were reduction of the oil viscosity during the reaction between triglycerides and alcohol in the presence of a catalyst or without it. Materials needed in the production of biodiesel transesterification method include: vegetable oil, alcohol and catalysts. The used oil in the production of biodiesel was sunflower oil, which was used 0.6 liters per each test in the production process base on titration method. Methanol with purity of 99.8 percent and the molar ratio of 6:1 to oil was used based on titration equation and according to the results of other researchers. The used catalyst in continuous production process was high-purity sodium hydroxide (99% that it is one of alkaline catalysts. Weight of hydroxide was 1% of the used oil weight in the

  17. Mars Propellant Production with Ionic Liquids Project

    Science.gov (United States)

    Falker, John; Thompson, Karen; Zeitlin, Nancy; Muscatello, Anthony

    2015-01-01

    This project seeks to develop a single vessel for carbon dioxide (CO2) capture and electrolysis for in situ Mars propellant production by eliminating several steps of CO2 processing, two cryocoolers, a high temperature reactor, a recycle pump, and a water condenser; thus greatly reducing mass, volume, and power.

  18. MAVEN's Imaging UV Spectrograph: Studying Atmospheric Structure and Escape at Mars

    Science.gov (United States)

    Schneider, Nicholas M.; McClintock, W. E.; IUVS Science Team

    2012-10-01

    MAVEN (Mars Volatile and Atmosphere EvolutioN) is a Mars Scout mission slated for launch in November 2013. The key hardware and management partners are University of Colorado, Goddard Space Flight Center, University of California at Berkeley, Lockheed Martin, and the Jet Propulsion Laboratory. MAVEN carries a powerful suite of fields and particles instruments and a sophisticated Imaging UltraViolet Spectrograph (IUVS). In this presentation we will describe IUVS' science goals, instrument design, operational approach and data analysis strategy. IUVS supports the top-level MAVEN science goals: measure the present state of the atmosphere, observe its response to varying solar stimuli, and use the information to estimate loss from Mars' atmosphere over time. The instrument operates at low spectral resolution spanning the FUV and MUV ranges in separate channels, and at high resolution around the hydrogen Lyman alpha line to measure the D/H ratio in the upper atmosphere. MAVEN carries the instrument on an Articulated Payload Platform which orients the instrument for optimal observations during four segments of its 4.5 hr elliptical orbit. During periapse passage, IUVS uses a scan mirror to obtain vertical profiles of emissions from the atmosphere and ionosphere. Around apoapse, the instrument builds up low-resolution images of the atmosphere at multiple wavelengths. In between, the instrument measures emissions from oxygen, hydrogen and deuterium in the corona. IUVS also undertakes day-long stellar occultation campaigns at 2 month intervals, to measure the state of the atmosphere at altitudes below the airglow layer and in situ sampling. All data will be pipeline-processed from line brightnesses to column abundances, local densities and global 3-D maps and provided to the PDS Atmospheres Node. The combined results from all instruments on ion and neutral escape will bear on the central question of the history of Mars' atmosphere and climate change.

  19. Microchannel Reactors for ISRU Applications

    Science.gov (United States)

    Carranza, Susana; Makel, Darby B.; Blizman, Brandon; Ward, Benjamin J.

    2005-02-01

    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.

  20. Design Study for a Low-Enriched Uranium Core for the High Flux Isotope Reactor, Annual Report for FY 2008

    Energy Technology Data Exchange (ETDEWEB)

    Primm, Trent [ORNL; Chandler, David [ORNL; Ilas, Germina [ORNL; Miller, James Henry [ORNL; Sease, John D [ORNL; Jolly, Brian C [ORNL

    2009-03-01

    This report documents progress made during FY 2008 in studies of converting the High Flux Isotope Reactor (HFIR) from highly enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum alloy. With axial and radial grading of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in reactor performance from the current level. Results of selected benchmark studies imply that calculations of LEU performance are accurate. Scoping experiments with various manufacturing methods for forming the LEU alloy profile are presented.

  1. Mar Capeans

    CERN Multimedia

    2017-01-01

    Mar Capeans, CERN researcher, answers the question to "What can we do in the world of sciences and innovation to make visible the invisible?". This piece belongs to a series of videos made by the Spanish Aquae Foundation, a supporter of the CERN & Society Foundation.

  2. Mar adentro

    OpenAIRE

    Florián Guerrero, Mayra

    2014-01-01

    La bravura del mar destruyó primero las canchas de fútbol, luego se tragó casas y finalmente las playas. El otrora balneario exclusivo de Buenos Aires, donde se fundó el famoso restaurant Morillas en los años 40, es ahora un tímido recuerdo en medio del chocar incesante de las olas.

  3. Spectral and geological study of the sulfate-rich region of West Candor Chasma, Mars

    Science.gov (United States)

    Mangold, Nicolas; Gendrin, Aline; Gondet, Brigitte; Le Mouelic, Stephane; Quantin, Cathy; Ansan, Véronique; Bibring, Jean-Pierre; Langevin, Yves; Masson, Philippe; Neukum, Gerhard

    2008-04-01

    Sulfates have been discovered by the OMEGA spectrometer in different locations of the planet Mars. They are strongly correlated to light toned layered deposits in the equatorial regions. West Candor Chasma is the canyon with the thickest stack of layers and one with the largest area covered by sulfates. A detailed study coupling mineralogy derived from OMEGA spectral data and geology derived from HRSC imager and other datasets leads to some straightforward issues. The monohydrated sulfate kieserite is found mainly over heavily eroded scarps of light toned material. It likely corresponds to a mineral present in the initial rock formed either during formation and diagenesis of sediments, or during hydrothermal alteration at depth, because it is typically found on outcrops that are eroded and steep. Polyhydrated sulfates, that match any Ca-, Na-, Fe-, or Mg-sulfates with more than one water molecule, are preferentially present on less eroded and darker outcrops than outcrops of kieserite. These variations can be the result of a diversity in the composition and/or of the rehydration of kieserite on surfaces with longer exposure. The latter possibility of rehydration in the current, or recent, atmosphere suggests the low surface temperatures preserve sulfates from desiccation, and, also can rehydrate part of them. Strong signatures of iron oxides are present on sulfate-rich scarps and at the base of layered deposits scarps. They are correlated with TES gray hematite signature and might correspond to iron oxides present in the rock as sand-size grains, or possibly larger concretions, that are eroded and transported down by gravity at the base of the scarp. Pyroxenes are present mainly on sand dunes in the low lying terrains. Pyroxene is strongly depleted or absent in the layered deposits. When mixed with kieserite, local observations favor a spatial mixing with dunes over layered deposits. Sulfates such as those detected in the studied area require the presence of liquid

  4. A study of concentrated acid hydrolysis conversion of lignocellulosic materials to sugars using a co-rotating twin-screw reactor extruder and plug flow reactor

    Science.gov (United States)

    Miller, William Scott

    Concerns about the ability of petroleum to continue supplying ever increasing global energy demands, at a price capable of generating continued economic growth, have spurred innovative research in the field of alternative energy. One alternative energy option that has the ability to provide long-term sustainable energy supplies for the global energy market is the conversion of lignocellulosic materials, via acid hydrolysis, to fermentable sugars for the production of fuel grade ethanol. This research demonstrates the ability of a co-rotating twin-screw reactor extruder and plug flow reactor to continuously convert lignocellulosic materials to fermentable sugars using high temperature concentrated acid hydrolysis. In addition to demonstrating continuous operation of the two-stage concentrated acid hydrolysis system, a number of design of experiments were conducted to model the twin-screw performance and maximize its ability to effectively solubilize lignocellulosic feedstocks in the high shear, elevated temperature, concentrated acid environment. These studies produced a base case twin-screw operating condition used to generate a standard extrudate composition for an extensive high temperature acid hydrolysis batch reactor kinetic modeling study. In this study a number of nonlinear and linear regression analyses were undertaken so that the concentration of less resistant cellulose, or the amount of solublilized extrudate cellulose, resistant cellulose, or non-solubilized extrudate cellulose, glucose, and decomposition products could be obtained as a function of time, temperature, and acid concentration. This study demonstrated that the theoretical cellulose conversion of 51% was limited by the amount of solubilized polysaccharides that could be produced in the twin-screw pretreatment. Further experimentation, showing twin-screw pretreatment lignocellulosic versatility, produced nearly identical results as the southern yellow pine sawdust experiments that were

  5. DOE plutonium disposition study: Analysis of existing ABB-CE Light Water Reactors for the disposition of weapons-grade plutonium. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    Core reactivity and basic fuel management calculations were conducted on the selected reactors (with emphasis on the System 80 units as being the most desirable choice). Methods used were identical to those reported in the Evolutionary Reactor Report. From these calculations, the basic mission capability was assessed. The selected reactors were studied for modification, such as the addition of control rod nozzles to increase rod worth, and internals and control system modifications that might also be needed. Other system modifications studied included the use of enriched boric acid as soluble poison, and examination of the fuel pool capacities. The basic geometry and mechanical characteristics, materials and fabrication techniques of the fuel assemblies for the selected existing reactors are the same as for System 80+. There will be some differences in plutonium loading, according to the ability of the reactors to load MOX fuel. These differences are not expected to affect licensability or EPA requirements. Therefore, the fuel technology and fuel qualification sections provided in the Evolutionary Reactor Report apply to the existing reactors. An additional factor, in that the existing reactor availability presupposes the use of that reactor for the irradiation of Lead Test Assemblies, is discussed. The reactor operating and facility licenses for the operating plants were reviewed. Licensing strategies for each selected reactor were identified. The spent fuel pool for the selected reactors (Palo Verde) was reviewed for capacity and upgrade requirements. Reactor waste streams were identified and assessed in comparison to uranium fuel operations. Cost assessments and schedules for converting to plutonium disposition were estimated for some of the major modification items. Economic factors (incremental costs associated with using weapons plutonium) were listed and where possible under the scope of work, estimates were made.

  6. Interim results of the study of control room crew staffing for advanced passive reactor plants

    Energy Technology Data Exchange (ETDEWEB)

    Hallbert, B.P.; Sebok, A.; Haugset, K. [OECD Halden Reactor Project (Norway)

    1996-03-01

    Differences in the ways in which vendors expect the operations staff to interact with advanced passive plants by vendors have led to a need for reconsideration of the minimum shift staffing requirements of licensed Reactor Operators and Senior Reactor Operators contained in current federal regulations (i.e., 10 CFR 50.54(m)). A research project is being carried out to evaluate the impact(s) of advanced passive plant design and staffing of control room crews on operator and team performance. The purpose of the project is to contribute to the understanding of potential safety issues and provide data to support the development of design review guidance. Two factors are being evaluated across a range of plant operating conditions: control room crew staffing; and characteristics of the operating facility itself, whether it employs conventional or advanced, passive features. This paper presents the results of the first phase of the study conducted at the Loviisa nuclear power station earlier this year. Loviisa served as the conventional plant in this study. Data collection from four crews were collected from a series of design basis scenarios, each crew serving in either a normal or minimum staffing configuration. Results of data analyses show that crews participating in the minimum shift staffing configuration experienced significantly higher workload, had lower situation awareness, demonstrated significantly less effective team performance, and performed more poorly as a crew than the crews participating in the normal shift staffing configuration. The baseline data on crew configurations from the conventional plant setting will be compared with similar data to be collected from the advanced plant setting, and a report prepared providing the results of the entire study.

  7. Neutronic design studies of a conceptual DCLL fusion reactor for a DEMO and a commercial power plant

    Science.gov (United States)

    Palermo, I.; Veredas, G.; Gómez-Ros, J. M.; Sanz, J.; Ibarra, A.

    2016-01-01

    Neutronic analyses or, more widely, nuclear analyses have been performed for the development of a dual-coolant He/LiPb (DCLL) conceptual design reactor. A detailed three-dimensional (3D) model has been examined and optimized. The design is based on the plasma parameters and functional materials of the power plant conceptual studies (PPCS) model C. The initial radial-build for the detailed model has been determined according to the dimensions established in a previous work on an equivalent simplified homogenized reactor model. For optimization purposes, the initial specifications established over the simplified model have been refined on the detailed 3D design, modifying material and dimension of breeding blanket, shield and vacuum vessel in order to fulfil the priority requirements of a fusion reactor in terms of the fundamental neutronic responses. Tritium breeding ratio, energy multiplication factor, radiation limits in the TF coils, helium production and displacements per atom (dpa) have been calculated in order to demonstrate the functionality and viability of the reactor design in guaranteeing tritium self-sufficiency, power efficiency, plasma confinement, and re-weldability and structural integrity of the components. The paper describes the neutronic design improvements of the DCLL reactor, obtaining results for both DEMO and power plant operational scenarios.

  8. A test study on treatment of high-strength polyester wastewater with anaerobic reactor

    Institute of Scientific and Technical Information of China (English)

    韩洪军; 陈秀荣; 徐春艳

    2002-01-01

    The treatment of polyester wastewater using Up-flow activated sludge bed anaerobic filer ( UASB-AF), demonstrated that UASB-AF reactors has a high efficiency, its volume loading is 10 ~ 12 kgCOD/( m3 @d) ,HRT is 22 ~24 h, and the removal of COD is about 80%. The reactor has advantage of fast starting andenduring pulse loading.

  9. A reverse flow catalytic membrane reactor for the production of syngas: an experimental study

    NARCIS (Netherlands)

    Smit, J.; Bekink, G.J.; Sint Annaland, van M.; Kuipers, J.A.M.

    2005-01-01

    In this paper experimental results are presented for a demonstration unit of a recently proposed novel integrated reactor concept (Smit et. al., 2005) for the partial oxidation of natural gas to syngas (POM), namely a Reverse Flow Catalytic Membrane Reactor (RFCMR). Natural gas has great potential a

  10. Comparative study of ion cyclotron waves at Mars, Venus and Earth

    Science.gov (United States)

    Wei, H. Y.; Russell, C. T.; Zhang, T. L.; Blanco-Cano, X.

    2011-08-01

    Ion cyclotron waves are generated in the solar wind when it picks up freshly ionized planetary exospheric ions. These waves grow from the free energy of the highly anisotropic distribution of fresh pickup ions, and are observed in the spacecraft frame with left-handed polarization and a wave frequency near the ion's gyrofrequency. At Mars and Venus and in the Earth's polar cusp, the solar wind directly interacts with the planetary exospheres. Ion cyclotron waves with many similar properties are observed in these diverse plasma environments. The ion cyclotron waves at Mars indicate its hydrogen exosphere to be extensive and asymmetric in the direction of the interplanetary electric field. The production of fast neutrals plays an important role in forming an extended exosphere in the shape and size observed. At Venus, the region of exospheric proton cyclotron wave production may be restricted to the magnetosheath. The waves observed in the solar wind at Venus appear to be largely produced by the solar-wind-Venus interaction, with some waves at higher frequencies formed near the Sun and carried outward by the solar wind to Venus. These waves have some similarity to the expected properties of exospherically produced proton pickup waves but are characterized by magnetic connection to the bow shock or by a lack of correlation with local solar wind properties respectively. Any confusion of solar derived waves with exospherically derived ion pickup waves is not an issue at Mars because the solar-produced waves are generally at much higher frequencies than the local pickup waves and the solar waves should be mostly absorbed when convected to Mars distance as the proton cyclotron frequency in the plasma frame approaches the frequency of the solar-produced waves. In the Earth's polar cusp, the wave properties of ion cyclotron waves are quite variable. Spatial gradients in the magnetic field may cause this variation as the background field changes between the regions in which

  11. Computational and experimental studies of neutron spectra in the IGR reactor

    CERN Document Server

    Gorin, N V; Litvin, V I; Gajdajchuk, V A; Kazmin, Y M; Pakhnits, V A; Skivka, A S; Vasilev, A P; Pavshuk, V A; Rychev, A S

    2000-01-01

    The results of experiments made in order to determine spectral composition of neutrons in the IGR impulse graphite moderated reactor experimental channel at fuel temperature close to the room one are considered. The set of activation and fission detectors with half-life period more than 0.5 days is applied for the neutron spectrum measurements. The algorithm based on the directed divergence method is used for reconstruction of neutron energy spectra in energy range of 0.6 eV - 18 MeV. The results of calculational studies into the influence of impurities in structural materials on portion of thermal neutrons in he spectrum in the channel centre are discussed as well. The conclusion is made that the calculational results agree well with experimental data

  12. Selected transport studies of a tokamak-based DEMO fusion reactor

    Science.gov (United States)

    Fable, E.; Wenninger, R.; Kemp, R.

    2017-02-01

    As a next-step in the tokamak-based fusion programme, the DEMO fusion reactor is foreseen to produce relevant output electricity, in the order of  ∼500 MW delivered to the network. The scenarios that are being presently investigated consist of a pulsed device, called DEMO1, and a steady-state device, called DEMO2. In this work, which is focused on the pulsed device DEMO1, scenarios are studied from the point of view of core transport, to assess plasma performance and limitations due to core microinstabilities. The role of radiated power, aspect ratio, and height of temperature pedestal are assessed as they impact both core energy and particle transport. Open issues in this framework are also discussed.

  13. The studies of irradiation hardening of stainless steel reactor internals under proton and xenon irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Chaoliang; Zhang, Lu; Qian, Wangjie; Mei, Jinna; Liu, Xiang Bing [Suzhou Nuclear Power Research Institute, Suzuhou (China)

    2016-06-15

    Specimens of stainless steel reactor internals were irradiated with 240 keV protons and 6 MeV Xe ions at room temperature. Nanoindentation constant stiffness measurement tests were carried out to study the hardness variations. An irradiation hardening effect was observed in proton- and Xe-irradiated specimens and more irradiation damage causes a larger hardness increment. The Nix-Gao model was used to extract the bulk-equivalent hardness of irradiation-damaged region and critical indentation depth. A different hardening level under H and Xe irradiation was obtained and the discrepancies of displacement damage rate and ion species may be the probable reasons. It was observed that the hardness of Xe-irradiated specimens saturate at about 2 displacement/atom (dpa), whereas in the case of proton irradiation, the saturation hardness may be more than 7 dpa. This discrepancy may be due to the different damage distributions.

  14. The study of core melting phenomena in reactor severe accident of PWR

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hong; Jeun, Gyoo Dong; Park, Seh In; Lim, Jae Hyuck; Park, Seong Yong [Hanyang Univ., Seoul (Korea, Republic of); Bang, Kwang Hyun; Kim, Ki Yong [Korea Maritime Univ., Busan (Korea, Republic of)

    1999-03-15

    After TMI-2 accident, it has been paid much attention to severe accidents beyond the design basis accidents and the research on the progress of severe accidents and mitigation and the closure of severe accidents has been actively performed. In particular, a great deal of uncertainties yet exist in the phase of late core melt progression and thus the research on this phase of severe accident progress has a key role in obtaining confidence in severe accident mitigation and nuclear reactor safety. In the present study, physics of late core melt progression, experimental data and the major phenomenological models of computer codes are reviewed and a direction of reducing the uncertainties in the late core melt progression is proposed.

  15. The study of core melting phenomena in reactor severe accident of PWR

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hong; Jeun, Gyoo Dong; Park, Seh In; Lim, Jae Hyuck; Park, Seong Yong [Hanyang Univ., Seoul (Korea, Republic of); Bang, Kwang Hyun; Kim, Ki Yong [Korea Maritime Univ., Busan (Korea, Republic of)

    1999-03-15

    After TMI-2 accident, it has been paid much attention to severe accidents beyond the design basis accidents and the research on the progress of severe accidents and mitigation and the closure of severe accidents has been actively performed. In particular, a great deal of uncertainties yet exist in the phase of late core melt progression and thus the research on this phase of severe accident progress has a key role in obtaining confidence in severe accident mitigation and nuclear reactor safety. In the present study, physics of late core melt progression, experimental data and the major phenomenological models of computer codes are reviewed and a direction of reducing the uncertainties in the late core melt progression is proposed.

  16. Aging biofilm from a full-scale moving bed biofilm reactor: characterization and enzymatic treatment study.

    Science.gov (United States)

    Huang, Hui; Ren, Hongqiang; Ding, Lili; Geng, Jinju; Xu, Ke; Zhang, Yan

    2014-02-01

    Effective removal of aging biofilm deserves to receive more attention. This study aimed to characterized aging biofilm from a full-scale moving bed biofilm reactor treating pharmaceutical wastewater and evaluate the hydrolysis effects of biofilm by different enzymatic treatments. Results from FTIR and biochemical composition analyses showed that it was a predominately organic-based biofilm with the ratio of total protein (PN) to polysaccharide (PS) of 20.17. A reticular structure of extracellular polymeric matrix (EPM) with filamentous bacteria as the skeleton was observed on the basal layer through SEM-EDS test. Among the four commercial proteases and amylases from Genencor®, proteases were shown to have better performances than amylases either on the removal of MLSS and PN/MLSS or on DOC (i.e., dissolved organic carbon)/MLSS raising of biofilm pellets. Difference of dynamic fluorescence characteristics of dissolved organic matters after treated by the two proteases indicated distinguishing mechanisms of the treating process.

  17. Study of moving bed biofilm reactor in diethyl phthalate and diallyl phthalate removal from synthetic wastewater.

    Science.gov (United States)

    Ahmadi, Ehsan; Gholami, Mitra; Farzadkia, Mahdi; Nabizadeh, Ramin; Azari, Ali

    2015-05-01

    Phthalic acid esters have received significant attention over the last few years since they are considered as priority pollutants. In this study, effects of different operation conditions including hydraulic retention time, phthalates loading rates and aeration rate on process performance of moving bed biofilm reactor (MBBR) for removing diethyl phthalate (DEP) and diallyl phthalate (DAP) from synthetic wastewater was evaluated. In optimum conditions, 94.96% and 93.85% removal efficiency were achieved for DEP and DAP, respectively. Moreover, MBBR achieved to remove more than 92% of COD for both phthalates. The results showed that DEP had a higher biodegradation rate compared to DAP, according to the selected parameters such as half saturation constant, overall reaction rate and maximum specific growth rate. The Grau second order model found as the best model for predicting MBBR performance due to its high correlation coefficients and more conformity of its kinetic coefficients to the results.

  18. Thermal stability study for candidate stainless steels of GEN IV reactors

    Energy Technology Data Exchange (ETDEWEB)

    Simeg Veternikova, J., E-mail: jana.veternikova@stuba.sk [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Degmova, J. [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Pekarcikova, M. [Institute of Materials Science, Faculty of Materials Science and Technology, Slovak University of Technology, Paulinska 16, 917 24 Trnava (Slovakia); Simko, F. [Department of Molten Salts, Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, 845 36 Bratislava (Slovakia); Petriska, M. [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Skarba, M. [Slovak University of Technology, Vazovova 5, 812 43 Bratislava (Slovakia); Mikula, P. [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Pupala, M. [Department of Molten Salts, Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, 845 36 Bratislava (Slovakia)

    2016-11-30

    Highlights: • Thermal resistance of advanced stainless steels were observed at 1000 °C. • GEN IV candidate steels were confronted to classic AISI steels. • ODS AISI 316 has weaker thermal resistance than classic AISI steel. • Ferritic ODS steels and NF 709 has better thermal resistance than AISI steels. - Abstract: Candidate stainless steels for GEN IV reactors were investigated in term of thermal and corrosion stability at high temperatures. New austenitic steel (NF 709), austenitic ODS steel (ODS 316) and two ferritic ODS steels (MA 956 and MA 957) were exposed to around 1000 °C in inert argon atmosphere at pressure of ∼8 MPa. The steels were further studied in a light of vacancy defects presence by positron annihilation spectroscopy and their thermal resistance was confronted to classic AISI steels. The thermal strain supported a creation of oxide layers observed by scanning electron microscopy (SEM).

  19. Study of the reactivity effect of bubble collapse in molten liquid metal cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Munno, F.J.; Sheaks, O.J.

    1977-08-01

    The reactivity effect of void collapse on a Core Disruptive Accident in a sodium free fast reactor core was studied. A two-dimensional transport theory computer code was employed to obtain a reactivity model which incorporated random distributions of voids in spatial location and bubble size. This model was implemented into VENUS-II and several excursions were investigated for the purpose of assessing the effect of bubble collapse reactivity on excursion energy. In addition, comparisons were made between the VENUS-II results obtained using the transport reactivity model and those obtained using a reactivity model developed from the Behrens' formulation of the leakage effects due to the presence of bubbles. The results indicate that excursion energy is sensitive to the shape of the reactivity versus void fraction function and that reactivity models based strictly on leakage effects are probably conservative compared to models which include both self-multiplication and leakage.

  20. Surface-catalyzed air oxidation reactions of hydrazines: Tubular reactor studies

    Science.gov (United States)

    Kilduff, Jan E.; Davis, Dennis D.; Koontz, Steven L.

    1988-01-01

    The surface-catalyzed air oxidation reactions of hydrazine, monomethylhydrazine, unsymmetrical dimethylhydrazine, symmetrical dimethylhydrazine, trimethylhydrazine and tetramethylhydrazine were investigated in a metal-powder packed turbular flow reactor at 55 plus or minus 3 C. Hydrazine was completely reacted on all surfaces studied. The major products of monomethylhydrazine (MMH) oxidation were methanol, methane and methyldiazene. The di-, tri- and tetra-methyl hydrazines were essentially unreactive under these conditions. The relative catalytic reactivities toward MMH are: Fe greater than Al2O3 greater than Ti greater than Zn greater than 316 SS greater than Cr greater than Ni greater than Al greater than 304L SS. A kinetic scheme and mechanism involving adsorption, oxidative dehydrogenation and reductive elimination reactions on a metal oxide surface are proposed.

  1. A study on the late core melt progression in pressurized water reactor severe accidents

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hong; Jeun Gyoo Dong; Bang, Kwang Hyun; Park, Seh In; Lim, Jae Hyuck; Park, Seong Yong [Hanyang Univ., Seoul (Korea, Republic of); Back, Hyung Hmm [Korea Maritime Univ., Busan (Korea, Republic of)

    1998-03-15

    After TMI-2 accidents, it has been paid much attention to severe accidents beyond the design basis accidents and the research on the progress of severe accidents and mitigation and the closure of severe accidents has been actively performed. In particular, a great deal of uncertainties yet exist in the phase of late core melt progression and thus the research on this phase of severe accident progress has a key role in obtaining in severe accident mitigation and nuclear reactor safety. In the present study, physics of late core melt progression, experimental data and the major phenomenological models of computer codes are reviewed and a direction of reducing the uncertainties in the late core melt progression os proposed.

  2. Membrane reactor. Membrane reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shindo, Y.; Wakabayashi, K. (National Chemical Laboratory for Industry, Tsukuba (Japan))

    1990-08-05

    Many reaction examples were introduced of membrane reactor, to be on the point of forming a new region in the field of chemical technology. It is a reactor to exhibit excellent function, by its being installed with membrane therein, and is generally classified into catalyst function type and reaction promotion type. What firstly belongs to the former is stabilized zirconia, where oxygen, supplied to the cathodic side of membrane with voltage, impressed thereon, becomes O {sup 2 {minus}} to be diffused through the membrane and supplied, as variously activated oxygenous species, on the anodic side. Examples with many advantages can be given such as methane coupling, propylene oxidation, methanating reaction of carbon dioxide, etc. Apart, palladium film and naphion film also belong to the former. While examples of the latter comprise, among others, decomposition of hydrogen sulfide by porous glass film and dehydrogenation of cyclohexane or palladium alloy film, which are expected to be developed and materialized in the industry. 33 refs., 8 figs.

  3. Studies on the properties of hard-spectrum, actinide fissioning reactors. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, J.B.; Prichard, A.W.; Schofield, P.E.; Robinson, A.H.; Spinrad, B.I.

    1980-01-01

    It is technically feasible to construct an operable (e.g., safe and stable) reactor to burn waste actinides rapidly. The heart of the concept is a driver core of EBR-II type, with a central radial target zone in which fuel elements, made entirely of waste actinides are exposed. This target fuel undergoes fission, as a result of which actinides are rapidly destroyed. Although the same result could be achieved in more conventionally designed LWR or LMFBR systems, the fast spectrum reactor does a much more efficient job, by virtue of the fact that in both LWR and LMFBR reactors, actinide fission is preceded by several captures before a fissile nuclide is formed. In the fast spectrum reactor that is called ABR (actinide burning reactor), these neutron captures are short-circuited.

  4. Study on the effect of the impeller and diffuser blade number on reactor coolant pump performances

    Science.gov (United States)

    Long, Y.; Yin, J. L.; Wang, D. Z.; Li, T. B.

    2016-05-01

    In this paper, CFD approach was employed to study how the blade number of impeller and diffuser influences reactor coolant pump performances. The three-dimensional pump internal flow channel was modelled by pro/E software, Reynolds-averaged Naiver-Stokes equations with the k-ε turbulence model were solved by the computational fluid dynamics software CFX. By post-processing on the numerical results, the performance curves of reactor coolant pump were obtained. The results are as follows, with the blade number of the impeller increasing, the head of the pump with different diffuser universally increases in the 8Q n∼1.2Q n conditions, and at different blade number of the diffuser, the head increases with the blade number of the impeller increasing. In 1.0Q n condition, when the blades number combination of impeller and diffuser chooses 4+16, 7+14 and 6+18, the head curves exist singular points. In 1.2Q n condition, the head curve still exists singular point in 6+18. With the blade number of the impeller increasing, the efficiency of the pump with different diffuser universally decreases in the 0.8Q n and 1.0Q n conditions, but in 1.2Q n condition, the efficiency of the pump with different diffuser universally increases. In 1.0Q n condition, the impellers of 4 and 5 blades are better. When the blade number combination of impeller and diffuser choose 4+11, 4+17, 4+18, 5+12, 5+17 and 5+18, the efficiencies relatively have higher values. With the blade number of the impeller increasing, the hydraulic shaft power of the pump with different diffuser universally increases in the 0.8Q n∼1.2Q n conditions, and with the blade number of the diffuser increasing, the power of different impeller overall has small fluctuation, but tends to be uniform. This means the increase of the diffuser blade number has less influence on shaft power.The influence on the head and flow by the matching relationship of the blades number between impeller and diffuser is very complicated, which

  5. Spent Nuclear Fuel Option Study on Hybrid Reactor for Waste Transmutation

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seong Hee; Kim, Myung Hyun [Kyung Hee University, Yongin (Korea, Republic of)

    2016-05-15

    DUPIC nuclear fuel can be used in hybrid reactor by compensation of subcritical level through (U-10Zr) fuel. Energy production performance of Hyb-WT with DUPIC is grateful because it has high EM factor and performs waste transmutation at the same time. However, waste transmutation performance should be improved by different fissile fuel instead of (U-10Zr) fuel. SNF (Spent Nuclear Fuel) disposal is one of the problems in the nuclear industry. FFHR (Fusion-Fission Hybrid Reactor) is one of the most attractive option on reuse of SNF as a waste transmutation system. Because subcritical system like FFHR has some advantages compared to critical system. Subcritical systems have higher safety potential than critical system. Also, there is suppressed excess reactivity at BOC (Beginning of Cycle) in critical system, on the other hand there is no suppressed reactivity in subcritical system. Our research team could have designed FFHR for waste transmutation; Hyb-WT. Various researches have been conducted on fuel and coolant option for optimization of transmutation performance. However, Hyb-WT has technical disadvantage. It is required fusion power (Pfus) which is the key design parameter in FFHR is increased for compensation of decreasing subcritical level. As a result, structure material integrity is damaged under high irradiation condition by increasing Pfus. Also, deep burn of reprocessed SNF is limited by weakened integrity of structure material. Therefore, in this research, SNF option study will be conducted on DUPIC (Direct Use of Spent PWR Fuel in CANDU Reactor) fuel, TRU fuel and DUPIC + TRU mixed fuel for optimization of Hyb-WT performance. Goal of this research is design check for low required fusion power and high waste transmutation. In this paper, neutronic analysis is conducted on Hyb-WT with DUPIC nuclear fuel. When DUPIC nuclear fuel is loaded in fast neutron system, supplement fissile materials need to be loaded together for compensation of low criticality

  6. Study on corium behavior in the reactor cavity during severe accidents

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soo Yong; Song, Y. M.; Kim, D. H. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2000-03-01

    The report contains following four results of studies on molten corium-concrete interaction, which has been recognized as important aspects of severe reactor accident; 1. MELCOR code modification has been performed for heat transfer model between ex-vessel molten corium and overlying water pool. The existing model do not consider debris particulation and water penetration in the ex-vessel debris cooling. The new model employs dryout heat flux in determining the heat removal from a debris bed by water penetration. 2. A parametric model which can evaluate ex-vessel concrete erosions has been developed. The model is expected to evaluate the concrete erosion in a limited error range with only a little effort. The model has been derived by the sensitivity studies using MELCOR and MAAP programs. 3. During the corium-concrete interaction, there is a temperature distribution inside basemat concrete. MELCOR calculates concrete response based on one-dimensional steady-state ablation, with no consideration given to conduction into the concrete or to decomposition in advance of the ablation front. Thus there is a necessity to improve the concrete decomposition model in MELCOR. In this report the transient conduction model and the methodology of implementation into MELCOR were suggested. 4. Major modeling assumptions and limits of MELTSPREAD-1, which is a transient one-dimensional computer code to predict the gravity-driven spreading of molten corium in the reactor cavity under severe accidents, are evaluated via review of general conservation equations and used models. The models being reviewed include heat transfer models at melt lower/upper surfaces, a concrete dryout model, and a shell heatup model. The evaluation results suggest the degree of MELTSPREAD-1 approximation compared with real spreading flow and the strong/weak points or restrictions of the code. 17 refs., 19 figs., 6 tabs. (Author)

  7. Sensitivity study on nitrogen Brayton cycle coupled with a small ultra-long cycle fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Seok Bin; Seo, Han; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2014-10-15

    The main characteristics of UCFR are constant neutron flux and power density. They move their positions every moment at constant speed along with axial position of fuel rod for 60 years. Simultaneously with the development of the reactors, a new power conversion system has been considered. To solve existing issues of vigorous sodium-water reaction in SFR with steam power cycle, many researchers suggested a closed Brayton cycle as an alternative technique for SFR power conversion system. Many inactive gases are selected as a working fluid in Brayton power cycle, mainly supercritical CO{sub 2} (S-CO{sub 2}). However, S-CO{sub 2} still has potential for reaction with sodium. CO{sub 2}-sodium reaction produces solid product, which has possibility to have an auto ignition reaction around 600 .deg. C. Thus, instead of S-CO{sub 2}, CEA in France has developed nitrogen power cycle for ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration). In addition to inactive characteristic of nitrogen with sodium, its thermal and physical similarity with air enables to easily adopt to existing air Brayton cycle technology. In this study, for an optimized power conversion system for UCFR, a nitrogen Brayton cycle was analyzed in thermodynamic aspect. Based on subchannel analysis data of UCFR-100, a parametric study for thermal performance of nitrogen Brayton cycle was achieved. The system maximum pressure significantly affects to the overall efficiency of cycle, while other parameters show little effects. Little differences of the overall efficiencies for all cases between three stages (BOC, MOC, EOC) indicate that the power cycle of UCFR-100 maintains its performance during the operation.

  8. An integrated approach to steam condensation studies inside reactor containments: A review

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Mahesh Kumar [Department of Mechanical Engineering, Indian Institute of Technology Kanpur, 208016 (India); Khandekar, Sameer, E-mail: samkhan@iitk.ac.in [Department of Mechanical Engineering, Indian Institute of Technology Kanpur, 208016 (India); Sharma, Pavan K. [Reactor Safety Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2016-04-15

    Occurrence of severe accidents, such as the Fukushima incident in 2011, is unlikely with a probability of 10{sup −5} per reactor per year. However, such kinds of accidents have serious consequences on both, short term as well as on long term public health, environment and energy policy and security. They also adversely affect the progress of nuclear power industry. Thus, despite such a low probability of occurrence, a need arises to review the safety standards of nuclear power plants, especially in the light of the Fukushima accident. Apart from other systems, a review of thermal-hydraulics and safety system for the reactor containment is vital, as it is the last barrier to radioactive leakage. Main threats to the containment integrity include over-pressurization, not only due to steam alone, but its coupling with the possibility of local hydrogen combustion, depending on the local mixture composition of steam-air-hydrogens. It must be emphasized that steam condensation rate affects the local mixture composition and presence of hydrogen significantly deteriorates the condensation rate. This intrinsic coupling needs to be understood. In this paper, steam condensation and related issues, including basics of condensation, modeling approaches, parameters affecting condensation and experiments performed (in both separate effect and integral test facilities) are critically reviewed, in the light of coupled issues of hydrogen transport and combustion. Such studies are necessary for correlation development and/or to find out the local distribution of steam-hydrogen-air mixture within the containment to locate the possible hydrogen combustion location(s) and hence, deployment of active/passive safety systems. In addition, it is important that future studies, both experimental and numerical modeling, focus on the coupled nature of the problem in a comprehensive manner for ensuring long term safety.

  9. A Study on the demands of research reactors and considerations for an export

    Energy Technology Data Exchange (ETDEWEB)

    Park, Cheol; Lee, Young Jun

    2008-11-15

    Among around 240 research reactors in operation over the world, around 80% have been operated for more than 20 years and 65% for more than 30 years. Hence the number of operable reactors is expected, between 2010 and 2020, to be reduced to 1/3 of the present situation if the lifetime of a research reactor is assumed to be 40 years. However, considering the recent re-highlighting of nuclear energy as a practical mass energy source and the contributions to the overall areas of science and technology, the demands for constructing a new research reactor and replacing the existing research reactors will be increased in the near future. On the other hand, vendors which participate in providing research reactors are not few, and AREVA in France and INVAP in Argentina are example of them in a positive position. Japan and Russia are regarded as potential competitors, but they do not actively appear in the market so far. Comparing those competitors with Korea, we have weak points regarding experiences on exports and the organizational systems as an integrated vendor. But we may have a competitiveness by grafting our experiences on the development of nuclear power technology and the construction and operation of the HANARO. In this report, the future potential demands for research reactors and the related considerations for exports have been surveyed and described, particularly, centering around the Netherlands, Vietnam and Thailand that are countries which may construct research reactors in the near future. Considerations for exporting a research reactor have been categorized into two groups of technical and nontechnical items. From a technical point of view, the issues on fuel and reactor type, design data and design ability, design codes, and technology property rights have been reviewed. For the non-technical items, an integrated project system, reasonable estimate of demands, social and economic conditions for potential demand countries, MOU status, nuclear non

  10. Oxidative coupling of methane in a fixed bed reactor over perovskite catalyst: A simulation study using experimental kinetic model

    Institute of Scientific and Technical Information of China (English)

    Nakisa Yaghobi; Mir Hamid Reza Ghoreishy

    2008-01-01

    The oxidative coupling of methane (OCM) to ethylene over a perovskite titanate catalyst in a fixed bed reactor was studied experimentally and numerically. The two-dimensional steady state model accounted for separate energy equations for the gas and solid phases coupled with an experimental kinetic model. A lumped kinetic model containing four main species CH4, O2, COx (CO2, CO), and C2 (C2H4 and C2H6) was used with a plug flow reactor model as well. The results from the model agreed with the experimental data. The model was used to analyze the influence of temperature and feed gas composition on the conversion and selectivity of the reactor performance. The analytical results indicate that the conversion decreases, whereas, C2 selectivity increases by increasing gas hourly space velocity (GHSV) and the methane conversion also decreases by increasing the methane to oxygen ratio.

  11. Experimental studies and mathematical modeling of an up-flow biofilm reactor treating mustard oil rich wastewater.

    Science.gov (United States)

    Chakraborty, Chandrima; Chowdhury, Ranjana; Bhattacharya, Pinaki

    2011-05-01

    Bioremediation of lipid-rich model wastewater was investigated in a packed bed biofilm reactor (anaerobic filter). A detailed study was conducted about the influence of fatty acid concentration on biomethanation of the high-fat liquid effluent of edible oil refineries. The biochemical methane potential (BMP) of the liquid waste was reported and maximum cumulative methane production at the exit of the reactor is estimated to be 785 ml CH(4) (STP)/(gVSS added). The effects of hydraulic retention time (HRT), organic loading rate (OLR) and bed porosity on the cold gas efficiency or energy efficiency of the bioconversion process were also investigated. Results revealed that the maximum cold gas efficiency of the process is 42% when the total organic load is 2.1 g COD/l at HRT of 3.33 days. Classical substrate uninhibited Monod model is used to generate the differential system equations which can predict the reactor behavior satisfactorily.

  12. 10-75-kWe-reactor-powered organic Rankine-cycle electric power systems (ORCEPS) study. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    1977-03-30

    This 10-75 kW(e) Reactor-ORCEPS study was concerned with the evaluation of several organic Rankine cycle energy conversion systems which utilized a /sup 235/U-ZrH reactor as a heat source. A liquid metal (NaK) loop employing a thermoelectric converter-powered EM pump was used to transfer the reactor energy to the organic working fluid. At moderate peak cycle temperatures (750/sup 0/F), power conversion unit cycle efficiencies of up to 25% and overall efficiencies of 20% can be obtained. The required operating life of seven years should be readily achievable. The CP-25 (toluene) working fluid cycle was found to provide the highest performance levels at the lowest system weights. Specific weights varies from 100 to 50 lb/kW(e) over the power level range 10 to 75 kW(e). (DLC)

  13. Analytical complex at the PIK reactor for studying the supra-atomic structure and dynamics of materials by neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Lebedev, V. M., E-mail: lebedev@pnpi.spb.ru; Lebedev, V. T.; Ivanova, I. N.; Orlova, D. N. [Russian Academy of Sciences, St. Petersburg Nuclear Physics Institute (Russian Federation)

    2011-12-15

    A project of the center for studying reactor materials and solving problems of materials science is presented which will be equipped with the following neutron instruments: a small-angle Membrana diffractometer, a spin-echo spectrometer, and a time-of-flight spectrometer. It is proposed to irradiate materials in the PIK reactor core and use neutron-scattering tools to analyze the structure and dynamics of these materials and investigate radiative defects in the complete experimental cycle (initial material-irradiation-strength tests, thermal loads, and other effects) using materials science techniques.

  14. Progress in studies of Li/sub 17/Pb/sub 83/ as liquid breeder for fusion reactor blankets

    Energy Technology Data Exchange (ETDEWEB)

    Casini, G.

    1983-09-01

    A review of the experimental and conceptual design work in progress at JRC-Ispra to investigate the feasibility of the eutectic Li/sub 17/Pb/sub 83/ as a liquid breeder for experimental power reactors is presented. Results of recent measurements to implement the data base of this material are given in the following areas: physical parameters, hydrogen solubility and recovery, chemical reactivity with air and water, compatibility with steel. The studies carried out on blanket concepts for the INTOR (International Tokamak Reactor)/NET (Next European Torus) projects are outlined and discussed.

  15. Study of filtration of reactor beam of neutrons with cadmium in a multilayer shield containing boron carbide

    Energy Technology Data Exchange (ETDEWEB)

    Megahid, R.M. (Atomic Energy Establishment, Cairo (Egypt)); El-Kalla, El-Sayed H. (Al-Azhar Univ., Cairo (Egypt)); Esmaiel, M.W. (Ain Shams Univ., Cairo (Egypt))

    1985-08-01

    Experimental measurements have been carried out to study the effect of cadmium on the distribution and attenuation of thermal neutrons emitted from a reactor core and thermal neutrons produced in a heterogeneous shield of water, iron, iron + B/sub 4/C and ordinary concrete. Measurements were performed using a cadmium filtered reactor neutron beam emitted from one of the horizontal channels of ET-RR-1. It was found that the presence of a cadmium sheet at the channel exit causes a marked decrease in the thickness of the shield required for attenuating the thermal neutron flux by a certain factor.

  16. VIS/NIR reflectance and fluorescence spectrometric studies of minerals, water, organics and biomarkers in MoonMars analogue samples

    Science.gov (United States)

    Vos, Heleen; Foing, Bernard; Kołodziejczyk, Agata; Vago, Jorge; Harasymczuk, Matt

    2017-04-01

    This study focuses on the detection and characterisation of elements, minerals, volatiles and organics using reflectance spectrometry. The goal is to create a calibration method to enable the use of spectrometers on analogue Moon/Mars missions and on a lander. For this study we use measurements that are done in the VIS and NIR spectrum, as well as fluorescence using different spectrometers. The first part of the study consists of measurements that are performed in a laboratory to create a calibration method. Different rock samples and soils are analysed and the reflectance and absorption of minerals, water, organics and biomarkers are measured. Also the influence of the grain size, light source and surroundings is being determined. An experiment on the reflectance spectra of plant growth in different soils is also done to determine the possibilities of detecting the presence of chlorophyll and other biomarkers, and to diagnose the growth and health of a plant. This analysis can result in a monitoring method for a Moon greenhouse, but also for general surface analysis. Using VIS and NIR spectrometry has a couple of advantages, one being the fact that measurements require no sample preparation, and also the small size of the spectrometer makes it an easy tool for different analyses on board space missions. However, VIS and NIR spectroscopy have detection limits which makes only certain characteristics detectable. Besides laboratory measurements, the different spectroscopy methods are tested during a field campaign in the Eifel, Germany. During this campaign we can determine the functionality of the spectrometer in the field and on a lander and the problems that can rise when a spectrometer is controlled from a distant or by a person who is not trained in using spectroscopy. These laboratory and field measurements can help in the scientific preparation for instruments on ExoMars rover, future MoonMars lander missions and for the MoonVillage.

  17. Reactor Materials Research

    Energy Technology Data Exchange (ETDEWEB)

    Van Walle, E

    2001-04-01

    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)

  18. Study on operation of a research reactor during one PCS pump failure accident

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Kyoung Woo; Yoon, Hyu Ngi; Kim, Seong Hoon; Chi, Dae Young; Yoon, Juh Yeon [KAERI, Daejeon (Korea, Republic of)

    2012-10-15

    The Primary cooling system (PCS) of a research reactor is designed to provide adequate cooling to the reactor core with a reasonable margin during all operation modes. The PCS consists of pumps, heat exchangers, and all necessary interconnecting pipes, valves, and instruments. The number of pumps is determined from a safety and economic point of view. As the number of pump trains increase, the cost increases according to the increase in safety class equipment. However, it is impossible to install one pump for a PCS because a zero flow can instantaneously occur during a pump failure such as a pump seizure. Thus, a PCS frequently consists of two parallel 50% capacity pumps and heat exchangers. In addition, check valves are generally installed to prevent a reversal flow when multiple pumps are designed to operate. However, if a swing type check valve is used, it should be estimated whether the slam due to instantaneous closing of the valve affects the system vibration. To reduce the vibration by a slam phenomenon, additional equipment such as a damper will be installed in the valve. The purpose of the check valve in PCS is to prevent the flow path when a reverse flow occurs. The installation of additional equipment will make it difficult to perform this function. In this study, it is estimated whether the PCS can operate without check valves. First, a flow analysis using Flowmaster was compared and verified by the calculation employing a empirical correlation. Second, the simulation for a one pump failure accident was performed and analyzed.

  19. José María Vargas (1786-1854): Reformer of anatomical studies in Venezuela.

    Science.gov (United States)

    Reverón, Rafael Romero

    2014-03-01

    José María Vargas (1786-1854): Venezuelan medical doctor, surgeon, optician, anatomist, chemist, botanist, professor, geologist, mineralogist, and mathematician. Second President of Venezuela (1835-1836), First republican dean, he reformed medicine studies in 1827 establishing human anatomical dissection in the Universidad Central de Venezuela where he taught human anatomy between 1827 and 1853 along with surgery and chemistry. In 1838, he wrote Curso de Lecciones y demostraciones Anatómicas, the first book on the subject printed in Venezuela for the teaching of human anatomy. Copyright © 2013 Wiley Periodicals, Inc.

  20. Reactor safety study. An assessment of accident risks in U. S. commercial nuclear power plants. Appendix VI. Calculation of reactor accident consequences. [PWR and BWR

    Energy Technology Data Exchange (ETDEWEB)

    1975-10-01

    Information is presented concerning the radioactive releases from the containment following accidents; radioactive inventory of the reactor core; atmospheric dispersion; reactor sites and meteorological data; radioactive decay and deposition from plumes; finite distance of plume travel; dosimetric models; health effects; demographic data; mitigation of radiation exposure; economic model; and calculated results with consequence model.

  1. ISRU in the Context of Future European Human Mars Exploration

    Science.gov (United States)

    Baker, A. M.; Tomatis, C.

    2002-01-01

    ISRU or In-Situ Resource Utilisation is the use of Martian resources to manufacture, typically, life support consumables (e.g. water, oxygen, breathing buffer gases), and propellant for a return journey to Earth. European studies have shown that some 4kg of reaction mass must be launched to LEO to send 1kg payload to Mars orbit, with landing on the Mars surface reducing payload mass still further. This results in very high transportation costs to Mars, and still higher costs for returning payloads to Earth. There is therefore a major incentive to reduce payload mass for any form of Mars return mission (human or otherwise) by generating consumables on the surface. ESA through its GSTP programme has been investigating the system level design of a number of mission elements as potential European contributions to an international human Mars exploration mission intended for the 2020-2030 timeframe. One of these is an ISRU plant, a small chemical factory to convert feedstock brought from Earth (hydrogen), and Martian atmospheric gases (CO2 and trace quantities of nitrogen and argon) into methane and oxygen propellant for Earth return and life support consumables, in advance of the arrival of astronauts. ISRU technology has been the subject of much investigation around the world, but little detailed research or system level studies have been reported in Europe. Furthermore, the potential applicability of European expertise, technology and sub- system studies to Martian ISRU is not well quantified. Study work covered in this paper has compared existing designs (e.g. NASA's Design Reference Mission, DLR and Mars Society studies) with the latest ESA derived requirements for human Mars exploration, and has generated a system level ISRU design. This paper will review and quantify the baseline chemical reactions essential for ISRU, including CO2 collection and purification, Sabatier reduction of CO2 with hydrogen to methane and water, and electrolysis of water in the context of

  2. Study of Pu consumption in light water reactors: Evaluation of GE advanced boiling water reactor plants, compilation of Phase 1C task reports

    Energy Technology Data Exchange (ETDEWEB)

    1994-01-15

    This report summarizes the evaluations conducted during Phase 1C of the Pu Disposition Study have provided further results which reinforce the conclusions reached during Phase 1A & 1B: These conclusions clearly establish the benefits of the fission option and the use of the ABWR as a reliable, proven, well-defined and cost-effective means available to disposition the weapons Pu. This project could be implemented in the near-term at a cost and on a schedule being validated by reactor plants currently under construction in Japan and by cost and schedule history and validated plans for MOX plants in Europe. Evaluations conducted during this phase have established that (1) the MOX fuel is licensable based on existing criteria for new fuel with limited lead fuel rod testing, (2) that the applicable requirements for transport, handling and repository storage can be met, and (3) that all the applicable safeguards criteria can be met.

  3. Studies on advanced water-cooled reactors beyond generation Ⅲ for power generation

    Institute of Scientific and Technical Information of China (English)

    CHENG Xu

    2007-01-01

    China's ambitious nuclear power program motivates the country's nuclear community to develop advanced reactor concepts beyond generation Ⅲ to ensure a long-term, stable, and sustainable development of nuclear power. The paper discusses some main criteria for the selection of future water-cooled reactors by considering the specific Chinese situation. Based on the suggested selection criteria, two new types of water-cooled reactors are recommended for future Chinese nuclear power generation. The high conversion pressurized water reactor utilizes the present PWR technology to a large extent. With a conversion ratio of about 0.95, the fuel utilization is increased about 5 times. This significantly improves the sustainability of fuel resources. The supercritical water-cooled reactor has favorable features in economics,sustainability and technology availability. It is a logical extension of the generation Ⅲ PWR technology in China.The status of international R&D work is reviewed. A new supercritieal water-cooled reactor (SCWR) core structure (the mixed reactor core) and a new fuel assembly design (two-rows FA) are proposed. The preliminary analysis using a coupled neutron-physics/thermal-hydranlics method is carded out. It shows good feasibility for the new design proposal.

  4. Simulation of loss of feedwater transient of MASLWR test facility by MARS-KS code

    Energy Technology Data Exchange (ETDEWEB)

    Park, Juyeop [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2013-05-15

    MASLWR test facility is a mock-up of a passive integral type reactor equipped with helical coil steam generator. Since SMART reactor which is being current developed domestically also adopts helical coil steam generator, KINS has joined this ICSP to evaluate performance of domestic regulatory audit thermal-hydraulic code (MARS-KS code) in various respects including wall-to-fluid heat transfer model modification implemented in the code by independent international experiment database. In the ICSP, two types of transient experiments have been focused and they are loss of feedwater transient with subsequent ADS operation and long term cooling (SP-2) and normal operating conditions at different power levels (SP-3). In the present study, KINS simulation results by the MARS-KS code (KS-002 version) for the SP-2 experiment are presented in detail and conclusions on MARS-KS code performance drawn through this simulation is described. Performance of the MARS-KS code is evaluated through the simulation of the loss of feedwater transient of the MASLWR test facility. Steady state run shows helical coil specific heat transfer models implemented in the code is reasonable. However, through the transient run, it is also found that three-dimensional effect within the HPC and axial conduction effect through the HTP are not well reproduced by the code.

  5. Nuclear reactors situation in Japan after the major earthquake of March 11, 2011. March 12, 2011, 8:00 PM status; Situation des reacteurs nucleaires au Japon suite au seisme majeur servenu le 11 mars 2011. Point de situation du 12 mars 2011 a 20 heures

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    This situation note is established according to the information gained on March 12, 2011, at 8:00 PM, by the crisis centre of the French institute of radiation protection and nuclear safety (IRSN). The situation of the reactors No. 1, 2 and 3 of the Fukushima I site is briefly presented with the progress of the accident management actions. The operation principles of a BWR-type reactor and of a PWR-type reactor are presented in appendix as well as the confinement principle specific to Mark I-type BWR reactors designed by General Electric. The meteorological forecasts of the day are presented in a figure. (J.S.)

  6. Study of the neutronic behavior of a fuel assembly with gadolinium of a reactor HPLWR; Estudio del comportamiento neutronico de un ensamble combustible con gadolinia de un reactor HPLWR

    Energy Technology Data Exchange (ETDEWEB)

    Barragan M, A.; Martin del Campo M, C.; Francois L, J. L. [UNAM, Facultad de Ingenieria, Departamento de Sistemas Energeticos, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Espinosa P, G., E-mail: albrm29@yahoo.com [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Area de Ingenieria en Recursos Energeticos, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)

    2012-10-15

    This work presents a neutronic study of a square assembly design of double line of fuel rods, with moderator box to center of the arrangement, for the nuclear reactor cooled with supercritical water, High Performance Light Water Reactor (HPLWR). For the fuel analyses of the reactor HPLWR the neutronic code Helios-2 was used, settling down as the first study on fuel under conditions of supercritical water that has been simulated with this code. The analyzed variables, essentials in the neutronic design of any reactor, were the infinite neutrons multiplication factor (k{infinity}) and the maximum power peaking factor (PPF{sub max}), as well as the reactivity coefficients by the fuel temperature. The k{infinity} and PPF{sub max} values were obtained under conditions in cold (293.6 K) and in hot (to 880.8 K). The tests were realized for a reference fuel assembly design, with 40 fuel rods with enrichments of 4 and 5% of U-235, and considering different concentrations of consumable poison (gadolinium - Gd{sub 2O3}) in some rods of the same assembly. The obtained results show values k{infinity} and PPF{sub max} minors to the present in the conventional light water reactors. Moreover, the reactivity coefficients by fuel temperature were verified with the purpose of satisfying the safety conditions required in the nuclear reactors. (Author)

  7. Student Collaboration in a Series of Integrated Experiments to Study Enzyme Reactor Modeling with Immobilized Cell-Based Invertase

    Science.gov (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.

    2015-01-01

    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…

  8. KINETIC STUDY OF ADSORPTION AND TRANSFORMATION OF MERCURY ON FLY ASH PARTICLES IN AN ENTRAINED FLOW REACTOR

    Science.gov (United States)

    Experimental studies were performed to investigate the interactions of elemental mercury vapor with entrained fly ash particles from coal combustion in a flow reactor. The rate of transformation of elemental mercury on fly ash particles was evauated over the temperature range fro...

  9. An experimental study of the selective oxidation of ethene in a wall cooled tubular packed bed reactor

    NARCIS (Netherlands)

    Borman, P.C.; Westerterp, K.R.

    1992-01-01

    The selective oxidation of ethene over a silver on ¿-alumina catalyst was studied in a wall cooled tubular reactor. Temperatures were measured inside the bed at different axial and radical positions as well as the overall conversion and selectivity. Locally measured temperatures vary after repacking

  10. Acetate conversion in anaerobic biogas reactors: Traditional and molecular tools for studying this important group of anaerobic microorganisms

    DEFF Research Database (Denmark)

    Schmidt, Jens Ejbye; Mladenovska, Zuzana; Lange, Marianne;

    2000-01-01

    Different methods were applied to study the role of aceticlastic methanogens in biogas reactors treating solid waste and wastewater. We used traditional microbiological methods, immunological and 16S rRNA ribosomal probes for detection of the methanogens. Using this approach we identified the met...

  11. STUDY OF MERCURY OXIDATION BY SCR CATALYST IN AN ENTRAINED-FLOW REACTOR UNDER SIMULATED PRB CONDITIONS

    Science.gov (United States)

    A bench-scale entrained-flow reactor system was constructed for studying elemental mercury oxidation under selective catalytic reduction (SCR) reaction conditions. Simulated flue gas was doped with fly ash collected from a subbituminous Powder River Basin (PRB) coal-fired boiler ...

  12. Possible use of the dedicated MARLY one meter telescope for intensive supernovae studies

    CERN Document Server

    Moniez, M

    2001-01-01

    The EROS2 microlensing search will end at the end of 2002. Apart of this microlensing search, EROS has discovered ~70 supernovae during 8 periods partially dedicated to a SN search. In this document, we investigated a new way of using the EROS telescope (The MARLY) after this date, as a dedicated nearby supernovae photometer. The performance of a set-up with two cameras allowing to simultaneously perform BVRI and U photometry have been estimated. Each year, of order of 100 type Ia supernovae at z ~0.05 should be photometrically followed-up during 80 days with a precision of 2% in BVRI and ~3,5% in U.

  13. Human life support during interplanetary travel and domicile. IV - Mars expedition technology trade study

    Science.gov (United States)

    Rohatgi, Naresh K.; Ferrall, Joseph F.; Seshan, P. K.

    1991-01-01

    Results of trading processing technologies in a closed-loop configuration, in terms of power and weight for the Mars Expedition Mission, are presented. The technologies were traded and compared to a baseline set for functional elements that include CO2 removal, H2O electrolysis, potable H2O cleanup, and hygiene H2O cleanup. These technologies were selected from those being considered for Space Station Freedom and represent only chemical/physical technologies. Attention is given to the technology trade calculation scheme, technology data and selection, the generic modular flow schematic, and life support system specifications.

  14. OECD/NEA STUDY ON THE ECONOMICS AND MARKET OF SMALL REACTORS

    Directory of Open Access Journals (Sweden)

    ALEXEY LOKHOV

    2013-11-01

    Full Text Available According to the OECD/NEA estimates, nuclear power plants (NPPs, whether with a large reactor or with small modular reactors (SMRs, are competitive with many other electricity generation technologies in a significant number of cases, one of the exceptions being natural gas in the USA with the current level of prices. However, SMRs have particular features and requirements setting conditions for their deployment. This paper presents the preliminary analysis by OECD/NEA of the economics, opportunities, and market for small nuclear reactors.

  15. Turbulence coefficients and stability studies for the coaxial flow or dissimiliar fluids. [gaseous core nuclear reactors

    Science.gov (United States)

    Weinstein, H.; Lavan, Z.

    1975-01-01

    Analytical investigations of fluid dynamics problems of relevance to the gaseous core nuclear reactor program are presented. The vortex type flow which appears in the nuclear light bulb concept is analyzed along with the fluid flow in the fuel inlet region for the coaxial flow gaseous core nuclear reactor concept. The development of numerical methods for the solution of the Navier-Stokes equations for appropriate geometries is extended to the case of rotating flows and almost completes the gas core program requirements in this area. The investigations demonstrate that the conceptual design of the coaxial flow reactor needs further development.

  16. Advances in the development of wire mesh reactor for coal gasification studies.

    Science.gov (United States)

    Zeng, Cai; Chen, Lei; Liu, Gang; Li, Wenhua; Huang, Baoming; Zhu, Hongdong; Zhang, Bing; Zamansky, Vladimir

    2008-08-01

    In an effort to further understand the coal gasification behavior in entrained-flow gasifiers, a high pressure and high temperature wire mesh reactor with new features was recently built. An advanced LABVIEW-based temperature measurement and control system were adapted. Molybdenum wire mesh with aperture smaller than 70 mum and type D thermocouple were used to enable high carbon conversion (>90%) at temperatures >1000 degrees C. Gaseous species from wire mesh reactor were quantified using a high sensitivity gas chromatography. The material balance of coal pyrolysis in wire mesh reactor was demonstrated for the first time by improving the volatile's quantification techniques.

  17. A Study on Conceptual Design of Fischer-Tropsch Reactors in GTL Applications

    OpenAIRE

    2016-01-01

    GTL (Gas-to-liquid) process is becoming an attractive technology which can produce liquid petroleum products using natural gas. As a part of preliminary design of GTL-FPSO application, process simulation analysis for conceptual design and optimization of reformers and F-T reactors are performed in GTL-FPSO applications by implementing the user made subroutine programs of kinetic equations into PRO/II PROVISION simulator. As for the F-T reactors, Plug Flow Reactor (PFR) model is used with deta...

  18. Management Of Competition And Besting Among Crew Members: A Study At The Mars Desert Research Station (MDRS) In Utah, USA

    Science.gov (United States)

    Allner, Matthew; Bishop, Sheryl; Gushin, Vadim; McKay, Chris; Rygalov, Vadim; Allner, Matthew

    Introduction: Psychosocial group functioning has become an increased international focus of many space faring nations due to the recent shift in focus of colonizing the Moon and then preparing to travel to Mars and beyond. Purpose: This study investigates the effects of competition and besting among crewmembers in isolated and confined extreme (ICE) environments. Furthermore, the study investigates the effects associated with both preand intra-mission management efforts, which included crewmember assessments at various mission phases (pre-, intra-, and end-mission). Suggestions on how to manage competition and besting within a crew were investigated by implementing preand intra-mission awareness strategies as well as group participation in the development and implementation of countermeasures to manage crewmember tendency towards competition and besting to promote the development of positive group functioning. Methods: A six person heterogeneous American crew conducted a Mars simulation mission at the Mars Society's Mars Desert Research Station in Utah, USA in 2006 as part of a new NASA training program called Spaceward Bound. Participants were administered assessments of personality, personal and group identity/functioning, subjective stress, and subjective motivation. All participants were also provided information (pre-mission) regarding past research findings and tendencies of group functioning, stressors, cognitive functioning, and competition and besting. Results: Anecdotal data obtained from personal interviews with crewmembers strongly showed that pre-mission discussions regarding competition and besting provided awareness that allowed crewmembers to continually self-assess to prevent this tendency from surfacing during the mission. The assessment data results showed support for recorded diary materials which indicated crewmembers felt strongly that continual reminders of the besting concept, along with being allowed to participate in the development and

  19. Mars Express 10 years at Mars: Observations by the Mars Express Radio Science Experiment (MaRS)

    Science.gov (United States)

    Pätzold, M.; Häusler, B.; Tyler, G. L.; Andert, T.; Asmar, S. W.; Bird, M. K.; Dehant, V.; Hinson, D. P.; Rosenblatt, P.; Simpson, R. A.; Tellmann, S.; Withers, P.; Beuthe, M.; Efimov, A. I.; Hahn, M.; Kahan, D.; Le Maistre, S.; Oschlisniok, J.; Peter, K.; Remus, S.

    2016-08-01

    The Mars Express spacecraft is operating in Mars orbit since early 2004. The Mars Express Radio Science Experiment (MaRS) employs the spacecraft and ground station radio systems (i) to conduct radio occultations of the atmosphere and ionosphere to obtain vertical profiles of temperature, pressure, neutral number densities and electron density, (ii) to conduct bistatic radar experiments to obtain information on the dielectric and scattering properties of the surface, (iii) to investigate the structure and variation of the crust and lithosphere in selected target areas, (iv) to determine the mass, bulk and internal structure of the moon Phobos, and (v) to track the MEX radio signals during superior solar conjunction to study the morphology of coronal mass ejections (CMEs). Here we report observations, results and discoveries made in the Mars environment between 2004 and 2014 over almost an entire solar cycle.

  20. Preliminary study of degradation from neutron effects of core-structural materials of Thai Research Reactor TRR-1/M1

    Science.gov (United States)

    Ampornrat, P.; Boonsuwan, P.; Sangkaew, S.; Angwongtrakool, T.

    2017-06-01

    Thai research reactor went first critical in 1962. The reactor was converted in 1977 from an MTR-type with high-enriched uranium fuel to a TRIGA-MARK III type using low-enriched uranium fuel, called TRR-1/M1. Since the TRR-1/M1 has been operated for almost 40 years, degradation of reactor structural materials is expected. In this preliminary study, the potential degradation from neutron effects of core-structural materials, e.g., fuel clad (SS304) and core components (Al6061) were studied. Assessment included calculation of neutron energy, flux and fluence in the reactor core to evaluate displacement rate (dpa) and irradiation effects on the material properties. Results showed maximum displacement rates on SS304 was 5.24×10-8 per cm3·sec and on Al6061 was 1.14×10-8 per cm3·sec. The corresponding maximum displacement levels were ∼17 dpa for SS304, and ∼4 dpa for Al6061. At these levels of displacement, it is possible for the materials to result in tensile strength increasing and ductility reduction. Further inspection on the core-structural materials needs to be conducted to validate the assessment results from this study.

  1. Light Water Reactor Sustainability Program Support and Modeling for the Boiling Water Reactor Station Black Out Case Study Using RELAP and RAVEN

    Energy Technology Data Exchange (ETDEWEB)

    Diego Mandelli; Curtis Smith; Thomas Riley; John Schroeder; Cristian Rabiti; Aldrea Alfonsi; Joe Nielsen; Dan Maljovec; Bie Wang; Valerio Pascucci

    2013-09-01

    The existing fleet of nuclear power plants is in the process of extending its lifetime and increasing the power generated. In order to evaluate the impact of these two factors on the safety of the plant, the Risk Informed Safety Margin Characterization (RISMC) project aims to provide insight to decision makers through a series of simulations of the plant dynamics for different initial conditions (e.g., probabilistic analysis and uncertainty quantification). This report focuses, in particular, on the impact of power uprate on the safety of a boiled water reactor system. The case study considered is a loss of off-site power followed by the loss of diesel generators, i.e., a station black out (SBO) event. Analysis is performed by using a thermo-hydraulic code, i.e. RELAP-5, and a stochastic analysis tool currently under development at INL, i.e. RAVEN. Starting from the event tree models contained in SAPHIRE, we built the input file for RELAP-5 that models in great detail system dynamics under SBO conditions. We also interfaced RAVEN with RELAP-5 so that it would be possible to run multiple RELAP-5 simulation runs by changing specific keywords of the input file. We both employed classical statistical tools, i.e. Monte-Carlo, and more advanced machine learning based algorithms to perform uncertainty quantification in order to quantify changes in system performance and limitations as a consequence of power uprate. We also employed advanced data analysis and visualization tools that helped us to correlate simulation outcome such as maximum core temperature with a set of input uncertain parameters. Results obtained gave a detailed overview of the issues associated to power uprate for a SBO accident scenario. We were able to quantify how timing of safety related events were impacted by a higher reactor core power. Such insights can provide useful material to the decision makers to perform risk-infomed safety margins management.

  2. Feasibility Study of a Three-Stage Radioisotope-Powered Mars Ascent Vehicle

    Science.gov (United States)

    Chalpek, T. M.; Allen, R. E.; Guan, J. Y.; Rao, S. S.; Howe, S. D.

    Recent advancements in methods of housing radioisotopes at the Center for Space Nuclear Research have led to the concept of a radioisotope thermal rocket--a rocket powered by the accumulated heat of radioisotope decay. Heat energy from the decay can be accumulated over long periods of time in a material of high heat capacity to create a thermal capacitor. The capacitor can then be discharged at such a rate as to provide high power for short periods of time; in this case, the heat is transferred to a gas propellant. This paper explores the feasibility of using a radioisotope thermal rocket with in-situ atmospheric CO2 propellant to deliver a 10 kg payload from the Martian surface to a 200 km circular orbit about Mars. Models of heat transfer, gas dynamics, and ascent mechanics are constructed to test performance of different core materials and geometries. Of the configurations tested, the best simulation results fail to meet the altitude and velocity requirements by 12 km and 50 m/s respectively. The proximity to success indicates that the given models are capable of reaching orbital parameters if optimization algorithms and closed-loop guidance methods are employed. It is believed, however, that the current models underestimate expansion losses to the degree that if more realistic and computationally-intensive models are incorporated, the effect will definitively disprove the concept with currently available technology. Based on this preliminary research, radioisotope thermal rockets utilizing current technology are not capable of serving as Mars ascent vehicles.

  3. Mission from Mars

    DEFF Research Database (Denmark)

    Dindler, Christian; Eriksson, Eva; Iversen, Ole Sejer

    2005-01-01

    In this paper a particular design method is propagated as a supplement to existing descriptive approaches to current practice studies especially suitable for gathering requirements for the design of children's technology. The Mission from Mars method was applied during the design of an electronic...

  4. Mission from Mars:

    DEFF Research Database (Denmark)

    Dindler, Christian; Eriksson, Eva; Iversen, Ole Sejer

    2005-01-01

    In this paper a particular design method is propagated as a supplement to existing descriptive approaches to current practice studies especially suitable for gathering requirements for the design of children's technology. The Mission from Mars method was applied during the design of an electronic...

  5. Study on mixed convective flow penetration into subassembly from reactor hot plenum in FBRs

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, J.; Ohshima, H.; Kamide, H.; Ieda, Y. [Power Reactor and Nuclear Fuel Development Corporation, Ibaraki (Japan)

    1995-09-01

    Fundamental experiments using water were carried out in order to reveal the phenomenon of mixed convective flow penetration into subassemblies from a reactor`s upper plenum of fast breeder reactors. This phenomenon appears under a certain natural circulation conditions during the operation of the direct reactor auxiliary cooling system for decay heat removal and might influence the natural circulation head which determines the core flow rate and therefore affects the core coolability. In the experiment, a simplified model which simulates an upper plenum and a subassembly was used and the ultrasonic velocity profile monitor as well as thermocouples were applied for the simultaneous measurement of velocity and temperature distributions in the subassembly. From the measured data, empirical equations related to the penetration flow onset condition and the penetration depth were obtained using relevant parameters which were derived from dimensional analysis.

  6. Preliminary Study for Inventories of Minor Actinides in Thorium Molten Salt Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Choong Wie; Kim, Hee Reyoung [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2015-05-15

    It has different characteristic with the conventional reactors which use a solid fuel. It can continually supply the fuel by online refueling and reprocessing of minor actinides so that those can be separated and eliminated from the reactor. The MSR maintains steady state except initial stage and the reactor becomes stable. In this research, considering online refueling, bubbling and reprocessing, the basic concept for evaluation of the inventory of minor actinide in the molten salt reactor is driven using the Bateman equation. The simulation results, where REM and MCNP code from CNRS (Centre National de la Recherche Scientifique) applied to the concept equation are analyzed. The analysis of the basic concept was carried out for evaluation of the inventory of the minor actinides in MSR. It was thought that the inventories of the minor actinides should be evaluated by solving the modified Bateman equation due to the MSR characteristic of online refueling, chemical reprocessing and bubbling.

  7. A computational fluid dynamics study of hydrogen bubbles in an electrochemical reactor

    Directory of Open Access Journals (Sweden)

    Renata da Silva Cavalcanti

    2005-06-01

    Full Text Available Most electrochemical reactors present reactions with the growth and departure of gas bubbles which influence on the reactor hydrodynamics and this study is usually complex, representing a vast field for research. The present paper had as objective to study a bi-phase (gas-liquid system aiming to foresee the influence of departure of hydrogen bubbles generated on effective electrode surface situated on cathodic semi-cell. Nevertheless, it was idealized that the gas was injected into the semi cell, through the effective electrode surface With this hypothesis, it was possible to study, and numerically analyze, the hydrodynamic behavior of the hydrogen bubbles in the interior of the study domain, applying concepts of computational fluid dynamics by using the computational applicative CFX-4 for the application of the MUSIG ("MUltiple-SIze-Group" model, taking into consideration the phenomena of coalescence and the distribution of the diameter of the bubbles.A maioria dos reatores eletroquímicos apresenta reações com crescimento e desprendimento de bolhas de gás influenciando na hidrodinâmica dos reatores e seu estudo é, geralmente, complexo representando um campo amplo para pesquisas. O presente artigo teve por objetivo estudar um sistema bifásico (gás-líquido visando prever a influência do desprendimento das bolhas de hidrogênio geradas na superfície específica do eletrodo localizada na semicélula catódica. No entanto, foi idealizado que o gás fora injetado no interior da semicélula através da superfície específica do eletrodo. Com esta hipótese, foi possível estudar e analisar numericamente o comportamento hidrodinâmico das bolhas de hidrogênio no interior do domínio de estudo, aplicando-se os conceitos de fluidodinâmica computacional usando o aplicativo computacional CFX-4 para aplicação do modelo MUSIG ("Multiple-size-group" levando em consideração os fenômenos da coalescência e da distribuição do diâmetro das

  8. A controllability study of TRUMOX fuel for load following operations in a CANDU-900 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Trudell, D.A., E-mail: trudelda@mcmaster.ca [McMaster Univ., Hamilton, Ontario (Canada)

    2012-07-01

    Using a core model of a generic CANDU-900 reactor in RFSP-IST, load following simulations have been performed to assess the controllability of the reactor due to Xenon transients. Week long load following simulations have been performed with daily power cycles 12 hours in duration. Simulations have shown that Natural Uranium fuel can be safely cycled between 100 and 90% Full Power without adjuster rod movement while TRUMOX fuel can be safely cycled between 100 and 85% Full Power. (author)

  9. Feasibility Study of Supercritical Light Water Cooled Reactors for Electric Power Production

    Energy Technology Data Exchange (ETDEWEB)

    Philip MacDonald; Jacopo Buongiorno; James Sterbentz; Cliff Davis; Robert Witt; Gary Was; J. McKinley; S. Teysseyre; Luca Oriani; Vefa Kucukboyaci; Lawrence Conway; N. Jonsson: Bin Liu

    2005-02-13

    The supercritical water reactor (SCWR) has been the object of interest throughout the nuclear Generation IV community because of its high potential: a simple, direct cycle, compact configuration; elimination of many traditional LWR components, operation at coolant temperatures much higher than traditional LWRs and thus high thermal efficiency. It could be said that the SWR was viewed as the water counterpart to the high temperature gas reactor.

  10. Preliminary Design Study of Medium Sized Gas Cooled Fast Reactor with Natural Uranium as Fuel Cycle Input

    Science.gov (United States)

    Meriyanti, Su'ud, Zaki; Rijal, K.; Zuhair, Ferhat, A.; Sekimoto, H.

    2010-06-01

    In this study a fesibility design study of medium sized (1000 MWt) gas cooled fast reactors which can utilize natural uranium as fuel cycle input has been conducted. Gas Cooled Fast Reactor (GFR) is among six types of Generation IV Nuclear Power Plants. GFR with its hard neuron spectrum is superior for closed fuel cycle, and its ability to be operated in high temperature (850° C) makes various options of utilizations become possible. To obtain the capability of consuming natural uranium as fuel cycle input, modified CANDLE burn-up scheme[1-6] is adopted this GFR system by dividing the core into 10 parts of equal volume axially. Due to the limitation of thermal hydraulic aspects, the average power density of the proposed design is selected about 70 W/cc. As an optimization results, a design of 1000 MWt reactors which can be operated 10 years without refueling and fuel shuffling and just need natural uranium as fuel cycle input is discussed. The average discharge burn-up is about 280 GWd/ton HM. Enough margin for criticallity was obtained for this reactor.

  11. Study on the flow characteristics and the wastewater treatment performance in modified internal circulation reactor.

    Science.gov (United States)

    Wang, Jiade; Xu, Weijun; Yan, Jingjia; Yu, Jianming

    2014-12-01

    A modified internal circulation (MIC) reactor with an external circulation system was proposed and the performance of treating dyeing wastewater using both MIC and typical IC reactor were compared. Utilization of the external circulation system in the MIC reactor could dramatically improve the mixing intensity of the biomass with the wastewater and resulted in better performance. The COD removal efficiency, biogas production, volatile fatty acids and effluent color were approximately 87%, 98 L d−1, 180 mg L−1 and 100 times, respectively, in the MIC reactor with a hydraulic retention time of 5 h and organic loading rate of 15 kg COD m−3 d−1. The hydrodynamics of the MIC reactor under different flows rate of external circulation were also analyzed using computational fluid dynamics (CFD) method. The optimal flow rate of external circulation was 12 L min−1, which resulted in a corresponding up-flow velocity of 40 m h−1. The consistency of the result between experiment and simulation validated the scientificity of CFD technique applied to numerical simulation of the MIC reactor.

  12. Experimental study on temperature characteristics and energy conversion in packed bed reactor with dielectric barrier discharge

    Science.gov (United States)

    Li, Sen; Tang, Zuchen; Gu, Fan

    2010-10-01

    The temperature characteristics and energy conversion in packed bed reactor combined with a dielectric barrier discharge (DBD) plasma was investigated experimentally. The pellet temperatures of two types packed bed reactor, cylindrical reactor and parallel-plate reactor, was measured in conditions of various inlet voltage of DBD plasma. The relationship between pellet temperature of the packed bed and applied voltage of DBD plasma was discovered. The experimental result indicates a tendency that the pellet temperature of packed bed increases as the applied voltage of inlet plasma increases. When the voltage of inlet plasma is high enough, the pellet temperature increment decreases. Simultaneously,the packed bed temperature is sensitive to the inlet plasma energy and there is a potential application to heat exchanger. Moreover the proportion of energy consumption of plasma inputting into packed bed reactor was analyzed and calculated. The mechanisms that electrical energy of inlet plasma is transformed into heat energy in the two phases, gaseous and pellets of the packed bed reactor are different. The energy consumption in pellet phase is dielectric polarization loss and depends on packed bed geometry and DBD plasma etc. The energy consumption in gaseous phase is plasma sheath procedure. The important factors effecting on gas discharge are gaseous component and voltage, frequency of power.

  13. An ISRU Propellant Production System to Fully Fuel a Mars Ascent Vehicle

    Science.gov (United States)

    Kleinhenz, Julie; Paz, Aaron

    2017-01-01

    ISRU of Mars resources was base lined in 2009 Design Reference Architecture (DRA) 5.0, but only for Oxygen production using atmospheric CO2The Methane (LCH4) needed for ascent propulsion of the Mars Ascent Vehicle (MAV) would need to be brought from Earth. HOWEVER: Extracting water from the Martian Regolith enables the production of both Oxygen and Methane from Mars resources Water resources could also be used for other applications including: Life support, radiation shielding, plant growth, etc. Water extraction was not base lined in DRA5.0 due to perceived difficulties and complexity in processing regolith. The NASA Evolvable Mars Campaign (EMC) requested studies to look at the quantitative benefits and trades of using Mars water ISRU Phase 1: Examined architecture scenarios for regolith water retrieval. Completed October 2015Phase 2: Deep dive of one architecture concept to look at end-to-end system size, mass, power of a LCH4LO2 ISRU production system.Evolvable Mars CampaignPre-deployed Mars ascent vehicle (MAV)4 crew membersPropellants: Oxygen MethaneGenerate a system model to roll up mass power of a full ISRU system and enable parametric trade studies. Leverage models from previous studies and technology development programs Anchor with mass power performance from existing hardware. Whenever possible used reference-able (published) numbers for traceability.Modular approach to allow subsystem trades and parametric studies. Propellant mass needs taken from most recently published MAV study:Polsgrove, T. et al. (2015), AIAA2015-4416MAV engines operate at mixture ratios (oxygen: methane) between 3:1 and 3.5:1, whereas the Sabatier reactor produces at a 4:1 ratio. Therefore:Methane production is the driving requirement-Excess Oxygen will be produced.

  14. Characteristic Studies of Micron Zinc Particle Hydrolysis in a Fixed Bed Reactor

    Directory of Open Access Journals (Sweden)

    Lv Ming

    2015-09-01

    Full Text Available Zinc fuel is considered as a kind of promising energy sources for marine propeller. As one of the key steps for zinc marine energy power system, zinc hydrolysis process had been studied experimentally in a fixed bed reactor. In this study, we focus on the characteristics of micron zinc particle hydrolysis. The experimental results suggested that the steam inner diffusion is the controlling step of accumulative zinc particles hydrolysis reaction at a relative lower temperature and a relative higher water partial pressure. In other conditions, the chemical reaction kinetics was the controlling step. And two kinds of chemical reaction kinetics appeared in experiments: the surface reaction and the gas-gas reaction. The latter one occurs usually for larger zinc particles and high reaction temperature. Temperature seems to be one of the most important parameters for the dividing of different reaction mechanisms. Several parameters of the hydrolysis process including heating rate, water partial pressure, the particle size and temperature were also studied in this paper. Results show that the initial reaction temperature of zinc hydrolysis in fixed bed is about 410°C. And the initial reaction temperature increases as the heating rate increases and as the water partial pressure decreases. The total hydrogen yield increases as the heating rate decreases, as the water partial pressure increases, as the zinc particle size decreases, and as the reaction temperature increases. A hydrogen yield of more than 81.5% was obtained in the fixed bed experiments.

  15. Experimental studies and computational benchmark on heavy liquid metal natural circulation in a full height-scale test loop for small modular reactors

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Yong-Hoon, E-mail: chaotics@snu.ac.kr [Department of Energy Systems Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826 (Korea, Republic of); Cho, Jaehyun [Korea Atomic Energy Research Institute, 111 Daedeok-daero, 989 Beon-gil, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Lee, Jueun; Ju, Heejae; Sohn, Sungjune; Kim, Yeji; Noh, Hyunyub; Hwang, Il Soon [Department of Energy Systems Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826 (Korea, Republic of)

    2017-05-15

    Highlights: • Experimental studies on natural circulation for lead-bismuth eutectic were conducted. • Adiabatic wall boundaries conditions were established by compensating heat loss. • Computational benchmark with a system thermal-hydraulics code was performed. • Numerical simulation and experiment showed good agreement in mass flow rate. • An empirical relation was formulated for mass flow rate with experimental data. - Abstract: In order to test the enhanced safety of small lead-cooled fast reactors, lead-bismuth eutectic (LBE) natural circulation characteristics have been studied. We present results of experiments with LBE non-isothermal natural circulation in a full-height scale test loop, HELIOS (heavy eutectic liquid metal loop for integral test of operability and safety of PEACER), and the validation of a system thermal-hydraulics code. The experimental studies on LBE were conducted under steady state as a function of core power conditions from 9.8 kW to 33.6 kW. Local surface heaters on the main loop were activated and finely tuned by trial-and-error approach to make adiabatic wall boundary conditions. A thermal-hydraulic system code MARS-LBE was validated by using the well-defined benchmark data. It was found that the predictions were mostly in good agreement with the experimental data in terms of mass flow rate and temperature difference that were both within 7%, respectively. With experiment results, an empirical relation predicting mass flow rate at a non-isothermal, adiabatic condition in HELIOS was derived.

  16. Experimental and analytical study of stability characteristics of natural circulation boiling water reactors during startup transient

    Science.gov (United States)

    Woo, Kyoungsuk

    Two-phase natural circulation loops are unstable at low pressure operating conditions. New reactor design relying on natural circulation for both normal and abnormal core cooling is susceptible to different types of flow instabilities. In contrast to forced circulation boiling water reactor (BWR), natural circulation BWR is started up without recirculation pumps. The tall chimney placed on the top of the core makes the system susceptible to flashing during low pressure start-up. In addition, the considerable saturation temperature variation may induce complicated dynamic behavior driven by thermal non-equilibrium between the liquid and steam. The thermal-hydraulic problems in two-phase natural circulation systems at low pressure and low power conditions are investigated through experimental methods. Fuel heat conduction, neutron kinetics, flow kinematics, energetics and dynamics that govern the flow behavior at low pressure, are formulated. A dimensionless analysis is introduced to obtain governing dimensionless groups which are groundwork of the system scaling. Based on the robust scaling method and start-up procedures of a typical natural circulation BWR, the simulation strategies for the transient with and without void reactivity feedback is developed. Three different heat-up rates are applied to the transient simulations to study characteristics of the stability during the start-up. Reducing heat-up rate leads to increase in the period of flashing-induced density wave oscillation and decrease in the system pressurization rate. However, reducing the heat-up rate is unable to completely prevent flashing-induced oscillations. Five characteristic regions of stability are discovered at low pressure conditions. They are stable single-phase, flashing near the separator, intermittent oscillation, sinusoidal oscillation and low subcooling stable regions. Stability maps were acquired for system pressures ranging 100 kPa to 400 kPa. According to experimental investigation

  17. Comparing Simulation Results with Traditional PRA Model on a Boiling Water Reactor Station Blackout Case Study

    Energy Technology Data Exchange (ETDEWEB)

    Zhegang Ma; Diego Mandelli; Curtis Smith

    2011-07-01

    A previous study used RELAP and RAVEN to conduct a boiling water reactor station black-out (SBO) case study in a simulation based environment to show the capabilities of the risk-informed safety margin characterization methodology. This report compares the RELAP/RAVEN simulation results with traditional PRA model results. The RELAP/RAVEN simulation run results were reviewed for their input parameters and output results. The input parameters for each simulation run include various timing information such as diesel generator or offsite power recovery time, Safety Relief Valve stuck open time, High Pressure Core Injection or Reactor Core Isolation Cooling fail to run time, extended core cooling operation time, depressurization delay time, and firewater injection time. The output results include the maximum fuel clad temperature, the outcome, and the simulation end time. A traditional SBO PRA model in this report contains four event trees that are linked together with the transferring feature in SAPHIRE software. Unlike the usual Level 1 PRA quantification process in which only core damage sequences are quantified, this report quantifies all SBO sequences, whether they are core damage sequences or success (i.e., non core damage) sequences, in order to provide a full comparison with the simulation results. Three different approaches were used to solve event tree top events and quantify the SBO sequences: “W” process flag, default process flag without proper adjustment, and default process flag with adjustment to account for the success branch probabilities. Without post-processing, the first two approaches yield incorrect results with a total conditional probability greater than 1.0. The last approach accounts for the success branch probabilities and provides correct conditional sequence probabilities that are to be used for comparison. To better compare the results from the PRA model and the simulation runs, a simplified SBO event tree was developed with only four

  18. Studying the NE Eridania sedimentary sequence through the Mars 2020 rover

    Science.gov (United States)

    Pajola, M.; Carter, J.; Rossato, S.; Baratti, E.; Mangili, C.; Coradini, M.; McBride, K. S.

    2014-04-01

    The landing sites we are proposing for the next Mars 2020 rover span between 28°29'30"S-28°53'0"S Latitude and 178°56'30"W°178°28'0"W Longitude, i.e. on the NE floor of a 1.1×106 km2 closed drainage basin [1]. This area, see Fig. 1, belongs to the bigger (3×106 km2) Eridania basin that gave birth to the Ma'adim Vallis through catastrophic overflow, and presenting a water table between 950 and 1250 m [1,2,3]. The crater counting chronology for this area gives an age between Early to Middle Noachian [4]. By means of OMEGA [5] and CRISM [6] data, a large clay-bearing sedimentary unit has been identified over almost the entire margin of the Eridania basin [7]. On our specific site, i.e. the NE margin of the Eridania basin, sequences of aqueous minerals are observed. Such sedimentary minerals are accessible through erosional windows into the first several tens of meters of the sedimentary sequence. The top-down mineral sequence identified on the landing sites area presents an unaltered capping unit that is overlying an Al-rich clay stratum (see Fig. 2) akin to Al-smectite and/or kaolins with a 3.8 Ga) during which liquid water was durably stable at the surface. The most valuable candidates for ancient Martian microbial life sustainability and preservation are longlasting environments, characterized by the presence of ponding water [10,11,12]: hence, the proposed site presents a high exobiological potential that is just waiting to be unveiled. Besides that, when putting into context the future results on Eridania Basin, i.e. the Ma'adim Vallis source, together with those obtained from the Spirit rover inside Gusev Crater (see Fig. 1), i.e. the Ma'adim Vallis mouth, a wide understanding of this intriguing canyon and of the Mars megaflooding age is foreseen. Besides the above scientific analysis showing