Energy Technology Data Exchange (ETDEWEB)

The mass asymmetry of fragments from nuclear fission of heavy nuclei is reviewed. While mass asymmetry is a common and well-known phenomenon for low-energy fission of the lighter actinides, more recent experiments have demonstrated that, for the heaviest actinides, the mass distribution switches to a symmetric one. On the other hand, it has been discovered that, though for fissioning nuclei with mass numbers A< or [approx]225 the mass distribution is basically symmetric, an asymmetric component is clearly to be identified for nuclei down to the Pb-region. In the absence of a generally accepted dynamical theory of fission, the above experimental findings are discussed in terms of static energy considerations. Triggered from the outset by the structure of the potential energy surface at the saddlepoint, the energy balance at the scission point between the available energy (Q-value) ...

UK PubMed Central (United Kingdom)

SpoIIIE is an FtsK-related protein that transports the forespore chromosome across the Bacillus subtilis sporulation septum. We use membrane photobleaching and protoplast assays to...Full Text Available

International Nuclear Information System (INIS)

An integrated beam optics-nuclear processes framework is essential for accurate simulation of fragment separator beam dynamics. The code COSY INFINITY provides powerful differential algebraic methods for modeling and beam dynamics simulations in absence of beam-material interactions. However, these interactions are key for accurately simulating the dynamics of heavy ion fragmentation and fission. We have developed an extended version of the code that includes these interactions, and a set of new tools that allow efficient and accurate particle transport: by transfer map in vacuum and by Monte Carlo methods in materials. The new framework is presented, along with several examples from a preliminary layout of a fragment separator for a facility for rare isotope beams.

International Nuclear Information System (INIS)

... electrophoresis fission products gamma radiation gamma spectra half-life

British Library Electronic Table of Contents (United Kingdom)

In [W. Ye, F. Wu, H.W. Yang, Phys. Lett. B 647 (2007) 118] prescission protons and ? particles of high-isospin 206Pb were shown to be almost independent of the dissipation strength Formula Not Shown . Subsequently, in [P.N. Nadtochy, et al., Phys. Lett. B 685 (2010) 258] prescission light charged particles (LCPs) were shown to have approximately the same sensitivity as neutrons to Formula Not Shown for 206Pb and 204Hg nuclei. In this Letter we point out that the reason for the apparent contradictory conclusions is that the authors in the latter did not compute the changes in the absolute yields of prescission LCPs multiplicities with increasing Formula Not Shown and compare them with typical experimental uncertainties. It is shown that the expected changes are very small in the case of ne...

British Library Electronic Table of Contents (United Kingdom)

Correct prediction of the fission products inventory in irradiated nuclear fuels is essential for accurate estimation of fuel burnup, establishing proper requirements for spent fuel transportation and storage, materials accountability and nuclear forensics. Such prediction is impossible without accurate knowledge of neutron induced fission yields. The uncertainty of the fission yields reported in the ENDF/B-VII.0 library is not uniform across all of the data and much of the improvement is desired for certain fissioning isotopes and fission products. We discuss our measurements of cumulative fission yields in nuclear fuels irradiated in thermal and fast reactor spectra using Inductively Coupled Plasma Mass Spectrometry.

Energy Technology Data Exchange (ETDEWEB)

Careful measurements do not confirm an anomalous anisotropy in the angular distribution of fission fragments from the fast neutron fission of Americium 242. The energy range covered was 1.60-3.15 MeV. (AIP)

UK PubMed Central (United Kingdom)

We explored transcriptional responses of the fission yeast Schizosaccharomyces pombe to various environmental stresses. DNA microarrays were used to characterize changes in expression...Full Text Available

International Nuclear Information System (INIS)

Published in summary form only.

International Nuclear Information System (INIS)

Muon captures by nucleon pairs via meson-exchange currents produce a high energy excitation tail in heavy nuclei. The muon induced fission by these excitations is calculated in several subactinide nuclei with high threshold fission barriers. The probability for delayed fission ranges from 4 x 10"-"5 to 4 x 10"-"3 for the isotopes considered. (orig.).

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared

Energy Technology Data Exchange (ETDEWEB)

Published in summary form only.

Energy Technology Data Exchange (ETDEWEB)

The mass and charge distributions in an unseparated mix of fission product nuclei from thermal-neutron fission of /sup 242m/Am were studied through semiconductor gamma-ray spectrometry. Samples of the fissionable material under study were irradiated in a vertical irradiation tube of the MIFI IRT research reactor. Following irradiation, measurements were made on aperture-calibrated semiconductor detectors. For broader identification of fission fragment nuclides three experiments were conducted that differed substantially in irradiation duration. The spectrum of gamma radiation from the mix of fission products and the time dependences of count rate at total absorption peaks were analyzed on SM-4 and Iskra-226 computers. The values of yields obtained were compared with data of investigations conducted earlier with other experimental methods, and also with the results of calculations.

CERN Document Server

Dynamic system identification

Energy Technology Data Exchange (ETDEWEB)

Mass distribution in 28.5 MeV alpha particle induced fission of {sup 232}Th has been determined using gamma spectrometric technique. The chain yields of 24 different fission products covering both symmetric and asymmetric mass divisions were determined. The mass distribution was found to be asymmetric with peak positions at mass numbers 96 and 136 respectively while the peak to valley ratio was 3.86. The results are compared with the available literature on 14 MeV neutron induced fission of {sup 235}U. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The deexcitation of quasi-projectiles (QP) released in binary Au on Au collisions as been studied from 60 to 100 MeV/u. Bimodality between two different decay patterns has been observed for intermediate violence collisions. The main experimental result is that the system jumps from one mode to the other on a narrow range of energy deposit and/or impact parameter. The sorting of the events (according to the violence of the collision) has been provided by the perpendicular energy of the light charged particles emitted on the quasi-target side. Such a sorting prevents spurious autocorrelation effects between the sorting variable and the observed mechanism. The two modes of the QP decay correspond on the one side to residue or fission fragments production, and on the other side to the multifragmentation channel. A detailed study has been performed in order to try to establish the origin of the observed bimodality in disentangling dynamical or ...

Science.gov (United States)

The calculated radioactive waste inventories of the Turkey Point pressurized water fission reactor (PWR) and the Starfire conceptual fusion tokamak are compared as a function of time from initial start-up to 10,000 years after decommissioning. Only materi...

Energy Technology Data Exchange (ETDEWEB)

An unexpectedly high probability of collisions between the fission particles and the atoms in an ionization chamber along the entire particle track causes a strong fluctuation of the shapes of the Bragg curves. This fluctuation imposes an upper limit of the charge resolution ..delta..Z/Z which can be achieved.

International Nuclear Information System (INIS)

The fission fragments from spontaneous fission of 252Cf have been measured with the spectrometric and position-sensitive semiconductor pixel detector Medipix2. Fragments are identified by pattern recognition of clusters generated in the Medipix2 pixel matrix sensor upon heavy particle hit. From analysis of cluster area, the distribution of kinetic energy of fission fragments is obtained. Together with a novel USB readout interface, the Medipix2/USB system operates as active nuclear emulsion in single-quantum and on-line tracking mode.

International Nuclear Information System (INIS)

... compilation fission products j codes mixed oxide fuels neutron reactions

Energy Technology Data Exchange (ETDEWEB)

Absolute fission rate measurements using modified National Bureau of Standards fission chambers were performed in the Fast Flux Test Facility at two core locations for isotopic deposits of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu. Monitor chamber results at a third location were analyzed to support other experiments involving passive dosimeter fission rate determinations.

Energy Technology Data Exchange (ETDEWEB)

The emission of light charged particles from heavy fragments of uranium fission induced by 153-MeV protons is studied. The probability of their emission is 2.7 x 10{sup - 2} per fission event. It is found that these particles affect the distribution of angles of fragment divergence and the angular distribution of heavy fragments with respect to the primary-proton beam. Experimental results suggest that the preequilibrium emission of particles is correlated with fission. Two mechanisms of interaction between 153-MeV protons and uranium nuclei are considered. 13 refs., 10 figs., 1 tab.

International Nuclear Information System (INIS)

The fission gas xenon bonded in bubbles, in pore, and in the lattice of mixed carbide fuels is measured by electron-probe microanalysis. Radial xenon distribution and release curves are determined and are calibrated by gas chromatography of the bonded fission gas and by burnup analysis in the respective pin sections of the irradiation experiments FR2 6A and 6C, Mol 11/K 2, and DFR 330/1. The results are correlated to the microstructure of the fuel, bonding medium, temperature, and burnup. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

The most important aim of the title program is to investigate the possibility to convert long-lived actinides and mobile fission products in short-lived and stable isotopes by means of nuclear transmutation and recycling. First, an overview is given of the present situation regarding fission material waste, the origin of such waste in light water reactors and the options for interim and ultimate storage. Next, attention is paid to the aim of the the RAS program, the working method and the results so far of national and international research on the transmutation of actinides and fission products. Speculative expectations for the future are briefly outlined. The report also contains four appendices with technical aspects of the title subject: the RAS program of ECN, chemical aspects of reprocessing fission material, transmutation in fission reactors and in accelerators. 12 figs., 7 ...

Science.gov (United States)

Analysis of ENSO Dynamics and ThermoDynamics in the Western Pacific Warm Pool - An Application of Multi-Sensor Satellite Observations. ...

International Nuclear Information System (INIS)

Short-lived fission gas release from fuel pellets during irradiation was investigated based on the experimental results of the gas-flow rigs irradiated in the Halden Heavy Water Reactor (HBWR). The release-to-birth (R/B) rates of short-lived fission gas were measured by means of gas-flow measurement during the irradiation experiments. Surface-to-volume (S/V) ratios of fuel pellets and diffusion coefficients of short-lived fission gas release were evaluated from the obtained (R/B) values. The increase of (S/V) ratio agreed well with the point where the fuel temperature exceeded the threshold of 1% fission gas release. This indicates that the interlinkage of fission gas bubbles occurred there. The evaluated diffusion coefficients scattered in the range between 10"-"2"3 and 10"-"1"7 m"2/s, and the effects of fuel type (UO_2 or MOX) were not clearly observed. In addition, it is likely ...

International Nuclear Information System (INIS)

Full text of publication follows: Understanding the dynamic irradiation effects on silica glasses is important for developing the diagnostic systems used in fusion and fission environments. While fundamental defects having an un-pared electron such as the E' center have been extensively studied, the neutral oxygen deficiency defects have been insufficiently clarified for lack of the detection methods. The ion induced luminescence is one of the probes that can be used to detect non-paramagnetic defects, and to observe creation and annihilation behavior dynamically. In the present study, we examined the characteristics of the ion induced luminescence such as energy, fluence flux and temperature dependence of the luminescence efficiency to analyze damage process quantitatively. Samples of SiO2 glasses were commercially available fused and synthesized silica glasses, produced by Toshiba Ceramics, Co. Ltd.. A thin films of SiO2 ...

Energy Technology Data Exchange (ETDEWEB)

The objective of this report is to review the different technologies for trapping the gaseous wastes containing Cs, Ru, Tc, {sup 14}C, Kr, Xe, I and {sup 3}H from a voloxidation process. Based on literature reviews and KAERI's experimental results on the gaseous fission products trapping, appropriate trapping method for each fission product has been selected considering process reliability, simplicity, decontamination factor, availability, and disposal. Specifically, the most promising trapping method for each fission product has been proposed for the development of the INL off-gas trapping system. A fly ash filter is proposed as a trapping media for a cesium trapping unit. In addition, a calcium filter is proposed as a trapping media for ruthenium, technetium, and {sup 14}C trapping unit. In case of I trapping unit, AgX is proposed. For Kr and Xe, adsorption on solid is proposed. SDBC (Styrene Divinyl Benzene ...

International Nuclear Information System (INIS)

The fission cross section of /SUP 242m/ Am has been measured from 0.005 eV to 20 MeV using time-of-flight techniques at the Oak Ridge Electron Linear Accelerator. A hemispherical plate fission ionization chamber with five pairs of plates contained three deposits totaling 507 #mu#g of /SUP 242m/ Am, one deposit of 168 #mu#g "2"3"5U, and a ''weightless'' deposit of "2"5"2Cf, which served as a monitor of chamber performance. The fission of "2"3"5U, served as the cross-section standard for energies above 101 keV while "6Li(n,#alpha#), normalized to "2"3"5U fission in the 7.8- to 11.0-eV interval, served as a shape standard below 101 keV. Approximately 360 h of data were obtained at a flight path distance of 9.1 m, primarily with 40-ns bursts. Particular attention was paid to correction of backgrounds, especially inscattered-neutron-induced events. The fission resonance integral was ...

Energy Technology Data Exchange (ETDEWEB)

Delayed-neutron (DN) energy spectra following thermal neutron induced fission of /sup 239/Pu as a function of time after fission have been measured, using the beta-neutron time-of-flight (TOF) spectrometer at the University of Lowell. Thermal/epithermal neutrons were produced on the 5.5-MV Van de Graaff accelerator using the /sup 7/Li(p,n)/sup 7/Be reaction. Time spectra over the neutron energy range of 0.01-4.0 MeV were measured for seven different time intervals after fission, each interval containing varying contributions from the six delayed neutrons groups. The DN energy spectra following induced thermal fission of /sup 239/Pu are compared to those resulting from induced thermal fission of /sup 235/U for each of the seven delay time intervals. Decomposition of the measured spectra into six-group DN spectra was accomplished employing an iterative least-squares method, ...

Energy Technology Data Exchange (ETDEWEB)

The uranium target of a gas jet transport system for fission products has been modified by the addition of an aluminum cover foil. The new modification allows fission fragments of low mass to enter a continuous chemistry system while heavier fragments are stopped in the aluminum. The elimination of the heavier homologues allows development of simpler and faster chemical separation procedures. In addition, since the lighter fragments are slowed down by the cover foil a smaller target chamber can be used. This leads to a reduction in system holdup time.

International Nuclear Information System (INIS)

Based on the single-particle levels given by Nilsson, the intrinsic and effective (with collective effects) level density parameters as a function of the excitation energy for the "1"8"6Os, "1'8"7Ir, "1"8"9Os and "1"9"3Au deformation nuclei have been calculated in the range of the excitation energy up to 150 MeV. The calculated fission probabilities P_f (U) are consistent satisfactorily with the experimental data when a nonadiabatic estimation of the collective effects was used to calculated the nuclear level density parameters.

International Nuclear Information System (INIS)

This paper analyzes fission neutron multiplicity for the /sup 242m/Am(n,f) reaction. The fission neutron multiplicity, v bar, of /sup 242m/Am(n,f) was measured relative to that of /sup 235/U(n,f) using the neutron time-of-flight facility at the Lawrence Livermore National Laboratory 100-MeV electron Linac. A comparison of the measured energy dependence of v-bar is made with semi-empirical models of neutron emission from the actinides. 22 refs.

International Nuclear Information System (INIS)

The isotopic composition of Pd, Ag, Cd and Te has been measured by solid source mass spectrometry for four samples from reactor zones 2, 3-4, 5-6 and 7, and from four host rock samples external to the reactor zones from the Oklo mine site. The concentrations of these elements have also been determined in the eight samples using the stable isotope dilution technique. Cumulative fission yields have been derived from the reactor zone samples after correcting where necessary for the terrestrial component of the element concerned. It has been shown that fission-produced Pd and Te are retained almost in their entirety in the uraninite reactor zone samples, whereas a significant fraction of fission-produced Ag and Cd have migrated from the reactor zones. Fission product Cd is observed in the host rock samples, whereas no strong evidence of fission-produced Ag could be found. This the ...

Energy Technology Data Exchange (ETDEWEB)

The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of /sup 233/U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW m/sup -2/, and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are unusually rapid.

Energy Technology Data Exchange (ETDEWEB)

Mass distributions of fragments in the low-energy fission of nuclei from {sup 187}Ir to {sup 213}At have been analysed. This analysis has shown that shell effects in symmetric-mode fragment mass yields from the fission of pre-actinide nuclei could be described if one assumes the existence of two strongly deformed neutron shells in the arising fragments with neutron numbers N{sub 1}{approx}52 and N{sub 2}{approx}68. A new method has been proposed for quantitatively describing the mass distributions of the symmetric fission mode for pre-actinides with A{approx}180-220. (orig.) 28 refs.

Energy Technology Data Exchange (ETDEWEB)

The neutron-induced fission cross-section of {sup 233}U has been measured at the CERN n-TOF facility relative to the standard fission cross-section of {sup 235}U between 0.5 and 20MeV. The experiment was performed with a fast ionization chamber for the detection of the fission fragments and to discriminate against {alpha} -particles from the natural radioactivity of the samples. The high instantaneous flux and the low background of the n-TOF facility result in data with uncertainties of {approx} 3%, which were found in good agreement with previous experiments. The high quality of the present results allows to improve the evaluation of the {sup 233}U (n,f) cross-section and, consequently, the design of energy systems based on the Th/U cycle. (orig.)

International Nuclear Information System (INIS)

Neutron cross sections for Pu-239 and Am-241, -242m, -243 have been analyzed with the aid of theoretical models. A deformed optical potential that fits total, elastic and inelastic differential cross section data and neutron strength functions for Pu-239 and Am-241 have been used. In case of Pu-239 the consistency of absolute fission data and (n, 2n) cross section is investigated. Because of the strong discrepancies in Am fission cross section data a consistent set of calculated cross section values for the chain of Am nuclei is proposed. The present state of knowledge concerning first chance fission cross section allows to analyze fission cross section data of Am-241, -242m, -243, up to 20 MeV. The results thus obtained are compared with ENDF/B-V and JENDL-3 libraries. (orig.).

International Nuclear Information System (INIS)

The "1"2C induced fission of "2"0"9Bi at particle energy of 84.2 MeV has been studied using gamma ray spectrometry. The cross sections for the production of fission products have been determined. The charge distribution has also been studied and the relative fractional cumulative yields of "9"2Y, "9"7Zr, "9"9Mo, "1"0"1Mo, "1"0"5Rh, "1"1"2Pd and "1"1"7"mCd determined. The yield distribution of fission products has been found to be broad (FWHM #approx =# 18) with a peak near mass #approx =# 105. (author). 7 refs., 2 tabs.

Energy Technology Data Exchange (ETDEWEB)

Of some interest is the comparison between the actinide nuclide burning up (fission) rates such as americium 241, americium 242, curium 244, and neptunium 237, in the reactors with fast or thermal neutron spectra.

Energy Technology Data Exchange (ETDEWEB)

The /sup 252/Cf-source-driven noise analysis method determines the subcriticality of a system containing fissionable material from the ratio of cross power spectral densities between the detectors that detect particles from the fission process and between these detectors and an ionization chamber containing a spontaneously fissioning neutron source which provides neutrons to induce fission in the system. This method has two advantages: (1) a calibration is not required and thus subcriticality can be determined from measurements only on the subcritical system of interest, and (2) the subcriticality is independent of the type of detector or its efficiency. These properties of this technique are illustrated by measurements.

International Nuclear Information System (INIS)

We consider particle evaporation and fission of an ensemble of hot, rotating compound nuclei as a stochastic process. We derive a set of coupled differential equations formed by a Fokker-Planck equation describing fission, and master equations for calculating particle evaporation. From these equations, we are able to determine multiplicities of prefission neutrons, protons and #alpha#-particles, their energy spectra and their angular momentum distributions. A comparison of our results with experimental data provides us with information regarding the reduced friction coefficient #beta#, the fission barrier height and the level density parameter. For different iridium isotopes, ("1"8"1","1"8"5","1"8"7Ir), "1"8"5Os and "1"5"8Er, we obtain as an upper limit #beta##<=#8.0x10"2"1 s"-"1. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Presented are results of a test of a method for measuring neutron fluences using detectors with fissionable nuclides. The investigations show the soundness of of using neutron-activation detectors of the type Am for mesurements in nuclear installations for values of thermal-neutron fluence of from 10/sup 13/ to 10/sup 20/ neutrons/cm/sup 2/ with exposure for up to several months. The proposed method can be used for prolonged measurements in strong fields of both thermal and fast neutrons.

Energy Technology Data Exchange (ETDEWEB)

A review of fission product yields and delayed neutron data for Np-237, Pu-242, Am-242m, Am-243, Cm-243 and Cm-245 has been undertaken. Gaps in understanding and inconsistencies in existing data were identified and priority areas for further experimental, theoretical and evaluation investigation detailed. (author)

Science.gov (United States)

Recent radiochemical investigations of the PWR reactor coolant have corfirmed earlier observations that the level of activities of 33 m Cs/sup 138/, 2.8 hr Kr , and 8.1 day 1/sup 131/ are more than ten times higher than those predicted for the estimated U contamination of the Zircaloy cladding. The present fission product activity levels have not, as yet, presented any problems in the PWR. (W.L.H.)

Energy Technology Data Exchange (ETDEWEB)

The mass-energy spectra of the fragments of thermal fission of {sup 242m}Am are measured using the time-of-flight technique. The resulting mass-yield curve and peak-to-valley ratio agree with radiochemical data. The parameters of the kinetic energy distribution of the fragments are determined for the first time. Data on the fine structure of mass spectra in the region of cold fragmentation are presented. 15 refs., 4 figs.

Energy Technology Data Exchange (ETDEWEB)

Prompt neutron spectra for Am isotopes ({sup 241}Am, {sup 242m}Am, {sup 243}Am) were calculated on the basis of a modified version of the Madland-Nix model combined with multimodal fission model. The predicted spectra were found to be in fair agreement with recent data. (author)

Energy Technology Data Exchange (ETDEWEB)

In the investigations reported here, a helium-jet/tape-transport system was used for the rapid transfer of fission products to a low-background environment where their aggregate beta and gamma-ray spectra were measured as a function of delay time after neutron induced fission of {sup 235}U, {sup 238}U and {sup 239}Pu. Beta and gamma-ray energy distributions have been deduced for delay times as short as 0.2 s and extending out to 100,000s. Instrumentation development during the initial phase of the project included: (1) assembly and characterization of a NaI(Tl) spectrometer for determining aggregate gamma-ray energy distributions, (2) development and characterization of a beta spectrometer (having excellent gamma-ray rejection) for measuring aggregate beta-particle energy distributions, (3) assembly and characterization of a Compton-suppressed HPGe spectrometer for determining gamma-ray intensities of individual fission ...

International Nuclear Information System (INIS)

Measurements of gamma-ray spectra, following the thermal neutron fission of "2"3"5U have been made using a high purity germanium detector at the University of Massachusetts Lowell (UML) Van de Graaff facility. The gamma spectra were measured at delay times ranging from 0.2 s to nearly 10000 s following the rapid transfer of the fission fragments with a helium-jet system. On the basis of the known gamma transitions, forty isotopes have been identified and studied. By measuring the relative intensities of these transitions, the relative yields of the various precursor nuclides have been calculated. The results are compared with the recommended values listed in the ENDF/B-VI fission product data base (for the lifetimes and the relative yields) and those published in the Nuclear Data Sheets (for the beta branching ratios). This information is particularly useful for the cases of short-lived fission products ...

Energy Technology Data Exchange (ETDEWEB)

Attention was focused on the fission process in light nuclear systems. A model calculation based on the transition-state model of nuclear fission was applied to [sup 47]V fission as populated through multiple entrance channels and to fusion-fission cross sections for production of [sup 28]Al through three different entrance channels. Angular distributions are shown for different mass channels of the [sup 29]Si+[sup 27]Al reaction at E[sub lab] = 125 MeV. Pronounced structure is seen in the symmetric and near-symmetric fission channels from the [sup 24]Mg+[sup 24]Mg reaction; cross sections for binary fragment emission are shown for E[sub lab] = 90 MeV. A large Bragg-curve detector was used in this experiment. Ways to optimize detector response were studied; in addition, the Bragg detector was instrumented with an internal position-sensitive multiwire proportional counter.

Energy Technology Data Exchange (ETDEWEB)

Oxygen-16 induced fission studies of [sup 209]Bi have been carried out at particle energies of 89.5 MeV using gamma ray spectrometry. The cross sections for the production of fission products have been determined. The yield distribution of fission products has been found to be broad (FWHM [approx equal] mass units) with a peak near mass [approx equal] 108. The charge distribution in the [sup 16]O ion induced fission of [sup 209]Bi has also been studied at particle energy of 89.5 MeV. The relative cumulative yields of [sup 92]Sr, [sup 97]Zr, [sup 99]Mo, [sup 101]Mo, [sup 112]Pd and [sup 117m]Cd have been determined using gamma ray spectrometry. The width of charge distribution has been found to be broad. (orig.)

International Nuclear Information System (INIS)

The "1"6O induced fission studies of "2"0"9Bi have been carried out at particle energies of 89.5 MeV using gamma ray spectrometry. The cross sections for the production of fission products have been determined. The yield distribution of fission products has been found to be broad (FWHM=16) with a peak near mass 107. The charge distribution in the "1"6O particle induced fission of "2"0"9Bi has been studied at "1"6O particle of 89.5 MeV. The fractional cumulative yields of "9"2Y, "9"7Zr, "9"9Mo, "1"0"1Mo, "1"0"5Rh, "1"1"2Pd and "1"1"7"mCd have been determined using gamma ray spectrometry. (author). 7 refs., 2 tabs.

International Nuclear Information System (INIS)

Fusion energy has been studied in many countries such as U.S., France, Japan, Korea etc. Because it would provide much more energy for a given weight of fuel than any technology currently in use, and the fuel itself (primarily deuterium) exists abundantly in the Earth's ocean. Nuclear fusion reactor uses tritium and deuterium as fuel while nuclear fission reactor uses uranium and plutonium as fuel. Besides, inherent design characteristics and driving condition of nuclear fusion reactor is different from those of nuclear fission reactor. Therefore, we cannot apply the regulation rules of nuclear fission reactor to nuclear fusion reactor without change and thus it is needed to development of the safety regulation concept which reflects the characteristics of nuclear fusion reactor. Safety regulation of nuclear fusion reactor employs deterministic approach until sufficient data are secured. However, regulation methodology of ...

International Nuclear Information System (INIS)

The super simulator 'SAMPSON' has been developed to show that there exist certain safety margins for light water reactors under hypothetical severe accidents and to investigate realistic measures of accident management by simulating accidents with a parallel computer. Heat-up of fuel rods and release of fission products from fuels are important factors to evaluate source terms. Models for fuel rod heat-up, hydrogen production due to cladding oxidation and cladding deformation and failure in the core region have been developed in the fuel rod heat-up analysis module. Fuel temperatures were calculated by solving the heat conduction equation. The calculated results for fuel temperature and hydrogen production were compared with CORA-13 experiment results. The comparisons showed prediction capability for the heat-up of fuel rods. The fission product release analysis module incorporates with models for fission product transport ...

DEFF Research Database (Denmark)

Udgivelsesdato: 2008

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

This report contains the study on the dynamic characteristics of Wolsung fuel rod and on the dynamic balancing of rotating machinery to evaluate the performance of nuclear reactor components. The study on the dynamic characteristics of Wolsung fuel rod wa...

International Nuclear Information System (INIS)

This is the second revision of the ETDE/INIS Joint Thesaurus, including all updates up to September 2006. It contains 21 147 valid descriptors and 9 114 forbidden terms. The Joint Thesaurus contains the controlled terminology for indexing all information within the subject scopes of the International Nuclear Information System (INIS) and the Energy Technology Data Exchange (ETDE). The terminology is intended for use in subject descriptions for input or retrieval of information in these systems. The thesaurus is a terminological control device used in translating from the natural language of documents, indexers or users into a more constrained system language It is also a controlled and dynamic vocabulary of semantically and generically related terms which covers a specific domain of knowledge. The basic terminology in this thesaurus goes back to the 1969 edition of the EURATOM Thesaurus. The structure subsequently given to that terminology was the result of a ...

International Nuclear Information System (INIS)

Fuel rod failures produce a release of fission products into primary coolant system. Since nuclear power plants have licensing limits for the release of volatile fission products to the environment (off-gas limits) detailed monitoring of the development of clad failure is necessary. In case of fuel rod failure a release of fission products into the primary coolant system arises. Fission gases accumulated in the free volume of a fuel rod escape through the clad defect. Water entering the fuel rod reacts with fission products, forming volatile chemical compounds. These may escape in a similar manner into the fission gases. Other compounds may dissolve and may be carried outside the fuel rod as dissolved species. Consequently, the distribution of these fission products, in the cross section of the fuel rod, is modified. An implementation of the ...

CERN Document Server

We present a description of nuclear spontaneous fission, and generally of quantum tunneling, in terms of instantons - periodic imaginary-time solutions to time-dependent mean-field equations - that allows for a comparison with more familiar and used generator coordinate (GCM) and adiabatic time-dependent Hartree-Fock (ATDHF) methods. It is shown that the action functional whose value for the instanton is the quasiclassical estimate of the decay exponent fulfils the minimum principle when additional constraints are imposed on trial fission paths. In analogy with mechanics, these are conditions of energy conservation and the velocity-momentum relations. In the adiabatic limit the instanton method reduces to the time-odd ATDHF equation, with collective mass including the time-odd Thouless-Valatin term, while the GCM mass completely ignores velocity-momentum relations. This implies that GCM inertia generally overestimates instanton-related decay ...

Energy Technology Data Exchange (ETDEWEB)

Making use of a back-to-back type double fission chamber and a lead slowing-down spectrometer driven by a 46 MeV electron linear accelerator, the fission cross sections of Am-241, Am-242m and Am-243 have been measured relative to that of U-235 from 0.1 eV to 10 keV with the energy resolution of about 40 % full width at half maximum. Each of the measured result has been compared with (1) the evaluated nuclear data in ENDF/B-VI and JENDL-3.2, and (2) the existing experimental data, whose evaluated and measured data were broadened by the energy resolution function of the spectrometer.

International Nuclear Information System (INIS)

One measured fission and fusion cross sections of "4","6He+"2"0"9Bi and "7Li+"2"0"8Pb reactions within the range from the Coulomb barrier up to 200 MeV. The measured functions of fission and fusion for the mentioned reactions are shown to have close values within the excitation energy wide range. One analyzed the excitation functions of fusion and fission for "4He+"2"0"9Bi, "6He+"2"0"9Bi and "7Li+"2"0"8Pb reactions resulting in formation of "2"1"3","2"1"5At compound systems

International Nuclear Information System (INIS)

The alpha particle induced fission of "2"0"9Bi has been investigated for E_#alpha# = 55.7 and 58.6 MeV using gamma ray spectrometry. The cross sections for the production of fission products have been determined. The mass distributions have been found to be broad with a peak near mass 104. The charge distribution has been studied at the same particle energies. The fractional cumulative yields of "9"7Zr, "9"9Mo, "1"0"1Mo, "1"1"2Pd and "1"1"7"mCd have been determined using gamma ray spectrometry. The width of charge distribution is broad. (orig.).

UK PubMed Central (United Kingdom)

Tropomyosin (Tm) is a conserved dimeric coiled-coil protein, which forms polymers that curl around actin filaments in order to regulate actomyosin function. Acetylation of the Tm N-terminal...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This paper describes a functional slide rule that provides a readily usable ?in-hand? method for estimating nuclear criticality accident information from sliding graphs, thereby permitting (1) the rapid estimation of pertinent criticality accident information without laborious or sophisticated calculations in a nuclear criticality emergency situation, (2) the appraisal of potential fission yields and external personnel radiation exposures for facility safety analyses, and (3) a technical basis for emergency preparedness and training programs at nonreactor nuclear facilities. The slide rule permits the estimation of neutron and gamma dose rates and integrated doses based upon estimated fission yields, distance from the fission source, and time-after criticality accidents for five different critical systems. Another sliding graph permits the estimation of critical solution fission yields based upon ...

Energy Technology Data Exchange (ETDEWEB)

This report discusses the following topics: Fusion-fission in light nuclear systems; High-resolution Q-value measurement for the {sup 24}Mg+{sup 24}Mg reaction; Heavy-ion reactions and limits to fusion; and Hybrid MWPC-Bragg curve detector development.

International Nuclear Information System (INIS)

Processes and apparatus are disclosed for generation of radioisotope contaminant fission fragment free ozone from oxygen containing streams by chemonuclear irradiation accomplished by passing the stream past high energy radiation sources placed in sealed chambers.

Energy Technology Data Exchange (ETDEWEB)

Yields of light fission products (A = 68, 70-84, 87, 88, 94, 96, 98, 102 and 106-108), their kinetic energies and nuclear charge distributions (A 71-84, 87 and 88) in the thermal neutron induced fission of the odd-Z nucleus {sup 242m}Am(Z = 95) were measured using the mass-separator Lohengrin at the Institute Laue-Langevin in Grenoble (France). The mass yield curve shows a fine structure at A = 70, probably due to shell and/or odd-even effects affecting also the nuclear charge distribution. The analysis of isotopic chain yields gives evidence for a very low excitation energy of the lightest fission fragments observed. A preferential formation of fragments with even Z is found for this odd-Z compound nucleus. Calculated values for the local odd-even effect are comparable with those for the neighbouring even-Z fissile nuclides and increase from 13% to 30% with increasing asymmetry of the mass split (A{sub L} = 84 to 68 and ...

UK PubMed Central (United Kingdom)

On agar plates, daughter cells of Escherichia coli mutually slide and align side-by-side in parallel during the first round of binary fission. This phenomenon has been previously attributed...Full Text Available

International Nuclear Information System (INIS)

The Fast Flux Test Facility (FFTF) features a three-loop, sodium-cooled 400 MWt mixed oxide fueled reactor designed for the irradiation testing of fuels and materials for use in liquid metal cooled fast reactors. To establish the ultimate capability of a particular fuel design and thereby generate information that will lead to improvements, many of the fuel irradiations are continued until a loss of cladding integrity (failure) occurs. When the cladding fails, fission gas escapes from the fuel pin and enters the reactor cover gas system. If the cladding failure permits the primary sodium to come in contact with the fuel, recoil fission products can enter the sodium. The presence of recoil fission products in the sodium can be detected by monitoring for the presence of delayed neutrons in the coolant. It is the present philosophy to not operate FFTF when a failure has occurred that permits fission ...

UK PubMed Central (United Kingdom)

Recent studies have indicated that the DNA replication machinery is coupled to silencing of mating-type loci in the budding yeast Saccharomyces cerevisiae, and a similar silencing mechanism...Full Text Available

International Nuclear Information System (INIS)

Solving a coupled set of differential equations formed by a Fokker-Planck equation and a set of master equations, we can calculate the number of 'prefission' particles (n,p,a), which are emitted from a hot, rotating compound nucleus. Furthermore we get their energy spectrum and their angular momentum distribution. Our results depend sensitively on the friction parameter #gamma#, the inertia M and the fission potential. Comparing the results with experimental data, we may learn something about these quantities. The investigations have been made for "1"8"7Ir and "1"8"5Os. (orig.).

Science.gov (United States)

The total half-life and the half-life for spontaneous fission are evaluated for the various long-lived nuclides of interest. Recommended values are presented for /sup 241/Am, /sup 242m/Am, /sup 243/Am, /sup 242/Cm, /sup 243/Cm, /sup 244/Cm, /sup 245/Cm, /sup 246/Cm, /sup 247/Cm, /sup 248/Cm, and /sup 250/Cm. The uncertainties are provided at the 95% confidence limit for each of the recommended values.

Energy Technology Data Exchange (ETDEWEB)

Measurements of the half-lives of some long-lived nuclides of elements Z = 92, 94, 95 and 96 have been compiled and evaluated. Recommended values are presented for {sup 232-236,238}U, for {sup 236,238-242,244}Pu, for {sup 241,242m,243}Am, and for {sup 242-248,250}Cm. Values are presented for both spontaneous fission half-life and total half-life. Problems with reported uncertainties are also discussed. (author).

Energy Technology Data Exchange (ETDEWEB)

Measurements were made of the cross section for /sup 242/Am/sup m/ fission induced by neutrons in the energy range 0.04< or =E/sub n/< or =4.52 MeV as well as by neutrons with E/sub n/roughly-equal14.8 MeV. An electrostatic generator and a low-voltage accelerating tube were used to generate the quasimonochromatic neutrons. Measurements in the low-energy region were made by using the time-of-flight technique in neutrons from a nuclear explosion. Results of the measurements are compared with previously published data.

Science.gov (United States)

Major contributions during this contract period have been in developing an analytical procedure for Pu measurement, and in applying the developed procedures to determining the plutonium concentration and distribution in coral from the Bikini Atoll. In conjunction with these contributions, measurements using the fission-track method have been made of the uranium distribution and concentrations in several carbonate samples from drill cores obtained from the Runit Island Enewetak Atoll. Petrographic studies on these drill core samples have been made to correlate the uranium data with the mineralogical data. (auth)

Energy Technology Data Exchange (ETDEWEB)

The experience base regarding fission product behavior developed during the Rover program, the nuclear rocket development program of 1955--1972, will be useful in planning a renewed nuclear rocket program. During the Rover program, 20 reactors were tested at the Nuclear Rocket Development Station in Nevada. Nineteen of these discharged effluent directly into the atmosphere; the last reactor tested, a non-flight-prototypic, fuel-element-testing reactor called the Nuclear Furnace (NF-1) was connected to an effluent cleanup system that removed fission products before the hydrogen coolant (propellant) was discharged to the atmosphere. In general, we are able to increase both test duration and fuel temperature during the test series. Therefore fission product data from the later part of the program are more interesting and more applicable to future reactors. We have collected fission product retention (and ...

Energy Technology Data Exchange (ETDEWEB)

A study of the electron beam dynamics in the linac is conducted for the FERMI free electron laser (FEL) founded for construction at the Sincrotrone Trieste

UK PubMed Central (United Kingdom)

In this paper, we suggest that perception could be modeled by assuming that sensory input is generated by a hierarchy of attractors in a dynamic system. We describe a mathematical model which exploits...Full Text Available

UK PubMed Central (United Kingdom)

Fungal and oomycete populations and their dynamics were investigated following the introduction of the biocontrol agent Pythium oligandrum into the rhizosphere of tomato plants grown...Full Text Available

UK PubMed Central (United Kingdom)

Dynamic clamp is a powerful method that allows the introduction of artificial electrical components into target cells to simulate ionic conductances and synaptic inputs. This method is based...Full Text Available

Science.gov (United States)

... of the cycle shows that the separation area ea. ... with suitable flow solvers based on the Reynolds ... AGARD 75th Fluid Dynamics Panel Meeting and ...

International Nuclear Information System (INIS)

Description of program or function: Format: ENDFB-6 format; Nuclides: Th-232, U-233, U-234, U-235, U-236, U-238, Np-237, Np-238, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Am-241, Am-242, Am-243, Cm-243, Cm-244, Cm-245, and from the spontaneous fission of Cm-242, Cm-244, and Cf-252. Origin: New evaluation (Crouch 1, 2, 3, 4; UKFY1; JEF-1). A new evaluation of fission product yields from the thermal, fast, and 14 MeV neutron-induced fission of the following nuclides has been prepared in ENDFB-VI format: "2"3"2Th, "2"3"3U, "2"3"4U, "2"3"5U, "2"3"6U, "2"3"8U, "2"3"7Np, "2"3"8Np, "2"3"8Pu, "2"3"9Pu, "2"4"0Pu, "2"4"1Pu, "2"4"2Pu, "2"4"1Am, "2"4"2"mAm, "2"4"3Am, "2"4"3Cm, "2"4"4Cm, "2"4"5Cm; and from the spontaneous fission of "2"4"2Cm, "2"4"4Cm, and "2"5"2Cf

International Nuclear Information System (INIS)

The neutron data required to completely analyze fission reactors includes many isotopes and covers a broad energy range. In both fast and thermal reactors, the neutron inventory is a fine balance determined by the fission properties of "2"3"5U, "2"3"9Pu and "2"3"8U and by the capture cross sections of "2"3"8U, fuel materials, structural materials and coolant materials. In fast reactors, the spectrum of neutrons ranges from 1 keV to 3 MeV and is influenced by the elastic and inelastic scattering properties of "2"3"8U and the structural and coolant materials. For neutron shielding applications, the important neutron data include the total cross sections of structural and coolant materials in the MeV range. The impact of these basic nuclear data in fission reactor applications is most suitably described by sensitivity analysis. For example, sensitivity coefficients computed for a typical large plutonium fueled fast reactor ...

Science.gov (United States)

S.M. Goltz; NASA Goddard Space Flight Center, Forest Ecosystem Dynamics Project ...

KoreaScience (Korea)

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International Nuclear Information System (INIS)

... Netherlands Kormendy, J. Dominion Astrophysical Observatory, Victoria, British

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

No abstract prepared

Norwegian Open Research Archives (NORA)

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Indian Institute of Science Theses & Dissertations (India)

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KoreaScience (Korea)

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KoreaScience (Korea)

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Science.gov (United States)

Three aspects of the physical geographic environment of the Amazon Basin are considered: (1)

KoreaScience (Korea)

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CERN Document Server

In the present paper we prove moderate deviations for a Curie-Weiss model with external magnetic field generated by a dynamical system, as introduced by Dombry and Guillotin-Plantard. The results extend those already obtained in the case of a constant external field by Eichelsbacher and L\\"owe. The Curie-Weiss model with dynamic external field is related to the so called dynamic Z-random walks. We also prove a moderate deviation result for the dynamic Z-random walk, completing the list of limit theorems for this object.

International Nuclear Information System (INIS)

High temperature thermochemistry of thoria-urania fuel for Advanced Heavy Water Reactor was investigated. Oxygen potential development within the matrix and distribution behaviors of the fission products (fps) in different phases were worked out with the help of thermodynamic and transport properties of the fps as well as fission generated oxygen and the detailed balance of the elements. Some of the necessary data for different properties were generated in this laboratory while others were taken from literatures. Noting the behavior of poor transports of gases and volatile species in the thoria rich fuel (thoria-3 mol% urania), the evaluation shows that the fuel will generally bear higher oxygen potential right from early stage of burnup, and Mo will play vital role to buffer the potential through the formation of its oxygen rich chemical states. The problems related to the poor transport and larger retention of fission ...

Energy Technology Data Exchange (ETDEWEB)

The Oklo natural fossil fission reactors in Gabon, Equatorial Africa, have been studied as a natural analogue for spent nuclear fuel in a geological environment. For these studies, it is important to know what has happened to these reactors since they formed. This review is focussed on existing geological and geochronological information concerning the Oklo reactors and the surrounding ore. A sequence of geological and geochemical events in the Oklo area, as described in the literature, is given. The data and the studies behind this established geochronology are discussed and evaluated. Of the regional geology, special attention is given to the dating of the Francevillian sediments, and the intrusion of a dolerite dyke swarm. The processes that led to the mineralisation at Oklo, the subsequent formation of the nuclear reactors and later migration of fission products are described. Further discussion concerns the studies of the dolerite dyke ...

International Nuclear Information System (INIS)

The "2"3"3U(n, f) cross-section has been measured at n_TOF in a wide energy range with a dedicated fission ionization chamber. We report here the results from 0.30 meV to 1 MeV neutron energy. The "2"3"3U(n, f) cross-section has been determined relative to a reference sample of "2"3"5U(n, f) measured simultaneously with the same detector. The very high instantaneous neutron flux and the intrinsically low background of the n TOF installation result in an accuracy around 3% in the whole energy range, while the energy resolution of the neutron beam allows for an accurate description of the fission cross-section by means of R-matrix analysis over a wide energy range. The present data provide the basis for a more precise evaluation of the "2"3"3U fission cross-section, and for improving the reliability of databases needed for the design of new energy systems based on the Th/U cycle. (Author)

International Nuclear Information System (INIS)

The Fast Flux Test Facility (FFTF) is a liquid-metal-cooled test reactor located on the Hanford site. A dual computer system has been developed to monitor the reactor cover gas to detect and characterize any fuel or test pin fission gas releases. The system acquires gamma spectra data, identifies isotopes, calculates specific isotope and overall cover gas activity, presents control room alarms and displays, and records and prints data and analysis reports. The fission gas monitor system makes extensive use of commercially available hardware and software, providing a reliable and easily maintained system. The design provides extensive automation of previous manual operations, reducing the need for operator training and minimizing the potential for operator error. The dual nature of the system allows one monitor to be taken out of service for periodic tests or maintenance without interrupting the overall system functions. A built-in calibrated ...

Energy Technology Data Exchange (ETDEWEB)

A generic reactor model is used to examine the economic viability of electricity generation by magnetic fusion. The simple model uses components which are representative of those used in previous reactor studies of deuterium-tritium burning tokamaks, stellarators, bumpy tori, reverse field pinches and tandem mirrors. Conservative costing assumptions are made. The generic reactor is not a tokamak but rather it is intended to emphasize what is common to all magnetic fusion reactors. The reactor uses a superconducting toroidal coil set to produce the dominant magnetic field. To this extent it is a less good approximation to systems, such as the reversed field pinch in which the main field is produced by a plasma current. The main output of the study is the cost of electricity as a function of the weight and size of the fusion core - blanket, shield, structure and coils. The model shows that a 1200 MW/sub e/ power plant with a fusion core weight of about 10,000 tonnes should be competitive ...

Energy Technology Data Exchange (ETDEWEB)

Based on preliminary studies, some conclusions can be drawn concerning the Accelerator Fuel Enricher and Fission Product Exterminator (APEX). APEX-1 and APEX-2 systems can destroy TU's, /sup 137/Cs, and /sup 90/Sr at acceptable cost and efficiency. The principal difference between APEX-1 and APEX-2 is the in-reactor and in-circuit inventory of /sup 137/Cs and /sup 90/Sr. Stable and low hazard wastes can be disposed of by burial. Accelerator breeders can effectively sustain a fission reactor economy indefinitely. Military waste can be blended into commercial fuel cycle for transmutation. Accelerator and target technologies appear practical and could be developed in a few years. More detailed studies are needed to better define the technical and economic features of the LAFER and APEX cycles, so that comparative assessments can be made between these cycles, as well as with other transmutation and waste disposal concepts.

Energy Technology Data Exchange (ETDEWEB)

Producing nuclear energy in order to reduce anthropic CO{sub 2} emission and to meet high energy demand, implies three conditions to the nuclear plants of the IV. generation: safety improvements, radioactive waste minimization, and fuel breeding for a sustainable use of the resources. The Thorium fuel cycle used in Molten Salt Reactors seems promising. Many numerical studies based on probabilistic codes are carried out in order to analyse the behaviour of such reactors. Nevertheless, one of the most important parameters is badly known: the alpha ratio of {sup 233}U, ratio of the neutron capture cross section to fission one for {sup 233}U. This key-parameter is necessary to calculate the breeding ratio and thus, the deployment capacities of those reactors. This Ph-D thesis was intended to prepare a precise measurement of the alpha ratio of {sup 233}U between 1 eV and 10 keV. Preliminary measurements have been performed on the experimental platform PEREN. This ...

International Nuclear Information System (INIS)

Measurements of the half-lives of some long-lived nuclides of elements Z = 92, 94, 95 and 96 have been compiled and evaluated. Recommended values are presented for "2"3"2"-"2"3"6","2"3"8U, for "2"3"6","2"3"8"-"2"4"2","2"4"4Pu, for "2"4"1","2"4"2"m","2"4"3Am, and for "2"4"2"-"2"4"8","2"5"0Cm. Values are presented for both spontaneous fission half-life and total half-life. Problems with reported uncertainties are also discussed. (author).

Energy Technology Data Exchange (ETDEWEB)

In addition to the ability to solve the static transport equation, we have also incorporated time dependence into our parallel 3-D S{sub {ital N}} code DANTSYS/MPI. Using a semi-implicit scheme, DANTSYS/MPI is capable of performing time-dependent calculations for both fissioning and pure source driven problems. We have applied this to various types of problems such as nuclear well logging and prompt fission experiments. This paper describes the form of the time- dependent equations implemented, their solution strategies in DANTSYS/MPI including iteration acceleration, and the strategies used for time-step control. Results are presented for a model nuclear well logging calculation.

Energy Technology Data Exchange (ETDEWEB)

Data and functions of the cell burnup calculation of the SRAC system were revised to improve mainly the accuracy of the burnup calculation of high conversion light water reactors (HCLWRs). New burnup chain models were developed in order to treat fission products (FPs) and actinide nuclides in detail. Group cross section library, SRACLIB-JENDL2, was generated based on JENDL-2 nuclear data file. In generating this library, emphasis was placed on FPs and actinides. Also revised were the data such as the average energy release per fission for various actinides. These improved data were verified by performing the burnup analysis of PWR spent fuels. Some new functions were added to the SRAC system for the convenience to yield macroscopic cross sections used in the core burnup process. (author).

International Nuclear Information System (INIS)

Preparations are under way for the initial startup and testing of the Fast Flux Test Facility (FFTF). The FFTF Reactor Characterization Program is that part of the startup test plan that deals with the determination of the neutron, gamma ray and thermal hydraulic characteristics of the reactor. This program encompasses measurements and calculations of: neutron spectra, flux and fluence; gamma-ray spectra, dose and heating; fission rate distributions; capture rate distributions; other reaction rates of interest; fission product yields; and thermal hydraulic data. Measurements of these parameters will be made in the reactor core and reflectors, will extend vertically downward to the vicinity of the core support structure and upward to the top of the sodium pool, and will extend radially outward to include in-vessel fuel storage locations and the cavity between the reactor vessel and the concrete wall.

Energy Technology Data Exchange (ETDEWEB)

Geometrical shapes and diameter of nuclear tracks changes continuously during the process of etching for various incident angles. Besides, there is also a marked difference amongst their profiles, as evidenced by the SEM analysis, when the incoming particles fall on the detector at different angles of incidence. This work outlines this aspect of fission fragment tracks in a glass detector and has set out a few empirical relationships between the mean track diameter, d-bar and the etching time, t, within experimental limits. This study, therefore, sheds some light in the follow up the origins and characteristics of heavy ions in some terrestrial and extra-terrestrial materials and also in studying the collimation accuracy of heavy ion bombardments. The implications of the results in discerning the measurements of incident angles of various types of ions are described in detail in the paper.

Energy Technology Data Exchange (ETDEWEB)

By using a charge-sensitive preamplifier and methods of energy spectroscopy we investigated the response of a parallel plate avalanche counter in order to scan the Bragg curve. The detector was operated in butane, pentane and heptane which also served as stopping gases. In this paper, we report on results obtained with fission fragments from a /sup 252/Cf source. We achieved a separation of the light and heavy fragment groups in the interval of gas absorber thickness from about 500 ..mu..g cm/sup 2/ to 1.5 mg cm/sup 2/. The best energy loss resolution was achieved with pentane at E/papprox.=70 V cm/sup 1/ Torr/sup 1/ resulting in delta..delta..E/..delta..Eapprox.=13%. The corresponding shape of the ..delta..E spectrum reproduces correctly the nuclear charge distribution of the fragments. (orig.).

British Library Electronic Table of Contents (United Kingdom)

Synchronized cultures of the green alga Scenedesmus quadricauda were grown in the absence (untreated cultures) or in the presence (FdUrd-treated cultures) of 5-fluorodeoxyuridine, the specific inhibitor of nuclear DNA replication. The attainment of commitment points, at which the cells become committed to nuclear DNA replication, mitosis and cellular division, and the course of committed processes themselves were determined for cell cycle characterization. FdUrd-treated cultures showed nearly unaffected growth and attainment of the commitment points, while DNA replication(s), nuclear division(s) and protoplast fission(s) were blocked. Interestingly, the FdUrd-treated cells possessed a very high mitotic histone H1 kinase activity in the absence of any nuclear division(s). Compared with the ...

Science.gov (United States)

A mass spectrometric determination was made of the Sr/sup 88/ and Sr/sup 90/ yieldd from Pu/sup 239/ irradiated by an integral flux of 2.7 x 10/sup 20/ nvt of slow neutrons. (R.V.J.)

Energy Technology Data Exchange (ETDEWEB)

Information is presented concerning new trends in licensing; seismic considerations and system structural behavior; TMI-2 risk assessment and thermal hydraulics; statistical assessment of potential accidents and verification of computational methods; issues with respect to improved safety; human factors in nuclear power plant operation; diagnostics and activities in support of recovery; LOCA transient analysis; unresolved safety issues and other safety considerations; and fission product transport.

Energy Technology Data Exchange (ETDEWEB)

Independent isomeric yield ratios of {sup 131}Te, {sup 133}Te and {sup 134}I have been determined at five different energies in the range of 25-44 MeV alpha particle induced fission of {sup 238}U using radiochemical and gamma spectrometric techniques. From the independent isomeric yield ratios, fragment angular momenta (J{sub rms}) have been deduced using a statistical model analysis. The J{sub rms} were also calculated theoretically based on thermal equilibration of various collective modes after considering the occurrence of multichance fission. These data and the literature data for various fragments in the mass region 126-136 in {sup 238}U ({alpha},f), {sup 238}U (p,f) and {sup 238}U ({gamma},f) show the following important features: (i) Both the entrance channel excitation energy and input angular momentum affect the fragment angular momentum in the exit channel. (ii) There are two groups of fission products from the ...

Energy Technology Data Exchange (ETDEWEB)

This report discusses the following topics: Fusion-fission in light nuclear systems; High-resolution Q-value measurement for the {sup 24}Mg+{sup 24}Mg reaction; Heavy-ion reactions and limits to fusion; and Hybrid MWPC-Bragg curve detector development.

Energy Technology Data Exchange (ETDEWEB)

Modern particle accelerators offer new opportunities to dramatically reshape the way we think about nuclear energy, and challenge some of the thorniest problems linked to its industrial use, e.g. nuclear waste. A powerful proton accelerator driving a sub-critical fission reactor could be used for producing energy more safely and burning up the extra spent fuel which so far has been stored in geological repositories.

International Nuclear Information System (INIS)

The possibility of separation in plasma-mass-separator POMS-E-3 spent nuclear fuel (SNF) in 3 fractions: transuranic elements, and two groups of fission products. New scheme of compact energy-mass analyzer for monitoring the separation process spent nuclear fuel in the POMS-E- 3 offered.

Energy Technology Data Exchange (ETDEWEB)

Numerical errors of PALLAS calculation due to spatial mesh sizes are examined for a typical deep penetration shielding problem of isotropic incident fission neutrons penetrating a 200-cm-thick water slab. The exponential approximation for the source spatial distribution to solve the transport equation based on the direct integration method is verified to be effective for radiation transport in attenuating medium, while the linear approximation employed in the old PALLAS code is found to produce large errors for calculations with large mesh sizes.

Energy Technology Data Exchange (ETDEWEB)

This report discusses the following topics: Prompt fission neutron energy spectra for {sup 235}U and {sup 239}Pu; Two-parameter measurement of nuclear lifetimes; ``Black`` neutron detector; Data reduction techniques for neutron scattering experiments; Inelastic neutron scattering studies in {sup 197}Au; Elastic and inelastic scattering studies in {sup 239}Pu; and neutron induced defects in silicon dioxide MOS structures.

Energy Technology Data Exchange (ETDEWEB)

This paper continues, with respect to the transplutonium nuclides, earlier efforts to collate and evaluate data from the scientific literature on the prompt neutron multiplicity distribution from fission and its first moment = ..sigma..nuPnu. The isotopes considered here for which P/sub nu/ and or data (or both) were found in the literature are of americium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), fermium (Fm), and nobelium (No).

UK PubMed Central (United Kingdom)

1. A cell-free system, prepared from Pseudomonas N.C.I.B. 9340 grown on 4-chloro-2-methylphenoxyacetate (MCPA) was shown to catalyse the reaction sequence: 5-chloro-3-methylcatechol...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Using Gammasphere data on prompt gamma rays from spontaneous fission of 252Cf, we propose energy-level schemes for 110,111,112, & 113Rh (Z=45). The fission-gamma data complement earlier studies of others on beta decay of fission products in that prompt fission gammas mainly populate yrast or near-yrast levels, while beta decay populates lower-spin levels. For the odd-A rhodium nuclei studied here, their ground bands and collective sidebands are compared with model calculations using triaxial-shaped nucleus with one odd quasi-proton. The energies and E2 transition rates are best fit by a shape slightly to the prolate side of maximum triaxiality, namely, gamma = 28 deg. The model calculations also show a K=1/2+ band with energies not in good agreement with a corresponding experimental band. The experimental 1/2+ band is regarded as an intruder band from a prolate-driving proton orbital 1/2[431] above ...

Energy Technology Data Exchange (ETDEWEB)

This report provides key information on the irradiation environment of the MONJU fuel tests MFA-1 and MFA-2 in the Fast Flux Test Facility (FFTF). This information includes the fission powers, neutron fluxes, sodium temperatures and sodium flow rates in MFA-I, MFA-2 and adjacent assemblies. It also includes MFA-1 and MFA-2 compositions as a function of exposure. The work was performed at the request of Power Reactor and Nuclear Fuels Corporation (PNC) of Japan.

International Nuclear Information System (INIS)

The "2"3"3U(n,f) cross section has been measured at the white neutron source n_TOF in a wide energy range with a dedicated fission ionization chamber. We report here the results from #approx#30 meV to 1 MeV neutron energy. The "2"3"3U(n,f) cross section has been determined relative to a reference sample of "2"3"5U(n,f) measured simultaneously with the same detector. The very high instantaneous neutron flux and the intrinsically low background of the n_TOF installation result in an accuracy around 3% in the whole energy range, while the energy resolution of the neutron beam allows for an accurate description of the fission cross section by means of R-matrix analysis over a wide energy range. The results are, in general, in good agreement with the most recent high-accuracy measurement of this fission cross section, over the more limited range of the previous measurements, and indicated that even the latest evaluations ...

International Nuclear Information System (INIS)

This paper presents the results obtained in the gamma scanning of two fuel pins from the bent subassembly of the fast breeder test reactor (FBTR) using a segmented gamma scanning system employing segment correlation developed for the assay of glove box solid waste. In addition to the actinide profiles, the paper also discusses the fission products and clad activation product profiles and tries to correlate the experimental values of the latter with computed values. (author). 4 refs., 1 fig., 1 tab.

International Nuclear Information System (INIS)

Source term release characteristics are analyzed for the severe SGTR (Steam Generator Tube Rupture) sequences beyond the design basis accidents in Wolsong 2/3/4 plants which are of CANDU6 type reactor. In PWRs, SGTR sequences have long been recognized to be important and are distinctly different from the non-bypass sequences since there is a direct fission product release path from the primary system to the environment bypassing the containment gas volume. Meanwhile, a SGTR in a CANDU reactor is analyzed not to provide a complete and direct path into the environment for the source term resulting from a severe accident. This is because the majority of the fission product released arises from heatup and interactions of the disassembled fuel channel segments and debris in the calandria tank rather than from fuel heatup in the fuel channel. These fission products are released from the calandria tank into the containment ...

International Nuclear Information System (INIS)

The cross section for the reaction "8"8Sr(n,p)"8"8Rb was found to be (0.0155 +- 0.0017) mb. This value corresponds well with those calculated by Roy, Hawton, Calamand, and Nasyrov. (author).

International Nuclear Information System (INIS)

Results on defect structure study and degree of molybdenum radiation hardening irradiated by fission neutrons and medium energy alpha-particles are presented. It is shown that molybdenum irradiation by alpha-particles and neutrons leads to different degree of material hardening for the same damage level. It is established that molybdenum radiation hardening is mainly defined by radiation defect clusters visible in electron microscope whose coefficient of rigidity depends on their size. 5 refs.; 6 figs.; 2 tabs. (author).

International Nuclear Information System (INIS)

This paper describes a long term course of research into the fundamentals of two phase flow regime dynamics that had lead to a differential description of regime properties. The development has included experiment, microscale simulation, and mathematical averaging to produce a dynamic equation for interfacial area.

UK PubMed Central (United Kingdom)

AbstractWe combined atomistic molecular-dynamics simulations with quantum-mechanical calculations to investigate the sequence dependence of the stretching behavior of duplex DNA. Our...Full Text Available

UK PubMed Central (United Kingdom)

Reliable characterization of locomotor dynamics of human walking is vital to understanding the neuromuscular control of human locomotion and disease diagnosis. However, the inherent oscillation and...Full Text Available

UK PubMed Central (United Kingdom)

Combined QM(PM3)/MM molecular dynamics simulations together with QM(DFT)/MM optimizations for key configurations have been performed to elucidate the enzymatic catalysis mechanism on the detoxification...Full Text Available

UK PubMed Central (United Kingdom)

Specific criteria have been developed based on computerized dynamic posturography (CDP) to assist clinicians in identifying patients with psychogenic balance problems (Cyr and Cevette, Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The aim of this project was to develop an understanding of the dynamical processes that evolve within an electric utility firm, and without it. This volume covers organizational dynamics and control, and planning under uncertainty. (DLC)

UK PubMed Central (United Kingdom)

Understanding the dynamics of porcine reproductive and respiratory syndrome virus (PRRSV) vertical transmission is important to enhance the accuracy of monitoring protocols for endemically infected...Full Text Available

UK PubMed Central (United Kingdom)

In order to maintain stable functionality in the face of continually changing input, neurones in the CNS must dynamically modulate their electrical characteristics. It has been hypothesized that in...Full Text Available

Science.gov (United States)

... 4.4+9 4.30 ds~ ;'* Page 24. Table 3 Ultimate Compressive Strength Data Static Dynamic Round Strength Range Strength Range No. Avg Rise 0No. ...

UK PubMed Central (United Kingdom)

SummaryWe develop a new class of models, dynamic conditionally linear mixed models, for longitudinal data by decomposing the within-subject covariance matrix using a special Cholesky...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This book contains over 20 selections. Some of the titles are: Continuum damage mechanics studies on the dynamic fracture of concrete; Dynamic compressive strength of cementitious materials; Rate-sensitivity of mode I and mode II fracture concrete; and An impact damage model of concrete.

UK PubMed Central (United Kingdom)

The realization theory linear dynamical systems, previously developed over a field, are extended to a large class of commutative rings. The principal result is that the existence criterion for a finite...Full Text Available

Science.gov (United States)

... Tunable semiconductor lasers are essential components for links employing optical frequency modulation (OFM) for enhanced dynamic range or ...

Science.gov (United States)

Wikileaks was inevitable. The Dynamics of. Information. Take advantage of the eddy currents. You can't step in the same river ...

Science.gov (United States)

... Dynamics Panel Executive AGARD 7 rue ... 4 AXIAL FLOW IN CORNERS AT SUPERSONIC ... AND HYPERSONIC FLOWS INCLUDING SEPARATION ...

British Library Electronic Table of Contents (United Kingdom)

This article presents a decentralized control scheme for the complex problem of simultaneous position and internal force control in cooperative multiple manipulator systems. The proposed controller is composed of a sliding mode control term and a force robustifying term to simultaneously control the payloads position/orientation as well as the internal forces induced in the system. This is accomplished independently of the manipulators dynamics. Unlike most controllers that do not require prior knowledge of the manipulators dynamics, the suggested controller does not use fuzzy logic inferencing and is computationally inexpensive. Using a Lyapunov stability approach, the controller is proven to be robust in the face of varying systems dynamics. The payloads position/orientation and the inte...

Energy Technology Data Exchange (ETDEWEB)

The microstructures of magnesium AZ31 are examined following hot compression testing and annealing. The grain size, fraction dynamically recrystallized and, in a couple of cases, the crystallographic texture are reported. It was found that the progress of dynamic recrystallization is strongly sensitive to processing conditions but that the dynamically recrystallized grain size was less sensitive to stress than in other metals. It was also found that, for structures containing between 80 and 95% dynamic recrystallization, abnormal grain growth occurs during annealing. The crystallographic texture produced is also sensitive to the deformation conditions. (orig.)

KoreaScience (Korea)

Full Text Available

CERN Document Server

Full-Potential Electronic Structure Method

DEFF Research Database (Denmark)

Udgivelsesdato: 2008-Sep

Science.gov (United States)

... measurement. Power spectral density measurements are made by the dynamic signal analyzer for each channel. A cross power ...

Science.gov (United States)

Page 1. Adaptive system and method for responding to computer network security attacks Abstract A dynamic network security ...

Energy Technology Data Exchange (ETDEWEB)

We propose a continuum description for the axial separation of granular materials in a long rotating drum. The model, operating with two local variables, concentration difference and the dynamic angle of repose, describes both initial transient traveling wave dynamics and long-term segregation of the binary mixture. Segregation proceeds through ultraslow logarithmic coarsening. {copyright} {ital 1999} {ital The American Physical Society}

International Nuclear Information System (INIS)

Dynamical models are presented that start with interstellar gas in an initial diffuse state and consider their gravitational collapse and the formation of dense cores. Frozen-in tangled magnetic fields are included to mimic forces that might oppose gravitational contraction and whose effectiveness may increase with increasing core densities. Results suggest the possibility that dense cloud cores may be dynamically evolving ephemeral objects, such that their lifespan at a given core density decreases as that density increases. 66 refs.

Energy Technology Data Exchange (ETDEWEB)

The mainly nonstationary operation of a solar-heated receiver can be simulated with sufficient accuracy only if data about the dynamic behavior are available. For this reason, the dynamic behavior of a solar cavity receiver with parabolic dish collector is investigated. The development of a mathematical simulation considering heat transfer and storage processes is presented and the procedure for a numerical solution is illustrated. The performance of the calculation method is finally demonstrated by simulating the passage of a cloud.

International Nuclear Information System (INIS)

This paper discusses the concept of controllable subspace for open quantum dynamical systems. It is constructively demonstrated that combining structural features of decoherence-free subspaces with the ability to perform open-loop coherent control on open quantum systems will allow decoherence-free subspaces to be controllable. This is in contrast to the observation that open quantum dynamical systems are not open-loop controllable. To a certain extent, this paper gives an alternative control theoretical interpretation on why decoherence-free subspaces can be useful for quantum computation.

CERN Document Server

After two decades of direct dynamical simulation of large-scale structure in the universe, it is safe to say the subject is now mature. Still, there are parts of the problem that are less well developed than others. In general, the collisionless dynamics of the dark matter component is better understood than the collisional gas dynamics of the baryonic component. In situations where the gas dynamics is relatively simple, such as the Lyman-$\\alpha$ forest and the intracluster medium in X-ray clusters, our ability to reproduce observational data has evolved rapidly, and the interpretive and predictive power of such experiments should now be taken seriously. A comparison of twelve gas dynamic codes to the problem of forming a single X-ray cluster shows that numerical inaccuracies are modest (typically below ten percent), leaving missing physics as the main source for large systematic ...

Energy Technology Data Exchange (ETDEWEB)

We consider the dynamics towards the initial singularity of Bianchi type IX vacuum and orthogonal perfect fluid models with a linear equation of state. Surprisingly few facts are known about the 'Mixmaster' dynamics of these models, while at the same time most of the commonly held beliefs are rather vague. In this paper, we use Mixmaster facts as a base to build an infrastructure that makes it possible to sharpen the main Mixmaster beliefs. We formulate explicit conjectures concerning (i) the past asymptotic states of type IX solutions and (ii) the relevance of the Mixmaster/Kasner map for generic past asymptotic dynamics. The evidence for the conjectures is based on a study of the stochastic properties of this map in conjunction with dynamical systems techniques. We use a dynamical systems formulation, since this approach has so far been the only successful path ...

Energy Technology Data Exchange (ETDEWEB)

The fully energy-damped yields from the {sup 35}Cl + {sup 12}C reaction have been systematically investigated using particle-particle coincidence techniques at a {sup 35}Cl bombarding energy of {approx} 8 MeV/nucleon. The fragment-fragment correlation data show that the majority of events arises from a binary-decay process with rather large numbers of secondary light-charged particles emitted from the two excited exit fragments. No evidence is observed for ternary breakup events. The binary-process results of the present measurement, along with those of earlier, inclusive experimental data obtained at several lower bombarding energies are compared with predictions of two different kinds of statistical model calculations. The methods give comparable predictions and are both in good agreement with the experimental results thus confirming the fusion-fission origin of the fully-damped yields. (author). 39 refs. Submitted to Physical Review, C (US).

International Nuclear Information System (INIS)

The Accelerator Transmutation Waste System is under development at the Los Alamos National Laboratory. The goal is to perform an independent verification of the feasibility of actinide and long-lived fission product burning in this system. The authors' work is divided into five tasks: (a) production of an actinide and long-lived fission product cross section library from JEF 2.2; (b) simulation using MCNP and KENO IV Monte Carlo codes, of the Accelerator Transmutation Waste System configurations existing in literature; (c) validation of HETC Monte Carlo code (production of spallation source); (d) validation of the cross sections by comparison of Keff and reaction rate results, calculated with MNCP and KENO IV, with experimental benchmarks and intercomparison between the authors' calculations of a PWR unit cell and the computations carried out with various codes and cross section libraries (NEACRP critically group data); and (e) simulation of ...

International Nuclear Information System (INIS)

In the framework of nuclear waste transmutation studies, the Mini-INCA project has been initiated at CEA/DSM with objectives to determine optimal conditions for transmutation and incineration of minor actinides (MA) in high intensity neutron fluxes. Our experimental tools based on alpha- and gamma-spectroscopy of the samples and the development of micro fission chambers could gather either microscopic information on nuclear reactions (total or partial cross sections for neutron capture and/or fission reactions) or macroscopic information on transmutation and incineration potentials. Neutron capture cross sections of selected actinides ("2"4"1Am, "2"4"2Am, "2"4"2Pu, "2"3"7Np) have already been measured at ILL, showing some discrepancies when compared to evaluated data libraries but in overall good agreement with recent data. The studies and possibilities offer by the MEGAPIE project to assess neutronic performances of a 1 MW spallation target ...

Energy Technology Data Exchange (ETDEWEB)

The behaviour of tetracycline as an extracting agent for Sr, I, Ba, Mo, Tc, Zr, Nb, Cs, Ru, Te and U was studied and the influence of the acidity of the aqueous phase upon extraction of the elements mentioned was examined. Experiments were made to determine whether the species extracted into the organic phase is the complex formed between tetracycline and the elements considered and to determine the time of shaking necessary so that the equilibrium between the phases is attained. As a practical application, the possibility of using the tetracycline-benzyl alcohol system for separating the fission products sup(137)Cs, sup(140)La, sup(141)Ce, sup(103)Ru, sup(95)Nb from each other and from uranium is presented. The same study was made for sup(131)I, sup(99m)Tc, sup(99)Mo, sup(132)Te, sup(239)Np and uranium and the steps necessary for the separation of these elements are proposed.

Energy Technology Data Exchange (ETDEWEB)

One of the key features of ANL's Integral Fast Reactor (IFR) concept is a close-coupled fuel cycle. The proposed fuel cycle is similar to that demonstrated over the first five to six years of operation of EBR-II, when a fuel cycle facility adjacent to EBR-II was operated to reprocess and refabricate rapidly fuel discharged from the EBR-II. Locating the IFR and its fuel cycle facility on the same site makes the IFR a self-contained system. Because the reactor fuel and the uranium blanket are metals, pyrometallurgical processes (shortned to ''pyroprocesses'') have been chosen. The objectives of the IFR processes for the reactor fuel and blanket materials are to (1) recover fissionable materials in high yield; (2) remove fission products adequately from the reactor fuel, e.g., a decontamination factor of 10 to 100; and (3) upgrade the concentration of plutonium in uranium sufficiently to replenish the ...

International Nuclear Information System (INIS)

LLNL is developing the nuclear fusion based Laser Inertial Fusion Energy (LIFE) power plant concept. The baseline design uses a depleted uranium (DU) fission fuel blanket with a flowing molten salt coolant (flibe) that also breeds the tritium needed to sustain the fusion energy source. Indirect drive targets, similar to those that will be demonstrated on the National Ignition Facility (NIF), are ignited at #approx#13 Hz providing a 500 MW fusion source. The DU is in the form of a uranium oxycarbide kernel in modified TRISO-like fuel particles distributed in a carbon matrix forming 2-cm-diameter pebbles. The thermal power is held at 2000 MW by continuously varying the "6Li enrichment in the coolants. There are many options to be considered in the engine design including target yield, U-to-C ratio in the fuel, fission blanket thickness, etc. Here we report results of design variations and compare them in terms of various figures of merit such as ...

DEFF Research Database (Denmark)

Investigations into sexual differentiation and pheromone response in the fission yeast Schizosaccharomyces pombe are complicated by the need to first starve the cells of nitrogen. Most mating-related experiments are therefore performed on non-dividing cells. Here we overcome this problem by using two mutants that bypass the nutritional requirements and respond to the M-factor mating pheromone in rich medium. The first mutant lacks the cyr1 gene which encodes adenylate cyclase and these cells contain no measurable amounts of cAMP. When M-factor is added to a growing h+ cyr1- strain it causes a transient G1 arrest of cell division, transcription of mat1-Pm, and elongation of the cells to form shmoos. The second mutant contains the temperature-sensitive pat1-114 allele. At 30 degrees C this mutant was previously shown not only to bypass the nutritional signal but also to stop growing in a state derepressed for pheromone-controlled functions. We now report that an h+ ...

Science.gov (United States)

Summaries are presented for those research contracts which expired between December 31, 1960 and December 31, 1981. Topics covered include: factors controlling distribution of fission products in biosphere, non-destructive methods of evaluating the U/sup 235/ and Pu content of irradiated fuel elements, studies of contamination in local marine resources, tracer studies of anemia, non-destructive analysis of irradiated fuel elements using a flux integrating monitor, mechanism of proteolysis of I/sup 131/-labeled fibrinogen, radiosensitivity of spermatogonia of Drosophila melel elements by gamma scanning, uptake and loss of radioactive material by marine bacteria, factors which influence the movement of radioactive strontium from soils to plants, biological concentration of fission products in mollusks from water, decay scheme of Tl/sup 210/, calcium balance in metabolic bone disease, development of radioactive drugs ...

Energy Technology Data Exchange (ETDEWEB)

The Evaluated Nuclear Data File (ENDF) formats and libraries are decided by the Cross Section Evaluation Working Group (CSEWG), a cooperative effort of national laboratories, industry, and universities in the U.S. and Canada, and are maintained by the National Nuclear Data Center (NNDC). Earlier versions of the ENDF format provided representations for neutron cross sections and distributions, photon production from neutron reactions, a limited amount of charged-particle production from neutron reactions, photo-atomic interaction data, thermal neutron scattering data, and radionuclide production and decay data (including fission products). Version 6 (ENDF-6) allows higher incident energies, adds more complete descriptions of the distributions of emitted particles, and provides for incident charged particles and photonuclear data by partitioning the ENDF library into sub-libraries. Decay data, fission product yield data, thermal scattering data, ...

Energy Technology Data Exchange (ETDEWEB)

The newly developed techniques by the Hot Laboratory (JMTR HL) have provided for us the key information on behavior of specimens due to mechanical / physical / chemical / synergistic effects of radiation, stress and water for fission and fusion reactor environment. These techniques are focused on several topics as follows; (1) miniaturized specimen test for the development of fusion reactor materials, (2) slow strain rate tensile testing (SSRT) and crack propagation measuring tests for the study of Irradiation Assisted Stress Corrosion Cracking (IASCC) of core internals of LWR, (3) handling technique on specimens including tritium for the research and development of tritium breeders and neutron multiplier as fusion blanket materials, (4) joining method using the Tungsten Inert Gas (TIG) welding technique for re-assembling of capsule and re-fabrication of specimen and (5) nondestructive evaluation using ultrasonic wave and infrared thermography for the quantitative ...

Energy Technology Data Exchange (ETDEWEB)

The characterization data obtained to date are described for Approved Testing Material (ATM)-106 spent fuel from Assembly BT03 of pressurized-water reactor Calvert Cliffs No. 1. This report is one in a series being prepared by the Materials Characterization Center at Pacific Northwest Laboratory on spent fuel ATMs. The ATMs are receiving extensive examinations to provide a source of well- characterized spent fuel for testing in the US Department of Energy Office of Civilian Radioactive Waste Management (OCWRM) program. ATM-106 consists of 20 full-length irradiated fuel rods with rod-average burnups of about 3700 GJ/kgM (43 MWd/kgM) and expected fission gas release of /approximately/10%. Characterization data include (1) as-fabricated fuel design, irradiation history, and subsequent storage and handling; (2) isotopic gamma scans; (3) fission gas analyses; (4) ceramography of the fuel and metallography of the cladding; (5) calculated nuclide ...

Energy Technology Data Exchange (ETDEWEB)

The characterization data obtained to data are described for Approved Testing Material 105 (ATM-105), which is spent fuel from Bundles CZ346 and CZ348 of the Cooper Nuclear Power Plant, a boiling-water reactor. This report is one in a series being prepared by the Materials Characterization Center at Pacific Northwest Laboratory (PNL) on spent fuel ATMs. The ATMs are receiving extensive examinations to provide a source of well-characterized spent fuel for testing in the US Department of Energy Office of Civilian Radioactive Waste Management (OCRWM) Program. ATM-105 consists of 88 full-length irradiated fuel rods with rod-average burnups of about 2400 GJ/kgM (28 MWd/kgM) and expected fission gas release of about 1%. Characterization data include (1) descriptions of as-fabricated fuel design, irradiation history, and subsequent storage and handling; (2) isotopic gamma scans; (3) fission gas analyses; (4) ceramography of the fuel and metallography ...

Energy Technology Data Exchange (ETDEWEB)

The long-lived nuclides of the americium and curium elements are of interest for their use in certain safeguard applications and for nuclear reactor burnup studies in waste management. Recommended values are presented for /sup 241,242m,243/Am, and for /sup 242,243,244,245,246,247,248,250/Cm. These values result from a consistent evaluation of all these half-lives. These preliminary estimates were presented earlier. The uncertainties are provided at the 95% confidence limit for each of the recommended values. It will be noted that many of the recommended errors considerably exceed errors quoted by individual authors in their publication, by up to an order of magnitude, e.g. the total half-life of /sup 242,246,248/Cm and the spontaneous fission half-life of /sup 244/Cm. These preliminary estimates for the half-lives were given previously. Efforts continue to reevaluate the various experiments to better gauge the systematic errors involved and reassess the total ...

International Nuclear Information System (INIS)

To estimate the waste management needs of a fusion power reactor, a scheme for handling radioactive waste from a fusion plant has been devised. The handling scheme proceeds with radioactive waste, primarily from blanket replacement, being stored on-site; waste in cooled and shielded casks is then isolated off-site; finally, the materials are recycled. Using activities and component lifetimes supplied by designers, several conceptual fusion power reactors have been analyzed and their waste streams compared to fission reactors with regard to total activity, specific activity, and lifetimes of activity.

International Nuclear Information System (INIS)

The section on environmental impacts covers global environmental concerns and air pollution. Energy systems includes the following: alternative fuels; co-generation; fossil fuels; mechanical thermal storage; fission/fusion; thermal management; electric and hybrid vehicles. The section on renewable energy sources includes biomass, hydrogen, and solar. This volume also contains separate sections for stirling cycles, policy issues, and new technologies for energy utilization. Separate abstracts were prepared for 150 papers of this volume.

Energy Technology Data Exchange (ETDEWEB)

The Oak Ridge National Laboratory (ORNL) is a multiprogram, multipurpose laboratory that conducts research in the physical, chemical, and life sciences; in fusion, fission, and fossil energy; and in energy conservation and other energy-related technologies. This review outlines some current endeavors of the lab. A state of the laboratory presentation is given by director, Alvin Trivelpiece. Research of single crystals for welding is described. The Science Alliance, a partnership between ORNL and the University of Tennessee, is chronicled. And several incites into distinguished personnel at the laboratory are given. (GHH)

International Nuclear Information System (INIS)

Full text: Climatic problems associated to the greenhouse effect have recently stimulated a renewed interest in nuclear energy production, and triggered new studies aimed at developing future generation systems that would address current major safety, proliferation and waste concerns. In particular a possible solution to the waste problem could come from transmutation of the highly radiotoxic nuclear waste in Accelerator Driven Systems or in Generation-IV fast nuclear reactors. The design and operation of the new systems require accurate cross-section data on a large number of isotopes, in particular plutonium, minor actinides, long-lived fission fragments and structural materials. An important contribution to the field is being provided since a few years by a new time of-flight facility operative at CERN, n_TOF. The main features of the neutron beam, in particular the wide energy spectrum, ranging from thermal energy to hundreds of MeV, the very high instantaneous ...

International Nuclear Information System (INIS)

Modelling the behaviour of fission product (FP) in a nuclear reactor coolant system (RCS) undergoing a hypothetical severe accident is an important step in the evaluation of radioactive release outside a nuclear power plant. This paper scrutinize Small Break LOCA sequence for WWER1000 reactor in order to investigate the possible paths for release of FP from fuel pallets to the reactor containment. Contemporaneous computer code for simulation of RCS will be use for the analysis. The results from analysis of fuel damage and release of FP trough the break of cold leg are present. (author)

Energy Technology Data Exchange (ETDEWEB)

The prompt neutron spectra of {sup 241}Am, {sup 242m}Am, and {sup 243}Am were evaluated for the next version of Japanese Evaluated Nuclear Data Library, using the methodology developed by the authors. The method is based on the Madland-Nix theory with some improvements to consider the multimodal nature of the fission process, and shell effects on the level density parameters and the neutron multiplicity from light and heavy fragments. The results were compared with previous evaluations. (authors)

Energy Technology Data Exchange (ETDEWEB)

This standard is applicable to operations with the following: /sup 237/Np, /sup 238/Pu, /sup 240/Pu, /sup 241/Pu, /sup 242/Pu, /sup 241/Am, /sup 242m/Am, /sup 243/Am, /sup 243/Cm, /sup 244/Cm, /sup 245/Cm, /sup 247/Cm, /sup 249/Cf and /sup 251/Cf. Subcritical mass limits are presented for isolated fissionable units. The limits are not applicable to interacting units.

Energy Technology Data Exchange (ETDEWEB)

This report describes the progress of the Dutch RAS programme on `Recycling and Transmutation of Actinides and Fission Products` over the year 1995, which is the second year of the 4-year programme 1994-1997. An extensive listing of reports and publications from 1991 to 1995 is given. Highlights in 1995 were: -The completion of the European Strategy Study on Nuclear Waste Transmutation as a result of which the understanding of transmutation of plutonium, minor actinides and long-lived fission products in thermal and fast reactors has been increased significantly. Important ECN contributions were given on Am, {sup 99}Tc and {sup 129}I transmutation options. Follow-up contracts have been obtained for the study of 100% MOX cores and accelerator-based transmutation. - Important progress in the evaluation of CANDU reactors for burning very large amounts of transuranium mixtures in inert matrices. - The first RAS irradiation experiment in the HFR, in ...

Energy Technology Data Exchange (ETDEWEB)

The feasibility was evaluated using MCNP-DSP, an analog Monte Carlo transport cod to simulate source-driven measurements. Models of an isolated Westinghouse 17x17 PWR fuel assembly in a 1500-ppM borated water storage pool were used. In the models, the fuel burnup profile was represented using seven axial burnup zones, each with isotopics estimated by the PDQ code. Four different fuel assemblies with average burnups from fresh to 32 GWd/MTU were modeled and analyzed. Analysis of the fuel assemblies was simulated by inducing fission in the fuel using a {sup 252}Cf source adjacent to the assembly and correlating source fissions with the response of a bank of {sup 3}He detectors adjacent to the assembly opposite the source. This analysis was performed at 7 different axial positions on each of the 4 assemblies, and the source-detector cross-spectrum signature was calculated for each of these 28 simulated measurements. The magnitude of the ...

International Nuclear Information System (INIS)

An effort to expand the irradiation mission of the Fast Flux Test Facility (FFTF) beyond testing fuels and materials for the liquid-metal reactor (LMR) program included a study of the feasibility of producing commercial quantities of "6"0Co. The "6"0Co would be produced by neutron capture in assemblies containing an array of natural cobalt pins and hydrogen-bearing moderator pins located at the periphery of the FFTF core. Adding hydrogenous material to the assemblies enhances "6"0Co production by slowing neutrons into energy ranges where the "5"9Co capture cross section is higher. Some of the moderated neutrons leak from the moderated region to adjacent fuel regions, increasing local fission rates. In order to validate calculated fission rates and establish calculational biases and uncertainties, experiments were conducted in the zero-power plutonium reactor (ZPPR) to measure fission rates in fuel regions adjacent to a ...

International Nuclear Information System (INIS)

The activation aspects of pure fusion and hybrid fusion technology is studied to assess the radioactive safety of various fusion concepts including tokamak pure fusion, fissile fuel producing hybrid and radio waste transmuting hybrid. The activation properties of breeding, coolant and structural materials in fusion reactors might be quite different from those in fission reactors because of the high energy D-T fusion neutrons from the fusion cores. A study on the involved activation reactions and the uncertainties of the associated nuclear cross-sections is carried. The activation properties of various first wall concepts and blanket concepts are discussed. The radioactive inventory during the operation lifetime and the potential hazard of the radioactive nuclides with respect to near term (reprocessing) and long term (waste disposal) aspects are calculated, with reference to ITER/NET (International Thermonuclear Experiment Reactor/Next European Torus), STARFIRE (a ...

Energy Technology Data Exchange (ETDEWEB)

This study presents a dynamic analysis of a rotor supported by two turbulent flow model journal bearings and lubricated with couple stress fluid under nonlinear suspension. The dynamics of the rotor center and bearing center is studied. The dynamic equations are solved using the Runge-Kutta method. The analysis methods employed in this study is inclusive of the dynamic trajectories of the rotor center and bearing center, power spectra, Poincare maps and bifurcation diagrams. The maximum Lyapunov exponent analysis is also used to identify the onset of chaotic motion. The results show that the values of dimensionless parameters l* strongly influence dynamic motions of bearing and rotor centre. It is found that couple stress fluid improve the stability of the system when l* > 0.4 even if the flow of this system is turbulent. We also demonstrated that the dimensionless rotational ...

International Nuclear Information System (INIS)

To systematically analyze the dynamical implications of the matter content in cosmology, we generalize earlier dynamical systems approaches so that perfect fluids with a general barotropic equation of state can be treated. We focus on locally rotationally symmetric Bianchi type IX and Kantowski-Sachs orthogonal perfect fluid models, since such models exhibit a particularly rich dynamical structure and also illustrate typical features of more general cases. For these models, we recast Einstein's field equations into a regular system on a compact state space, which is the basis for our analysis. We prove that models expand from a singularity and recollapse to a singularity when the perfect fluid satisfies the strong energy condition. When the matter source admits Einstein's static model, we present a comprehensive dynamical description, which includes the qualitative asymptotic behavior, of models in the ...

Energy Technology Data Exchange (ETDEWEB)

This safety design guide for pipe rupture protection identifies high-energy systems in which pipe ruptures must be postulated to occur, as well as systems that must be protected from the dynamic effects of such ruptures. Dynamic effects considered in this SDG consist of pipe whip (including missiles generated by pipe ruptures, if any) and jet impingement, Requirements for protection against the dynamic effects of a postulated pipe rupture and method of protection of essential structures, systems and components are specified for these effects. The change status for the regulatory requirements, code and standards should be traced and this safety design guide shall be updated accordingly. 2 tabs., 5 refs. (Author) .new.

Science.gov (United States)

This investigation concerns the nonlinear dynamics of heat transfer from a surface using an upstream eddy promoter. A numerical model is developed for the coupled fluid flow and heat transfer process based on a modified MacCormack scheme. Numerical simulations are carried out to determine the response and heat transfer enhancement due to the promoter. The average heat transfer from a cavity floor is seen to be increased by a factor of approximately five over the unpromoted'' flow. Another interesting feature of the study is the nonlinear viscous flow dynamics from the cylinder-wall interaction which differ significantly from the familiar cylinder-free stream patterns.

Energy Technology Data Exchange (ETDEWEB)

The centroid and envelope dynamics of a high-intensity charged particle beam are investigated as a beam smoothing technique to achieve uniform illumination over a suitably chosen region of the target for applications to ion-beam-driven high energy density physics and heavy ion fusion. The motion of the beam centroid projected onto the target follows a smooth pattern to achieve the desired illumination, for improved stability properties during the beam-target interaction. The centroid dynamics is controlled by an oscillating "wobbler", a set of electrically-biased plates driven by RF voltage. __________________________________________________

Science.gov (United States)

In the present work we introduce a novel multi-agent model with the aim to reproduce the dynamics of a double auction market at microscopic time scale through a faithful simulation of the matching mechanics in the limit order book. The agents follow a noise decision making process where their actions are related to a stochastic variable, the market sentiment, which we define as a mixture of public and private information. The model, despite making just few basic assumptions over the trading strategies of the agents, is able to reproduce several empirical features of the high-frequency dynamics of the market microstructure not only related to the price movements but also to the deposition of the orders in the book.

Science.gov (United States)

... The lateral cross spectral density measurements are normalized on the autospectrum. Frequency is normalized on r3 , and we take Uc _" 0.7 U0 . ...

CERN Document Server

We prove, using the AdS/CFT correspondence, that the long wavelength dynamics of the shear stress tensor in a strongly coupled N=4 SYM plasma is not described by the relaxation-type, fluid dynamical equations proposed by Israel and Stewart: the coarse grained dynamics will necessarily contain a second-order comoving derivative of the shear stress tensor. We argue that this should be true for any strongly-coupled gauge theory with a gravity dual. If the QGP formed in heavy ion collisions can indeed be described in terms of a (yet unknown) theory of gravity in higher dimensions, the equations of motion used in hydrodynamical simulations of the QGP must necessarily include second order comoving derivatives of the shear stress tensor.

UK PubMed Central (United Kingdom)

Humans, like other animals, are exposed to a continuous stream of signals, which are dynamic, multimodal, extended, and time varying in nature. This complex input space must be transduced and sampled...Full Text Available

UK PubMed Central (United Kingdom)

Axon outgrowth and guidance to the proper target requires the coordination of filamentous (F)-actin and microtubules (MTs), the dynamic cytoskeletal polymers that promote shape change and locomotion....Full Text Available

Science.gov (United States)

The H-Coal ebullated bed reactor contains at least four discrete components: gas, liquid, catalyst, and unconverted coal and ash. Because of the complexity created by these four components, it is desirable to understand the fluid dynamics of the system. The objective of this program is to establish the dependence of the ebullated bed fluid dynamics on process parameters. This will permit improved control of the ebullated bed reactor. Progress has been made in the study undertaken for defining the hydrodynamic properties of gas/liquid/solid systems as related to the H-Coal process. The literature search was completed, and a report will be issued shortly. Design and construction of the fluid dynamics unit proceeded as planned. Unit completion is scheduled for May 1, 1978.