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Journal Articles

SFCOMPO-2.0; An OECD NEA database of spent nuclear fuel isotopic assays, reactor design specifications, and operating data

Michel-Sendis, F.*; Gauld, I.*; Martinez, J. S.*; Alejano, C.*; Bossant, M.*; Boulanger, D.*; Cabellos, O.*; Chrapciak, V.*; Conde, J.*; Fast, I.*; et al.

Annals of Nuclear Energy, 110, p.779 - 788, 2017/12

 Times Cited Count:65 Percentile:99.16(Nuclear Science & Technology)

Journal Articles

Simulation methods in discretized systems, 1

Yamamoto, Toshihisa*; Mori, Takamasa

Nihon Genshiryoku Gakkai-Shi, 48(8), p.579 - 585, 2006/08

no abstracts in English

JAEA Reports

Study on improvement of reactor physics analysis method for FBRs with various core concept (2)

Takeda, Toshikazu*; Tagawa, Akihiro; *; Kitada, Takanori*; *

JNC TJ9400 2001-009, 239 Pages, 2001/02

JNC-TJ9400-2001-009.pdf:8.71MB

Investigation was made on the following three themes as a part of the improvement of reactor physics analysis method for FBR with various core concepts. [Part 1: Investigations on Improvement of Neutron Spectrum Evaluation by the Use of Co-variance Matrices and Bias Corrections] In order to improve the neutron spectrum unfolding method used in the experimental fast reactor JOYO, investigation was made on the bias corrections to the initial neutron spectrum and error evaluation of nuclear data with the co-variance matrices. The error estimation was done by accumulating each bias correction factor and the co-variance matrix. It was concluded that the accumulated error for the initial neutron spectrum is relatively small, and a considerable improvement was achieved by the use of bias corrections. [Part 2: Evaluation of Neutron Streaming in Gas Cooled Fast Reactors by the use of Monte Carlo Method] As a part of investigations on the evaluation of the anisotropic diffusion coefficients for gas cooled fast reactors, a new tally function was added to a Monte Carlo code so that the neutron streaming can be calculated with heterogeneous core configurations. It was found that the neutron streaming becomes larger when the heterogeneous model was used. The tendency was more distinct in lower energy range. The same types of comparison was also done for the difference of core calculation models and the transport/diffusion theory. The final result shows that the transport/diffusion error has positive values in higher energy range, and the heterogeneous/homogeneous error has negative values in lower energy range. [Part 3: Investigation on the Calculation Method for Nuclear Converters with Neutron Moderators] A new calculation system which can deals with the target assemblies with neutron moderators was proposed. This concept has been investigated as a device to achieve high conversion rate for long life fission products. It was concluded that the characteristics method is ideal, wh

JAEA Reports

Study on improvement of reactor physics analysis method for FBRs with various core concept

*; Kitada, Takanori*; Tagawa, Akihiro; *; Takeda, Toshikazu*

JNC TJ9400 2000-006, 272 Pages, 2000/02

JNC-TJ9400-2000-006.pdf:9.69MB

Investigation was made on the follwing three themes as a part of the improvement of reactor physics analysis method for FBR with various core concept. Part 1: Investigation of Error Estimation of Neutron Spectra in FBR and Suggestions to Improve the Accuracy. In order to improve the spectrum unfolding method used in fast experimental reactor JOYO, a trial was made to evaluate the error in the estimated neutron spectrum, cause by cause. And the evaluated errors were summed up to obtain the most probable and reasonable error as possible. The summed up error was found relatively small compared to the error caused by the uncertainty of cross section data: most of the error in the spectrum unfolding method can be attributed to the error in cross sections. It was also found that the error due to the fission spectrum causes a considerable error in the high energy neutron spectrum which is over several MeV. Part 2: Study on Reactor Physics Analysis Method for Gas-Cooled FBR. In gas-cooled FBR, the portion of coolant channels in core volume is larger than sodium-cooled FBR. This leads to strong neutron streaming effects. For sodium-cooled FBR, several methods were proposed to evaluate the neutron streaming effect, however, these methods can not be used directly to gas-cooled reactor because the direction dependent diffusion coefficient becomes infinitive along the direction pararel to the coolant chammel. In this study, a new method is proposed to evaluate the neutron streaming effect, based on the method taking the axial buckling into consideration, which method was originally proposed by K$"o$hler. Part 3: Study on Reactor Physics Analysis Method for Water-Cooled FBR An investigation was made on low-moderated water-cooled FBR, on the point that the ordinary used analysis method for FBR may give considerable difference in results in such core. In light water reactors, it is well known that the space dependence of self-shielding effect of heavy nuclides are considerably ...

JAEA Reports

Improvement of numerical analysis method for FBR core characteristics (IV)

Takeda, Toshikazu*; *; Kitada, Takanori*

JNC TJ9400 99-002, 171 Pages, 1999/03

JNC-TJ9400-99-002.pdf:4.44MB

Investigation was made on the following three themes as a part of the improvement of numerical analysis method for FBR core characteristics. [Part 1: Improvement of Reaction Rate Calculation Method in Blanket Region.] A method to calculate multiband parameters directly from the precise energy structure of a cross section was established. This method can treat the precise neutron balance equation including the inter-band scattering. The procedure to treat the multiband effect with the conventional Sn code by the use of direction-dependent microscopic cross sections is shown. This procedure was applied to reaction rate distribution analysis on MONJU. As the result, the reaction rates increased in the blanket regions: the maximum increase was 1O% for U-238 cap, 12% for Pu-239 fis, 12% for U-235 fis, and 1% for U-238 fis. It became clear that the effect of the use of direction-dependent microscopic cross sections is small; thus most of the effect can be attributed to the change of microscopic cross section itself. [Part 2: Improvement of Reactivity Calculation by the Use of Monte Carlo Perturbation Method.] Applicability of the two Monte Carlo perturbation methods; the correlated sampling method and the derivative operator sampling method, to the perturbation problems with large change in material densities was investigated through numerical calculations. The result shows the fact that the present derivative operator sampling method, which treats only the first order term, is insufficient and higher order terms should be considered for such a large perturbation. Investigation was made on the new method which can treat the effect of adjoint flux change in energy and space distribution due to the perturbation, and a new formulation based on the exactperturbation was derived. [Part 3: Investigation of Error Estimation of Neutron Spectra in FBR and Suggestions to Improve the Accuracy.] A comparison was made between the two methods to improve the accuracy ...

JAEA Reports

Improvement of numerical analysis method for FBR core characteristics (III)

Takeda, Toshikazu*; Kitada, Takanori*; *; *

PNC TJ9605 98-001, 267 Pages, 1998/03

PNC-TJ9605-98-001.pdf:11.65MB

As the improvement of numerical analysis method for FBR core characteristics, studies on several topics have been conducted; multiband method, Monte Carlo perturbation and nodal transport method. This report is composed of the following three parts. Part 1: Improvement of Reaction Rate Calculation Method in the Blanket Region Based on the Multiband Method. A method was developed for precise evaluation of the reaction rate distribution in the blanket region using the multiband method. With the 3-band parameters obtained from the ordinary fitting method, major reaction rates such as U-238 capture, U-235 fission, Pu-239 fission and U-238 fission rate distributions were analyzed. As for the nuclides to be analyzed, the elements of structure material, such as iron, nickel, chrome and sodium were considered. By the present method, all the reactions became larger at the deep region in the blanket. The maximum correction amounted as much as 5%. This tendency lessen the disagreement between the ordinary calculation and the experiment. It was made clear that the treatment in inter-band scattering term is veryimportant because it has large sensitivity on the result. An alternative method to determine the multiband parameters whieh method is based on more direct approach and is free from drawbacks in the present method, was also investigated. Part 2 : Improvement of Estimation Method for Reactivity Based on Monte-Carlo Perturbation Theory. Perturbation theory based on Monte-Carlo perturbation theory have been investigated and introduced into the calculational code. The continuous energy Monte-Carlo perturbation code has been developed by using not only the correlated sampling method which is already used before, but also the derivative operator sampling method. The Monte-Carlo perturbation code was applied to MONJU core and the calculational results were compared to the reference. The change of eigenvalue caused by the change of sodium density in the GEM or dummy ...

JAEA Reports

Accuracy of MA transmutation calculation with MA specimens irradiated in the experimental fast reactor "JOYO"

*; Takeda, Toshikazu*; ; Kitada, Takanori; Aoyama, Takafumi

PNC TN9410 96-265, 64 Pages, 1996/05

PNC-TN9410-96-265.pdf:3.09MB

The accuracy to calculate the transmutation of minor actinides (MAs) was evaluated using MA specimens irradiated in the Experimental Fast Reactor JOYO. The $$^{237}$$Np transmutation characteristics were analyzed in this study. The transmutation ratio of $$^{237}$$Np was calculated by the one point burnup calculation code "ORIGEN2." The neutron fluxes which were input to "ORIGEN2" were calculated with the JOYO core management code system "MAGI" and "CITATION", both are based on three dimensional diffusion theory with 7 energy group. The continuous energy Monte-Carlo code "MVP" was introduced in order to evaluate the detail flux distribution inside the subassembly. The neutron flux obtained by a radiometric dose analysis without $$^{237}$$Np dosimeter was also used for the transmutation calculation. By comparing the flux distributions by MVP with and without the geometric heterogeneity in a subassembly, it was found that there had little effect on the calculation of $$^{237}$$Np transmutation near the core center of JOYO Mark-II. Calculated $$^{237}$$Np transmutation ratio with neutron fluxes by the MAGI and CITATION were 30% larger than that obtained from the $$gamma$$-ray spectrum measurement, whereas the calculated value with the adjusted neutron flux by a radiometric dose analysis was about 12$$sim$$20% larger than the measured value. It is apparently due to an overestimation of the neutron fluxes by the MAGI and CITATION. As it was also found that there were large uncertainties in the adjusted neutron flux and the measured $$^{237}$$Np transmutation ratio, further investigation is required. As a result of this study, the points to be considered were found to improve the accuracy of the analysis.

Journal Articles

JAEA Reports

A Feasibility study on MA loading in fast reactor cores

PNC TN9410 95-162, 121 Pages, 1995/06

PNC-TN9410-95-162.pdf:5.22MB

As one of the efforts to investigate the possibility of realizing an advanced fuel recycling system to recycle MA, a feasibility study is carried on upon a modified PUREX process which is based on the MOX fuel cycle. Although numerous studies have been made so far on the MA burning options in fast reactors, little effort has been devoted to apply the actual loading method of MA or to the proposal of taking measures against the presumable problems when such method is taken. In this study, which is based on design, an attempt to select a recycling process that satisfies all the design requirements and optimization through the evaluations on the merits and demerits in the overall recycle process is done. The selected option enables high performance in MA burning with low impact on the reactor operation or recycle facilities, in which Am is loaded with a non-U diluent in a target pin and placed in the fuel assembly with driver fuel pins. The feasibility study on the selected loading method considers the thermal criteria of the target pin, decay heat from spent fuel, and the impact on core performance. The selected option satisfies all the specified design criteria and at the same time high performance in MA burning.

JAEA Reports

Improvement of the precise reactor physics analysis code TRITAC

Yamamoto, Toshihisa

PNC TN9410 95-069, 65 Pages, 1995/04

None

JAEA Reports

PNC's Results on the Metal-Fueled Fast Reactor Benchmarks

Oki, Shigeo; Yamamoto, Toshihisa

PNC TN9410 95-001, 54 Pages, 1994/12

PNC-TN9410-95-001.pdf:1.39MB

WPPR(Working Party on Physics of Plutonium Recycling) has been organized in Nuclear Science Committee of OECD/NEA since November l992. More than ten advanced countries (France, United Kingdom, Germany, Russia, United States, Canada, Japan, etc.) participate in this working party. An aim of WPPR is to clarify some physical issues related to the technology for recycle of plutonium. To evaluate different scenarios for the use of plutonium, international benchmarks were developed for various types of reactors (MOX-fueled fast reactor, metal-fueled fast reactor, PWR and advanced converter). Among these, we contributed to the metal-fueled fast reactor benchmarks. In this report, our calculated results are summarized with all the information required. Each result is listed independently in a table according to the sequence indicated in the benchmark proposal, NEA/NSC/DOC(93)24.

Journal Articles

None

; Nomura, Norio; ; Koyama, Shinichi;

Donen Giho, (92), 0 Pages, 1994/12

None

Journal Articles

None

;

Nihon Genshiryoku Gakkai-Shi, 36(11), p.1031 - 1038, 1994/11

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

None

JAEA Reports

None

; ;

PNC TN9410 93-157, 142 Pages, 1993/06

PNC-TN9410-93-157.pdf:5.64MB

None

JAEA Reports

None

; ; ; ; Aoyama, Takafumi; Uto, Nariaki;

PNC TN9410 93-024, 75 Pages, 1993/01

PNC-TN9410-93-024.pdf:6.54MB

None

Journal Articles

Theoretical Analysis of Two-Detector Coherence Functions in Large Fast Reactor Assemblies

Yamamoto, Toshihisa; Nishina, Kojiro*; *; *

Journal of Nuclear Science and Technology, 28(11), p.1019 - 1028, 1991/00

None

JAEA Reports

JUPITER-III experiment analyses (III)

*; *; *; 7 of others*

PNC TN2410 89-003, 349 Pages, 1989/03

PNC-TN2410-89-003.pdf:8.55MB

The works of JUPITER sub-working group in FT'88 are summarized in this report. JUPITRR-III program is the co-operative research program between PNC and DOE, using ZPPR in ANL-W. The JUPITER sab-working group is organized by the reactor physics group of Reactor Research and Development Project, PNC, for planning and analysis of the experiment in JUPITER-III program. The first half of the JUPITER-III program, the ZPPR-17 program, was physics benchmark experiments to study the neutronic behavior of a 650 MWe-size, axially heterogeneous LMR core. The second half of the program, the ZPPR-18 program, was 1000 MWe-size two-zone homogeneous cores. ZPPR-17 was analysed almost completely, but ZPPR-18 analysis is being prepared. The main results of this year are as follows. (1)The following conclusions were obtained from the ZPPR-17 analysis. (i)In addition to the standard analysis model, the center-line and multi-drawer models were used. The effects on criticality were +0.17% for the former model and +0.08$$sim$$0.09% for the latter model. The C/E values were almost the same as those for ZPPR-9 and ZPPR-13A. (ii)The C/E values were about 0.9 at the core center, and became about 5% higher at the core edge. The similar radial variations of C/E were observed in reaction rate distributions. The magnitude of 5$$sim$$10% in the mispredictions are consistent with the previous values obtained in the analysis of the homogeneous core. (iii)The C/E values of sodium void reactivities were about 1.2$$sim$$1.5 for the core regions, and about 0.8 for the internal blanket regions. The C/E values of sample reactirities in the internal blanket region were smaller than those in the core region by about 20% for $$^{239}$$Pu sample and by about 10% for $$^{10}$$B sample. The same underprediction in the internal blanket region was also seen in ZPPR-13A. (2)An attempt was made for building a data base system for the JUPITER program using the ZPPR-17A experimental data as an example. Some ...

Journal Articles

lmprovement af Calculation Method for FBR Control Rod Reactivity

Shirakata, Keisho; Yamamoto, Toshihisa

Donen Giho, (67), p.76 - 78, 1988/09

None

Journal Articles

None

Donen Giho, 75 Pages, 1986/00

JAEA Reports

Evaluation of neutron transport effect in fast reactors

Kawabata, Hironobu*; Shinhara, Koei*; Nakabasami, Yoshio*; Yamamoto, Toshihisa*; Bando, Masaru*; Takeda, Toshikazu*

PNC TJ299 84-07, 76 Pages, 1984/03

PNC-TJ299-84-07.pdf:1.48MB

no abstracts in English

27 (Records 1-20 displayed on this page)