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Sasa, Narimasa
Journal of the Physical Society of Japan, 91(5), p.054001_1 - 054001_8, 2022/05
Times Cited Count：0 Percentile：0(Physics, Multidisciplinary)Shibata, Hiroshi; Takeuchi, Tomoaki; Seki, Misaki; Shibata, Akira; Nakamura, Jinichi; Ide, Hiroshi
JAEA-Data/Code 2021-018, 42 Pages, 2022/03
JAEA-Data-Code-2021-018.pdf:2.78MB
JAEA-Data-Code-2021-018-appendix(CD-ROM).zip:0.15MB
Japan Materials Testing Reactor (JMTR) in Oarai Research and Development Institute of the Japan Atomic Energy Agency has been developing various reactor materials, irradiation techniques and instruments for more than 30 years. Among them, the development of self-powered neutron detectors (SPNDs) and gamma detectors (SPGDs) has been carried out, and several research results have been reported. However, most of the results are based on the design study of the detector development and the results of in-core irradiation tests and gamma irradiation tests using Cobalt-60. In this report, a numerical code is developed based on the paper "Neutron and Gamma-Ray Effects on Self-Powered In-Core Radiation Detectors" written by H.D. Warren and N.H. Shah in 1974, in order to theoretically evaluate the self-powered radiation detectors.
Ebihara, Kenichi
Materia, 57(7), p.338 - 344, 2018/07
no abstracts in English
Clark, A. J.*; Denman, M. R.*; Takata, Takashi; Ohshima, Hiroyuki
SAND2017-12409, 39 Pages, 2017/11
Two sodium spray fire experiments performed by Sandia National Laboratories (SNL) were used for a code-to-code comparison between CONTAIN-LMR and SPHINCS. Both computer codes are used for modeling sodium accidents in sodium fast reactors. The comparison between the two codes provides insights into the ability of both codes to model sodium spray fires. The SNL T3 and T4 experiments are 20 kg sodium spray fires with sodium spray temperatures of 200
C and 500C, respectively. The vessel in the SNL T4 experiment experienced a rapid pressurization that caused of the instrumentation ports to fail during the sodium spray. Despite these unforeseen difficulties, both codes were shown in good agreement with the experiments. SPHINCS showed better long-term agreement with the SNL T3 experiment than CONTAIN-LMR. The unexpected port failure during the SNL T4 experiment presented modelling challenges.
Togashi, Tomoaki*; Shimizu, Noritaka*; Utsuno, Yutaka; Abe, Takashi*; Otsuka, Takaharu*
Procedia Computer Science, 29, p.1711 - 1721, 2014/06
Times Cited Count：1 Percentile：30.04(Computer Science, Theory & Methods)Computing Hamiltonian matrix elements between non-orthogonal Slater determinants is often needed for nuclear-structure calculations, and it is the most time-consuming part in many cases. In this paper, we demonstrate that utilizing GPGPU is an efficient way to perform this calculation. In our earlier study, we showed that the calculation of the Hamiltonian matrix elements between non-orthogonal Slater determinants is transformed into the multiplication of matrices. This method is useful for the GPGPU calculation because of less memory access compared to the usual method. We implement the GPGPU computation in the Monte Carlo shell-model code and measure the elapsed time. The resulting performance is over 0.6 TFLOPS for the GPU that has 1.13 TFLOPS peak performance. This method is particularly effective for large-scale calculations because higher efficiency is obtained for the calculation of larger model spaces.
Ebihara, Kenichi; Watanabe, Tadashi
Dai-18-Kai Suchi Ryutai Rikigaku Shimpojiumu Koen Yoshishu (CD-ROM), 7 Pages, 2004/12
The Ishii-Grolmes experimental correlation, which represents the inception criteria of the droplet entrainment, has been reproduced by the lattice Boltzmann simulation[Ebihara et al., Nagare 23, 253(2004)]. It has been observed in the simulation that the droplet broke off the wave which was generated on the smooth interface of the horizontal stratified two-phase flow. The numerical and physical influence on the reproduction of the experimental correlation is discussed in this paper. It is verified that the lattice size was enough for the reproduction of the experimental correlation though the discretization of the lattice affects the simulation result numerically. It is also seen that the shape of the generated wave and the flow velocity distribution affect the simulation results as the physical influence.
Yamada, Susumu; Shimizu, Futoshi; Kaji, Yoshiyuki; Kaburaki, Hideo
Keisan Kogaku Koenkai Rombunshu, 7(1), p.167 - 170, 2002/05
no abstracts in English
; Ueno, Fumiyoshi
JNC TN9400 2000-017, 10 Pages, 2000/03
JNC-TN9400-2000-017.pdf:0.58MB
lt is difficult to get hold the behave of growth of cavity which nucleates in grain boudaly in experimental observation. lt is considerd that numerical simulation is effective for the grasp of behave of cavity growth, because it is able to grasp the microscopic behavior of internal material whici is hardly observation. We examine the factor that the diffusive ratio and the stress etc., affected growth of cavity on grain boundary with numerical simulation using diffusive equation. As the result, a following knowledge was obtained. (1)With dominant of grain boundary diffusion, the shape of cavity transitions from quasi-equilibrium to crac-like. ln other hand, with dominant of surface diffusion, cavity grows up with initial shape. (2)With dominate of grain boundary diffusion, it accelerates the growth rate of the cavity near the tip by grain boundaly diffusion induced stressing perpendicular to gain boundary (3)With dominant of surface diffusion, the distribution of chemical potential is uniformity on cavity surface. ln other hand, with dominant of grain boundary diffusion compare to that of surface diffusion, the gradient of chemical potential is increased at the tip of cavity.
Takeuchi, Suehiro
Proc. of 8th Int. Conf. on Heavy Ion Accelerator Technology, p.244 - 251, 1999/00
no abstracts in English
He-Ne-Ar gas laser for its optimizationSakasai, Kaoru; Kakuta, Tsunemi; Nakazawa, Masaharu*
Japanese Journal of Applied Physics, Part 1, 37(9A), p.4806 - 4811, 1998/09
Times Cited Count：2 Percentile：13.54(Physics, Applied)no abstracts in English
*
JAERI-Data/Code 98-020, 45 Pages, 1998/06
JAERI-Data-Code-98-020.pdf:1.5MB
no abstracts in English
Jinno, Kenji*; Nakagawa, Kei*; *; *; Ijiri, Yuji*; *; Watari, Shingo
PNC TY1606 98-001, 54 Pages, 1998/03
no abstracts in English
Takeda, Toshikazu*; Kitada, Takanori*; *; *
PNC TJ9605 98-001, 267 Pages, 1998/03
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 ...
*
Joho Shori Gakkai Rombunshi, 39(3), p.529 - 541, 1998/03
no abstracts in English
Takase, Haruhiko; Senda, Ikuo; Araki, Masanori; Shoji, Teruaki; Tsunematsu, Toshihide
IAEA-CN-69/FTP/28, 4 Pages, 1998/00
no abstracts in English
; Ohshima, Hiroyuki
PNC TN9410 97-104, 69 Pages, 1997/12
As the part of the improvement of single-phase subchannel analysis code ASFRE-III, verification study about fuel-pin heat transfer model and flow resistance model of the code was carried out. Temperature distributions in a fuel pin predicted by the fuel-pin heat transfer model of ASFRE-III were compared with those calculated by the structure analysis code FINAS, which has been well validated and applied to various structure analyses, using the same boundary conditions. The comparison showed that the results by these two codes agreed with maximum difference of 1 %. and therefore the validity of the model was confirmed. With respect to the flow resistance model, distributed resistance model (DRM), which can enhance the consistent description of the fluid flow and wire-spacer interaction, was examined through analyses of two hydraulic simulation tests using the fifth mock-up fuel subassembly for the prototype LMFBR and the second mock-up fuel subassembly for the experimental rector. The calculated pressure difference between pressure measurement taps whose positions were near the top and the bottom of the fuel-pin bundle agreed with the measured data of both tests. The predicted pressure distribution in a horizontal cross section was also compared with the calculational result by the finite element analysis code SPIRAL and agreement was good.
Nakagiri, Toshio; Miyake, Osamu; Ohno, Shuji
PNC TN9410 97-102, 166 Pages, 1997/11
The calculation of Sodium Fire Test - I (Run - E6) was performed using the ASSCOPS (Analysis of Simultaneous Sodium Combustions in Pool and Spray) code version 2.0 in order to determine the parameters used in the code for the calculations of sodium combustion behavior of small or medium scale sodium leak, and to validate the applicability of the code. The parameters used in the code were determined and the validation of the code was confirmed because caluculated temperatures, calculated oxygen concentration and other calculated values almost agreed with the test results.
Maruyama, Tadashi; ; ; Onose, Shoji;
PNC TN9410 97-077, 177 Pages, 1997/07
Postirradiation examinations of JOYO MK-II control rods have been carried out since 1983, where 16 subassemblies with total 110 absorber pins of initial load to the fifth reload control rods have been subjected to a number of both non-destructive and destructive examinations. In the course of postirradiation examinations, a cracking of cladding tube was found in the total 15 absorber pins in five control assemblies. This paper indicates the results of postirradiation examinations and analysis of absorber pin performance using CORAL code to elucidate the cause of absorber pin cracking in JOYO MK-II control rods. No crack was found in absorber pins whose maximum burnup was lower than 39 
10
cap/m, whereas all the cracked pins had burnup of higher than 43 10 cap/m with the initial gap between B
C pellet and cladding larger than 0.44 mm. The cracks were found at around positions corresponding to the lowest BC pellet in the stack. The ceramography analysis indicated that BC pellet exhibited extensive cracking and a part of gap between pellet and cladding closed. The cladding deformation had an ovality and the cracks tended to occur at the shorter diameter side. The cracked surface of absorber pin was of a typical grain boundary fracture. The result of He analysis for the cladding material indicated a substantial amount of He accumulation at the inner surface of cladding, but the bulk He content was not anomalously high compared with those in the neutron irradiated stainless steels. TEM observation indicated He bubbles was not clearly found in the as-irradiated cladding material. The cause of cladding failure was attributed to the ACMI where the gap closure due to relocation of BC pellet took place from early times of irradiation. The code analysis by CORAL indicated that the cladding strain due to ACMI was not fully absorbed by the irradiation creep and that the plastic strain became large enough to ...
PNC TN9410 97-039, 187 Pages, 1997/05
A numerical evaluation system, which is consisted of four codes, AQUA, DINUS-3, THEMIS and BEMSET has been developed for thermal striping phenomena. To validate the system for the phenomena, thermally fluid - structure interaction analysis was carried out using a existing sodium experiment of parallel impinging jet simulating the outlet region of an LMFBR core. Calculational results on the RMS values of temperature fluctuation, the histograms of temperature amplitudes and frequencies, the auto-power spectral density distributions of temperature fluctuations and the damping characteristics of temperature fluctuations showed good agreement with the measured values under the test conditions of various flow velocity. From the comparisons with the experimental data, it was concluded that the numerical evaluation system is applicable to the evaluation of thermally fluid - structure interaction phenomena related to the thermal striping.
