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Yanagisawa, Hiroshi
JAEA-Technology 2021-023, 190 Pages, 2021/11
JAEA-Technology-2021-023.pdf:5.25MB
Computational analyses on nuclear criticality characteristics were carried out for heterogeneous lattice systems composed of water moderator and fuel rods utilized in low-power research and test reactors, in which the depletion of fuel due to burnup is relatively small, by using the continuous-energy Monte Carlo code MVP Version 2 with the evaluated nuclear data library JENDL-4.0. In the analyses, the minimum critical number of fuel rods was evaluated using calculated neutron multiplication factors for the heterogeneous systems of the uranium dioxide fuel rod in the Static Experiments Critical Facility (STACY) and the Tank-type Critical Assembly (TCA), and the uranium-zirconium hydride fuel rod in the Nuclear Safety Research Reactor (NSRR). In addition, six sorts of the ratio of reaction rates, which are components of neutron multiplication factors, were calculated in the analyses to explain the variation of neutron multiplication factors with the ratio of water moderator to fuel volume in a unit fuel rod cell. Those results of analyses are considered to be useful for the confirmation of reasonableness and validity of criticality safety measures as data showing criticality characteristics for water-moderated heterogeneous lattice systems composed of the existing fuel rods in research and test reactors, of which criticality data are not sufficiently provided by the Criticality Safety Handbook.
Kai, Tetsuya; Harada, Masahide; Maekawa, Fujio; Teshigawara, Makoto; Konno, Chikara; Ikeda, Yujiro
Journal of Nuclear Science and Technology, 41(Suppl.4), p.172 - 175, 2004/03
In J-PARC neutron source, intense protons (3 GeV,1 MW) pass through a proton-beam window and bombard a Hg target in a target-moderator-reflector-assembly (TMRA). The SS316 target chamber is the most highly activated. Decouplers (Ag-In-Cd (AIC) alloy) are also highly activated. Some neutron extraction holes of Be and AL-coated iron reflector are lined with AIC alloy. A SS316 shield is located outer the TMRA. All these components are cooled by H
O or DO. We estimated the induced-radioactivity of the TMRA components and the cooling water using NMTC/JAM, MCNP4 and DCHAIN-SP. As results, the remote maintenance and massive shields were indispensable. For example, a 30 cm thick Fe cask for the reflector assembly was necessary to attenuate the radiation less than 1 mSv/h. The cask required a 130-ton crane. The AL-coated Fe of the reflector was adopted instead of SS316 resulting in eliminating the high activity of Ni in SS316 and reduction of the cask weight. Based on these results, shielding wall designs and maintenance scenarios of the highly activated components are developed.
Cao, X.; Suzaki, Takenori; Kugo, Teruhiko; Mori, Takamasa
JAERI-Tech 2003-069, 36 Pages, 2003/08
JAERI-Tech-2003-069.pdf:3.77MB
From the viewpoint of nuclear criticality safety of fuel rod storage and transport, a series of critical experiments concerning effects of water hole size, water gap width, water-to-fuel volume ratio and non-uniform arrangement of water moderator have been performed at the Tank-type Critical Assembly (TCA) of Japan Atomic Energy Research Institute. In the present study, the effects of volume fraction and non-uniform arrangement of water moderator on reactivity are evaluated by the water level worth method and analyzed by the SRAC code. Error sources of experiments and calculations are discussed, especially for an energy group model. The calculation results of diffusion model with 17-group model show good agreement with the experiment results within a few dozen cents.
Nakashima, Hiroshi; Takada, Hiroshi; Kasugai, Yoshimi; Meigo, Shinichiro; Maekawa, Fujio; Kai, Tetsuya; Konno, Chikara; Ikeda, Yujiro; Oyama, Yukio; Watanabe, Noboru; et al.
Journal of Nuclear Science and Technology, 39(Suppl.2), p.1155 - 1160, 2002/08
no abstracts in English
Kasugai, Yoshimi; Takada, Hiroshi; Meigo, Shinichiro; Maekawa, Fujio; Nakashima, Hiroshi; Ikeda, Yujiro; Ino, Takashi*; Sato, Setsuo*; Jerde, E.*; Glasgow, D.*
JAERI-Data/Code 2000-042, 62 Pages, 2001/02
JAERI-Data-Code-2000-042.pdf:1.96MB
no abstracts in English
Kugo, Teruhiko; Okubo, Tsutomu; *
JAERI-Research 99-057, p.29 - 0, 1999/09
JAERI-Research-99-057.pdf:1.77MB
no abstracts in English
; ;
JAERI-Tech 98-052, 69 Pages, 1998/11
no abstracts in English
Kugo, Teruhiko; Shimada, Shoichiro*; Okubo, Tsutomu; Ochiai, Masaaki
JAERI-Research 98-059, 40 Pages, 1998/10
JAERI-Research-98-059.pdf:1.73MB
no abstracts in English
