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Tomioka, Dai; Kochiyama, Mami; Ozone, Kenji; Nakata, Hisakazu; Sakai, Akihiro
JAEA-Technology 2024-023, 38 Pages, 2025/03
JAEA-Technology-2024-023.pdf:1.54MB
Japan Atomic Energy Agency is an implementing organization of near-surface disposal for low-level radioactive wastes generated from research, industrial and medical facilities in Japan. Information on the radioactivity concentration of these radioactive wastes is dispensable for the design and conformity assessment of the waste disposal facilities for the licensing application of the disposal project and its safety review. Radioactive Wastes Disposal Center has been improving the radioactivity evaluation procedure for the dismantling waste generated from the research reactors based on the activation calculation. In order to investigate the applicability of the ORIGEN code (included in SCALE6.2.4), which enables more accurate activation calculations using multigroup neutron spectra, we performed activation calculations with the ORIGEN-code and the ORIGEN-S code (included in SCALE6.0), which has been widely used in the past, for the dismantled wastes from the Rikkyo University Research Reactor, where radioactivity analysis data for the structural materials around the reactor core were compiled. As a result, the calculation time difference between ORIGEN and ORIGEN-S was small and the evaluated radioactivity concentrations of the former were in the range of 0.8-1.0 times those of the latter, which was in good agreement with those of radiochemical analysis in the range of 0.5-3.0 times. The applicability of ORIGEN was confirmed. In addition, activation calculations assuming trace elements in structural materials of nuclear reactor were performed with ORIGEN and ORIGEN-S and the results were compared. The causes of the large differences among 170 nuclides that are important for dose assessment in near-surface disposal were assessed each nuclide.
Sato, Shinichi*; Araki, Masanori; Omori, Junji*; Oono, Isamu*; Sato, Satoshi; Yamauchi, Michinori*; Nishitani, Takeo
JAERI-Tech 2002-083, 126 Pages, 2002/10
JAERI-Tech-2002-083.pdf:4.07MB
It is one of the foremost goals for ITER to demonstrate the attractiveness with regard to safety and environmental potential. This implies that the radioactive materials and waste at decommissioning phase should carefully be treated with prescribed regulations. As possible activities during the Coordinated Technical Activity (CTA), Japanese Participant Team (JA-PT) has proposed a study for searching the possibility of more reduction in the activated level by taking account of minimum material changes while keeping original design concept and structure. Based on it, reassessment of the activation level and the amount of activation volumes will give us positive aspects for public acceptance.
Seki, Yasushi; Aoki, Isao; Ueda, Shuzo; Nishio, Satoshi; Kurihara, Ryoichi; Tabara, Takashi*
Fusion Technology, 34(3), p.353 - 357, 1998/11
no abstracts in English
Tabara, Takashi*; Yamano, Naoki*; Seki, Yasushi; Aoki, Isao
JAERI-Tech 97-054, 164 Pages, 1997/10
no abstracts in English
Seki, Yasushi; Aoki, Isao; Yamano, Naoki*; Tabara, Takashi*
Journal of Fusion Energy, 16(3), p.205 - 210, 1997/00
Times Cited Count：8 Percentile：55.41(Nuclear Science & Technology)no abstracts in English
