Study on disposal of waste from reprocessing for commercial HTGR spent fuel

Fukaya, Yuji; Maruyama, Takahiro; Goto, Minoru; Ohashi, Hirofumi; Higuchi, Hideaki

JAEA-Research 2023-002, 19 Pages, 2023/06

JAEA-Research-2023-002.pdf:1.48MB

A study on disposal of waste derived from commercial High Temperature Gas-cooled Reactor ("HTGR") has been performed. Because of significant difference between the reprocessing of Light Water Reactor ("LWR") and that of HTGR due to difference in structures of the fuel, adoptability of the laws relating to reprocessing waste disposal, which is enacted for LWR, to HTGR waste should be confirmed. Then, we compared the technologies and waste of reprocessing and evaluated radioactivity concentration in graphite waste by activation and contamination based on whole core burn-up calculation. As a result, it was found that SiC residue waste should be disposed of into a geological repository as 2nd class designated radioactive waste in the Designated Radioactive Waste Final Disposal Act (Act No.117 of 2000), by way of amendment of the applicable order, same as hull and end-piece of LWR, and graphite waste should be shallowly disposed of than geological disposal as 2nd class waste for pit disposal in the Act on the Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactors (Act No.166 of 1957) same as a channel box of LWR.

The r-process element abundance with a realistic fission fragment mass distribution

Chiba, Satoshi; Koura, Hiroyuki; Maruyama, Toshiki; Ota, Masahisa*; Tatsuda, Sayuki*; Wada, Takahiro*; Tachibana, Takahiro*; Sumiyoshi, Kosuke*; Otsuki, Kaori*; Kajino, Toshitaka*

AIP Conference Proceedings 1016, p.162 - 167, 2008/05

https://doi.org/10.1063/1.2943568

Effect of the -delayed fission in r-process abundance is investigated. The data base for the fission fragment mass distribution used in the r-process network calculation is constructed based on the 2-center shell model and Langevinequation. The -decay rates (no emissive, neutron emission and -delayed fission) are also newly calculated with the gross theory. The differences appeared in the final element abundance calculated with and without fission process are demonstrated and the mass region modified by the fission products is presented.

Improvement of tritium accountancy technology for the ITER fuel cycle safety enchancement

Ohira, Shigeru; Hayashi, Takumi; Nakamura, Hirofumi; Kobayashi, Kazuhiro; Tadokoro, Takahiro*; Nakamura, H.*; Ito, Takeshi*; Yamanishi, Toshihiko; Kawamura, Yoshinori; Iwai, Yasunori; et al.

Nuclear Fusion, 40(3Y), p.519 - 525, 2000/03

https://doi.org/10.1088/0029-5515/40/3Y/312

no abstracts in English

Improvement of tritium accountancy technology for the ITER fuel cycle safety enhancement

Ohira, Shigeru; Hayashi, Takumi; Nakamura, Hirofumi; Kobayashi, Kazuhiro; Tadokoro, Takahiro*; Nakamura, H.*; Ito, Takeshi*; Yamanishi, Toshihiko; Kawamura, Yoshinori; Iwai, Yasunori; et al.

Fusion Energy 1998, 3, p.1069 - 1072, 1998/10

no abstracts in English

Impact of fission fragment mass distribution on r-process nucleosynthesis pattern

Chiba, Satoshi; Koura, Hiroyuki; Maruyama, Toshiki; Ota, Masahisa*; Tatsuda, Sayuki*; Wada, Takahiro*; Tachibana, Takahiro*; Kajino, Toshitaka*; Sumiyoshi, Kosuke*; Otsuki, Kaori*

no journal, , 

We introduce -delayed fission in r-process calculation, and investigate the difference of the abundance pattern of synthesized nuclei depending on the model of fission fragment mass distribution. We further discuss the impact of it on nucleo-cosmochronometer and possibility to restrict the physical condition of r-process sites.

A Survey on new standard materials for U-Pb dating of carbonate using LA-ICP-MS

Yokoyama, Tatsunori; Kokubu, Yoko; Murakami, Hiroaki; Watanabe, Takahiro; Hirata, Takafumi*; Sakata, Shuhei*; Danhara, Toru*; Iwano, Hideki*; Maruyama, Seiji*; Miyazaki, Takashi*; et al.

no journal, , 

Chronological and geochemical studies of carbonates, which are commonly found as fracture filling minerals in rocks, can provide information about geochemical conditions present during formation including in deep subsurface environments. A dating technique for the carbonates using laser ablation-multiple collector-inductively coupled plasma mass spectrometry (LA-MC-ICPMS) is still immature partly because of a lack of a consensus international carbonate standard for the in-situ dating technique. In this study, we performed a survey on the carbonate standard materials that may be suitable for high precision U-Th-Pb dating using LA-MC-ICPMS. We examined carbonate standard materials JCp-1 and JCt-1 issued by the Geological Survey of Japan (GSJ). Based on solution-based bulk analysis using MC-ICP-MS, heterogeneities in Pb isotope compositions were confirmed. Nevertheless, the 206Pb-based isotopic compositions were all within 1.2 per mill variations acceptable for a standard used for age determination using LA-MC-ICPMS. Additional tests on the heterogenities in U-Th-Pb compositions of the carbonate standards along with determinations of other trace elements using a 2D imaging LA-ICP-MS are ongoing. Examinations on both natural standards and synthetic standards are ongoing for further efforts in determination of the standard suitable for U-Th-Pb dating of carbonates.