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Yokochi, Masaru; Sasaki, Shunichi; Yanagibashi, Futoshi; Asada, Naoki; Komori, Tsuyoshi; Fujieda, Sadao; Suzuki, Hisanori; Takeuchi, Kenji; Uchida, Naoki
Nihon Hozen Gakkai Dai-20-Kai Gakujutsu Koenkai Yoshishu, p.1 - 4, 2024/08
Tokai Reprocessing Plant, which is shifted to decommissioning stage, stores large amount of high-level radioactive liquid waste (HLLW) generated by reprocessing of spent nuclear fuels in High-level Active Waste facility (HAW). Radioactive risk related to HLLW has been concentrated in HAW until the completion of vitrification. Natural disasters such as earthquake may damage cooling function of HAW. Therefore, HAW must improve earthquake resistance, as exchanging the ground around HAW facility and pipe trench by concrete. This earthquake resistance construction starts from July of 2020 and completed in March 2024. This report summarizes the construction work and describes the inspection results after the construction.
Omori, Kazuki; Yamauchi, Sho; Yanagibashi, Futoshi; Sasaki, Shunichi; Wada, Takuya; Suzuki, Hisanori; Domura, Kazuyuki; Takeuchi, Kenji
Nihon Hozen Gakkai Dai-18-Kai Gakujutsu Koenkai Yoshishu, p.245 - 248, 2022/07
Tokai Reprocessing Plant (TRP), which is shifted to decommissioning stage, stores large amount of high-level radioactive liquid waste (HLLW). Although TRP is implementing vitrification of HLLW to reduce the risks related to HLLW storage, additional 20 years are required to complete vitrification of HLLW. Therefore, TRP is implementing safety countermeasure related to seismic resistance of HLLW storage facility as one of the top priorities. The results of the seismic evaluation indicate that although the facility itself is seismically resistant, there is a risk of insufficient binding force acting between the facility and the surrounding ground. Thus, replacement of the surrounding ground with concrete is performed. Since the countermeasures, to protect existing buries structure and coordinate with the other construction projects around the site, are required, the dedicated team was setup to handle the process and safety management of the concrete replacement construction.
Kudo, Atsunari; Kurabayashi, Kazuaki; Yanagibashi, Futoshi; Sasaki, Shunichi; Sato, Takehiko; Fujimoto, Ikuo; Obu, Tomoyuki
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04
The Co-processing process is the extraction process to recover Pu/U mixed product solution with given Pu/U ratio for improving of nuclear proliferation resistance. In addition, Np is also recovered with U and Pu because Np is one of minor actinides and a long-lived radionuclide and Np has the extractability into TBP solvent. Development of its flowsheet achieves to decrease environmental effect of waste materials. The orientation of development about Co-processing process is to demonstrate of reprocessing the future spent fuels from a LWR, a LWR-MOX hybrid, and a FR-MOX with one cycle. We demonstrated by use of miniature reflux-type centrifugal contactors at the partitioning unit. The test conditions of the Pu/U ratio in the loaded solvents were 1%, 3%, and 5% considering the composition of spent fuels. We used the HAN as the reductant of Np (VI) for back extraction. The results of these tests were very good. We got the prospect of U, Pu, and Np Co-processing flowsheet.
Kudo, Atsunari; Kurabayashi, Kazuaki; Yanagibashi, Futoshi; Sato, Takehiko; Fujimoto, Ikuo; Obu, Tomoyuki
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Yanagibashi, Futoshi; Nishida, Naoki; Suwa, Toshio; Fujimoto, Ikuo; Obu, Tomoyuki; Kashimura, Takao
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Fujimoto, Ikuo; Yanagibashi, Futoshi; Akiyama, Hideki; Morimoto, Kazuyuki; Obu, Tomoyuki; Taki, Kiyotaka
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Masui, Kenji; Yanagibashi, Futoshi; Kuno, Takehiko; Tanaka, Kenji
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Kudo, Atsunari; Nagaoka, Shinichi; Kurabayashi, Kazuaki; Yanagibashi, Futoshi; Obu, Tomoyuki
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Fujimoto, Ikuo; Yanagibashi, Futoshi; Yamamoto, Kohei; Sato, Takehiko; Obu, Tomoyuki; Taki, Kiyotaka
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Yamamoto, Kohei; Yanagibashi, Futoshi; Fujimoto, Ikuo; Sato, Takehiko; Obu, Tomoyuki; Taki, Kiyotaka; Hayashi, Shinichiro
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Kudo, Atsunari; Nagaoka, Shinichi; Yanagibashi, Futoshi
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Yanagibashi, Futoshi; Nagaoka, Shinichi; Isobe, Hiroyasu; Yasuda, Takeshi; Yada, Yuji; Suzuki, Shohei; Tokoro, Hayate; Kusaka, Shota; Shoji, Keita; Samoto, Hirotaka
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Tokai Reprocessing Plant (TRP) retained nuclear materials, such as low-concentration Pu solution due to TRP's shift to decommissioning in anticipation of resuming reprocessing. Pu solution required disposal as Flush-out before decontamination of equipment. Considering the operational range, the processing period, and the utilization after processing, Pu solution was transferred to high-active liquid waste tanks without evaporation or MOX conversion. During transferring, there was a critical risk due to Pu polymer formation caused by increasing in liquid temperature and decreasing in acid concentration. Based on past experience, U solution was mixed before transfer, and the acid concentration of the receiving tanks was adjusted. These measures prevented Pu polymer formation, ensured critical safety, and completed the disposal of low-concentration Pu solution.
Kudo, Atsunari; Yanagibashi, Futoshi; Hoshi, Takahiro; Tada, Kazuhito; Sato, Takehiko; Fujimoto, Ikuo; Obu, Tomoyuki
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Kudo, Atsunari; Yanagibashi, Futoshi; Tada, Kazuhito; Hoshi, Takahiro; Fujimoto, Ikuo; Obu, Tomoyuki
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