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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.
Tozawa, Katsuhiro
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 27(2), p.119 - 133, 2020/12
Since Monju started decommissioning with fuel in the reactor vessel, fuel removal from the reactor vessel will be given top priority until the year 2022 in the first stage. The number of fuel subassemblies to be handled has been changed from the initially planned 100 to 86 because there were 232 problems in the fuel handling work in FY2018 due to the fact that the continuous handling of fuel subassemblies up to that time was not sufficient. The problems that occurred were dealt with by three main measures, "Measures for increasing the fuel gripper torque of the main body A of the fuel transfer machine", "Measures for increasing torque of main gripper torque of the main body B of the fuel transfer machine ", and "Measures for software defects". As a result, the number of problems in the fuel handling work in 2020 was significantly reduced to 27, and the number of fuel handling is from initially planned 130 to 174.
Okano, Masanori; Akiyama, Kazuki; Taguchi, Katsuya; Nagasato, Yoshihiko; Omori, Eiichi
Dekomisshoningu Giho, (57), p.53 - 64, 2018/03
The construction of Tokai Reprocessing Plant (TRP) was initiated in June 1971, and its hot test using spent fuel started in September 1977. Thereafter TRP had been operated to reprocess 1,140 tons of spent fuel for approximately 30 years until May 2007, according to the reprocessing contract with domestic electric power companies. JAEA announced a policy of TRP in report of JAEA reform plan published in September 2014. The policy shows that TRP will shift to a decommissioning stage by economic reasons. Based on the policy, application of approval for TRP decommissioning plan was submitted to Nuclear Regulation Authority (NRA) in June 2017. This plan provides basic guidelines such as procedures for decommissioning and specific activities for risk reduction, and implementation divisions of decommissioning, management of spent fuels and radioactive wastes, decommissioning budget, and decommissioning schedule. The process of TRP decommissioning is planned to continue for approximately 70 years until the release of controlled areas of approximately 30 facilities.