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Omori, Takazumi; Otsuka, Kaoru; Endo, Yasuichi; Takeuchi, Tomoaki; Ide, Hiroshi
JAEA-Review 2021-015, 57 Pages, 2021/11
The JMTR reactor facility was selected as a decommissioning one in the Medium/Long-Term Management Plan of JAEA Facilities formulated on April 1, 2017. Therefore, the decommissioning plan was submitted to Nuclear Regulation Authority on September 18, 2019, and the approval was obtained on March 17, 2021 after two amendments. Currently, preparations for decommissioning are underway. The JMTR reactor facility has been aged for more than 50 years since the first criticality in March 1968. However, some of the water piping systems has not been updated since its construction, and there is a possibility of pipe wall thinning due to corrosion, etc. Therefore, the integrity of the water piping was investigated for the facilities that circulate cooling water and pump radioactive liquid waste. In this investigation, the main circulation system of the reactor primary cooling system, the pool canal circulation system, the CF pool circulation system, the drainage system of the liquid waste disposal system, and the hydraulic rabbit irradiation system of the main experimental facility were measured for the pipe wall thickness using the Ultrasonic Thickness Measurement (UTM) method. These values satisfied the technical standards for research and test reactor facilities. No loss of integrity is expected to occur during the upcoming decommissioning period. In the future, we will periodically confirm that there is no wall thinning in the piping of the cooling water circulation and the water transmission system during the decommissioning period by using this result as basic data.
Oba, Toshihiro; Suetsugu, Hidehiko*; Yano, Masaya*; Kato, Chiaki; Yanagihara, Takao
JAERI-Tech 2002-082, 47 Pages, 2003/01
The demonstration test for evaluating reliability of the acid recovery evaporator at Rokkasho Reprocessing Plant has been carried out at JAERI. For the nondestructive measurement of the thickness of heat transfer tubes of the acid recovery evaporator in corrosion test, we have developed thickness measurement apparatus for heat transfer tubes by ultrasonic immersion method with high resolution. The ultrasonic prove in a heat transfer tube can be moved vertically and radially. The results obtained by this apparatus coincident well with those obtained by a destructive method using an optical microscope.
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Journal of Nuclear Science and Technology, 21(7), p.515 - 527, 1984/00
Times Cited Count:10 Percentile:70.64(Nuclear Science & Technology)no abstracts in English