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Mori, Eito; Yamamoto, Masahiko; Taguchi, Shigeo; Sato, Soichi; Kitao, Takahiko; Surugaya, Naoki
Nihon Hozen Gakkai Dai-11-Kai Gakujutsu Koenkai Yoshishu, p.132 - 138, 2014/07
The contamination of the radioactive material was observed on the filter casing surface of the glove box installed at the analytical laboratory in Tokai Reprocessing Plant. The cause of the contamination was investigated with visual inspection, penetrant testing and ultrasonic thickness measurement. It was found that a micro through-hole due to the corrosion of stainless-steel was generated in the glove box filter casing. The repair work of the filter casing was performed keeping the glove box negative pressure. The corrosion part of filter casing was replaced and newly fabricated casing was connected to the glove box with Tungsten Inert Gas welding method.
Suzuki, Hisanori; Nagayama, Tetsuya; Horigome, Kazushi; Ishibashi, Atsushi; Kitao, Takahiko; Surugaya, Naoki
Nihon Hozen Gakkai Dai-11-Kai Gakujutsu Koenkai Yoshishu, p.214 - 219, 2014/07
The Tokai Reprocessing Plant (TRP) is developing the technology to recover uranium and plutonium from spent nuclear fuel. There is an analytical laboratory which was built in 1978, as one of the most important facilities for process and material control analyses at the TRP. Samples taken from each process are analyzed by various analytical methods using hot cells, glove boxes and hume-hoods. A large number of maintenance work have been so far done and different types of experience have been accumulated. This paper describes our achievements in the maintenance activities at the analytical laboratory at the TRP.
Nishida, Naoki; Suwa, Toshio; Tanaka, Naoki; Inada, Satoshi; Kuno, Takehiko
Nihon Hozen Gakkai Dai-11-Kai Gakujutsu Koenkai Yoshishu, p.121 - 126, 2014/07
Corroded pore was found at stainless pipe for liquid waste solution from the analytical laboratory. Part of the pipe was cut for preparing samples to investigate the cause of the corrosion. The same size of stainless pipe was welded to recover it, under the strict radiation control. The restoration work was done inside of the vinyl house, as it is called "greenhouse", which was the small room completely separated by vinyl sheet. All the works, cutting, decontamination, digging groove and welding with back seal gas, were done inside of the greenhouse. We report the work method for recovery of corroded pipe containing radioactive materials
Tanaka, Naoki; Suwa, Toshio; Nishida, Naoki; Kuno, Takehiko; Inami, Shinichi
Nihon Hozen Gakkai Dai-11-Kai Gakujutsu Koenkai Yoshishu, p.127 - 131, 2014/07
Corroded pore was found at stainless pipe for liquid waste solution from the analytical laboratory. In order to find out the cause of corrosion, analytical samples were prepared cutting from the pipe. Reagents contained chloride, which had been used analytical laboratory more than ten years before the date, were found to be the trigger of the localized corrosion. We checked up all the pipes, which have been wasted including chloride solutions, by phased array instrument. We report the investigation of cause of corrosion and results of non-destructive testing.
Ishiyama, Toru; Kawasaki, Ichio; Miura, Hirohito*
Nihon Hozen Gakkai Dai-11-Kai Gakujutsu Koenkai Yoshishu, p.33 - 36, 2014/07
There are 4-boiler systems in NCL. These boilers have been operated in the long term over 20 years. One of them, the leakage of boiler water was found at one of the generating tubes, and 2 adjoining generating tubes were corroded in Dec, 2011. These generating tubes were investigated by immersion ultrasonic testing (UT) for measure thickness of the tube. As a result, thinner tube was found in a part of a bend and near the water drum. These parts are covered with sulfide deposit, it seems that the generating tubes were corroded by sulfide.