1.緒言 日本原子力研究開発機構の東海再処理施設では、長期 の使用により、グローブボックスや配管の一部にステン レス鋼の腐食が懸念される。万が一腐食が発生した場合、 放射性物質を閉じ込める機能を維持できなくなる可能性 があるため、腐食原因の究明は、施設の維持・管理を行 う上で重要事項である。また、腐食が生じたグローブボ ックスを負圧などの安全機能を維持した状態において補 修を行う技術の構築も必要である。本稿では、放射性物質を取扱うグローブボックスに接 続された排気用フィルターケーシングに生じたステンレ ス......
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The cause of corrosion occurred in a glove box filter casing and its repair technique

In the new regulation formulated after the accident at Fukushima Daiichi Nuclear Power Plant, it is demanded that the glove box consists of incombustible or noncombustible materials. However, combustible acryl materials are used for many glove boxes installed in nuclear fuel cycle facilities. In this work, the glove box acryl panel has been replaced to incombustible material with accordance to the new regulation. The new panels have been manufactured by polycarbonate which satisfied the UL94 V-0 incombusti...
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Replacement of the Glove Box Panel in Nuclear Fuel Reprocessing Facility

Chloroprene rubber gaskets are often used to seal the glove box body and its panels. Such gaskets are deformed with compressive pressure and its elastic restoring force keeps sealing property. Therefore, gaskets play an important role in glove box sealing. However, physical properties of those used in glove box have not reported so far. In this study, hardness, elongation, tensile strength and compression set are investigated and its sealing performances are evaluated. The gaskets samples are taken fro...
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Physical property of seal-gasket for glove box panel in reprocessing facilities

Radioactive liquid waste from the Tokai Reprocessing Facility Analytical Laboratory is temporarily stored in intermediate waste storage tanks by using receiving valves. Then, the liquid waste is transferred to liquid treatment facility by using liquid feed valves. The deterioration of the gasket part of these valves (leakage of waste liquid) was confirmed in 2004. Since then, the material of gaskets was changed from polyethylene to polytetrafluoroethylene(PTFE). In 2016, the gaskets were replaced by periodi...
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Physical property evaluation of valve seal material at analytical radioactive liquid waste storage tanks in reprocessing facility

Tokai Reprocessing Plant (TRP) is implementing its decommissioning activities based on the decommissioning plan approved by Nuclear Regulation Authority (NRA). In the decommissioning, safety countermeasure against earthquakes and tsunamis is a top priority matter, especially for High Active liquid Waste facility (HAW) and Tokai Vitrification Facility (TVF), which handle highly radioactive liquid waste with high safety risks. This study focuses on the immediate tsunami countermeasures among the other safety ...
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Evaluation of Tsunami debris impact on Tokai Reprocessing Plant

A leakage was found on the sea release pipe of the Tokai reprocessing plant The leak point was discovered in a part buried in the sea floor The damaged part was cut and was collected, and investigation into the cause was subsequently carried out As a result, external force and hydrogen embrittlement were estimated to be the cause that produced a crack on the pipe As restoration of the leak part, a construction method using a coupling technique was proposed considering steady sealability on the restore...
英字タイトル:
Liquid leakage from the sea release pipe of the Tokai reprocessing plant- Restoration of the leak point at the see release pipe --