Irradiation tests of radiation hard materials for ITER blanket remote handling system

ITERブランケット遠隔保守装置における耐放射線性機器の照射試験

齋藤 真貴子; 小坂 広; 丸山 孝仁; 野口 悠人; 武田 信和; 角舘 聡; 他1名*

Saito, Makiko; Kozaka, Hiroshi; Maruyama, Takahito; Noguchi, Yuto; Takeda, Nobukazu; Kakudate, Satoshi; 1 of others*

The ITER Blanket Remote Handling System (BRHS) will handle the blanket modules (BMs), which can weigh up to 4.5 ton and be larger than 1.5 m, stably and with a high degree of positioning accuracy. When the ITER has stopped plasma operations for maintenance, the BRHS will be installed in the vacuum vessel, whose components are radioactive, to remove and install the BMs. Therefore, the BRHS will be operated in a high radiation environment (up to 250 Gy/h) having an estimated total dose of 5 MGy during two years maintenance. As components may degrade by gamma irradiation, some equipment is expected to malfunction which causes delays in the in-vessel maintenance schedule. In this study, as the polymer material for the O-rings, bellows, cable sheaths, and coating materials is of the utmost priority in the design of the BRHS, additional material property tests to verify radiation hardness were performed after the candidate materials were irradiated with rays up to 5 MGy. After selection the radiation hard materials for BRHS by property test, function test such as sealing tests and repeat test were performed as the second step to confirm that the materials could still function properly as an O-ring and bellows.