Speaker
Makiko Saito
(Naka Fusion Institute)
Description
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 5MGy during maintenance (maximum of two years). The radiation hardness requirement for ITER BRHS components is 1MGy total dose. As components may degrade by gamma irradiation, some equipment is expected to malfunction which causes delays in the in-vessel maintenance schedule. Therefore, failure mode and effects analyses (FMEA) were performed on the BRHS components and FMEA results suggest trouble with the power supply and signals due to degradation of the insulation of electrical components, and malfunctioning motors due to degradation of the lubricants of mechanical components. Material selections and irradiation tests were performed to AC servo motor and non-halogen cable in the past study. As a result, radiation hardness of 8MGy and 3MGy were confirmed for AC servo motor and non-halogen cable, respectively. 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 materialproperty tests to verify radiation hardness were performed after the candidate materials were irradiated with gamma rays up to 5MGy. 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.
Co-authors
Hiroshi Kozaka
(Naka Fusion Institute, Japan Atomic Energy Agency, Naka, Ibaraki, Japan)
Makiko Saito
(Naka Fusion Institute, Japan Atomic Energy Agency, Naka, Ibaraki, Japan)
Nobukazu Takeda
(Naka Fusion Institute, Japan Atomic Energy Agency, Naka, Ibaraki, Japan)
Satoshi Kakudate
(Naka Fusion Institute, Japan Atomic Energy Agency, Naka, Ibaraki, Japan)
Takahito Maruyama
(Naka Fusion Institute, Japan Atomic Energy Agency, Naka, Ibaraki, Japan)
Yuto Noguchi
(Naka Fusion Institute, Japan Atomic Energy Agency, Naka, Ibaraki, Japan)
