Development of a DC -1 MV Insulating Transformer for Neutral Beam Injectors

A dc -1 MV insulating transformer has been developed for the power supply of the neutral beam injector (NBI) at ITER. A dc long pulse -1 MV insulation structure between the primary and secondary windings, considering potential variation in the insulator for dc long pulse, has been designed. Simultaneous development of a compound bushing which consists of an ac 500 kV condenser bushing inside a cylindrical fiber reinforced plastic (FRP) tube has been carried out. The dc -1 MV insulation design has been verified by high voltage insulation tests of ac 50 Hz 1300 kV peak for 1 minute; dc -1200 kV for one hour; and a long duration test of dc -1060 kV for 5 hours. These results showed that the insulating transformer satisfy the power supply requirements for the ITER NBI

ガンマ線照射を模擬した非照射の湿度制御環境での炭素鋼の腐食モニタリング

ガンマ線照射環境下における炭素鋼の腐食挙動を調査した。種々の温湿度及びオゾン濃度が腐食速度に与える影響について、腐食電位の実測により評価した。その結果、腐食速度は、相対湿度とオゾン濃度とともに増加することが明らかとなった