Development of welding tool for remote maintenance of ITER blanket

Tanigawa, Hisashi; Ueno, Kenichi; Inoue, Ryuichi; Takeda, Nobukazu; Kakudate, Satoshi

The shield blanket in ITER has an active cooling structure necessitating hydraulic connections to the cooling water manifold. To maintain or replace the blanket, welding the hydraulic connection by remote handling is necessary. Access for the welding is limited in a small hole in the first wall because of spatial constraints related to neutron and heat fluxes. A bore welding tool is required. Laser and TIG welding tools have been developed, and the welding conditions have been optimized for all position welding to horizontally located pipes. Additionally capability of re-welding between as-cut and new pipes has been confirmed. Based on the results, applicability of laser and TIG welding are comparatively assessed.