Design and development of supporting system for ITER/CDA blanket box structure

For ITER/CDA, a conceptual design of support structure for replaceable blanket box structure and its associated R and D activities, conducted from '90 to 92', are described. Since the sufficient stiffness against the enormous electromagnetic loads and the easy replaceability are required for the support structure, the cotter driven by hydraulic pressure has been employed as a locking/unlocking mechanism. Two kinds of hydraulic driving mechanism have been designed, manufactured and tested. Those are a 'piston jack' type and a 'flexible tube' type. In the latter type, the stroke is obtained by changing the cross section of the flexible tube from a flat racetrack shape to a fat shape by hydraulic pressure. According to the results of performance test, both of two mechanisms are found to be practically available. The surface condition of in-vessel components have been designed to be insulating or conducting in accordance with electric design requirements. For the insulation coating, Al2O3 has been selected as the material and a plasma spray method has been applied as the coating procedure. For the conduction coating, Cr3C2 has been selected as the material and JET-KOTE method has been applied as the coating procedure. Both methods have been successfully developed and have been confirmed to be applicable to the actual machine. (author)