Development and testing of large-scale nuclear components and remote handling system in JAERI

Abstract

This paper overviews JAERI's activities on fusion nuclear technology specifically being performed for ITER. The topics include the development of the divertor, blanket, vacuum vessel, and remote handling system. Large-scale divertor mock-ups were developed and tested with hydrogen ion beams at two different heat load conditions. One is a heat flux of 5 MW/m 2 for 30 s, and the other is 20 MW/m 2, 10 s. The former simulates the ITER steady state condition and the latter does the transient condition. The mock-ups successfully withstood the steady state condition for more than 3000 cycles and also the transient condition for more than 1000 cycles. The results satisfy the requirement of the ITER divertor. A hot isostatic pressing (HIP) method has been developed to fabricate the shield blanket, especially for the simultaneous joining of DSCu/DSCu, DSCu/SS and SS/SS. An optimized HIP condition was found to be 1050°C, 150 MPa, and a 2-h holding time. On the basis of this result, a prototype module of the shield blanket with 1.6 m wide, 0.9 m high and 0.35 m thick has been successfully manufactured. Two half-sector models of the ITER full-scale vacuum vessel were successfully fabricated with an accuracy of below 3 mm. These models were assembled on site using automatic TIG welding in accordance with the basic procedure of the ITER initial assembly. The results have shown that the final assembly tolerance including fabrication tolerance is less than 10 mm, well below the requirement of 20 mm. A rail-mounted vehicle manipulator system was developed for remote maintenance of the ITER blanket. Full-scale vehicle manipulator equipment for handling a 4-ton blanket module has been fabricated and tested. From the performance tests of the fabricated full-scale vehicle manipulator equipment, handling capability of 4-ton blanket module was fully verified, together with the quantitative assessment on mechanical characteristics under the design loads. It has been concluded that the vehicle manipulator equipment satisfies the maintenance requirements for the ITER blanket and the fundamental technology for blanket maintenance has been well established.