A EUROPEAN PROPOSAL FOR AN ITER WATER-COOLED SOLID BREEDER BLANKET

The water-cooled solid breeder blanket concept proposed here aims to r eplace the shielding blanket for the enhanced performance phase of the international thermonuclear experimental reactor (ITER). The nominal performances are as follows: an average neutron wall load of 1 MW m(-2 ) which corresponds to a fusion power of about 1.5 GW, and an average neutron fluence of 1 MWy m(-2) The proposed blanket concept has been d esigned to accept a power increase of about 30% and power transients u p to 3-5 GW for a short time. This blanket concept is based on a breed er inside tube (BIT)-type blanket with poloidal breeding elements made of 316 L-type stainless steel and filled with lithium metazirconate a nd beryllium pebbles. Inlet and outlet water temperatures of 160 and 2 00 degrees C have been considered with a medium-pressure cooling syste m during plasma burn. The diameters of the breeding elements are compa tible with the space available in test fission reactor core channels, making in-pile testing, required for blanket development and qualifica tion, easier. A conservative approach using qualified materials, a bla nket concept easily testable in fission reactors and on-going mock-up testing, which can be qualified using blanket test modules during the basic performance phase of ITER, will allow the blanket reliability re quired for the enhanced performance phase to be achieved.