CERAMIC BREEDING BLANKET DEVELOPMENT FOR EXPERIMENTAL FUSION-REACTOR IN JAERI

The ceramic breeding blanket is a promising breeding blanket concept f or experimental fusion reactors, and worldwide efforts have been devot ed to their design and R&D. A layered pebble bed type ceramic breeder blanket with water cooling was proposed by JAERI during ITER/CDA, and has been improved based on detailed analysis and consideration of fabr icability. In this concept, beryllium and ceramic breeder pebble bed l ayers are arranged alternately, in which the beryllium layer works as a thermal resistance layer between the breeder layer and a cooling pan el as well as a neutron multiplier. The use of the breeding material a nd beryllium in the form of small pebbles has been proposed to accommo date dimensional changes by irradiation effects. A wide variety of R&D has also been conducted on the design progress. The development of th e fabrication technology for the blanket box structure and its mechani cal testing, elementary testing on the thermal performance of the pebb le bed, and engineering-oriented material tests of breeder and berylli um pebbles, such as compatibility with structural materials and therma l cycle durability, are the main recent achievements. The present pape r outlines recent progress in the design of the ceramic breeder blanke t in JAERI and the major results of R&D on box structure fabrication a nd elementary out-of-reactor testing are also described.