Recent Progress in Solid Breeder Blanket Development at JAEA

Japan Atomic Energy Agency (JAEA) plays a role of the principal institute in Japan for the design and the development of a solid breeder (WCSB) blanket and a helium cooled solid breeder (HCSB) blanket, in the ITER Test Blanket Modules (TBM) programt. The WCSB and HCSB modules consist of reduced activation ferritic/martensitic steel, F82H, as the structural material, Li₂TiO₃ as the tritium breeder material, beryllium or Be-Ti alloy as the neutron multiplier. One of the R&Ds for the WCSB TBM, the mockup of the first wall with embedded cooling channels was fabricated by applying HIP technique. Pebbles of Be₁₂Ti, which is a candidate material for the advanced neutron multiplier, were produced by a small-scale rotating electrode method. Mechanical and chemical properties and irradiation effects have been studied for Be₁₂T pebbles. Both oxidation and steam interaction were about 1/1000 as small as those of beryllium metal, which indicates a possibility to reduce a risk of a water or air ingress accident. The test schedule of TBMs is discussed according to the ITER operation phases.