Current status of Japanese water cooled ceramic breeder TBM

日本の固体増殖水冷却テストブランケットモジュールの現状について

廣瀬 貴規; 関 洋治; 谷川 尚; 榎枝 幹男

Hirose, Takanori; Seki, Yohji; Tanigawa, Hisashi; Enoeda, Mikio

The fabrication process of WCSB TBM has been demonstrated using full scale mock ups. As for tritium related issue, feasible fabrication process of tritium permeation barrier deserves more attention. The TBM contains Li ceramic pebble as a tritium breeder, Be pebble as a neutron multiplier. The breeder pebble bed must be separated from the multiplier with welded gastight box structure to avoid tritium adsorption on the Be. Several tritium permeation barriers have been investigated to reduce tritium inventory and permeation to coolant. Although the surface facing breeder and coolant should be covered with the barrier, it is difficult to cover entire surface especially for welds. Oxide film have been investigated as diffusion barrier. However, structural material covered with the film cannot be welded to avoid slag-inclusion. On the other hand, the barrier made after welding has difficulty in quality assurance of the barrier because it must be made on the interior surface of the box.