[1] Japan Atom Energy Agcy, Blanket Irradiat & Anal Grp, Fus Res & Dev Directorate, Oarai, Ibaraki 3111393, Japan
[2] Kaken Co Ltd, Mito, Ibaraki 3100903, Japan
[3] Univ Tokyo, Inst Engn Innovat, Bunkyo Ku, Tokyo 1138656, Japan
[4] Univ Tokyo, Dept Nucl Engn, Bunkyo Ku, Tokyo 1138656, Japan
[5] Univ Tokyo, Management Sch Engn, Bunkyo Ku, Tokyo 1138656, Japan
[6] Univ Tokyo, Sch Engn, Nucl Profess Sch, Ibaraki 3191188, Japan