[1] JAERI, Oarai Res Estab, Ibaraki 3111394, Japan
[2] Sangyo Kagaku Co Ltd, Tokai, Ibaraki 3191112, Japan
[3] Japan Atom Energy Res Inst, Tokai Res Estab, Tokai, Ibaraki 3191195, Japan
[4] Naka Fus Res Estab, Japan Atom Energy Res Inst, Naka, Ibaraki 3110193, Japan