*Hikaru Miura¹, Takashi Ishimaru², Yukari Ito², Jota Kanda², Atsushi Kubo³, Shigeyoshi Otosaka⁴, Yuichi Kurihara⁵, Daisuke Tsumune¹, Yoshio Takahashi⁴ (1.Central Research Institute of Electric Power Industry, 2.Tokyo University of Marine Science and Technology, 3.Shizuoka University, 4.The University of Tokyo, 5.Japan Atomic Energy Agency)