Performance of new tritium calorimeter in TPL/JAEA

Hayashi, Takumi; Isobe, Kanetsugu; Kobayashi, Kazuhiro; Suzuki, Takumi; Yamada, Masayuki; Nakamura, Hirofumi; Yamanishi, Toshihiko

Calorimetric method is one of the important methods for tritium accountancy. It is very useful measurement for rather smaller size sample with larger decay heat. Recently, a tritium calorimeter has been used in TPL/JAEA, which improved Isotope Nano Calorimeter: INC-7200 made by Tokyo Riko Co. Ltd. with Toyama University. The main improvement points are larger size of heat detective cell (52mm:diameter 30mm:hight) and digital voltmeter of KEITHLEY 2128A. Design sensitivity and minimum detective heat are 0.4 micro-V/micro-W and 20 nano-W, respectively, which are same of the original model. These performances have been demonstrated with standardized liquid tritium sources, which are calibrated by liquid scintillation counter. As one of the important tritium accounting tools, this calorimeter will be used at a new tritium handling facility in Rokkasho site of JAEA under Broader Approach activity, where can handle 7.4 TBq of tritium per day.