Investigation of temperature measurement method in HTTR reactor

Tomimoto, Hiroshi; Hamamoto, Shimpei  ; Tochio, Daisuke ; Ueta, Shohei   ; Umeda, Masayuki; Nishihara, Tetsuo 

HTTR (High Temperature Engineering Test Reactor) loaded the first driver fuel in July 1998 and reached first criticality state in November 1998. After power increasing examination, HTTR has been conducting safety demonstration test and sequentially acquiring basic technical data of high temperature gas cool reactor. Temperature measurement inside the reactor is planed in the next midterm plan to improve HTTR performance. This report describes the investigation result of fuel temperature measurement method which is applicable to critical irradiation test.