Development of in-reactor observation system using Cherenkov light, 4

Kimura, Nobuaki ; Takeuchi, Tomoaki   ; Shibata, Akira ; Takemoto, Noriyuki ; Kimura, Akihiro ; Naka, Michihiro ; Nishikata, Kaori  ; Tanimoto, Masataka ; Tsuchiya, Kunihiko ; Sano, Tadafumi*; Unesaki, Hironobu*; Fujihara, Yasuyuki*; Okumura, Kiyoshi*; Nakajima, Ken*

In research reactors, CCD cameras are used to observe reactor core for reactor operation management, e.g. to prevent debris from falling. In order to measure the reactor power and fuel burnup exactly by means of observation of Cherenkov light, the development of the on-line measurement device started in 2009. In this study, the wavelength and the absolute irradiance of the Cherenkov light were measured by a spectrometer, and the Cherenkov light was observed by the CCD camera. As a result, the measurement value is good agreement with the nominal value. On the other hand, the value by the visible imaging system was obtained the same tendency of nominal transmittance value of ND-filters.