Development of in-reactor observation system using Cherenkov light, 3

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

In research reactors, a CCD camera is used to observe reactor core for reactor operation management, e.g. to prevent debris falling. In order to measure the reactor power and fuel burnup exactly by means of observation of Cherenkov light and ray information, the development of the on-line measurement device has been started since 2009. In this study, as a part of development of in-reactor surveillance, wavelength and absolute irradiance of Cherenkov light were measured by spectroscopy, and Cherenkov light was observed by the CCD camera. The neutral density filters (ND-filters) were used to investigate the transmittance of Cherenkov light in these measurements.