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Sugawara, Takanori; Nishihara, Kenji; Iwamoto, Hiroki; Yagi, Takahiro*; Pyeon, C. H.*
KURRI Progress Report 2012, P. 212, 2013/10
An Accelerator-Driven System (ADS) has been investigated in Japan Atomic Energy Agency (JAEA) to transmute minor actinides discharged from nuclear power plants. The ADS proposed by JAEA is a lead bismuth eutectic (LBE) cooled-tank-type ADS. It has been known that there was a major upgrade for the cross section data of lead isotopes from JENDL-3.3 to JENDL-4.0 and the upgrade affects to the neutronic design of the ADS. This study aims to measure replacement reactivity from aluminum plates to lead plates at KUCA (Kyoto University Critical Assembly) to know which nuclear data library, JENDL-3.3 or JENDL-4.0 is reasonable for the lead isotopes. As the result, the replacement reactivity from the aluminum plates to the lead ones was measured as the positive value and the calculation results indicated that the lead nuclear data in JENDL-4.0 might be more reasonable than those in JENDL-3.3.
Kimura, Nobuaki; Takeuchi, Tomoaki; Shibata, Akira; Takemoto, Noriyuki; Kimura, Akihiro; Naka, Michihiro; Nishikata, Kaori; Tanimoto, Masataka; Tsuchiya, Kunihiko; Sano, Tadafumi*; et al.
KURRI Progress Report 2012, P. 209, 2013/10
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.
Tsujimura, Norio; Yoshida, Tadayoshi; Yashima, Hiroshi*
KURRI Progress Report 2012, P. 289, 2013/10
The latest model of the criticality accident alarm system (CAAS), recently developed and installed at the Tokai Reprocessing Plant of the Japan Atomic Energy Agency, consists of a plastic scintillator combined with a cadmium-lined polyethylene moderator and responds both to 
rays and neutrons. To evaluate the neutron absorbed dose rate response of the CAAS detector, a 24 keV quasi-monoenergetic neutron irradiation experiment was performed at the B-1 facility of Kyoto University Research Reactor. The B-1 facility consists of 45-cm-thick iron and 35-cm-thick aluminum filters built into a radial beam tube of the reactor and provides an intense beam of 24 keV neutrons transmitted through "resonance window" in the cross-sections of iron and aluminum. The CAAS detector was mounted on a wooden platform horizontally scanning across the collimated neutron beam extracted from the beam column. A neutron rem counter and an energy-compensated GM counter were also placed on the platform to measure the reference absorbed dose rates of neutrons and rays, respectively. The neutron response of the CAAS detector was derived by dividing the neutron-induced net reading, deduced by subtraction of the estimated -ray fractional reading based on the GM reading, by the reference neutron dose rate. The evaluated neutron response of the detector was confirmed to be in reasonably good agreement with the prior computer-predicted response.
