Feasibility study of technology for Pu solution monitoring including FP; Development of gamma spectra detector for high active liquid waste

Sekine, Megumi ; Matsuki, Takuya ; Tokoro, Hayate; Tsutagi, Koichi ; Kitao, Takahiko ; Nakamura, Hironobu ; Tomikawa, Hirofumi

In a reprocessing facility, it is necessary to develop a detector which can measure plutonium (Pu) content in the Pu solutions containing fission products (FP) in order to expand the application of Pu monitoring. In order to establish this technology, JAEA has studied a system measure -rays was utilized since it applicable for Pu monitoring. Ce:GAGG (Ce:GdAlGaO) scintillator detector can measure a wide energy range in a high-dose environment and has reasonable resolution. -ray measurements were performed inside of the concrete cell containing the High Active Liquid Waste tank at the Tokai reprocessing plant. In the spectra, the two significant peaks were measured by the GAGG above 800 keV and were considered to be from Eu-154. There -ray measurements will be combined with previous neutron measurements and both will be compared to MCNP models for future Pu monitoring technology. This presentation will describe the detector selection, the design system, the results of -ray spectral measurements and the applicability for Pu monitoring. This project has been carried out under the support of the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of the Japanese government.