2022 Annual Meeting

Presentation information

Oral presentation

II. Radiation, Accelerator, Beam and Medical Technologies » 202-2 Radiation Physics, Radiation Detection and Measurement

[2B13-19] Homeland Security and Nuclear Reactor Measurement 2

Thu. Mar 17, 2022 3:55 PM - 5:50 PM Room B

Chair: Ikuo Kanno (Kyoto Univ.)

4:55 PM - 5:10 PM

[2B17] Improvement of in-situ alpha air monitor (IAAM) for the measurement of airborne radioactive concentration in decommissioning

*Youichi Tsubota1, Fumiya Honda1, Masato Yoshida1, Takahiro Nakagawa1, Yuki tamakuma2, Shinji Tokonami2, Atsushi Ikeda-Ohno1 (1. JAEA, 2. Hirosaki Univ.)

Keywords:Continuous air monitor, in-situ monitoring, alpha aerosols, nuclear fuel debris, decommissioning

A large amount of radioactive aerosols are expected to be dispersed during large-scale retrieval of fuel debris at the decommissioning of Fukushima Daiichi Nuclear Power Plant (1F) and nuclear fuel facilities. Particulates containing alpha-nuclides (alpha-aerosols) have high effective dose coefficients upon inhalation, therefore appropriate control and monitoring are required. Conventional dust monitors using SSBD have difficulties with moisture resistance and clogging of filter paper. We have developed an in-situ alpha air monitor (IAAM) that directly measures alpha-rays from aerosols using thin scintillator, multi-anode photomultiplier tube and flat-type-flow path equipped with a heater. In this presentation, we report on the basic performance evaluations, the change in particle size due to air drying, and the improvement of the power supply for on-site implementation at 1F.