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Grambow, B.; Nitta, Ayako; Shibata, Atsuhiro; Koma, Yoshikazu; Utsunomiya, Satoshi*; Takami, Ryu*; Fueda, Kazuki*; Onuki, Toshihiko*; Jegou, C.*; Laffolley, H.*; et al.
Journal of Nuclear Science and Technology, 59(1), p.1 - 24, 2022/01
Times Cited Count:31 Percentile:77.63(Nuclear Science & Technology)Tsubota, Yoichi; Laffolley, H.; Porcheron, E.*; Journeau, C.*; Delacroix, J.*; Guvar, C.*; Brackx, E.*; Lallot, Y.*; Bouland, A.*
no journal, ,
In order to safely remove fuel debris from the Fukushima Daiichi Nuclear Power Station (1F), it is necessary to quantitatively evaluate radioactive airborne particulate generated by the cutting of nuclear fuel debris. We fabricated Uranium-bearing simulated fuel debris (SFD) with In/Ex-Vessel compositions and evaluated the physical and chemical properties of aerosols generated by heating the SFDs. Based on these results, we estimated the isotopic composition and radioactivity of aerosols produced when 1F-Unit2 fuel debris is laser cut, which is a typical example of a heating method. Plutonium, mainly Pu,
Am, and
Cm were found to be the alpha nuclide, and
Pu,
Cs-Ba, and
Sr-Y were found to be the beta nuclide of interest.
Laffolley, H.; Tsubota, Yoichi; Tsuji, Tomoya; Honda, Fumiya; Nitta, Ayako; Kikuchi, Riku
no journal, ,
In support of the decommissioning efforts at the Fukushima Daiichi Nuclear Power Station, the Japan Atomic Energy Agency (JAEA) is developing the TRACE software for the accurate discrimination of alpha, beta, and gamma radiation sources in radioactive samples. This new technology utilizes the MiniPIX, a commercial 2D imaging semiconductor radiation sensor. The MiniPIX provides both a spatial image of radiation interactions within its pixel matrix and quantification of the energy transferred. The TRACE software analyzes the data from the MiniPIX by examining the energy and shape of pixel clusters created by radiation events. It identifies alpha particles primarily through the higher energy transferred in their interactions. For other events, it extracts shape parameters: gamma particles, having a quasi-straight path, create very small pixel clusters, while beta particles, being more deviated, generate snake-like clusters. The software can also provide an energy spectrum split by radiation type to assist in identifying radioisotopes. A core component of TRACE is a machine learning algorithm, trained using data acquired from standard sources such as Cobalt-60, Strontium-90, Cesium-137, and Americium-241, chosen for their relevance to Fukushima samples. Planned future integration with an XYZ motorized stage aims to automate data acquisition, improve efficiency, facilitate handling of radioactive and non-flat samples, and enable real-time adjustment of acquisition duration.