Development of a fiber-coupled laser-induced breakdown spectroscopy instrument for analysis of underwater debris in a nuclear reactor core |
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Authors: | Morihisa Saeki Akio Iwanade Chikara Ito Ikuo Wakaida Blair Thornton Tetsuo Sakka |
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Affiliation: | 1. Quantum Beam Science Center, Sector of Nuclear Science Research, Japan Atomic Energy Agency, 2-4, Shirane Shirakata, Tokai-mura, Ibaraki 319-1195, Japan;2. Oarai Research and Development Center, Japan Atomic Energy Agency, 4002, Naritacho, Oarai, Ibaraki 311-1393, Japan;3. Nuclear Science and Engineering Center, Sector of Nuclear Science Research, Japan Atomic Energy Agency, 2-4, Shirane Shirakata, Tokai-mura, Ibaraki 319-1195, Japan;4. Institute of Industrial Science, the University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505, Japan;5. Graduate School of Engineering, Kyoto University, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8510, Japan |
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Abstract: | To inspect the post-accident nuclear core reactor of the TEPCO Fukushima Daiichi nuclear power plant (F1-NPP), a transportable fiber-coupled laser-induced breakdown spectroscopy (LIBS) instrument has been developed. The developed LIBS instrument was designed to analyze underwater samples in a high-radiation field by single-pulse breakdown with gas flow or double-pulse breakdown. To check the feasibility of the assembled fiber-coupled LIBS instrument for the analysis of debris material (mixture of the fuel core, fuel cladding, construction material and so on) in the F1-NPP, we investigated the influence of the radiation dose on the optical transmittance of the laser delivery fiber, compared data quality among various LIBS techniques for an underwater sample and studied the feasibility of the fiber-coupled LIBS system in an analysis of the underwater sample of the simulated debris in F1-NPP. In a feasible study conducted by using simulated debris, which was a mixture of CeO2 (surrogate of UO2), ZrO2 and Fe, we selected atomic lines suitable for the analysis of materials, and prepared calibration curves for the component elements. The feasible study has guaranteed that the developed fiber-coupled LIBS system is applicable for analyzing the debris materials in the F1-NPP. |
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Keywords: | inspection laser post-irradiation examination transportable fiber-coupled LIBS instrument underwater debris high-radiation field single-pulse breakdown with gas flow, double-pulse breakdown |
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