Analysis of microparticles generated by laser processing and development of a methodology for their nuclear identification (Contract research); FY2018 Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development

Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*

JAEA/CLADS, conducted the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") in FY2018. The Project aimed to contribute to solving problems in the field of nuclear energy represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. For this purpose, intelligence was collected from all over the world, and basic research and human resource development was promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barriers of conventional organizations and research fields. Among the adopted proposals in FY2018, this report summarizes the research results of the "Analysis of microparticles generated by laser processing and development of a methodology for their nuclear identification". Although laser processing has various advantages, one well-known disadvantage is that it generates a large amount of microparticles during the processing. Therefore, the application of laser processing to decommissioning waste contaminated with radioactive materials has been hesitant because the mechanism generating the microparticles has not been fully understood. In this study, the mechanism of microparticle production by laser processing is investigated from fundamentals. Also, we develop a laser on-line principle device to examine the nuclides present in the microparticles that are produced, based on the measurement of the particle size distribution by collecting the microparticles using aerodynamic lenses.