Precise boron determination in metallic fuel debris

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K15209
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 31010:Nuclear engineering-related
• Research Institution: Japan Atomic Energy Agency
• Principal Investigator: Sumita Takehiro 国立研究開発法人日本原子力研究開発機構, 福島研究開発部門 福島研究開発拠点 廃炉環境国際共同研究センター, 研究職 (50851325)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 燃料デブリ / ホウ素 / 即発ガンマ線分析

Outline of Final Research Achievements

In order to decommission the nuclear reactors damaged by severe accidents, It is important to study "fuel debris", which is melted and solidified nuclear reactor materials such as fuel rods, control rods, and structural materials. In this research theme, we focused on the high concentration of boron in "metallic fuel debris," which consists mainly of stainless steel, boron carbide (B4C), and metallic zirconium, and investigated a general-purpose boron concentration determination method that can be applied to metallic fuel debris.
Although the nature of the fuel debris has not yet been revealed, the proposed method could be applied to determine the boron concentration in metallic fuel debris using a general-purpose analytical method as long as the properties of the fuel debris are similar to those of the samples assumed in this study.

Free Research Field

高温材料

Academic Significance and Societal Importance of the Research Achievements

本研究成果は廃炉作業を進める上で重要である、“燃料デブリ”の形成メカニズム及びその性状の推定・把握に基礎科学的観点から貢献するものである。本研究で得られた知見は、燃料デブリの取出しや、その後の処置・処分方法を検討する上でも非常に重要であり、例えば、取り出し後の燃料デブリの臨界管理においては、燃料デブリ中のホウ素分布の推定が重要である。本研究の結果により、ホウ素がどのような化合物相に濃縮し易いか、その濃縮相がどのような形態か、等についても検討できるようになる。