Wettability and release behaviour of fission products on solid nuclear fuels

2022 Fiscal Year Final Research Report

• Project/Area Number: 18H01918
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 31010:Nuclear engineering-related
• Research Institution: Kyoto University
• Principal Investigator: Kurosaki Ken 京都大学, 複合原子力科学研究所, 教授 (90304021)
• Co-Investigator(Kenkyū-buntansha): 宇埜 正美 福井大学, 附属国際原子力工学研究所, 教授 (00232885) ; 橋本 直幸 北海道大学, 工学研究院, 教授 (50443974)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 核燃料 / ぬれ性 / 核分裂生成物

Outline of Final Research Achievements

Focusing on the wettability between solid nuclear fuels and liquid fission product (FP) chemical species, the objective is to clarify the relationship between wettability and FP release behaviour from fuels through wettability evaluation tests between solids with fluorite-type crystal structures such as UO2 and various Cs halides such as CsI and FP release tests from simulated fuels. The objective of this study was to clarify the relationship between wettability and fission product release behaviour from fuels.
In this study, the wettability between solid and liquid was comprehensively verified using parameters such as the crystal orientation, crystal structure and surface roughness of the solid oxide, and the melt structure and bonding mode of the liquid caesium halides. Based on all the results obtained in this study, a new fission product (FP) release behaviour model was developed and proposed with the newly added effect of wettability.

Free Research Field

原子力工学

Academic Significance and Societal Importance of the Research Achievements

1F事故以降、事故の原因究明や発電所を安定化させることを目的として、様々な基礎研究が行われているが、それらの中でも、高揮発性のFPであるCsとIの燃料からの放出挙動を評価することは優先度の高い重要な課題とされている。ところが、公開されているデータのばらつきは大きく、燃料からのFP放出挙動には多くの不確かさが残されている。本研究の着目点であるぬれ性とFP放出挙動を結びつけることができれば、多くの不確かさが残されているFP放出挙動の解明の一助となり、FP放出のソースターム評価や原子炉事故時の放射性物質の放出抑制技術の確立につながる。