Research on multi-scale creep behaviors of UN-U3Si2 composite fuels

YANG Qingfeng; XIE Zhexiao; CHEN Ping; ZHANG Jing; GAO Shixin; DING Guochen; ZHOU Yi; YIN Chunyu; DING Shurong; HE Liang; SUN Dan

doi:10.11889/j.0253-3219.2022.hjs.45.120601

He jishu (Dec 2022)

Research on multi-scale creep behaviors of UN-U3Si2 composite fuels

YANG Qingfeng,
XIE Zhexiao,
CHEN Ping,
ZHANG Jing,
GAO Shixin,
DING Guochen,
ZHOU Yi,
YIN Chunyu,
DING Shurong,
HE Liang,
SUN Dan

Affiliations

YANG Qingfeng: Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610213, China
XIE Zhexiao: Institute of Mechanics and Computational Engineering, Department of Aeronautics and Astronautics, Fudan University, Shanghai 200433, China
CHEN Ping: Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610213, China
ZHANG Jing: Institute of Mechanics and Computational Engineering, Department of Aeronautics and Astronautics, Fudan University, Shanghai 200433, China
GAO Shixin: Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610213, China
DING Guochen: Institute of Mechanics and Computational Engineering, Department of Aeronautics and Astronautics, Fudan University, Shanghai 200433, China
ZHOU Yi: Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610213, China
YIN Chunyu: Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610213, China
DING Shurong: Institute of Mechanics and Computational Engineering, Department of Aeronautics and Astronautics, Fudan University, Shanghai 200433, China
HE Liang: Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610213, China
SUN Dan: Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610213, China

DOI: https://doi.org/10.11889/j.0253-3219.2022.hjs.45.120601
Journal volume & issue: Vol. 45, no. 12
pp. 120601 – 120601

Abstract

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BackgroundUN-U3Si2 composite fuels have a promising prospect in advanced future accident tolerant fuel elements. Its irradiation creep and thermal creep caused by in-reactor operation have an important influence on the irradiation-induced thermo-mechanical coupling behavior and safety of the fuel elements.PurposeThis study aims to develop a stochastic modeling method according to the metallographic structure of composite fuel and numerical simulation of the uniaxial tensile creep test of the UN-U3Si2 composite fuel (20% U3Si2).MethodsBased on the data of creep experiments from literatures, the dominated creep mechanisms of UN and U3Si2 polycrystalline fuels were analyzed, and their creep rate models considering vacancy diffusion and dislocation motion mechanisms were obtained by curve fitting. Then, the correlation model between the macroscopic creep of composite fuel and the contribution of each component was established on the basis of the homogenization theory and the removal of irradiation swelling effect. Finally, based on the metallographic structure diagram of composite fuels in the literatures, stochastic modeling method was developed and applied to the numerical simulation of the uniaxial tensile creep test of the UN-U3Si2 composite fuel (20% U3Si2).ResultsThe model predictions of UN and U3Si2 creep rates are in good agreement with the experimental results, validating the effectiveness of the model. The contribution of the component fuels to the macroscopic equivalent creep of the composite fuel is obtained by analysis of the underlying creep mechanism. When the fission density reaches 4.32×1027 fissions·m-3, the maximum von Mises stress at the interface between particles and matrix is about 6 times of the homogeneous tensile stress applied externally.ConclusionsThe research results indicate that the difference in the irradiation swelling of UN and U3Si2 will result in the strong internal mechanical interaction in the composite fuel whilst the existence of weakened stress regions leads to the negligible effect of irradiation swelling on the macroscopic equivalent creep strain of the composite fuel.

Published in He jishu

ISSN: 0253-3219 (Print)
Publisher: Science Press
Country of publisher: China
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Nuclear engineering. Atomic power
Website: https://www.hjs.sinap.ac.cn/

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