Three-dimensional FE analysis of the thermal¨Cmechanical behaviors in the nuclear fuel rods

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• 作者：Yijie Jiang ; Yi Cui ; Yongzhong Huo ; Shurong Ding&#xA0 ; ; &#xA0 ; ^{dsr1971@163.com}
• 关键词：Three-dimensional finite element model ; Thermal&ndash ; mechanical behaviors ; Parametric study ; Nuclear fuel rod
• 刊名：Annals of Nuclear Energy
• 出版年：2011
• 出版时间：November 2011
• 年：2011
• 卷：38
• 期：11
• 页码：2581-2593
• 全文大小：2088 K

文摘

In order to implement numerical simulation of the thermal¨Cmechanical behaviors in the nuclear fuel rods, a three-dimensional finite element model is established. The thermal¨Cmechanical behaviors at the initial stage of burnup in both the pellet and the cladding are obtained. Comparison of the obtained numerical results with those from experiments validates the developed finite element model. The effects of the constraint conditions, several operation and structural parameters on the thermal¨Cmechanical performances of the fuel rod are investigated. The research results indicate that: (1) with increasing the heat generation rates from 0.15 to 0.6 W/mm³, the maximum temperature within the pellet increases by 99.3 % and the maximum radial displacement at the outer surface of the pellet increases by 94.3 % . And the maximum Mises stresses in the cladding all increase; while the maximum values of the first principal stresses within the pellet decrease as a whole; (2) with increasing the heat transfer coefficients between the cladding and the coolant, the internal temperatures reduce and the temperature gradient remains similar; when the heat transfer coefficient is lower than a critical value, the temperature change is sensitive to the heat transfer coefficient. The maximum temperature increases only 7.13 % when h changes from 0.5 W/mm² K to 0.01 W/mm² K, while increases up to 54.7 % when h decreases from 0.01 W/mm² K to 0.005 W/mm² K; (3) the initial gap sizes between the pellet and the cladding significantly affect the thermal¨Cmechanical behaviors in the fuel rod; when the gap size varies from 0.03 mm to 0.1 mm, the highest temperature in the pellet increases by 19.7 % , and the maximum first principal stress at the outer pellet surface decreases by 17.4 % ; it is critical to optimize the gap size in order to reduce the pellet¨Ccladding mechanical interaction and avoid their contact at early stage. This study lays a foundation for the further research on the irradiation-induced mechanical behaviors in the fuel rods.