Simulation of the Thermomechanical State of the Fuel Element Section Considering Contact, Cracking and Creep

Abstract

The paper presents the developed numerical algorithm for solving axisymmetric multicontact interaction problems for a system of deformable bodies considering cracking and creep. We used the mortar method to consider the contact interaction. The stress-strain state simulation of a fuel element section, including 10 pellets in the surrounding cladding, has been carried out using the constructed algorithm. Stresses and deformations occur due to the release of heat in fuel pellets. The time dependence of the heat dissipation power is taken close to the real one. The paper provides a detailed description of the constructed numerical algorithm. It is based on the use of the finite element method, in which the significant and changing inconsistency of grids in contacting bodies is considering using the mortar method. We used the flow theory to model the creep deformation development and the smeared crack model to consider the fuel pellet cracking. We carried out a series of calculations using realistic thermomechanical properties of materials over a time interval of up to a year to assess the effects of various inelastic effects on the fuel rods stress-strain state. The comparative analysis results showed that the chosen model allows reducing the level of tensile stresses several times and considering the characteristics of the behavior of pellet and cladding materials at a qualitative level

Please cite this article in English as:

Aronov P.S., Galanin M.P., Rodin A.S. Simulation of the thermomechanical state of the fuel element section considering contact, cracking and creep. Herald of the Bauman Moscow State Technical University, Series Natural Sciences, 2025, no. 4 (121), pp. 4--22 (in Russ.). EDN: PZVQMB

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