Dynamic stress analysis method in nuclear fuel fission crushing process

Abstract

The invention discloses a UO2 / Zr nuclear fuel plate fission mechanical analysis finite element model. The model is composed of a Zr alloy matrix, two UO2 core particles and fission air holes wrappingUO2 cores, wherein the UO2 / Zr nuclear fuel plate fission model is of a 1 / 4 circular fan-shaped thin plate structure; a Zr alloy cladding is arranged outside the fuel plate, a UO2 core body is arrangedinside the fuel plate, and meanwhile small particles mixed with UO2 and Zr, air holes and the like are included. Pores, UO2 and Zr particles are assumed to be spherical; and in order to apply a surface load to the LS-DYNA, a sheet three-dimensional body is established by taking a sphere center as a central point as a geometric model, and only one layer of unit is divided in the thickness direction, so that the finite element calculation amount is greatly reduced, and the finite element solving speed is increased.

Description

technical field [0001] The invention relates to a dynamic stress analysis method in the process of nuclear fuel fission and fragmentation. Background technique [0002] The core component of the current commercial nuclear reactor is the fuel assembly, and Zr and UO 2 It is a commonly used nuclear material, which is generally made of monolithic UO 2 / Zr fuel plate composition. The assembly is similar to metal-based composites, that is, composed of micron-scale UO 2 The particles are dispersed and distributed inside the Zr matrix alloy. The preparation process generally includes ball milling, mixing, hot isostatic pressing, and subsequent extrusion or rolling to reduce the porosity and achieve control. The dual purpose of shape and control performance. However, at UO 2 During the actual service of the / Zr single-piece fuel plate, it is often faced with harsh environments such as high temperature, high pressure and radiation, and it will inevitably be used in the UO 2 A l...

AI Technical Summary

Problems solved by technology

However, at UO 2 In the actual service process of / Zr monolithic fuel plate, it is often faced with harsh environments such as high temperature, high pressure and radiation, and it will inevitably be used in UO 2 A large amount of high-temperature fission gas is accumulated in the pores at the inner or interface of the plate, and under such complex multi-field coupling, iterative explosive impacts will occur on the Zr alloy matrix, which may bring plasticity to the Zr alloy matrix. Risk of injury or even destruction

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