【作者】 肖红星； 龙冲生；

【Author】 XIAO Hong-xing,LONG Chong-sheng (Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China,Chengdu of Sichuan Prov.610041,China)

【机构】 中国核动力研究设计院反应堆燃料及材料重点实验室；

【摘要】 通过分析和借鉴国内外关于二氧化铀燃料辐照肿胀行为研究的相关理论,对已有的Rest理论计算模型进行了改进,初步建立了适用于计算二氧化铀弥散型燃料辐照肿胀的Modified Rest理论计算模型。根据建立的Modified Rest模型编写了计算程序并采用文献中的相关物理参数分别在相同条件下对二氧化铀弥散型燃料辐照肿胀尤其是对燃料内裂变气体行为特征的相关数据进行了计算,将计算结果与辐照试验数据进行了对比。结果表明,燃料的辐照肿胀以及燃料内裂变气体气泡的密度和大小随燃耗、辐照温度等条件的变化趋势与试验结果一致。当燃耗较高时,辐照产生的缺陷会引起燃料相的亚晶化。亚晶界网络的出现加速了裂变气体的迁移,引起大尺寸气泡的产生,最终导致燃料的加速肿胀。本研究工作为今后开发燃料辐照肿胀行为模拟计算程序并评价燃料元件的物理性能奠定了一定的理论基础。更多还原

【Abstract】 The correlative theories of the uranium dioxide fuels swelling driven by the precipitation of the insoluble fission products in the fuels matrix have been analyzed.After modified the Rest model,a suitable theoretical model has been established to carry out numerical simulation in the study of the irradiation-induced swelling in dispersion fuel. Based on the established Modified Rest model,a computational program has been compiled and then used to calculate the irradiation-induced swelling of the dispersion fuel especially the fission gas behavior in the same conditions quantitatively. The results indicate that the trends of the irradiation-induced swelling rate,density and radius of the bubbles as a function of burn-up and temperature are confirmed with the irradiation experimental data in comparison.When the burn-up is high enough,the irradiation induced defects led to the subdivision of the grains in fuel.The subgrain boundary net work promotes the migration of fission gas.This will result in large bubbles formed in subgrain boundary and then induced the accelerated rate of irradiation-induced swelling in fuel.This work paves the way for both the development of numerical computational program for the irradiation-induced swelling behavior in fuel and assessing physical property of the nuclear fuel elements.更多还原