半衰期为数天的惰性气体和卤素裂变产物在UO2颗粒中的扩散与释放

摘要

在考虑吸附效应等物理过程的基础上,得到了裂变产物在UO2颗粒中扩散与释放模型的严格解,并导出了不同反应堆运行状态下裂变产物累积释放份额F(t)、释放-产出比R(t)/B(t)的严格表达式.利用上述结果以及相应的近似解、数值解,对半衰期为数天的惰性气体和卤素裂变产物(131I、131Xem、133Xe和133Xem)在不同堆芯历史条件下的F(t)和R(t)/B(t)进行了比较计算.分析表明,F(t)与R(t)/B(t)的结果均有所差别,但当反应堆运行时间达一定长度后,它们的数值相等.此外,严格解去掉了近似解中不必要的保守性,也比数值解更符合物理实际.%The exact solutions of diffusion and release model of noble gas and halogen fission products in UO2 particle of HTGR were built under the conditions of adsorption effect and other physical processes. The corresponding release fractions (F(t)) and the ratio of release and productive amounts (R (t)/B (t)) of fission products were also derived. Furthermore, the F(t) and R(t)/B(t) of 131I, 131Xem, 133Xe and 133Xem whose half-lifes are several days in UO2 particle with the exact solutions, approximate solutions and corresponding numerical solutions under different temperature histories of reactor core were investigated. The results show that the F(t) and R(t)/B(t) are different in numerical values unless the time of release is long enough. The properties of conservation of exact solutions are much more reasonable than the ones of approximate solutions. It is also found that the results of exact solutions approach the actual working conditions more than the approximate and numerical solutions.