高放废物核心处置单元传热数值模拟研究OA

It is of significant engineering importance to study the heat transfer mechanism in the core disposal element of high-level radioactive waste(HLW),especially for the design of buffer material and the overall disposal concept.In this paper,the core disposal element was taken as the research object,and a corresponding numerical model for heat transfer was established.This study employed the numerical simulation software COMSOL Multiphysics to investigate the effects of gap width and gap filling with buffer granules on the heat transfer performance of the disposal element.The results indicated that when the width of outer gap was 50 mm and the inner gap was 15,10,and 5 mm,respectively,the maximum temperatures of the buffer material were 363.4,363.16 and 362.91 K,respectively.Varying the gap width has no significant effect on the maximum temperature of the buffer material.When the width ofouter gap was 50 mm and the width ofinner gap was 10 mm,the maximum temperatures of the buffer material were 363.16 and 366.1 K for the cases with and without buffer granular filling in the inner gap,respectively.The presence of granular filling in the inner gap of the disposal element enhanced the heat transfer from the vitrified waste to the surrounding granite.When the width of outer gap was fixed at 50 mm and the width of inner gap measured 15 mm,10 mm,and 5 mm respectively,without buffer granular filling,the maximum temperatures of the buffer material were 366.95,366.1 and 364.73 K.This indicates that if a gap between the canister and the buffer material is unavoidable,a smaller gap width is more favorable for the outward conduction of heat released by the vitrified waste.