乏燃料贮运容器辐射传热特性影响因素分析

Analysis of the influencing factors of radiation heat transfer characteristics of vessels for storage and transportation of spent fuel

为揭示乏燃料贮运容器的壁面辐射参数的影响规律,基于传导-对流-辐射的流固热耦合CFD模型,采用不同太阳暴晒条件、筒体外壁面发射率、内部格架壁面发射率和外部环境发射率,分析容器各部件最高温度、自然对流流速、外壁面辐射功率的变化规律。结果表明:CFD辐射传热功率与公式计算结果基本吻合,误差小于10%;筒体外壁面发射率的增加能使无太阳暴晒工况的容器各部位温度显著减小,但对太阳暴晒工况的作用不明显,发射率从0.30增加至0.80,前者计算的燃料包壳最高温度变化幅度是后者的3.51倍。内部壁面发射率对容器各部件温度分布影响较小,内部壁面发射率从0.22增加至0.90,燃料包壳温度仅降低约2℃;外部环境发射率对容器传热主导方式影响明显。本文可为乏燃料贮运容器辐射传热分析及结构选材提供技术指导。

In order to reveal the radiation heat transfer characteristics of the vessels for storage and transportation of spent fuel,based on fluid-structure coupling CFD numerical simulation taking into account conduction,convection and radiation,the change rules of maximum temperature of components,the maximum velocity of natural convection and the outer wall radiation heat transfer rate under different outer wall emissivity,inner wall emissivity and external environment emissivity with the effect of solar radiation were analyzed.The results show that the radiation heat transfer rates obtained by CFD are consistent with the formula results,with deviation of less than 10%.Without solar radiation,the maximum temperature decreases obviously when the emissivity of the outer wall increases.But this trend becomes much less significant for solar radiation.When this emissivity increases from 0.30 to 0.80,the maximum temperature variation of fuel cladding in former condition is 3.51 times that in latter condition.The inner wall emissivity has little influence on the temperature distribution of vessel components.When this emissivity increases from 0.22 to 0.90,and the temperature of fuel cladding is reduced by only about 2℃.While the external environment emissivity has obvious influence on the heat transfer mechanisms of vessel components.This study can provide technical guidance for radiation heat transfer analysis and selection of structural material of spent fuel storage and transportation vessel.