气隙和接触热阻对乏燃料干法转运容器热工安全影响研究

Research on Influence of Air Gap and Contact Thermal Resistance on Thermal Safety of Container for Spent Fuel Dry Transfer

结构壳体与铅层之间的间隙是转运容器向外排出衰变热的重要路径之一,2者之间的传热受到接触热阻的影响。在对转运容器热工安全评估的基础上,针对灌铅工艺中产生的铅层和结构壳体之间的接触热阻设定不同厚度的空气间隙,采用FLUENT软件进行了水平转运期间的瞬态数值模拟。结果表明,铅层和结构壳体之间的空气间隙层所产生的接触热阻致使2者之间产生显著的温差,温差随空气层厚度增加而变大,温差过大易导致铅层过热从而失去屏蔽安全功能;在转运容器的设计和制造中,灌铅工艺的优化应以缩小铅层和结构壳体间的间隙为目标,增强2层结构间的贴合度,以提高转运容器的热工安全性能。

The gap between the structural shell and the lead layer is one of the important paths for the transfer container to discharge decay heat,and the heat transfer between the two is affected by the contact thermal resistance.Based on the thermal safety assessment of the transfer container,the air gap with different thickness is set for the contact thermal resistance between the lead layer and the structural shell produced during the lead filling process,and the transient numerical simulation during horizontal transfer is carried out by using FLUENT software.The results show the contact thermal resistance generated by the air gap layer between the lead layer and the structural shell causes a significant temperature difference between the two.The temperature difference increases with the thickness of the air layer.Excessive temperature difference can easily cause the lead layer to overheat and lose the shielding safety function;In the design and manufacturing process of the transfer container,the optimization of the lead filling process shall aim to reduce the gap thickness between the lead layer and the structural shell,and enhance the fit degree between the two layers,so as to improve the thermal safety performance of the transfer container.