压水堆核电厂乏燃料组件源项计算分析

核燃料贮存、运输以及后处理过程中的安全是构成核与辐射安全的重要内容，为保证安全性，提高运输经济性，减小后处理厂对环境的排放，须获得乏燃料组件的包络源项，因此，采用ORIGEN-ARP程序分析组件运行历史、初始富集度、燃耗深度等参数对源项的影响。运行历史在卸料初期对源项略有影响，可采用合适的保守因子予以包络，在冷却一定时间后，其影响可忽略不计；初始富集度、燃耗深度均不同的组件须经对比计算以获得包络源项。计算表明：在目前核电厂乏燃料组件中，²³⁵U初始富集度为4.45%、燃耗深度为55 GW•d/tU的AFA-3G型组件源项是包络的，可作为乏燃料水池、运输容器设计，以及后处理厂排放源项分析的初始源项。

Source Term Calculation of Spent Fuel Assembly of PWR Nuclear Power Plants

The safety of nuclear fuel storage, transportation, and post-processing is important component of nuclear and radiation safety. The envelope source term should be obtained to ensure safety of storage and transportation of spent fuel assemblies and enhance economic performance of spent fuel transportation, meanwhile, to reduce environmental radioactivity release of post-processing plant. The ORIGEN-ARP program was utilized to analyze the impact of power history, uranium enrichment and burnup on assembly source terms. Power history has some effect on source term, but an appropriate envelope factor can be adopted on cover it, and this impact can also be ignored after certain cooling time. Calculation shows that the source term of spent fuel assembly which with enrichment of 4.45% and burnup of 55 GW•d/tU is enveloped among current spent fuel assembly, and can be used as initial source term for design of spent fuel and shipping cask and analysis of environmental radioactivity release.