基于衰变热的堆芯重要核素选取

衰变热在反应堆设计及安全分析中至关重要，目前计算衰变热主要基于行业标准和专用程序两种方法。通过对PWR燃料组件分别采用两种方法进行计算分析，相互验证了结果。详细分析了停堆不同时刻多种核素对衰变热的贡献，筛选出主要贡献者，为堆芯源项核素的选择提供参考。结果显示约50个核素即可包络停堆后100 h~50 a内95%以上的衰变热贡献。并对标准与程序结果的差异进行了分析，提出了标准适用范围的建议。

Significant Isotopes Selection of Core Inventory Based on Decay Heat

Decay heat is extremely important in core design and safety analysis. At present decay heat calculations are usually based on industrial standards or professional computer codes. Using the two methods to calculate the PWR assembly irradiation respectively, the validation was done by comparing the results with the two methods and the results were reasonably close. The analytical work was carried out on specific contributions made by important isotopes to decay heat at different shutdown time and the main contributors were screened out as a reference for the core source term inventory selection. The result shows that about 50 isotopes can bound 95% decay heat during 100 h50 a  after shutdown. Discrepancies between the standard and computer code were also investigated. Some instructive advices on suitable region were given for applying the standard.