钠冷快堆系统分析程序FR-Sdaso衰变热计算模型开发与验证

反应堆停堆后的余热导出是反应堆的重要安全功能之一，停堆初期余热由裂变功率和衰变热构成，停堆后期余热主要取决于衰变热。本文开发了应用于钠冷快堆系统分析程序FR-Sdaso的衰变热计算模型，该模型可考虑裂变功率和功率历史的影响。通过与ANSI/ANS-5.1-2005标准和SAS4A/SASYS-1程序对比进行了模型验证。FR-Sdaso程序的计算结果与ANSI/ANS-5.1-2005标准的最大相对偏差约为0.1%，与SAS4A/SASYS-1的最大相对偏差在10-8量级，初步证明了所开发模型的正确性。最后，基于中国实验快堆的设计数据，分析了紧急停堆过程中裂变功率对衰变热的影响，结果表明，忽略裂变功率的影响导致衰变热的最大相对偏差约-7%，出现在停堆初期。因此，计算停堆初期衰变热时应考虑裂变功率的影响。

Development and Validation of Decay Heat Model for Sodium-cooled Fast Reactor System Code FR-Sdaso

Removement of residual heat is one of the significant safety functions of a nuclear reactor, and the shutdown residual heat at the beginning is composed of fission power and decay heat, meanwhile the long-term residual heat mainly depends on the decay heat. In this paper, a calculation model for the decay heat of sodium-cooled fast reactor system analysis code FR-Sdaso was developed, which has the ability to take the effects of fission power and power history into consideration. The model was validated by comparing with ANSI/ANS-5.1-2005 standard and SAS4A/SASYS-1 code. The maximum relative deviation between FR-Sdaso and ANSI/ANS-5.1-2005 standard is about 0.1%, and the maximum relative deviation between FR-sdaso and SAS4A/SASYS-1 is on the order of 10-8, which initially proves the correctness of the developed model. Finally, based on the design data of China Experimental Fast Reactor, the effect of fission power on the decay heat during the emergency shutdown process was analyzed. The results show that the maximum relative deviation of the decay heat caused by neglecting fission power is about -7%, which appears at the initial shutdown. Therefore, the effect of fission power should be considered in the calculation of decay heat at the initial shutdown.