小型自然循环铅铋快堆无保护超功率事故不确定性分析研究  

Uncertainty analysis of unprotected transient overpower of small natural circulation lead-bismuth cooled fast reactor

作　　者：余清远 漆静雯 赵鹏程[1] 赵亚楠 于涛[1] YU Qingyuan;QI Jingwen;ZHAO Pengcheng;ZHAO Yanan;YU Tao(School of Nuclear Science and Technology,University of South China,Hengyang 421001,China)

机构地区：[1]南华大学核科学技术学院,衡阳421001

出　　处：《核技术》2022年第8期89-98,共10页Nuclear Techniques

基　　金：国家自然科学基金(No.11905101);国家级大学生创新与实验研究计划(No.S202010555037)资助。

摘　　要：典型瞬态事故对铅铋快堆安全运行具有极大挑战,将不确定性量化分析方法应用于瞬态事故计算,可降低瞬态安全参数的“不确定带”,更精确地评估反应堆安全特性。基于自主开发的快堆分析程序CFD/PFS,采用非参数统计法开展了小型自然循环铅铋快堆无保护超功率事故(Unprotected Transient Overpower,UTOP)的不确定性分析。首先,通过文献资料以及工程经验判断,考虑了三类不确定性输入参数:热工水力模型参数、中子物理模型参数以及燃料制造公差;然后,采用拉丁超立方对输入参数进行抽样,对瞬态安全参数进行不确定性量化分析,并通过相关系数分析法评估输入参数对瞬态安全参数的敏感度。分析结果表明:包壳、燃料峰值温度等目标参数的不确定带均能包络名义值;燃料峰值温度容忍上限值为2 757.25 K,包壳峰值温度容忍上限值为1 208.66 K;稳态燃料平均温度以及反应性反馈系数是最主要的不确定性来源。[Background] Typical transient accidents pose a great challenge to the safe operation of lead-bismuth fast reactors. [Purpose] This study aims to apply uncertainty analysis methods to transient calculations to reduce the "uncertainty band" of transient parameters and obtain more accurately assess reactor safety characteristics. [Method]Based on the self-developed fast reactor analysis CFD/PFS code, non-parametric statistical methods was employed to carry out the uncertainty analysis of the unprotected overpower accident(UTOP) of small natural circulation leadbismuth cooled fast reactor. Three types of uncertain input parameters, i. e., thermal-hydraulic model parameters,neutron physical model parameters, and fuel manufacturing tolerances, were considered according to the literature and engineering experience. Based on the uncertainty analysis procedure SIMLAB, the Latin hypercube sampling(LHS) was carried out for the input parameters, and the uncertainty of the transient safety parameters was quantitatively analyzed. Finally, the sensitivity of the input parameters to the transient safety parameters was evaluated by the correlation coefficient analysis method. [Results & Conclusion] Computational results show that uncertainty bands of target parameters, such as peak cladding temperature and peak fuel temperature, can all envelop the nominal value. The maximum tolerance of peak fuel temperature is 2 757.25 K, and the maximum tolerance of peak cladding temperature is 1 208.66 K. The analysis results indicate that the fuel average temperature and the reactivity feedback coefficient are the main sources of uncertainty.

关 键 词：铅铋快堆 CFD/PFS 无保护超功率事故 不确定性分析 敏感性分析 

分 类 号：TL329[核科学技术—核技术及应用]