基于子通道程序的铅铋反应堆失流事故不确定性分析  

Uncertainty analysis of loss of coolant flow accident in lead–bismuth reactor using subchannel code

作　　者：王凯[1] 杨俊康 赵鹏程[1] WANG Kai;YANG Junkang;ZHAO Pengcheng(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》2024年第8期119-128,共10页Nuclear Techniques

基　　金：核反应堆系统设计技术重点实验室运行基金(No.KFKT-05-FW-HT-20220014)资助~~。

摘　　要：子通道程序是反应堆热工领域的重要计算工具,利用不确定性分析方法能够有效识别和量化程序输入参数和模型假设的不确定性,从而提高程序的可靠性,为热工水力参数设计提供更可靠的参考依据。本文基于子通道程序SUBCHANFLOW,对10 MW小型铅铋反应堆在稳态和失流事故瞬态情况下进行了不确定性分析。首先,建立了全堆芯子通道模型,并确定了可能影响目标参数的输入参数。随后,采用最优拉丁超立方抽样方法在输入参数分布范围内采样,并输入到SUBCHANFLOW中得到失流事故瞬态和稳态情况下的不确定带。最后,通过灰色关联度分析,对瞬态和稳态敏感性进行了评估。计算结果表明:在瞬态和稳态情况下,目标参数的不确定带均能包络名义值;在瞬态情况下,芯块最高温度容忍上限为674.55℃,包壳最高温度容忍上限为618.31℃,且各参数计算精度基本小于7%;目标参数的不确定性主要来自入口温度、燃料棒高度、出口压力、总功率和包壳热导率等参数,其中入口温度影响最大。本研究揭示了在失流事故瞬态和稳态条件下,SUBCHANFLOW程序的计算不确定性以及各参数对系统响应的敏感性差异,有助于进一步优化和改进反应堆设计和运行策略,提高铅铋反应堆的安全性和可靠性。[Background]Subchannel codes constitute an important computational tool in the field of reactor thermo-hydraulics.Uncertainty analysis methods can be used to effectively identify and quantify the uncertainties of code input parameters and model assumptions,thus improving the reliability of the code so as to provide a more reliable reference for thermo-hydraulic parameter design.[Purpose]This paper aims to present an uncertainty analysis of a 10 MW small lead-bismuth reactor in steady-state and transient loss-of-flow accident scenarios by using the subchannel code SUBCHANFLOW.[Methods]First,a full reactor core subchannel was modeled,and the input parameters that affect the target parameters were identified.Second,the optimal Latin hypercubic sampling method was used for sampling within the distribution range of the input parameters,and the samples were imported into SUBCHANFLOW to obtain the uncertainty bands for the steady-state and transient loss-of-flow accident scenarios.Finally,gray correlation analysis was employed to evaluate the steady-state and transient sensitivities.[Results]The computational results indicate that the uncertainty bands of the target parameters envelop the nominal values in both the transient and steady-state cases.In the transient case,the maximum temperature tolerance upper limit of the pellet is 674.55℃and that of the cladding is 618.31℃.Further,the calculation accuracy of each parameter is essentially below 7%.The uncertainty in the target parameters mainly originates from parameters such as the inlet temperature,fuel rod height,outlet pressure,total power,and thermal conductivity of the cladding,with the inlet temperature having the most significant effect.[Conclusions]This study demonstrated the computational uncertainty of the SUBCHANFLOW code and the difference in the sensitivity of each parameter to the system response under the steady-state and transient loss-of-flow accident scenarios.The findings help further optimize and improve the design and operation strategy of lead-

关 键 词：子通道程序 铅铋反应堆 失流事故 不确定性分析 灰色关联度 

分 类 号：TL425[核科学技术—核技术及应用]