石墨慢化通道式熔盐堆有效缓发中子份额计算方法研究  

Calculation Method of Effective Delayed Neutron Fraction in Graphite-moderated Channel-type Molten Salt Reactor

作　　者：崔勇 陈金根[1,2,3] 何帆[1,2,3] 李晓晓 蔡翔舟 CUI Yong;CHEN Jingen;HE Fan;LI Xiaoxiao;CAI Xiangzhou(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;CAS Innovative Academy in TMSR Energy System,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院上海应用物理研究所,上海201800 [2]中国科学院先进核能创新研究院,上海201800 [3]中国科学院大学,北京100049

出　　处：《原子能科学技术》2021年第8期1448-1455,共8页Atomic Energy Science and Technology

基　　金：中国科学院战略性先导科技专项(XDA02010000);国家自然科学基金(11790321);中国科学院前沿科学重点研究项目(QYZDY-SSW-JSC016)。

摘　　要：有效缓发中子份额(β_(eff))是研究反应堆动力学特性的关键参数。在液态燃料熔盐堆(MSR)中,燃料流动引起缓发中子先驱核(DNP)在堆内的再分布,并使部分DNP在堆外回路衰变,从而导致β_(eff)的计算方法与固态燃料反应堆不同。为评估石墨慢化通道式熔盐堆内燃料流动引起的反应性损失,研究缓发中子随燃料的流动行为,同时为堆设计和安全分析提供依据,分别基于解析方法和数值方法推导了计算β_(eff)的数学模型,计算了熔盐实验堆(MSRE)在额定工况下的DNP损失份额和堆内DNP浓度分布,并分析了燃料在堆外流动时间和入口流量对β_(eff)的影响。结果表明:两种方法均可对DNP行为提供合理描述;固定燃料在堆外流动时间,β_(eff)随入口流量的增加而减小;固定入口流量,β_(eff)随燃料在堆外流动时间的增加而减小,80 s后趋于稳定。The effective delayed neutron fraction(β_(eff))is an important reactor kinetics parameter.In liquid-fueled molten salt reactor(MSR),the fuel flow leads to the redistribution of delayed neutron precursors(DNP)in the core,and results in part of DNP decay in the external loop,which bring differences from solid-fueled reactors in the calculation method of β_(eff).In order to evaluate the reactivity loss caused by fuel flow,probe the flow behavior of the delayed neutrons driven by fuel salt,and provide a basis for design and safety analysis of the graphite-moderated channel-type MSRs,based on analytical and numerical methods,two mathematical models for calculating the β_(eff) of graphite-moderated channel-type MSR were derived,and the loss in DNP fractions and the DNP distribution of the molten salt reactor experiment(MSRE)were obtained.Besides,the impacts of inlet flow and residence time of fuel in external loop on β_(eff) were analyzed.The results show that both the two methods can provide a reliable description of DNP behavior.β_(eff) decreases with the rise of inlet flow rate when the residence time of fuel in external loop is kept constant,and with the rise of residence time of fuel in external loop,β_(eff) first decreases and then tends to be stable after 80 s when the inlet flow rate remains unchanged.

关 键 词：熔盐堆 缓发中子先驱核 有效缓发中子份额 动力学 

分 类 号：TL329[核科学技术—核技术及应用]