熔盐堆中燃料流动对缓发中子的影响分析  

Study of fluid fuel influence on delayed neutron in Molten Salt Reactor

作　　者：蔡军[1,2] 夏晓彬[1] 陈堃[1] 梅牡丹[1] 

机构地区：[1]中国科学院上海应用物理研究所,嘉定园区上海201800 [2]中国科学院大学,北京100049

出　　处：《核技术》2014年第3期65-70,共6页Nuclear Techniques

摘　　要：熔盐堆具有良好的中子经济性、固有安全性、可在线后处理、防核不扩散等特点,是六种第四代先进反应堆堆型中唯一的液体燃料反应堆。然而,熔盐堆中采用流动的熔盐作为液体燃料,从而缓发中子先驱核会随着燃料的流动流出堆芯并在堆芯外发生衰变,这不同于固体燃料反应堆。文中针对了一座实际运行过的熔盐实验堆(Molten Salt Reactor Experiment,MSRE),基于中子动力学模型,采用圆柱体均匀堆的近似处理方法推导了液体燃料反应堆的缓发中子先驱核浓度数学模型,研究了恒定流速下的反应性损失及不同燃料熔盐流速对缓发中子分布的影响。结果表明缓发中子在越靠近堆芯中心区域的位置就越多,同时熔盐流速的变化对衰变周期越短的缓发中子先驱核组数的影响比较小。通过本研究,可以了解熔盐堆中缓发中子随着燃料流动的变化情况,为熔盐堆安全分析提供参考依据。Background： The Molten Salt Reactor （MSR） is one of the six advanced reactor types for future nuclear energy systems in the Generation IV International Forum （GIF）, possessing the advantages of good neutron economics, inherent safety, processing online, nuclear nonproliferation, etc. Due to the fluid fuel, a part of delayed neutron precursors drifts out of the reactor and decays in the loop, which is different from the solid-fuel reactor. Purpose： The distribution of delayed neutrons with different fuel velocity for Molten Salt Reactor Experiment （MSRE） is analyzed to provide reference for safety design of MSR. Methods： Based on the neutron kinetics and approximate method of homogeneous reactor, a distribution model of delayed neutron was presented. This model is applied to the distribution study of delayed neutrons with different fuel velocity. Results： The number of delayed neutrons in a core radius of 20 cm was more than that in a core radius of 30 cm. When the flow velocity of fuel decreased by a half, the discrepancy of delayed neutrons between the fifth-group and sixth-group precursors is within 6%. Conclusion： The number of delayed neutrons is increasing toward the center of reactor core. The group of delayed neutron precursors with shorter half-time has little effect on the flow velocity of molten salt.

关 键 词：熔盐实验堆(Molten SALT REACTOR Experiment MSRE) 缓发中子先驱核 液体燃料 

分 类 号：TL329[核科学技术—核技术及应用]