熔盐堆^(135)Xe和^(135)Xe^(m)迁移效应对反应性的影响  

Effect of ^(135)Xe and ^(135)Xem Migration on Reactivity in Molten Salt Reactor

作　　者：吴辰 余呈刚[1,2] 蔡翔舟[1,2,3] 陈金根 WU Chen;YU Chenggang;CAI Xiangzhou;CHEN Jingen(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;Innovative Academies in TMSR Energy System,Chinese Academy of Sciences,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》2022年第12期2670-2677,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);中国科学院前沿科学重点研究项目(QYZDY-SSW-JSC016)。

摘　　要：熔盐堆采用液态燃料盐作为燃料,^(135)Xe作为反应堆中较重要的中子毒物,会随燃料盐的循环而在一回路流动。同时熔盐堆采用氦泡鼓气系统将裂变产物中的氪、氙等气体裂变产物吹出堆芯,提高中子经济性。根据TENDL—2021关于^(135)Xe^(m)热中子吸收截面的评估,其大于^(135)Xe的截面。为更准确地预测氙对反应性的影响,本文基于集总体积法,考虑燃料盐的流动效应,在模型中加入^(135)Xe^(m)热中子吸收截面相关数据,并采用美国8 MW熔盐实验堆(MSRE)的实验结果进行了验证。结果表明,模型计算结果与实验结果符合良好。将包含和不包含^(135)Xe^(m)影响的氙毒在^(233)U或^(235)U为燃料的情况下进行了对比,结果表明,^(135)Xe^(m)对稳态氙毒会产生一定的影响,且随功率的增大影响逐渐增大。最后通过石墨与氦泡之间的相互作用,评估了石墨、燃料盐和氦泡对氙毒的贡献,结果表明,氦泡与石墨之间的相互作用不可忽略。Fissile material dissolved in the molten salt is employed in molten salt reactor(MSR),which circulates through the primary loop.Considering the flow characteristic of fuel in MSR,the neutron poison calculation model such as Xe is different from traditional solid reactor.As an important neutron poison,^(135)Xe is free to migrate with the flow of molten salt in MSR.The helium bubble system of molten salt reactor can blow the fission products of krypton,xenon and other gases out of the reactor core to improve the neutron economy.The recent TENDL-2021 nuclear data library estimates the thermal neutron absorption cross section of ^(135)Xe^(m),which is much higher than ^(135)Xe thermal neutron absorption cross section.In order to predict the effect of xenon on core reactivity more accurately,the effect of ^(135)Xe^(m) thermal neutron absorption cross section was added into the Xe poison model based on the lumped volume method.The migration model is made up of cover gas calculation model and xenon worth calculation model.In order to calculate the xenon worth,the loop void fraction was calculated firstly,and the loop void fraction was inserted into the xenon worth calculation model.According to the rate balance equations and mass transfer equations,the concentration of xenon in loop could be calculated to compute the xenon worth.Firstly,the model results considering the flow effect of fuel salt were verified with the experimental results of 8 MW molten salt reactor experiment(MSRE).As the results shown,with the increase of loop void fraction,the steady-state xenon worth increases first and decreases later,which is in good agreement with experimental results of MSRE.Then the influence of fuel salt types and ^(135)Xe^(m) on steady-state xenon worth was considered in this paper.The steady-state xenon worth of the ^(233)U system with and without ^(135)Xe^(m) is made and compared to a ^(235)U system,indicating that the influence of ^(135)Xe^(m) on xenon worth cannot be ignored,which is much higher with the increase of power.F

关 键 词：熔盐堆 氙毒 ^(135)Xe^(m) 氦泡鼓气系统 

分 类 号：TL32[核科学技术—核技术及应用]