摘要
熔盐堆是钍资源核能利用的理想堆型,而燃料的钍(Th)含量会影响堆中子学特性和钍铀转换性能。基于MCNP(Monte Carlo N Particle Transport Code)和MOBAT(burnup code coupled with MCNP and ORIGEN2 using BATch language)程序分析了2 MW(热功率)熔盐实验堆不同Th添加量满功率运行300 d的钍铀转换及堆中子学特性。结果表明:Th消耗率随添加量增加而减小。Th转化率随Th添加量增加而增大,但增长率逐渐减小。233Th浓度达到最大值的速率与Th的质量呈线性关系,233Pa与233Th的变化趋势一致。Th装量越高,生成的233U的浓度也越高,233U的积累量随运行时间不断增加。Th装量越大,需添加的235U越多,135I浓度增加会增加Xe的平衡浓度。Th装量越大,中子能谱越硬,233U产量越高,意味着在快中子能谱下更易实现转换或增殖。80 kg Th运行4 d即可满足放化检测限。基于钍铀转化数据、反应性需求、放化检测限等因素综合考虑,实验堆可开展几十至百公斤级的Th利用与钍铀循环验证实验。
[Background]Thorium-uranium fuel cycle has the advantages of making use of abundant thorium resources,producing less nuclear waste and low toxicity,as well as nuclear non-proliferation.Molten salt reactor is an ideal type of nuclear energy utilization of thorium resources.The amount of thorium added in the core fuel can affect the thorium-uranium conversion performance in the molten salt reactor.[Purpose]This study aims to understand the effect of thorium addition on the conversion performance of thorium and uranium in molten salt reactor.[Methods]Based on MCNP(Monte Carlo N Particle Transport Code)program,the core physical model was established.The neutron physical characteristics and thorium-uranium conversion characteristics of 2 MW(thermal power)liquid fuel experimental reactor under different thorium additions running at full power for 300 days were analyzed by using MOBAT(burnup code coupled with MCNP and ORIGEN2 using BATch language)burnup program.Analysis objectives included the energy spectrum changes at the beginning and the end of burnup,Xe equilibrium,as well as the consumption ratio and transfer characteristics,and the evolution of important nuclides in thorium uranium chain.[Results]The results show that the consumption rate of thorium decreases with the increase of added amount.CR raises with the increase of Thorium addition,but the growth rate decrease gradually.The rate at which 233Th concentration reaches the maximum value is linearly related to the thorium mass,and the 233Pa has the same evolution trend as the 233Th.The higher the thorium content in the fuel,the higher the concentration of 233U,and the accumulation of 233U increases with the running time.Based on the radiochemical detection limit,80 kg thorium can meet the minimum detection value after 4 days.[Conclusions]Based on the data of thorium-uranium conversion,the amount of uranium fuel needed to maintain the back-up reactivity,the limit of radiochemical detection and other factors,the experimental reactor can carry out the utilization of thorium in the order of tens to hundreds of kilograms and the verification experiment of Thorium-Uranium cycle,with the priority of about 80 kg.In addition,the more thorium was added,the more Uranium needed to be added.The increase of 135I concentration will increase the equilibrium concentration of Xe.The more thorium is added,the harder the neutron spectrum and the higher the 233U output will be,which means that it is easier to achieve transformation or proliferation under the fast neutron spectrum.
作者
陈鹏
周波
严睿
邹杨
CHEN Peng;ZHOU Bo;YAN Rui;ZOU Yang(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《核技术》
CAS
CSCD
北大核心
2020年第10期66-74,共9页
Nuclear Techniques
基金
中国科学院战略性先导科技专项(No.XDA02010000)
钍铀燃料循环特性和若干关键问题研究项目(No.QYZDY-SSW-JSC016)
上海市自然科学基金(No.19ZR1468000)资助。
关键词
钍消耗率
钍铀链
钍铀转换
中子能谱
增殖
Consumption rate
Thorium-uranium chain
Thorium-uranium conversion
Neutron energy spectrum
Proliferation
