利用超铀核素启动的小型模块化钍基熔盐堆中子学性能研究  

Neutronic performances of small modular thorium-based molten salt reactor starting with TRUs

作　　者：邹春燕[1,2] 余呈刚 朱贵凤[1,2] 郭威[1,2] 蔡翔舟[1,2] 陈金根[1,2] 邹杨[1,2] ZOU Chunyan;YU Chenggang;ZHU Guifeng;GUO Wei;CAI Xiangzhou;CHEN Jingen;ZOU Yang(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;CAS Center for Excellence in TMSR Energy System,Chinese Academy of Sciences,Shanghai 201800,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

出　　处：《核技术》2020年第12期72-81,共10页Nuclear Techniques

基　　金：中国科学院战略性先导科技专项项目(No.XDA02010000);中国科学院前沿科学重点研究项目(No.QYZDY-SSW-JSC016);国家自然科学基金(No.11790321)资助。

摘　　要：压水堆乏燃料中的超铀燃料(Transuranic isotopes,TRUs)含有大于50%的易裂变燃料,可作为熔盐堆钍铀循环的启动燃料。基于小型模块化钍基熔盐堆,采用TRUs和Th分别作为裂变燃料和增殖燃料,研究堆芯熔盐石墨比和初始重金属摩尔份额两个重要参数对堆芯中子能谱、233U产量、石墨寿命、温度反应性系数、TRUs消耗量等中子学特性的影响,为利用TRUs和Th的小型模块化钍基熔盐堆的堆芯参数选择提供依据。基于批处理周期及固有安全性等限值,给出满足要求的TRUs启动小型模块化钍基熔盐堆的燃料利用方案,分析其燃耗时间内的中子学特性。结果表明:采用压水堆中超铀核素作为易裂变燃料,是启动小型模块化钍基熔盐堆钍铀燃料循环的理想选择。在满足5 a石墨寿命和固有安全性(−5~−8 pcm∙K−1)等限值的条件下,选择重金属摩尔份额为6%、堆芯熔盐石墨比为25%的堆芯结构参数可得到较佳的燃料利用率。此时,热功率为150 MW、满功率运行5 a时,铀的年产量可达16.0 kg∙a−1,TRUs的年消耗量约36.1 kg∙a−1,可有效减少当前超铀乏燃料的储存。[Background]Transuranic isotopes(TRUs)in the spent fuel of pressurized water reactor(PWR)contain more than 50%of fissile fuels and can be used as a starting fissile fuel for thorium fuel cycle.[Purpose]This study aims to analyze the neutronic performances of a small modular thorium-based molten salt reactor(SM-TMSR)core with TRUs as fissile fuel and Th as fertile fuel.[Methods]Considering the batch reprocessing period and the limit value of the inherent safety,proper scenarios for thorium utilization in the SM-TMSR initiated by TRUs were proposed for the evaluation of the neutronic characteristics.Reactor analysis software SCALE6.1 was employed to analyze the influences of two important parameters(fuel volume fraction and initial heavy metal mole fraction)on the characteristics of neutron spectrum,233U production,graphite life,temperature coefficient,TRUs consumption,etc.[Results&Conclusions]The calculation results show that TRUs are an ideal fuel for starting Th-U fuel cycle of the SM-TMSR.Considering the constraints of the graphite's five-year life and the intrinsic safety(−5~−8 pcm∙K−1),the core with 6%heavy metal mole fraction and 25%fuel volume fraction can obtain a preferable fuel utilization efficiency.With the thermal power of 150 MW for 5-year full-power operation,the uranium production is about 16.0 kg∙a−1 and the transmutation rate of TRUs can achieve about 36.1 kg∙a−1,which can effectively reduce the spent fuel containing TRUs.

关 键 词：小型模块化熔盐堆 超铀燃料 熔盐石墨比 重金属摩尔份额 

分 类 号：TL99[核科学技术—核技术及应用]