熔盐快堆U-Pu燃料循环增殖性能分析  

Analysis of U-Pu breeding in molten salt fast reactor

作　　者：李冬国[1] 周雪梅[1] 刘桂民[1] LI Dongguo;ZHOU Xuemei;LIU Guimin(Shanghai Institute of Applied Physics,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

出　　处：《核技术》2020年第8期13-19,共7页Nuclear Techniques

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

摘　　要：熔盐快堆增殖是当前国际上关注的热点,本文基于堆芯结构双流体方案,利用氟化或氯化熔盐中铀钚重金属盐高温下的高溶解度特性,获得熔盐快堆的高增殖。对铀钚燃料循环熔盐快堆的三种可行性熔盐燃料方案(LiF+PuF4+UF4、NaF+PuF4+UF4和NaCl+PuCl3+UCl3),采用基于反应堆安全分析和设计的综合性模拟程序SCALE(Standardized Computer Analyses for Licensing Evaluation),计算了中子能谱、反应性温度系数。分析了增殖比BR(Breeding Ratio)受反应堆裂变区、增殖区和中子反射层的尺寸影响,熔盐中6Li和35Cl同位素丰度对BR的影响,以及BR随运行时间动态变化。计算结果表明:氯盐方案(BR=1.46)与两种氟盐方案(BR≈1.06)相比较,具有更大的增殖能力优势。结合熔盐相图、BR随重金属摩尔浓度变化和BR最大值随熔盐平均工作温度变化曲线,可以在熔盐快堆设计中快速确定熔盐的工作温度、重金属摩尔浓度和反应堆增殖比。[Background] Molten salt reactor has been selected as one of the candidates for the fourth generation reactors due to its superior performance, and molten salt fast reactor has become one of the hot research subjects in the world. [Purpose] This study aims to find the most suitable molten salt fuel scheme in the uranium-plutonium cycle to achieve the purpose of high proliferation of fissile nuclides. [Methods] Based on the two-fluid cooling cycle scheme, independent cooling cycles for fission molten salt fuel and breeding molten salt, a comprehensive simulation program SCALE(Standardized Computer Analyses for Licensing Evaluation) was employed to calculate the neutron spectrum and reactivity temperature coefficient of three feasible molten salt fuel schemes(LiF+PuF4+UF4, NaF+PuF4+UF4 and NaCl+PuCl3+UCl3). High breeding ratio(BR) in the molten salt fast reactor was realized by utilizing the high solubility characteristics of plutonium and uranium heavy metal salts in fluorinated or chlorinated molten salts at high temperatures. Influence factors of BR, such as the sizes of fission zone, breeding zone and ZrC reflection layer, the isotopic abundances of 6Li and 35Cl in the molten salt, as well as the dynamic change of BR with running time, were computationally analyzed. [Results] The BR of two fluorinated molten salt schemes reaches about 1.06 whilst BR of the chlorinated molten salt scheme reaches 1.46 when the diameter and height of the fission zone are both 260 cm. [Conclusions] Combined with the phase diagram of molten salt, the variation curve of BR with the molar concentration of heavy metals and the variation curve of the maximum value of BR with the average operating temperature of molten salt, the operating temperature of molten salt, the molar concentration of heavy metals and the reactor BR can be be quickly determinated in the conceptual design of the molten salt fast reactor.

关 键 词：熔盐堆 快中子反应堆 增殖堆 中子物理 铀钚循环 

分 类 号：TL3[核科学技术—核技术及应用]