ESSM和Tone方法在熔盐堆共振计算中的适用性分析  

Applicability analysis of the ESSM and Tone's method in the resonance calculation of molten salt reactors

作　　者：戴明[1] 张奥 程懋松[1,2] DAI Ming;ZHANG Ao;CHENG Maosong(Shanghai Institute of Applied Physics,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]中国科学院大学,北京100049

出　　处：《核技术》2022年第9期101-114,共14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：基于ThorLAT栅格计算程序,以统一慢化方程形式实现了子群法、嵌入式自屏法(Embedded Self-Shielding Method,ESSM)、Tone和考虑不同燃料区影响的Tone-N共振计算方法。采用SHEM361能群结构,通过反应堆应用虚拟环境(Virtual Environment for Reactor Applications,VERA)组件基准题和熔盐堆燃料栅元基准题对ThorLAT中实现的各类共振计算方法进行了验证和分析。在VERA组件基准题中,有效增殖因子keff及棒功率与参考解均符合较好。对于熔盐堆燃料栅元基准题,基于均匀共振积分表插值的ESSM和Tone方法计算精度较高,且在存在温度分布的算例中计算精度和效率均优于不相关模型和全相关模型的子群法。Tone-N与Tone方法得到的熔盐堆燃料栅元基准题计算结果基本相同,说明了在Tone方法中使用均匀截面假设的合理性。相比XMAS172能群结构,SHEM361能群结构通过体现可分辨共振能区更精细的能谱来有效改进精度。上述结果初步表明,SHEM361能群结构下基于均匀共振积分表插值的ESSM和Tone方法可用于熔盐堆共振计算。[Background] With the improvement of the computer computing power, it has become a feasible scheme to generate few-group constants by two-dimensional full-core transport calculations for molten salt reactors(MSRs). [Purpose] This study aims to implement resonance calculation approaches which are suitable for MSRs with complex fuel assignments or temperature distributions due to the fuel fluidity. [Methods] The general slowingdown equations of a single resonant nuclide for the subgroup, the embedded self-shielding method(ESSM), Tone’s and Tone-N methods were summarized, and an integrated calculation process was designed and implemented in the ThorLAT code. The Tone-N method without uniform cross-section assumption in the Tone’s method was specially proposed, and it took the influence of other fuel regions into consideration by introducing two additional fixed source equations. With the use of the SHEM361 energy group structure, the virtual environment for reactor applications(VERA) benchmark problems were used for verification and the fuel lattice of a channel-type MSR was calculated and analyzed. [Results] The keffand pin power distributions for VERA benchmark problems are in good agreement with the reference solutions, and the maximum kefferror of 2.23×10^(-3) is from the VERA-4B-2D case, which shows the correctness of the implementation. The results obtained with the ESSM and Tone’s method, which are based on the interpolation of resonance integral tables for uniform materials, are acceptable for the MSR fuel lattice with uniform temperature or radial temperature distributions. The kefferrors calculated by the ESSM and Tone’s method for the MSR fuel lattice are less than 1.50×10^(-3), and the maximum errors of U-238 homogenized absorption cross sections in the fuel region are less than 3.1%. [Conclusions] The ESSM and Tone’s method are more accurate and has a significant efficiency advantage than the subgroup method with uncorrelated model or full correlation model for the case with radial temperatu

关 键 词：熔盐堆 共振计算 ESSM TONE 子群法 

分 类 号：TL329[核科学技术—核技术及应用]