熔盐堆钍铀、铀钚燃料循环核数据不确定度分析

反应堆物理设计不确定度是第4代核能系统的QMU（quantification of margins and uncertainties）有效性认证所必须的参数之一，核数据不确定度是其重要来源。基于自主开发的耦合程序BUND（burnup uncertainty of nuclear data），将SCALE程序TRITON和TSUNAMI-3D模块耦合，完成了熔盐堆钍铀燃料循环、铀钚燃料循环核数据引起的有效增殖因数k_eff不确定度分析，并与ENDF/B-Ⅶ.1协方差数据库计算结果进行了对比。结果显示：初始时刻，两种燃料循环模式下，核数据导致的k_eff不确定度分别为0.490%和0.582%。随燃耗的增加，核数据引起的k_eff不确定度增加。寿期末，两种燃料循环模式下，对k_eff不确定度影响显著增加的反应道分别为²³⁹Pu(nubar)、(n，f)、(n，γ)、¹⁰⁵Rh(n，γ)、¹³⁵Xe(n，γ)和²³⁴U(n，γ)、¹⁴³Nd(n，γ)、^131,135Xe(n，γ)等。

Uncertainty Analysis of Nuclear Data for Th-U and U-Pu Fuel Cycles in Molten Salt Reactor

Uncertainty of reactor physical design is one of the necessary parameters for the QMU (quantification of margins and uncertainties) validation of the Generation-Ⅳ nuclear reactors, and uncertainty of nuclear data is an important source. Using BUND (burnup uncertainty of nuclear data) code to couple TRITON and TSUNAMI-3D modules of SCALE code, calculations of uncertainties for the effective multiplication factor k_eff in the molten salt reactor for Th-U and U-Pu fuel cycles were performed. The results were compared with the calculation results of uncertainty for k_eff by the covariance data from ENDF/B-Ⅶ.1. It is found that, at the beginning of life, the uncertainties for k_eff of Th-U and U-Pu fuel cycles are 0.490% and 0.582%, respectively, and they increase with burnup time. At the end of life, reaction channels ²³⁹Pu (nubar), (n，f), (n，γ), ¹⁰⁵Rh (n，γ), ¹³⁵Xe(n，γ) and ²³⁴U (n，γ), ¹⁴³Nd (n，γ), ^131,135Xe(n, γ) are significant for k_eff uncertainties of U-Pu and Th-U fuel cycles.