基于CFD程序的物理热工耦合计算不确定性分析

基于计算流体力学（CFD）程序FLUENT的用户自定义函数（UDF），耦合中子动力学计算模型、燃料棒热传导计算模型、不确定性分析程序SIMLAB，开发了物理热工耦合计算不确定性分析平台CFD/PFS，并开展了小型自然循环铅基快堆SNCLFR-10的无保护超功率（UTOP）事故的不确定性量化，最后对计算结果进行不确定性分析和敏感性分析。研究表明，CFD/PFS平台的物理热工耦合计算具有良好的可靠性、精确性；总反应性峰值、功率峰值等瞬态安全参数的名义值均处于95/95双侧容忍限值内，且名义值与限值相对偏差小于3.95%；燃料多普勒系数是主要不确定性来源，对反应堆安全影响最大。

Uncertainty Analysis of Neutronics and Thermal-hydraulic Coupling Calculation Based on CFD Code

Based on the user-defined function (UDF) of the computational fluid dynamics (CFD) code FLUENT, coupled with the neutron dynamics model, fuel rod heat conduction model and uncertainty analysis code SIMLAB, the uncertainty analysis platform CFD/PFS was developed. Thereafter, CFD/PFS platform was used to simulate the unprotected overpower transient (UTOP ) accident of the SNCLFR-10 reactor, and the uncertainty quantification evaluation was performed. Furthermore，the results of uncertainty and sensitivity analysis were discussed. Research result shows that the neutronics and thermal-hydraulic coupling calculation of CFD/PFS platform has good reliability and accuracy. The nominal values of transient parameters are within the bilateral tolerance limits, and the relative deviation between the nominal values and the limits is less than 3.95%. The Doppler coefficient is the main source of uncertainty and has the most significant effect on reactor safety.