基于蒙特卡罗均匀化的异形几何燃料棒物理性能研究

Physical Properties of Heterogeneous Geometry Fuel Rods Based on Monte Carlo Homogenization

利用清华大学工程物理系自主开发的3维反应堆蒙特卡罗分析程序RMC-DAGMC模块直接通过CAD对螺旋十字型燃料棒建模并进行中子物理计算,同时,利用蒙特卡罗均匀化,即蒙特卡罗两步法进行组件-堆芯计算,验证了RMC-DAGMC临界计算功能和群常数功能的正确性。对不同螺距的螺旋十字型燃料棒物理性能进行了对比计算分析,结果表明:无扭转十字棒与传统圆棒的有效增殖系数keff有较大差异,螺距对螺旋十字棒keff影响较小。对复杂的异形几何堆芯进行了简要计算,计算方法和结果可为异形几何堆芯设计提供参考。

In this paper,the helical cruciform fuel rods are directly modeled and neutron physics calculations are performed through CAD by using the RMC-DAGMC module of 3D reactor Monte Carlo analysis program independently developed by the department of engineering physics at Tsinghua University.At the same time,Monte Carlo homogenization,i.e.the Monte Carlo two-step method,is used for component core calculations.The correctness of the critical calculation function and group constant function of RMC-DAGMC is verified by using Monte Carlo homogenization.The physical properties of helical cruciform fuel rods with different pitches are calculated and analyzed.The results show that there is a significant difference on k eff between the untwisted cruciform rods and the traditional round rods,and the pitch of the helical cruciform rods has an effect on k eff.A brief calculation is conducted on the complex irregular geometry core,and the calculation method and results can provide references for the design of irregular geometry cores.