基于MOOSE平台的燃料性能分析程序开发

Development of Fuel Performance Analysis Code Based on MOOSE Platform

为进行反应堆中子学、热工水力、燃料性能分析的多物理耦合研究,基于多物理耦合平台MOOSE开发了燃料性能分析程序NECP-CALF,对简化压水堆燃料棒进行了模拟;针对轴对称和非轴对称条件并存的燃料元件,程序实现了一种新的建模方法——混合维度法,可更好地兼顾精度与效率,之后使用混合维度法对发生堵流的超临界水冷堆燃料棒进行了模拟,分析了堵流对燃料性能的影响。结果表明,本文开发的程序可模拟燃料棒在堆内燃耗过程中的温度、应力和应变的变化,且此程序具备与燃料性能分析程序BISON、CAMPUS同等的计算精度;堵流会造成芯块最高温度显著升高,并使得包壳在堵流发生后立刻达到屈服极限,对燃料元件安全性极为不利。

Aiming at the multi-physics coupling research of neutronics,thermal-hydraulics and fuel performance,a new fuel performance analysis code,NECP-CALF,is developed based on a multi-physics coupling platform MOOSE,and a simplified PWR fuel rod is simulated.For the fuel element with both the axisymmetric region and the non-axisymmetric region,the code has implemented a new geometrical modeling approach named mixed dimensional approach,which can better balance the accuracy and efficiency.A supercritical water-cooled fuel rod with the flow blockage is modeled using the mixed dimensional approach to analyze the influence of the flow blockage on the fuel performance.The numerical results demonstrate that the code is with the capability to simulate the evolution of the temperature,stress and strain of the nuclear element in the reactor,which is of the same accuracy level as BISON and CAMPUS;the flow blockage will cause the pellet max temperature to rise significantly and the cladding Mises stress to exceed the yield strength immediately after the flow blockage,which threatens the safety of the fuel element.