核反应堆两相流和严重事故关键现象粒子法模拟研究

Simulation of the key phenomena in nuclear reactor two-phase flow and severe accident with particle method

针对核反应堆冷却剂两相流动沸腾和严重事故熔融物迁移行为等热工安全领域重要难点问题,开发了高精度移动粒子半隐式法求解技术,建立了大密度比相间复杂界面捕捉及汽液相变模拟的两相流粒子法模型,开发了核反应堆严重事故中堆芯降级行为的氧化共晶、高温蠕变、消熔凝固及再定位过程粒子法模型,形成了基于粒子法的核反应堆关键热工安全现象复杂过程分析软件平台PANDA,实现了核反应堆冷却剂两相流汽泡动力学、严重事故等复杂现象过程的准确模拟.

This study aims to address important and difficult problems in the thermal safety field,such as the boiling and two-phase flow of nuclear reactor coolant and the migration behavior of molten materials during severe accidents.A high-precision solution technique was proposed using the moving particle semi-implicit method.A two-phase flow particle model was established to capture the complex interface between phases with a large density ratio and simulate the vapor-liquid phase transition.Specifically,a particle method model was developed for analyzing the processes of oxidation eutectic,high-temperature creep,remelting-solidification,and the relocation of degraded nuclear reactor cores during severe accidents.To this end,a complex process analysis software platform PANDA was developed based on the particle method for investigating key thermal safety phenomena in nuclear reactors;thus,the accurate simulation of complex phenomena such as the two-phase flow bubble dynamics of nuclear reactor coolant and severe accidents was effectively realized.