压力管嵌入式燃料部件入口堵流事故多尺度热工模拟

压力管嵌入式燃料部件内冷却剂管道间不存在横向交混,若燃料辐照肿胀或碎片进入冷却管道内,容易引发堵流事故,造成局部冷却条件恶化,使燃料烧毁。考虑到次临界能源包层流动路径长、方向弯曲等特点,针对入口堵流事故提出一种多尺度热工模拟方法,通过RELAP5程序给计算流体力学(CFD)软件提供边界条件,对核功率密度最高的燃料部件入口处第一排单根流道部分堵塞和全部堵塞工况进行数值模拟,分析事故条件下燃料热工安全特性。结果表明:第一排单根流道部分堵塞时燃料温度仍满足安全限值,而全部堵塞时峰值温度将超过燃料相变温度限值。

Multi-scale thermal engineering simulation on the inlet flow blockage accident of pressure tube embedded fuel component

Due to that no cross flow exists in pressure tube embedded plate-type fuel component, the flow blockage accidents are apt to occur under some conditions, i.e., irradiation swelling of fuel or fragments entering into the cooling channel. The accidents may deteriorate the cooling condition and result in the phenomenon of departuring from nucleate boiling. Considering the special flow characteristics of the long and curved paths in fusion-fission hybrid energy reactor blanket, a simulation method with multi-scale thermal model is proposed. The boundary conditions calculated by RELAP5 code are provided to computational fluid dynamics (CFD) code. The thermal characteristics of the fuel component which has the largest deposited power density under partial and total flow blockage accidents are simulated. The results indicate that the fuel temperature still meet thermal safety criterion when the single cooling channel partially blocked. The peak temperature of fuel component will exceed the limit of phase-transition temperature when totally blocked.