芯块侧偏状态下的燃料棒温度场数值计算分析

Numerical Calculation and Analysis of Fuel Rod Temperature Field Under Pellet Side Deviation

燃料芯块侧偏状态下的燃料棒温度分布关系到反应堆燃料设计和安全运行。本文基于燃料棒的稳态扩散方程的一般形式,通过数值计算分析了芯块侧偏对燃料棒传热和温度分布的影响。结果表明:当燃料芯块侧偏时,芯块最高温度的位置向芯块侧偏的反方向偏移且最高温度下降,偏心率越大,最高温度的位置偏移程度越大,温降也越大。当偏心率e为0.5和0.8时,芯块最高温度分别下降1.3%和4.1%。而燃料棒包壳外壁面温度分布不均匀且最高温度随着偏心率的增大而升高,当偏心率e=0.8时,燃料棒包壳外壁面的最高温度为350℃,达到燃料棒的临界工作温度。

The temperature distribution of fuel rod under pellet side deviation state is related to the reactor fuel design and safe operation.Based on the general form of steady-state diffusion equation of fuel rod,the effect of pellet side deviation on heat transfer and temperature distribution of fuel rod was analyzed by numerical calculation.The results showed that when the fuel pellet was siding deviation,the position of the highest temperature of pellet was deflecting to the opposite direction and the highest temperature drops.The position deviation degree and temperature drop of the maximum temperature were increased with the increases of eccentricity.When eccentricity was 0.5 and 0.8,the maximum temperature of the pellet was decreased by 1.3%and 4.1%,respectively.The temperature distribution of the outer wall of the fuel rod shell was not uniform and the maximum temperature increases with the increase of eccentricity.When the eccentricity was 0.8,the highest temperature of the outer wall of the fuel rod shell was 350℃,reaching the critical temperature of the fuel rod.