新型热管反应堆堆芯热工安全分析

Thermal Safety Analysis of New Type Heat Pipe Reactor Core

针对新型空间热管反应堆,采用商用CFD软件FLUENT对其堆芯进行了稳态热工安全分析。根据MCNP物理计算的堆芯功率分布,选取功率份额最高的相邻3个燃料元件作为分析对象,对控制转鼓7种不同转动角度下的正常工况以及单根热管失效的事故工况进行计算分析,得到最热通道各层材料的温度分布。采用二维热管分析程序计算得到蒸汽区的温度分布,并作为三维计算模型的温度边界。堆芯功率分布采用用户自定义程序UDF进行添加。计算结果表明,在额定功率4.0 MW水平下,在正常工况以及单根热管失效事故工况下,热管具有足够的传热能力将堆芯裂变热导出,同时,堆芯最热通道各层材料温度均低于安全限值,且具有较大的安全裕度,满足设计要求。

The steady thermal characteristics of the new space heat pipe reactor were analyzed by applying the commercial CFD software FLUENT. According to the power distribution of core obtained by MCNP code calculation and selecting the three adjacent fuel elements with the highest power to analyze, seven normal working conditions with different control drum angles and single heat pipe failure accident condition were calcu- lated and analyzed. The temperature distribution of each layer of the hottest fuel-heat pipe element was obtained. The temperature distribution of steam zone was calculated by the two-dimensional heat pipe analysis program and used as the temperature bounda- ry of the three-dimensional model. The power distribution was added to the fuel by the user defined function （UDF）. The results show that the heat pipe has sufficient heat transfer capacity to remove the fission power under the designed value 4.0 MW. Mean- while, the material temperature of each layer is lower than the safety limits and has large safety margins. The core design meets the requirements.