Experimental and Numerical Investigation on the Hydrogen Behavior in Containment under Severe Accident
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摘要: 压水堆核电系统发生冷却剂丧失事故(LOCA)时,大量释放的水蒸气和氢气会对安全壳的完整性构成威胁,因此有必要对安全壳内的压力响应特性和氢气行为特性开展深入研究。本文对LOCA喷放和氢气释放过程进行了实验和数值模拟研究,通过稳压器向安全壳模拟体喷放高温高压水工质,采用浓度测量系统测量安全壳模拟体内不同位置水蒸气和氦气的体积浓度变化过程,利用三维计算流体力学程序Gasflow-MPI对实验过程进行数值模拟,基于实验和数值模拟结果对安全壳模拟体内的氢气分布进行进一步分析。实验和数值模拟结果表明,安全壳模拟体内无明显温度分层现象,而模拟体顶部氦气体积浓度高于底部氦气体积浓度,存在明显的分层现象。Abstract: During the loss of coolant accident (LOCA) in a pressurized water reactor, a large amount of steam and hydrogen released could pose a threat to the containment integrity. Therefore, it is necessary to conduct an in-depth study on the pressure response characteristics and hydrogen behavior in the containment. This study investigates the LOCA blowdownand hydrogen release processes through experimental and numerical simulations. The high-temperature and high-pressure working fluid was spewed to the containment simulator throughthe pressurizer. A concentration measurement system was employed to measure the evolution of the steam and helium volume concentration in the containment simulator. Furthermore, the three-dimensional computational fluid dynamics code Gasflow-MPI was utilized to simulate the experimental process. Base on the experimental and numerical simulation results, the hydrogen distribution in the containment simulator was further analyzed. The experimental and numerical simulation results show that there is no obvious temperature stratification in the containment simulator, but the helium volume concentration at the top of the simulator is higher than that at the bottom with an obvious stratification.
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Key words:
- Severe accidents /
- Containment /
- Hydrogen behavior /
- Numerical simulation
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