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在正常运行工况下高温气冷堆内石墨材料的氧化对石墨结构材料的服役时间有重要影响。主要介绍高温气冷堆燃料元件氦气孔道内石墨材料与水蒸气发生氧化反应的模拟。该模型使用COMSOL软件进行建模,采用k-ε模型模拟冷却剂的流动,使用Langmuir-Hinshelwood方程描述石墨与水蒸气的化学反应。使用该模型计算了冷却剂管道温度分布为线性、水蒸气压力低于1 Pa的氧化情况。计算结果表明,在堆芯底部氧化主要发生在表面,石墨材料转化率高于8%的厚度约1 mm。
The oxidation of graphite materials in high temperature gas-cooled reactors under normal operating conditions has an important impact on the service life of graphite materials. This paper mainly introduces the simulation of the oxidation reaction of graphite material and water vapor in helium gas passage of HTGR fuel element. The model was modeled using COMSOL software. The k-ε model was used to simulate the coolant flow. The Langmuir-Hinshelwood equation was used to describe the chemical reaction between graphite and water vapor. The model was used to calculate the linear temperature distribution of the coolant pipe and the oxidation of water vapor below 1 Pa. The calculated results show that the oxidation at the bottom of the core occurs mainly on the surface, and the graphite material has a thickness of about 1 mm with the conversion rate higher than 8%.