高温气冷堆内含硼碳材料吸湿特性与扩散系数研究

高温气冷堆（HTGR）是世界上首座具有第四代核电特征的堆型，堆内装载了大量石墨和碳作为结构材料和燃料元件基体。碳素材料是一种多孔材料，常温下吸附空气中的水分等杂质。高温气冷堆的初装堆除湿过程和事故后除湿过程，由水分扩散性能决定。通过含硼碳（BC）材料动态吸湿实验得到水分质量变化曲线，将其与模拟结果拟合得到材料中水分的有效扩散系数D_e＝7.30×10^-10 m²/s。通过吸湿实验得到湿度和温度对平衡吸湿量的影响。环境湿度越高，平衡吸湿量越大，二者近似呈线性关系；温度越高，平衡吸湿量越小。

Moisture Absorption Property and Diffusion Coefficient of Carbon Material with Boron Carbide in HTGR

High-temperature gas-cooled reactor (HTGR) is the first kind of power plant with fourth-generation features in the world, and a large amount of nuclear graphite and carbon material is adopted as structural material and fuel matrix material. The carbon material is porous material, and absorbs moisture and other impurities from air atmosphere. The dehumidifying process of initial reactor core or post-accident core was determined by the moisture diffusion. The time-moisture absorption capacity curve, which was obtained from the dynamic moisture absorption experiment on carbon material with boron carbide (BC), was fitted with simulation result to derive the effective moisture diffusion coefficient D_e in BC, and D_e is 7.30×10^-10 m²/s. The influence of humidity and temperature on equilibrium moisture adsorbance was introduced. The equilibrium moisture adsorbance increases linearly with the environmental humidity, and decreases with the increase of temperature.