氟化物熔盐在石墨中的逾渗机制研究

The exhaustion of fossil fuel makes the nuclear energy one of the most important energy sources available in the future. The molten salt reactor is believed to be a promising reactor type in the Generation IV reactor. There are several molten salt reactor development programs worldwide, and China was started the Thorium molten salt reactor program in 2011. For the graphite moderator contact with molten salt directly in the molten salt reactor, it is essential to understand the graphite/molten salt percolation mechanism. In this program, we are going to propose contact angle method to study the change rule of molten salt/graphite interfacial tension. Using computed tomography (CT) and mercury porosity method, and combined with fractal theory, the graphite structure physical model is established. Combined with percolation theory, the percolation model of molten salts in graphite was built. The effects of various parameters to the fluoride molten salt infiltration in graphite such as the molten salt composition, temperature and the size of graphite will be researched by experimental. Compared with the results of experimental and percolation model, the model parameters will be calibrated. The percolation model of molten salt in graphite will reveal the molten salt’s permeability mechanism in large size graphite material. The model also can provide a scientific basis for core design of molten salt reactor, safety analysis and life management in the future.

随着化石能源的枯竭，核能将成为未来能源的重要来源。熔盐堆被认为是未来最具发展潜力的反应堆堆型之一。熔盐堆中，石墨慢化体与冷却剂熔盐直接接触，熔盐在石墨中的逾渗机制一直是熔盐堆发展的重要课题。本课题拟采用接触角法分析熔盐/石墨界面张力变化规律；采用断层扫描与汞孔隙率法，并结合分形理论，建立石墨孔结构物理模型；以此为基础，结合逾渗理论，建立熔盐在石墨中的逾渗模型。通过熔盐浸渗实验，研究氟化物熔盐在石墨样品中的渗透规律。对比实验和逾渗模型分析结果，进而修正模型参数。逾渗模型可揭示熔盐在大尺寸石墨材料中的浸渗规律，为未来熔盐堆的堆芯设计、安全分析及寿命管理提供可借鉴的科学依据。

随着化石能源的枯竭，核能将成为未来能源的重要来源。熔盐堆被认为是未来最具发展潜力的反应堆堆型之一。熔盐堆中，石墨慢化体与冷却剂熔盐直接接触，熔盐在石墨中的逾渗机制一直是熔盐堆发展的重要课题。本课题采用压汞法以及3D-CT的方法对不同牌号的核石墨中的孔隙结构进行了系统地研究；通过熔盐浸渗实验，研究氟化物熔盐在石墨样品中的渗透规律，确定样品大小以及熔盐的种类对浸渗的影响，对比汞在石墨中的压汞曲线，增加我们对熔盐在石墨中的浸渗理论的认识；结合石墨中孔隙结构以及有限元模型，建立石墨孔结构物理模型，用以预测石墨的物理性能以及渗透率等。经过本课题的实施，我们对石墨的孔隙结构有了更进一步的认识，对熔盐在石墨中的行为也有了更深刻的理解，建立的石墨微观结构模型可以预测其渗透率等参数，为未来熔盐堆核石墨的发展打下的良好基础，同时也为未来熔盐堆的堆芯设计、安全分析及寿命管理提供可借鉴的科学依据。