Influence of Mushy Zone Constant on Solid-Liquid Phase Change Behaviors and Characteristics of Molten Salt in Filling Process

Molten salt reactor is a promising type of reactor with excellent safety and economy benefiting from the stable properties of its molten salt coolant at high temperatures. However, the freezing point of molten salt is usually high enough presencing a risk of coolant freezing that plugs pipelines, the phenomenon of its solid-liquid phase changing is an essential problem. Aims to present the process of the molten salt filling cold pipe with solidification-melting behaviors and study a relatively suitable value of mushy zone constant for molten salt.The commercial CFD code is used to numerically simulate the process and a existing experiment is used to support the research. The cases results show that mushy zone constant (5×103≤A-mush≤5×105) significantly affect penetration distance and A-mush= 5×104 is suitable for molten salt in mushy zone. Based on the study, proper selection of mushy zone constant is very much necessary for the accurate prediction of solid-liquid phase change behaviors and characteristics. The transient process of molten salt filling cold pipe is presented detailedly and a method for determining the mushy zone constant is proposed.