Material Properties’ Influence in Fuel-Coolant Interaction Codes

The melt droplets’ crust formation modeling, which is used in current fuel coolant interaction (FCI) codes, is rather basic. In the paper the development of the melt droplet heat transfer model, which enables the treatment of the material properties’ influence on the steam explosion, is presented. The model is complex enough to adequately predict the crust development during the melt droplets’ cooling in the premixing phase. At the same time the model is simple enough that it can be practically implemented into FCI codes and is thus being an optimal model for FCI applications. Fragmentation criteria are derived in order to take into account the influence of the formed crust on the steam explosion process. The derived criteria are based on experimental results and the thin plate approximation. To enable the use of the model and the fragmentation criteria in FCI codes with Eulerian formulation, adequate transport equations for model parameters are given.