Numerical analysis of two-phase flow and heat transfer of fuel particles and liquid metal for waste transmutation blanket

Development of fusion driven sub-critical reactor is a practical approach to the transmutation of long-lived nuclear waste, the production of nuclear fuel and the multiplication of energy. The waste transmutation blanket is regarded as one of the most attractive options for this system and various designs are proposed and investigated. The fuel particles which have been suspended inside the liquid metal lead lithium in the breeder zones are liquid-solid two-phase flows. The Eulerian model and the discrete phase model have been developed, taking into account high power density, fuel particle distribution, variability of viscosity, and velocity slippage between phases. The momentum equations and energy equations are modified to describe the unique characteristics of the two-phase flows. The velocity profile, temperature distribution and particle tracks are calculated. The correlation among the variants of particle size, power density and fuel particle's thermal conductivity has been established as a reference to the fuel particle design and the safety analysis of fuel particle circulation. The results demonstrate that the newly-developed approaches to numerical simulation can benefit the thermal-hydraulic analyses of the liquid breeder blanket and provide support to improve the design of fuel particles in the dual-cooled waste transmutation blanket.