Thermodynamic simulation of a liquid metal target on which impinges an intense proton beam

An hybrid reactor is made up of a charged-particle accelerator, a spallation target and a subcritical medium. The purpose of this work has been to study the thermodynamical behaviour of a liquid metal spallation target. The energy deposited in the target can reach 800 W/cm3 locally. A thimble allows the proton beam to reach the middle of the target. 2 directions of flowing have been studied: i) the front flowing i.e the flow is directed from the bottom towards the thimble (like natural convection), and ii) the receding flow i.e the flow is directed from the annular zone around the thimble towards the bottom. For this study the liquid metal chosen has been Pb-Bi eutectic whose fusion temperature is 125 Celsius degrees. The simulation has been performed by using the codes Trio-U and Castem-fluide. Calculations show that for an input temperature of 175 Celsius degrees and for an input velocity of 1 m/s, the velocity of the liquid metal against the thimble is under 1.2 m/s and the temperature of the thimble wall reaches 375 Celsius degrees. (A.C.)