Study of transient heat transfer at different proton beam energy in ADS windowless spallation target

Accelerator driven system (ADS) is a promising technique for reducing the amount of long-lived fission products in a safe manner. It consists of a subcritical core coupled with an accelerator by means of a spallation target arrangement. Thermal hydraulics of a spallation target is of great complexity due to the multiphase flow, the cavitation, and the coupling with the spallation reaction. In this paper, we firstly obtain the steady-state flow pattern of lead-bismuth eutectic (LBE) in the target, and then based on the flow pattern, the heat deposition with different proton beam energy is calculated via nuclear physics simulation. After that, the heat deposition is imported into CFD calculation to study the process of heat transfer. The transient temperature distributions with different proton beam energy are calculated. It is observed that the shape of temperature distribution varies with proton beam energy although the beam intensity is kept the same. The results also show that the temperature of recirculation zone is very effectively limited by adopting the annulus shaped proton beam. Above all, the temperature distribution depends on the heat deposition, the velocity and the flow pattern. The results are of great value and can be applied to the future design and optimization of the ADS windowless spallation target in China.