Preliminary neutronics optimization on the concept of multi-beam accelerator driven system

A new subcritical reactor concept is proposed as one accelerator beam splitting into multiple beams to drive the subcritical reactor in this work, which is so called Multi-Beam Accelerator Driven System (MB-ADS). The spallation target is designed as a target assembly to the fuel assembly. The high current proton beam is divided into multiple parts and injected into different targets scattered among the core to improve the beam efficiency and flatten the spatial power distribution of the core. Based on different MB-ADS schemes, neutronics were conducted on the effects of splitting beam number, target assembly arrangements, fuel zoning, and neutron data libraries. The results show that a reasonable multi-beam scheme can significantly improve the efficiency of the proton beam and flatten the power distribution of the reactor compared to the one target ADS scheme. With the improved beam efficiency, the beam density on the target window is greatly reduced.