Structural design on reactor coupled with the spallation target for a lead-based ADS

Abstract

In the Accelerator Driven Sub-critical System (ADS), the spallation neutron target is a core component connecting accelerator and the reactor, which makes the structure of different from the conventional fission reactor such as PWR and FBR. In the project of the China Initiative Accelerator Driven System (CiADS), the granular flow of the gravity driven Dense Granular flow Target (DGT) is adopted, which is an original spallation target scheme different from the existing international spallation target type. As a new form of target structure, DGT faces new technical challenges in the process of coupling with the reactor, i.e. special attention must be paid for the structure design of the reactor coupled with spallation target so that it can bear both of seismic and thermal loadings. In this paper, the coupling schemes of DGT and reactor are analyzed from engineering feasibility and safety, and the proposal of reactor-target coupling scheme is given. The supporting design and seismic analysis of the “hot pot type” design scheme and “bellows type” design scheme of reactor-target coupling systems for CiADS are carried out. A new damper-based support method is designed: roll-damper support. The calculation results show that the new support method effectively reduces the thermal stress of the container and the target, and realizes the shock absorption function even taking the effect of fluid–structure interaction (FSI) into account. Combining the advantages of the two schemes, a “hybrid type” optimization design scheme is proposed. The seismic calculation of the optimization scheme was completed by the time history analysis method, and then the stress evaluation was carried out. The results show that the “hybrid type” design scheme meets nuclear safety regulations and specifications. The research results can provide guidance for the selection of lead-based ADS reactor- target coupling systems, and propose optimization suggestions and ideas for reactor-target coupling problems.