Design of a Heavy Liquid Metal Neutron Spallation Target for Experimental Accelerator driven Sub-critical Reactor

In this paper detailed design of a liquid metal Lead-Bismuth-Eutectic (LBE) neutron spallation target for an experimental ADS reactor of ~30 MW with sub-criticality (k) of 0.975 is presented. The high energy beam consists of 650 MeV and 0.9 mA proton beam. The circulation of the liquid metal is based on gas lift method. Extensive numerical simulations have been carried out to optimise the target geometry, LBE/gas flow rate, beam parameters, neutron yield etc. This paper also includes time dependent two phase CFD analysis to study the effect of nitrogen gas flow rate on LBE flow rate, 3D thermal-hydraulic studies of liquid metal flow near the window and spallation region. The optimum asymmetric flow geometry at the bottom of the target to shift the stagnation zone to minimize the window temperature and estimation of thermo mechanical stress in the window has been carried out. In addition, spallation neutron generation and their energy spectrum, heat deposition distribution, spallation products and their activities have been estimated using high energy particle transport code FLUKA.