Neutron production and energy deposition in fissile spallation targets studied with Geant4 toolkit

A new Geant4-based code MCADS (Monte Carlo model for Accelerator Driven Systems) aimed at Monte Carlo simulations of Accelerator Driven Systems (ADS) is developed and validated. It is used to study neutron production and energy deposition in spallation targets made of non-fissile and fissile materials. Detailed simulations are performed for monolithic tungsten and uranium targets irradiated by 600 MeV protons. We have found that the number of produced neutrons per proton is about 3 times higher in the uranium target, while the energy deposition per neutron is almost the same in both targets. We have also considered a uranium target with admixture of 241Am and estimated its burning rate. Our conclusion is that up to 4–5 kg of minor actinides can be burnt by an ADS facility during the first year of its operation.