A simulation study on neutronic behavior of non-fissionable and fissionable materials of different geometries as spallation targets in ADS

‎Spallation process is the most significant process for neutron generation in industry and medicine‎. ‎This process has been used in the subcritical reactor core‎. ‎In this research‎, ‎we study the neutronic behavior of non-fissionable and fissionable spallation targets consists of U-238‎, ‎Th-232‎, ‎Lead Bismuth Eutectic (LBE) and W-184 materials in cylindrical and conic shapes using MCNPX code‎. ‎Neutronic parameters consist of spallation neutron yield‎, ‎deposition energy‎, ‎and angular spectrum of the neutron output‎. ‎The gas production rate and residual mass spectrum were investigated‎. ‎The results of this research indicate that the shape of the target must be selected based on target material and operational purposes‎. ‎The number of neutrons per energy unit is stable at energies higher than 1 GeV‎, ‎and the rate of change in neutron generation has been reduced after that‎. ‎Furthermore‎, ‎hydrogen is the principal factor in swelling of spallation target and consists of about 88% of gas production‎. ‎It was found that a target of LBE provides the most favorite parameters for both neutronic and physical properties‎.