New Cf-252 neutron source shielding design based Monte Carlo simulation using material combination

Neutron shielding has been a worldwide concern for decades and appropriate methods in nuclear reactors and associated facilities for shielding have been developed. Light materials such as paraffin and water cannot be used in neutron radiography due to structural and fire concerns, and a material in the solid form is needed for effective neutron shielding. Therefore, the present study developed a new neutron shielding design for fixed industrial radiography facilities with solid structures based on material combination. Different materials were investigated to find the most appropriate combination design to shield the spontaneous neutron emitted from a Cf-252 source (with an energy in the range from several keV up to 20 MeV). The combination of iron, graphite, boron (or borate materials), and lead in this order, respectively, were found to be the most appropriate shielding structure for an open Cf-252 source used in fixed industrial radiography. As iron is characterized by a high removal cross section, its use in shielding the californium spontaneous neutron source is the key outcome of the present study. These results were confirmed with the Monte Carlo simulation-based particle and heavy ion transport code system.