Monte-Carlo Simulations for Shielding of Thermal Neutron Radiograph Facility

The shielding of neutron radiograph facility is important for reduce the background of reactor hall as well as enhancing quality of neutron radiograph. In this study, Monte-Carlo simulation was utilized to conduct the calculation on the shielding of thermal neutron radiograph facility. The simulation result indicates that, in the case of heavy concrete (density 4.6 t/m3) in the thickness of 1.3 m is utilized for the collimator of the facility, as well as heavy concrete (density 3.6 t/m3) in the thickness of 75 cm is utilized for the flight tube, the dose rate outside shielding is able to reach the requirement of radiation levels of reactor hall.