Monte Carlo Modeling of Effective Shielding Systems for Fast Neutrons

Abstract

In this thesis, we have designed a shielding system consisting of dual layers to shield fast neutrons. Monte Carlo simulation code (MCNP5) was used to simulate the spectra of 252Cf-neutron source and to verify the performance of several moderating materials and absorbers as well. The performance of high density polyethylene (HDPE) as moderating material was examined against different thermal neutron absorbers such as; borated polyethylene (BPE), Boric acid (H3BO3) and Boron carbide (B4C). The optimal configuration was found to be (20cm HDPE +5cm B4C) since it has reduced the source energy by 88% and the intensity by 99%. To confirm the stability of the optimal configuration, its performance has been examined against two moderating materials such as; heavy water (D2O) and Beryllium (Be). It is found that the configuration (20cm HDPE +5cm B4C) is still dominant and has reduced neutron intensity with respect to configuration (20cm D2O+5cmB4C) by approximated 33% and with respect to configuration (20cm Be+5cm B4C) by approximated 18%.