Radiological Characterization of the Philippine Research Reactor-1 Legacy Neutron Sources via Monte Carlo Simulation
Three legacy neutron sources (LNS), one 239PuBe and two 252Cf, are currently stored in the Philippine Research Reactor-1 (PRR-1) facility. These LNS have been kept in the storage tank for the irradiated fuel in the PRR-1 facility for three decades. However, there is limited information available on these sources. Thus, in this paper, the dose rates associated with the irradiated fuel and the three LNS were calculated using Monte Carlo simulations. The dose distribution for the three LNS in a 200-L concrete-filled stainless steel container was also calculated. Results showed that the storage tank has provided adequate shielding against neutrons from the three LNS and the neutron doses are negligible compared with the gamma dose from the irradiated fuel. Simulation results demonstrated that the container has given sufficient radiation shielding for handling LNS. The results of this study will serve as a basis for developing procedures for safe handling, storage, transfer, disposal and use of LNS upon commissioning of the PRR-1 Subcritical Assembly for Training, Education, and Research (SATER). Moreover, this offers a reference for updating and improving the radiation protection measures in the PRR-1 facility.