Radiation shielding design of neutron source from Kartini reactor’s beam-port for SAMOP test facility

Abstract

SAMOP is a subcritical assembly for 99Mo production fueled with uranyl nitrate solution which is designed to be operated by using external neutron source from a neutron generator. The most common radioisotope used in diagnosis for medical imaging in nuclear medicine is 99mTc which is daughter isotope of 99Mo. The SAMOP experimental or test facility is a facility to be used for performance testing of the SAMOP system by using neutron source from radial beam port of Kartini reactor instead of using neutron generator. This paper presents the results of the radiation shielding design and calculation for external neutron source of SAMOP experimental facility. The method used is a modeling and calculation by using MCNPX computer code. Based on the assumed source terms, the materials being used, and the geometrical arrangements, it is concluded that by using paraffin of 60 cm thickness for the beam catcher and 50 cm for the concrete of the outer shield would be sufficient to reduce the radiation dose below the maximum recommended limit. The presence of beam catcher can significantly reduce the contribution of neutrons and secondary particles to the radiation dose.