Molybdenum-99 production calculation analysis of SAMOP reactor based on thorium nitrate fuel

SAMOP (Subcritical Assembly for Molybdenum-99 Production) has the potential to use thorium as fuel to produce ⁹⁹Mo after modifying the design, but the production performance has not been discovered yet. A study needs to be done to obtain the correlation between ⁹⁹Mo production with the mixed fuel composition of uranium and with SAMOP power on the modified SAMOP design. The study aims to obtain the production of ⁹⁹Mo based thorium nitrate fuel on SAMOP's modified designs. Monte Carlo N-Particle eXtended (MCNPX) is required to simulate the operation of the assembly by varying the composition of the uranium-thorium nitrate mixed fuel, geometry and power fraction on the SAMOP modified designs. The burnup command on the MCNPX is used to confirm the ⁹⁹Mo production result. The assembly is simulated to operate for 6 days with subcritical neutron multiplication factor (k_eff = 0.97-0.99). The neutron multiplication factor of the modified design (k_eff) is 0.97, the activity obtained from ⁹⁹Mo is 18.58 Ci at 1 kW power operation. (paper)