Implication of Removal of Cadmium Poison on Neutron Flux and Related Parameters in Nigeria Research Reactor - 1

Nigeria’s Miniature Neutron Source Reactor (MNSR) has been in function since 2004. Over the ten years of operation, several installation and calculation were made on Nigeria research reactor-1 for the safety under project supply agreements and IAEA member state. In this work, we show the implication of removal of cadmium poison on neutron flux and related parameter by using lattice code WIMS and core analysis code CITATION, to automatically carry out each of the following calculations on MNSRs: core excess reactivity, verification of some safety criteria, and calculating various temperature coefficients of reactivity. Results obtained before, after and after removal of cadmium poison are: excess core reactivity (3.72, 2.96 and 2.92) mk, fuel temperature coefficient reactivity (-0.0018, -0.0054 and -0.0060) mk/°C, power coefficient of reactivity (-0.2527, -0.1260 and 0.0575) mk/kW and predicted power of (15.23, 14.65 and 14.99) kW with coolant temperature (12.43, 12.10 and 12.50) °C respectively. The result will not only boost the sample handling capabilities of NIRR-1 but will also provide useful data to the MNSR community for upgrading their reactors and specifically ageing management.