Consummation of 19.75% UO 2 Fuel Material in the Core of Nigeria Miniature Neutron Source Reactor (MNSR)

Investigation has been done concerning the performance of 19.75% uranium dioxide (UO 2 ) fuel material in the core of the Nigeria Research Reactor-1 (NIRR-1), a Miniature Neutron Source Reactors (MNSRs) manufactured by China Institute of Atomic Energy (CIAE) using SCALE 6.1 and VENTURE-PC codes. This is in line with the current efforts to convert the core of NIRR-1 from Highly Enriched Uranium (HEU) core (90.2% enriched UAl 4 -Al fuel) to Low Enriched Uranium (LEU) core (19.75% enriched UO 2 -zircaloy-4 fuel). The geometry and dimensions of HEU and LEU cores were exactly the same except the increase in the fuel cell diameters from 1.2384cm to 1.632cm. Results obtained shows that the total control rod worth of 7.23mk (723pcm), clean cold core excess reactivity of 4.04mk (404pcm), of 1.0119634, shutdown margin of 3.19mk (319pcm) and neutron flux profile of with stability of vertical and horizontal variation less than three percent for the proposed LEU core are a bit more than that of the present HEU core. The model predictions of this parameters for NIRR-1 system in this study are perfectly in agreement with experimental results as well as the results from similar computations using different nuclear tools.