Minimization of uranium load in Miniature Neutron Source Reactors

The uranium load in the Syrian MNSR is minimized by reducing the clad thickness to a standard value of 0.38 mm instead of 0.60 mm based on a 3-D model of the reactor that included all reactor components. More than 31 fuel rods are saved. The effects of the reduction of the fuel load in the core on both the reactor safety and performance, in relation to its use as a tool for Neutron Activation Analyses, are analyzed.The impact of the proposed changes on thermohydraulics are expected to be negligible. The dependence of both the initial excess reactivity and the H/U235 ratio on the fuel rod radius is calculated and discussed. Functions like the dependence of the IER on the clad thickness for this reactor are discussed and analyzed as well.