Core Optimization of Uo2 Fuelled Allegro Reactor

Feasibility of UO2 core is investigated considering neutronic and thermal constraints. Calculations showed that the amount of UO2 fuel must be increased significantly to reach criticality. Irradiation time needed to reach the target value of 75 dpa increases by increasing fuel amount and keeping total thermal power constant. Changes in fuel composition and design-related differences of fissile isotope vectors in depleted fuel were studied. Beta effective value, void, Doppler and fuel expansion coefficients were calculated. Compliance to the shutdown criteria is demonstrated since reactivity worth of control rods is affected by the modifications of the core design. Assembly and pin-wise power distribution, as well as axial power distribution is examined for different core designs. Reactivity changes were calculated for the case of water ingress to the core as a result of design a basis event PRISE.