Neutronic analysis of the NuScale core using accident tolerant fuels with different coating materials

Highlights: • The NuScale reactor core is simulated with ATF with different coating materials. • Steady-state neutronic parameters are analyzed for U₃Si₂ and UO₂ fuels. • The use of the U₃Si₂ fuel is feasibly without changes related to UO₂ fueled core. The design flexibility of small modular nuclear reactors in synergy with accident-tolerant fuels provides a longer time to react to the loss of active cooling under severe accidents and offers comparable fuel performance during normal operation. The NuScale reactor has an integrated design with a fuel enrichment below 5%, a thermal power of 160 MW and 24-month operating cycles, also guaranteeing safe shutdown by redundant passive systems. In this work, the core of the NuScale reactor is simulated with the Serpent Monte Carlo code, with the objective of analyzing important steady-state core parameters and making a comparison using U₃Si₂ fuel with different coating materials. The results predict the behavior of the core through the neutron multiplication factor and ppm of boron vs fuel burnup, the Doppler, the moderator density and the temperature reactivity coefficients, the radial and axial power distributions and the neutron spectrum of each of the studied fuels and coating materials. The results show that the operation of the reactor with these materials is safe and feasibly according to the analyzed neutron parameters.