Investigation of a new approach for regulating the reactivity and achieving economic feasibility using thorium in a blanket‐seed assembly of pressurized water reactors

Summary The traditional methods for controlling reactor excess reactivity are expensive and have defects during reactor operation. By altering the fuel structure and fissile material distribution, this work presents a new technique for managing excess reactivity at the start of the fuel life. MCNPX code edition 2.7 was used to investigate the neutronic characteristics of the suggested blanket‐seed assembly models and compare them with the reference PWR fuel assembly. Instead of U‐238, Th‐232 was suggested as a fertile nuclide. The impact of the proposed models on the infinite multiplication factor, fuel component concentrations, reactor‐grade plutonium, minor actinides, radial flux of thermal neutrons, and the radial distribution of power has been analyzed. The safety parameters, including the control rods worth, Doppler effect, moderator temperature reactivity coefficients, and the effective delayed neutron fraction, have been studied to reach the most optimum fuel structure.