Fuel Management Strategy of LBE-Cooled Fast Reactor BLESS-D

As one of the six nuclear reactor candidates selected by the Generation IV International Forum (GIF), lead-cooled fast reactor (LFR) has become one of the most promising concepts and attracted more attention from the institutes. A lead-bismuth eutectic (LBE) cooled fast reactor called BLESS-D has been proposed by State Power Investment Corporation Research Institute of China. The fuel management is critical to reactor design because it affects reactor economics. Although the research on fuel management of PWR has matured, there are few studies on fuel management for LFR. Fuel management design includes the entire process from initial cycle to transition cycle, and to equilibrium cycle. To obtain a better refueling scheme and optimize the key parameters of equilibrium cycle, a new refueling scheme is first proposed, and then traditionally, the simulation covering the entire refueling operation is required cycle by cycle, resulting in consuming a massive computing resource. If the scheme fails to meet expectations, expenditure will multiply until the modified scheme meets the safety design criteria. Fuel management design using “pseudo-equilibrium cycle” instead of traditional method is carried out in this work. The “pseudo-equilibrium cycle” method can directly solve the core key parameters of equilibrium cycle by replacing fuel model with approximate nuclides densities estimated from initial core arrangement and refueling scheme. In this paper, a two-batch refueling scheme is proposed with “pseudo-equilibrium cycle” method and then transition cycle are designed to ensure the feasibility that the fresh core successfully transition to the “pseudo-equilibrium cycle” state. Afterwards, neutronics parameters are solved for each cycle from the fresh core and results show that when the burnup calculation comes to the 5th cycle, the reactor key parameters, including assembly peaking factor, linear power density, delayed neutron fraction, and prompt neutron lifetime are in good agreement with “pseudo-equilibrium cycle”, which proves that the “pseudo-equilibrium cycle” method can be used accurately and efficiently to design the refueling scheme.