Numerical investigation of the migration and retention of corrosion particles in a lead-cooled fast reactor

The lead–bismuth eutectic (LBE) coolant corrodes structural materials during nuclear reactor operations. The corrosion products accumulate and are deposited after long-term operations, blocking the narrow flow paths inside the reactor loop and reducing reactor performance. This study investigates the effects of the flow field and particle characteristics on the corrosion products. The discrete phase model was used to describe the movement of the corrosion products in the flow field. A lead-cooled fast reactor model was proposed to calculate the velocity and temperature fields of the single-phase flow for different mass flow rates of the LBE coolant. As the LBE velocity increased, the number of trapped particles and the coolant temperature in the reactor decreased. The particle size, density, and shape factor affected the particle movement. Particles with a small size (less than 75 μm), high particle density, or a small shape factor (more than 100 μm diameter) resulted in improved flow of the particles with the LBE coolant and lower particle retention rates in the fluid. As the particle size increased, the number of retained particles in the upper region and on the free surface of the reactor increased, whereas the number of particles reaching the pump outlet decreased.