Multi-Cycle Analysis on Spent Fuel Re-utilization in PWR Reload Core Design

Recycling has been studied by our team in Kyung Hee University. Direct recycling can be done without reprocessing, when PWR spent fuels are dis-assembled, re-assembled and re-utilized at the next cycle. This can be done only for part of spent fuel pins only if they are not burnt enough because of un-even power distribution in both radial and axial direction. Benefits of this re-utilization are expected in many ways. When the reconstructed fuel assemblies were replaced, a slight decrease in cycle length and an increase in radial peaking factor were observed due to the loss of reactivity. It is not only reduced the number of fresh fuel requirement, but also reduces the number of discharged fuel assemblies. In this study, the reconstructed fuel assemblies were placed at core periphery to compensate for the reactivity loss by increasing the neutron economics. As a result, the radial peaking factor was increased. In the future, if the optimization in reload core design is performed, cycle length loss and radial peaking will be minimized. Furthermore, a new equilibrium cycle core design with spent fuel re-loading is expected with a high feasibility for practice.