Feasibility study of 24-month fuel cycle for a 177-assembly core

Compared with the 18-month refueling, 24-month fuel cycle can reduce the times of overhaul, improve the load factor, and increase generating capacity. The core cycle length in a 177 assembly PWR meets 24-month refueling requirements by increasing the enrichment of the fresh fuel assemblies and the refueling fuel assembly components, considering the nominal and actual 24-month refueling. The economic evaluation was performed based on fuel management results, considering power generation revenue and cost including fuel cycle cost, refueling and overhaul cost, spent fuel storage costs. Preliminary results show that the 177-assembly PWR with 88 fresh fuel assemblies enriched at 4.95% is possible to achieve nominal 24-month refueling, and the average discharge burnup of fuel is about 48 GWd/tU. The cycle length with 104 fuel assemblies can achieve the actual 24 refueling cycle length, and neutron parameters meet the relevant safety limit requirements. It is shown that the 24-month refueling in the 177 assembly PWR is feasible, and its economy in the case of the high load factor is approximately similar with that of 18 months fuel cycle.