Techno-economical aspects of ultra long working cycles

The objective of the research reported in this paper was to evaluate the feasibility and costs of ultra-long operating cycles in existing pressurized water reactors while respecting current fuel burnup limits. Using the FUMACS/FEEC 2001 code package, a core design for a single batch ultra-long (36 month) operating cycle has been developed. An additional core design based on current fuel enrichment limitations (5 % w/o U235) is presented. A zirconium di-boride integral fuel burnable absorber is used to hold down initial reactivity and to control power peaking throughout the life of the core. The economical competitiveness of the ultralong operating cycle compared to standard 18-month operating cycle has also been considered. (author)