[en] Utility experience in the Untied States has shown that extending fuel cycle length from 12 to 18 months or more can provide a significant reduction in total power generation cost as a result of higher plant availability and reduced replacement power cost. An essential factor in the economic implementation of longer cycles is the use of advanced fuel design features, such a s high burnup, optimum burnable poisons, and low-leakage fuel-loading patterns, which compensate for the fuel cycle cost penalty that would otherwise be associated with longer cycles. Use of such features combined with advanced reactor engineering methods has enabled a smooth transition to extended cycles for many Combustion Engineering (C-E) customers. Cycle 8 of Calvert Cliffs unit 2, which began in the spring of 1987, makes the first 24-month cycle in a US pressurized water reactor. Unit 1 is scheduled to begin 24-month cycle operation in the spring of 1988. The two Calvert Cliffs units will refuel during the spring of alternated years, and the low-cost replacement power available to BG ampersand E during the spring season should produce savings of 1 to 2% of annual energy costs compared to present operations with 18-month cycles