Forsmark, Sweden [Operating experiences and lessons learned]

To reduce the effects on fuel cycle economics there are two ways to handle big outage delays. The first is to move the next outage the same amount as the delay. This fixes the problem with the impact on fuel economy but will have implications in maintenance planning for the coming outage. It can also be impossible if the unit is operated in a market where the power demand varies a lot over the year and the moved outage would end up in the high–power demand season of the year. If moving the outage is not possible another option is to change the core design or even reload the core if the core has already been loaded. One example of where this was done at unit 3 at Forsmark NPP in 2015. The outage was delayed for two months and the new core (12 months cycle) was loaded when the decision was made to reload the core and unload as much fresh fuel as possible. With a minimum number of shuffling operations about one fourth of the fresh batch could be unloaded and compensate for a large part of the fuel loss that would otherwise have been incurred from the delayed outage.