Washington — US nuclear power plants in 2014 had an average capacity factor of 91.8%, the highest level ever recorded, after a series of extended repair outages ended and plants shortened the time reactors shut for refueling, the Nuclear Energy Institute said Thursday.
US nuclear plants benefited from fewer and shorter refueling and maintenance outages and did a better job of avoiding unplanned outages, NEI data showed. The performance was boosted by a particularly strong output in December, when the capacity factor of the US reactor fleet was 98.9%, the data showed.
The capacity factor in 2014 was higher than the 90.9% figure in 2013 and well above the 2012 capacity factor of 87%, which was the lowest in a decade.
The capacity factor is based on the 100 nuclear units that operated during 2014.
Some of the gains came from avoidance of extended outages that had affected fleet performance going back to 2012, NEI said.
The calculation no longer includes data from Southern California Edison's two-unit 2,254-MW San Onofre station, which was permanently shut in 2013 after being offline for much of the year. San Onofre was included in the calculation of capacity factor for 2013.
Omaha Public Power District's 526-MW Fort Calhoun reactor in Nebraska -- another unit that had been offline for years, dragging down the capacity factor figures -- returned to service in late 2013.
Excluding San Onofre and Fort Calhoun, the 2013 capacity factor would have been 92.1%, slightly higher than the 2014 performance, NEI data showed.
The capacity factor was also bolstered by much shorter average refueling and maintenance outages for US plants in 2014, NEI said. The average refueling outage length fell to 37.2 days in 2014 from 41 days in 2013 and 46 days in 2012.
The shorter outages offset the fact that there were more refueling outages in 2014, NEI data showed.
Electricity generation from US nuclear plants in 2014 was 798.4 million MWh, the sixth-highest on record, NEI said. Record generation came in 2010, when there were 104 US reactors that produced 808.9 million MWh, the group said.