U.S. nuclear power plant outages averaged 4.6 gigawatts (GW) during the summer of 2017 (June through August), 10% lower than outages during the summer of 2016. Nuclear outages were highest in June, averaging 7.4 GW, but then averaged 3.8 GW in July and 2.6 GW in August. On August 14, nuclear outages reached their summer low, when just 0.4 GW of nuclear power plants were out.
Nuclear outages are typically lowest during the summer and winter months when electricity demand is relatively high. Outages can be either scheduled or unscheduled, and they can range from a partial outage, where only some of a plant’s capacity is offline, to a full outage, where the entire plant is shut down.