US Nuclear Plant Outages Remained Low in Summer
US nuclear electric generation plant outages averaged 2.7 GW during the summer of 2019 (June through August), about the same as during the summer of 2018. Nuclear plant availability was at its highest level, meaning that nuclear outages were at their lowest level from late June to early July, averaging 1.2 GW. Although the Three Mile Island Unit 1 retired in late September, daily nuclear outages that month were 67% lower than year-ago levels. Nuclear plants undergo planned outages, usually for maintenance and refueling, or unplanned outages, such as during hurricane-related disruptions.
Nuclear outages are usually lowest in the United States during summer and winter when electricity demand is relatively high so that plant operators can meet increased cooling and heating demand. Even in the spring and fall, when US electricity consumption is lowest, nuclear outages are typically at their highest, with only about 20% to 25% of US nuclear generating capacity offline at any time.
A planned nuclear generation outage is generally timed to coincide with a plant’s refueling cycle. In the United States, nuclear power plants typically refuel every 18 to 24 months, often during the fall and spring when electricity demand is lower. During a refueling outage, plants typically optimize downtime by scheduling facility upgrades, repairs, and other maintenance work while the reactor is offline.
Average refueling outage times have shortened in recent years, decreasing from an average of 46 days in 2012 to 32 days in 2019. So far in 2019, five reactors required refueling times of 20 days or fewer.
Source : Strategic Research Institute