Nuclear power plant outages see 10 percent decrease in Summer 2017

Nuclear power plant outages in the United States during the summer of 2017 averaged 4.6 gigawatts (GW), a 10 percent decrease from summer 2016.

June had the highest amount of outages with an average of 7.4 GW. July averaged 3.8 GW, and August averaged 2.6 GW. Nuclear outages hit their summer low on Aug. 14 when 0.4 GW of nuclear plants were out of service.

Outages are typically fewer during the summer and winter months when electricity demand is higher.

Outages might be either scheduled or unscheduled and could also be full or partial. Outages are scheduled for refueling, which must be done about every 18 to 24 months, and maintenance. Unscheduled outages may occur because of equipment failure, operational error, fuel shortages or limitations, or weather or environmental concerns. Most unplanned outages occur because of non-reactor core issues.

The summer of 2017 saw two significant unscheduled outages. Southeastern Tennessee’s Watts Bar Unit 2, the nation’s newest nuclear plant, shut down because of a steam condenser failure on March 23, just five months after it first entered service. The plant came back online on Aug. 11. Comanche Peak Unit 2, located near Fort Worth, Texas, shut down from June 5, 2017, until Aug. 15 for repairs to its main generator.

Hurricane Irma forced unscheduled outages for both of Florida’s nuclear power plants. Turkey Point, on Florida’s southeastern coast near Miami, and St. Lucie, located on Florida’s eastern coast, north of West Palm Beach, reduced power because of hurricane-force winds. As a precaution, nuclear power plants are required to shut down at least two hours before the onset of hurricane-force winds. St. Lucie and Turkey Point resumed full output on Sept. 14 and Sept. 18, respectively.