Several nuclear power plant units experienced unplanned outages during the winter weekend, according to data filed with the Nuclear Regulatory Commission on Jan. 25.
NRC records indicate that four commercial reactors went offline during the winter weekend when much of the eastern half of the nation was experiencing the so-called “Winter Storm Jonas.” At least one of the nuclear operators has acknowledged that their outage was weather-related.
Overall, 92 of the nation’s 100 commercial power reactors were listed as generating power early Jan. 25 by the NRC. Some were already offline for scheduled maintenance.
The Tennessee Valley Authority Watts Bar 2 unit has not actually commenced operation yet but is counted among the 100 active domestic units because it has been licensed.
Nuclear operators typically don’t divulge how long they expect an outage to last, citing competitive reasons. Here’s a rundown of the weekend’s unplanned outages:
· The Calvert Cliffs 1 unit in Maryland, operated by Exelon was manually tripped from 10 percent power due to elevated condenser sodium levels. All systems responded per design, according to an event report filed with NRC. The event happened shortly after 3 a.m. on Monday, Jan. 25. Unit 2 was not affected and remains at full power, according to the report.
· The Dominion Millstone 3 facility in Connecticut was at 100 percent power shortly before 2 a.m. on Jan. 25 when a problem with the ‘B’ reactor coolant pump “caused a reactor trip on low coolant flow,” according to the NRC report. The issue is under investigation and the dayshift will be troubleshooting the problem, the report said. A company spokesperson described the automatic shutdown as “safe and uncomplicated.”
· The Entergy FitzPatrick 1 facility in Upstate New York underwent a manual scram from 89 percent power late Jan. 23 “due to a lowering intake level,” according to the report to NRC. There was no release of radioactivity and no threat to workers or the public, an Entergy spokesperson told GenerationHub. “The lowering intake level indication was a result of frazil ice. Frazil ice is a slushy ice condition that occurs in Lake Ontario under a specific set of environmental and meteorological conditions involving water temperature, air temperature, and wind speed and direction. Frazil ice can create a blockage at the intake structure,” the spokesperson said.
· The FirstEnergy Perry plant in Ohio experienced a reactor shutdown "due to unidentified leakage in the drywell,” according to the NRC report. Perry plant personnel are performing maintenance on a weld on a plant piping system after shutting down early Sunday, Jan. 24, said a company spokesperson. “There are no adverse impacts to workers at the plant or to the public as a result of this work,” she said.