Talen Energy Corp. reconnected Unit 1 of the Susquehanna nuclear power plant near Berwick, PA, one week after it shut down due to a leak discovered during routine equipment testing.
Talen officials said Friday the unit was back on the regional power grid Thursday night. It shut down about 11:30 a.m. Nov. 12.
Talen said plant staff determined the shutdown was the result of an electrical problem that triggered one of the eight large valves that control the flow of steam from the reactor to the turbine-generator to close unexpectedly.
Workers found a leak on the lower seal cavity vent piping for a reactor recirculation pump, said Neil Sheehan, a spokesman with the U.S. Nuclear Regulatory Commission (NRC). He also said a faulty electrical coil caused the valve shutdown.
Sheehan described the leaked water as “slightly radioactive,” and he said it was contained and captured within the containment building and posed no environmental risk. The problem also had no effect on public safety and required no public action, according to Sheehan and Talen. Susquehanna Unit 2 continued to operate safely at full power.
Talen spokesman Todd Martin classified the minor leak as a pre-existing condition and said works closely monitored the situation. He said workers detected no other leaks in the containment structure.
Sheehan said NRC inspectors on site followed the company’s troubleshooting and repair efforts. He said Susquehanna Unit 1 restarted Thursday but needed to reach about 30 percent or higher of power to be able to connect to the power grid.
With Unit 1 shut down, plant operators decided to complete other maintenance they could only do when the reactor is not operating.
“We made the choice, while the unit was out of service during a period of mild fall weather and lower wholesale power prices, to advance some maintenance tasks we had planned for the refueling outage next spring,” said Jon Franke, Susquehanna site vice president. “Completing that work now enhances the unit’s reliability for the coming winter, when demand for electricity is increased.”
The Susquehanna plant is in Salem Township, Luzerne County, about 75 miles northwest of Allentown. Susquehanna Nuclear LLC and Allegheny Electric Cooperative Inc. jointly own the facility.
Susquehanna Nuclear LLC is one of Allentown-based Talen Energy’s generating affiliates.