Talen Energy reports automatic shutdown at Luzerne County nuclear power plant

The Susquehanna Steam Electric Station is part of the Allegheny Electric Cooperative Inc. (Photo via U.S. Nuclear Regulatory Commission)

One of two nuclear reactors at the Susquehanna Steam Electric Station in Luzerne County shut down automatically Tuesday night at the same time firefighters were dispatched to the plant, its owner Talen Energy reported to federal regulators.

A spokesperson for the company said an incident occurred when workers were filling a hydrogen tank and a cloud of the flammable gas unexpectedly ignited, triggering the shutdown. Hydrogen is normally vented when the tank is filled to ensure proper storage, Talen’s director of communications Taryne Williams said in a statement.

“Out of an abundance of caution, plant personnel contacted EMS. First responders were dispatched, but no emergency actions were necessary as there was no remaining fire and no injuries,” Williams said.

“The plant responded as designed and as part of its built-in safety mechanisms, Susquehanna Unit 2 went offline without incident,” Williams added. “It is currently stable, and operators are in the process of returning the unit to service. The station remains in a safe condition and there are no injuries or risk to employees or the public.”

Video captured by a firefighter driving near the plant at the time of the shutdown and posted on Facebook shows a prolonged bright flash that illuminated a cloud of smoke or vapor above the ground.

According to Talen’s report to the Nuclear Regulatory Commission (NRC), the plant’s Unit 2 reactor was operating at 100% power around 7 p.m. when it shut down in a safety procedure known as a SCRAM. The NRC defines a SCRAM as the sudden shut down of a reactor by the rapid insertion of control rods that halt the nuclear reaction. Talen said all systems performed as expected.

SCRAM events occur when a nuclear power plant’s control systems sense conditions outside of normal parameters. It triggers an automatic process to stop the reactor and other systems to safely shut down the plant, Dave Lochbaum, former director of the Nuclear Safety Project for the Union of Concerned Scientists, said.

Lochbaum, who worked as a consultant at the Susquehanna plant, said it’s not unusual for the cause of a SCRAM to be unknown immediately after the event. Talen has 60 days to investigate and report its findings to the NRC along with steps taken to correct the issue.

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“The owner wants to make sure that they fix the problem too. They’re trying to make money,” he said.

The Unit 2 reactor may resume operation before the follow-up report is submitted, Lochbaum said, but the NRC has inspectors assigned to the plant who will verify that it is safe to restart. 

The Susquehanna Steam Electric Station reactors have had eight SCRAM events since 2020, according to the NRC, which has recorded 29 SCRAM shutdowns at nuclear plants across the country so far this year.

“The local fire department responded to the site with lights and sirens active which caused heightened public concern on social media. An event of potential public interest notification was made to the Pennsylvania Emergency Management Agency (PEMA),” the report said.

Talen said in the report filed Tuesday night that it was investigating the event.

“The NRC is satisfied the plant responded appropriately to the situation, and the plant and community remain safe,” the agency said in a statement.

PEMA did not immediately respond to inquiries by the Capital-Star.

The 2,400 megawatt nuclear power plant in Salem Township is one of several Pennsylvania power plants that have attracted interest from data center operators.

Amazon Web Services announced in March that it had purchased a 1,200 acre site adjacent to the plant from Houston-based Talen. The company expects to build out the site with data centers. In June, Talen and Amazon entered a power purchase agreement in which the plant would supply more than 1,900 megawatts of electricity to power the data centers.