Automatic Susquehanna Unit 1 reactor shutdown in Pennsylvania probed

The Unit 1 reactor at the Susquehanna nuclear power plant, near Berwick, Pennsylvania, shut down automatically on Thursday, plant officials said.

"Susquehanna's nuclear professionals are investigating the exact cause of the shutdown and have confirmed that all systems are responding as expected," Jon Franke, Susquehanna site vice president, said. "Our operators followed established procedures and kept the unit in a safe and stable condition. We will ensure the cause of the shutdown is corrected prior to restarting Unit 1."

Unit 2 remained in full operation, the plant said.

The company has not released firm details on what caused the shutdown. The Standard Speaker newspaper said U.S. Nuclear Regulatory Commission (NRC) spokesman Neil Sheehan said high-pressure levels in the reactor prompted the shutdown based on preliminary information. It also reports that a main steam line was being tested by plant personnel at the time shutdown mechanisms activated.

In June, the NRC said the facility would be placed under enhanced oversight after the discovery of emergency-preparedness issues tied to drill exercises at the facility during an inspection.

The Susquehanna plant is jointly owned by Susquehanna Nuclear LLC, an affiliate of Talen Energy Corp., and Allegheny Electric Cooperative, and is operated by Susquehanna Nuclear.