Updated Monday, December 17, 2012 at 06:05 AM
An energy company says it's trying to figure out why a central Pennsylvania nuclear power plant reactor shut down unexpectedly.
PPL Corp. says Unit 2 at the Susquehanna nuclear facility near Berwick shut down early Sunday morning. The company says the reactor is safe and stable.
In a statement, Allentown-based PPL says the shutdown occurred during routine testing of a valve on the unit's main turbine system.
The company says the plant's other reactor is operating normally.
The Susquehanna plant is owned jointly by PPL and Allegheny Electric Cooperative Inc.