• An explosion in a transformer associated with turbine cooling in the Limerick Generation Station's Unit 1 caused a shutdown.
• The incident late Thursday morning was listed as an unusual event, Nuclear Regulatory Commission inspectors were onsite at the time, and the shutdown went smoothly and without danger in or around the two-unit station in Montgomery County, Pa.
• PJM Interconnect called on member utilities to invoke standby reductions by large customers to make up for the unit's lost capacity.

From the article:

One of two nuclear reactors at the Limerick Generating Station was shut down this morning after an electrical problem caused by an explosion in a transformer.