FirstEnergy's Beaver Valley Unit One nuclear reactor in Shippingport was shut down on January 6, because of a problem with the main unit transformer. According to the company and the Nuclear Regulatory Commission, the unplanned, non-emergency shutdown of the 911-megawatt nuclear reactor occurred at 4:59 p.m. The transformer converts power generated by the plant to voltage for use in the region's electric distribution system. Its relay tripped, a function designed to protect the transformer during a malfunction.

It is unknown whether the cold weather caused or contributed to the problem. The shutdown triggered the automatic activation of a fire-suppression system that doused the transformer with water, which immediately froze.