During inspections to determine the physical integrity of a failed pressurizer heater it was determined that the heater (number 26) was cracked. Due to the location of the pressurizer heater crack, this is considered a degradation of the
RCS Barrier. The initial visual inspection of heater 26 in November of 2011, did not identify the cracking. During efforts to remove the heater, a crack was observed on May 21, 2012. The crack is above and below the heater support plate. The crack is an axial crack showing some branching. The crack is about an inch above and inch below the heater support plate. These inspections were being performed as a result of the operating experience at the Sizewell B reactor in the United Kingdom.
The licensee has notified the NRC Resident Inspector.