In 2014, the Turkey Point Nuclear Power Plant experienced a hole and a steam leak through the shell of the Unit 4, #3B Low Pressure (LP) Feedwater Heater (FWH) near the drains outlet nozzle. Although the location of the hole in the shell was below the centerline of the heater in the Drain Cooler (DC) Zone, a video probe inspection through the drains outlet nozzle revealed that the cause of the leak was actually a hole through the DC top plate, which then allowed the steam to penetrate into the DC zone and erode the shell. The shell was able to be repaired in 2014, however there was not enough time to try to fix the hole in the top plate at that time. During a planned refueling outage in 2017, an access window was cut into the shell and the DC boundary repaired using a custom fit plate to cover the hole and prevent further leakage of steam into the DC zone. The unusual configuration of the DC sealing plates in that area made the repair challenging, but overall the repair was successful and the FWH was able to be returned to service.
Additionally, during the maintenance outage, two leaking tubes were discovered on the periphery of the bundle near one of the Steam Inlet Nozzles. In order to determine the source of the tube failure, a video probe inspection of the shell side of the heater was conducted. It was determined that Foreign Material (FM) was the cause of the failures. By removing the steam inlet piping elbow, the Foreign Material was able to be retrieved and removed from the heater.
