On April 27, 2012, while the Harris Nuclear Plant was shutdown for a scheduled refueling outage, the reactor vessel head penetrations were being examined in accordance with Inservice Inspection Program requirements. Examinations were being performed to identify flaws before they grow to a size that could effect the structural integrity of the reactor vessel. Those examinations identified flaws in four head penetration nozzles that exhibited characteristics of Primary Water Stress Corrosion Cracking. The four nozzles were repaired using the inner diameter temper bead welding process. Examinations performed following the repairs confirmed the repairs were successful.
This was originally submitted as a voluntary report on May 29, 2012 at 1511 EDT. The condition has since been determined to be reportable per 10CFR50.72(b)(3)(ii)(A).
The NRC Resident Inspector has been informed.
