On May 13, 2013, during a secondary review of ultrasonic data of the reactor vessel head
penetrations performed during Harris Nuclear Plant spring 2012 refueling outage, it was determined that the results for one of the
penetrations appeared to not meet the applicable acceptance criteria. Further evaluation completed on May 15, 2013, characterized the flaw as a 0.26 inch flaw an nozzle 49 that overlaps the J-grove
weld and exhibits characteristics of primary water
stress corrosion cracking. The original examinations were performed per NRC requirements.
Initial evaluation indicates that the flaw is not through wall and there is no evidence of leakage based on inspections performed on the top of the reactor vessel head during the spring 2012 refueling outage. Operators are shutting down the unit to make the necessary repairs. There is no impact to the health and safety of employees or the public.
The NRC resident inspector has been informed.
This report is being made in accordance with 10 CFR 50.72(b)(3)(ii)(A), discovery of a degraded condition, 10 CFR 50.72(b)(2)(i), plant shutdown required by technical specifications, and 10 CFR 50.72(b)(3)(v)(C), a condition which could have prevented the fulfillment of a safety function to control the release of radioactive material.