On August 4, 2017, at 1511 EDT, Unit 1
Secondary Containment was declared inoperable due to a small (i.e., approximately 0.75 inch diameter) hole in
Service Water system piping which was found during ultrasonic testing activities. The affected portion of piping penetrates
Secondary Containment and flow in the piping creates a vacuum condition; thus bypassing
Secondary Containment. The identified hole is being evaluated with respect to its impact on operability of the
Service Water system.
This condition is being reported in accordance with 10 CFR 50.72(b)(3)(v)(C), as an event or condition that could have prevented fulfillment of a safety function needed to control the release of radioactive material.
This event did not result in any adverse impact to the health and safety of the public.
Initial Safety Significance Evaluation: The initial safety significance of this event is minimal. At the time of discovery, Unit 1 was at 100% steady state conditions. Reactor Building Ventilation was in service in a normal alignment. No abnormal radioactivity conditions existed within Secondary Containment.
Corrective Actions: Temporary repair of the affected Unit 1 Service Water piping has been completed. This repair was evaluated by Engineering and it has been determined that the repair meets the requirements to maintain Secondary Containment operable. Unit 1 Secondary Containment operability was restored at 1704 EDT on August 4, 2017.
The licensee notified the NRC Resident Inspector.
- * * RETRACTION FROM MIKE BRADEN TO RICHARD SMITH AT 1447 EDT ON 9/27/17 * * *
Based upon further evaluation, Duke Energy is retracting Event Notification 52888. The safety objective of Secondary Containment is to limit the release of radioactivity to the environment after an accident so that the resulting exposures are kept to a practical minimum and are within regulatory limits. A bounding engineering evaluation was performed which demonstrates that potential releases from Secondary Containment could not have resulted in offsite or control room doses exceeding regulatory limits. Furthermore, the condition did not impact Technical Specification operability of Secondary Containment in that the ability of Secondary Containment to maintain the required vacuum was not impacted. Therefore, this condition does not represent an event or condition that could have prevented fulfillment of a safety function needed to control the release of radioactive material and is not reportable in accordance with 10 CFR 50.72(b)(3)(v)(C), and the event notification is being retracted.
The NRC Senior Resident was notified of this retraction.
Notified R2DO (A. Masters).
