The licensee discovered two separate issues that required the 1A
EDG and 2B
EDG to be declared inoperable. It was discovered that the 1A
EDG exhaust fan
damper had failed which required the 1A
EDG to be declared inoperable and 22A
Service Water Heat Exchanger Inlet strainer diversion valve was failed which required the 2B
EDG to be declared inoperable.
With both of the EDG's inoperable the licensee declared the Control Room Emergency Ventilation System (CREVS) and the Control Room Emergency Temperature System (CRETS) systems inoperable. This condition placed the licensee in a 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> LCO to place the plant in hot shutdown. At 0432 the 1A EDG was restored to operability and the applicable LCO was exited. The condition existed for 56 minutes. Subsequently the repairs were completed on the 22A Service Water Heat Exchanger Inlet strainer diversion valve and the 2B EDG was returned to service.
The licensee notified the NRC Resident Inspector.
- * * UPDATED AT 1248 EST ON 2/14/07 FROM JOE GIOFFRE TO S. SANDIN * * *
This notification is retracted based on the following:
On January 20, 2007, at 16:38 EST, EN 43109 was made by Calvert Cliffs Nuclear Power Plant in accordance with 10 CFR 50.72(b)(3)(v)(D), 'Event or Condition That Could Have Prevented Fulfillment of Safety Function'. At that time, a condition was believed to exist which, at the time of discovery, could have prevented the fulfillment of a system function that is needed to mitigate the consequences of an accident. Specifically, the onsite emergency power supplies to both trains of the Control Room Emergency Ventilation System (CREVS) and Control Room Emergency Temperature System (CRETS) were declared inoperable due to separate issues on the 1A EDG and the 2B EDG.
After further evaluation, it has been determined that both DG's were operable and, therefore, the CREVS/CRETS safety function was not lost. Significant margin existed to support operability for both DG's. Accordingly, this event is not reportable. EN43109 is, therefore, retracted by this notice.
The licensee informed the NRC Resident Inspector. Notified R1DO (White).
