ENS 43109
ENS Event | |
|---|---|
08:38 Jan 20, 2007 | |
| Title | Crevs and Crets Inoperable Due to 1A and 2B Edg Oos |
| Event Description | 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.
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). |
| Where | |
|---|---|
Calvert Cliffs  Maryland (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+8 h0.333 days <br />0.0476 weeks <br />0.011 months <br />) | |
| Opened: | Bruce Schick 16:38 Jan 20, 2007 |
| NRC Officer: | Jason Kozal |
| Last Updated: | Feb 14, 2007 |
| 43109 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Calvert Cliffs with 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
WEEKMONTHYEARENS 578442025-07-31T21:44:00031 July 2025 21:44:00
[Table view]10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Both Trains of Control Room Emergency Ventilation/Control Room Emergency Temperature System Inoperable ENS 536632018-10-11T04:00:00011 October 2018 04:00:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Air Start Solenoid Closure Failure ENS 534932018-07-07T04:00:0007 July 2018 04:00:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Control Room Ventilation Inoperable ENS 534012018-05-14T17:05:00014 May 2018 17:05:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Saltwater System Non-Conforming with Licensing Basis for Tornado Generated Missiles ENS 526402017-03-25T05:42:00025 March 2017 05:42:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Refueling Water Tank Level Inadvertently Lowered Below Ts ENS 431092007-01-20T08:38:00020 January 2007 08:38:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Crevs and Crets Inoperable Due to 1A and 2B Edg Oos 2025-07-31T21:44:00 | |