ENS 47512
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ENS Event | |
|---|---|
22:55 Dec 8, 2011 | |
| Title | Unanalyzed Condition Potentially Could Affect the Common Control Room |
| Event Description | At 1755 on 12/8/11, it was determined that an unanalyzed condition existed for the common Control Room for both Units. A high energy line break (HELB) barrier issue was discovered while performing a fire barrier surveillance and the condition is believed to have existed from initial plant construction. A HELB barrier was found to have a significant breach in it that could allow steam from a HELB in the Unit 2 Steam Generator Blowdown system to potentially impact equipment in the Control Room. The Control Room is not analyzed for a steam environment. The degree of the impact could not be readily determined, but could likely affect the safety related equipment in the Control Room. At 1803 on 12/8/11, Unit 2 Steam Generator Blowdown was secured to eliminate the potential for a HELB in the affected area which eliminated the potential unanalyzed condition. Therefore, an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> report to the NRC is required under 10 CFR 50.72(b)(3)(ii)(B) 'Any event or condition that results in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety' since there was not a reasonable expectation that the Control Room environment could support operation of safety related equipment with Unit 2 Steam Generator Blowdown in service. Further analysis is underway.
The licensee will notify the NRC Resident Inspector
Engineering performed an evaluation to address the impact of the degraded condition on the barrier's design functions. The evaluation concluded that the barrier remained capable of performing its design function with the degraded seal present. Therefore, this condition does not represent an unanalyzed condition that significantly degrades plant safety. The licensee will notify the NRC Resident Inspector. R1DO (Burritt) notified. |
| Where | |
|---|---|
Calvert Cliffs  Maryland (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| Time - Person (Reporting Time:+1.43 h0.0596 days <br />0.00851 weeks <br />0.00196 months <br />) | |
| Opened: | Brian Hayden 00:21 Dec 9, 2011 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Feb 7, 2012 |
| 47512 - 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 %) |
WEEKMONTHYEARENS 536632018-10-11T04:00:00011 October 2018 04:00:00
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