ENS Event | |
|---|---|
23:49 Jun 2, 2005 | |
| Title | Appendix R Assessment on Remote Shutdown Panel |
| Event Description | The licensee provided the following information via facsimile:
On 6/2/05, while performing an Appendix 'R' assessment, it was determined that the capability to achieve and maintain safe shutdown conditions, as required by Appendix 'R', has not been adequately demonstrated. Specifically, a postulated fire requiring the evacuation of the Control Room could also cause a spurious hot short in the protective relaying circuitry for the credited division of essential electrical power and subsequent loss of that division. It was recently determined that the hot short could occur at anytime during the transient, whereas previous evaluations had assumed any such hot short would be associated with the initiating event. Consequently, existing compensatory measures would only be implemented if the adverse consequences were apparent, and therefore might not be implemented within the timeframe required to assure satisfactory results. The result is that Appendix 'R' requirements are not met, and an unanalyzed condition that significantly degrades plant safety may exist. A 30 day LCO was entered at 1749 per Tech Spec LCO 3.3.3.2 Function 4.e for the Remote Shutdown Panel 'B' Essential 4160 Instrumentation transfer and control. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
Duane Arnold  Iowa (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| LER: | 05000331/LER-2005-001 Re Failure to Demonstrate the Capability to Achieve and Maintain Safe Shutdown Conditions |
| Time - Person (Reporting Time:+-1.97 h-0.0821 days <br />-0.0117 weeks <br />-0.0027 months <br />) | |
| Opened: | Hans Olson 21:51 Jun 2, 2005 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Jun 2, 2005 |
| 41742 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (94 %) |
| After | Power Operation (94 %) |
WEEKMONTHYEARENS 509432015-03-31T20:09:00031 March 2015 20:09:00
[Table view]10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Degraded Torus Coating ENS 424792006-04-05T23:55:0005 April 2006 23:55:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Abnormal Operating Procedure (Aop) for Station Blackout Could Not Be Performed in Specified Time Period ENS 420882005-10-27T18:28:00027 October 2005 18:28:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition ENS 417422005-06-02T23:49:0002 June 2005 23:49:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Appendix R Assessment on Remote Shutdown Panel 2015-03-31T20:09:00 | |