ENS 48212
ENS Event | |
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20:20 Aug 20, 2012 | |
Title | Rwcu System Isolation Differential Flow - High Function Inoperable |
Event Description | On 8-20-2012 during scheduled surveillance testing, the Reactor Water Cleanup (RWCU) System Isolation Differential Flow - High function was discovered to be inoperable at 1520 CDT. The high differential flow signal is provided to detect a break in the RWCU system when area or differential temperature would not provide detection (i.e. cold leg break). This instrumentation provides isolation signals to both inboard and outboard isolation valves and its loss is being reported pursuant to 10CFR50.72(b)(3)(v)(C).
The NRC Resident Inspector was notified.
Subsequent to the initial report, NextEra Energy Duane Arnold (NextEra) has determined that the RWCU Differential Flow High instrument loop was, at all times, capable of performing its TS function. Specifically an engineering analysis of the impact of the instrument as-found and as-left values on the overall instrument loop setting was performed. The analysis determined that the instrument in question was set at a value which would have isolated the RWCU Primary Containment Isolation Valves prior to reaching the Technical Specification (TS) allowable value and therefore the instrument loop remained capable at all times of performing its TS function. This event is not considered a Safety System Functional Failure or a Condition Prohibited by TS and is not reportable to the NRC as a Licensee Event Report (LER) per 10CFR50.73. The NRC Senior Resident Inspector has been notified. Notified the R3DO (Lipa). |
Where | |
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Duane Arnold Iowa (NRC Region 3) | |
Reporting | |
10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | |
Time - Person (Reporting Time:+-1.15 h-0.0479 days <br />-0.00685 weeks <br />-0.00158 months <br />) | |
Opened: | Andrew Hess 19:11 Aug 20, 2012 |
NRC Officer: | John Knoke |
Last Updated: | Sep 27, 2012 |
48212 - NRC Website
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Unit 1 | |
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Reactor critical | Critical |
Scram | No |
Before | Power Operation (100 %) |
After | Power Operation (100 %) |
Duane Arnold with 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | |
WEEKMONTHYEARENS 534962018-07-09T05:00:0009 July 2018 05:00:00
[Table view]10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Inoperable ENS 525112017-01-26T09:00:00026 January 2017 09:00:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Containment Valves Failed Surveillance Testing ENS 520532016-06-29T14:40:00029 June 2016 14:40:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Inoperable ENS 520222016-06-19T20:33:00019 June 2016 20:33:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Inoperable ENS 513532015-08-27T12:52:00027 August 2015 12:52:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Inoperable ENS 509892015-04-16T18:20:00016 April 2015 18:20:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Both Secondary Containment Airlock Doors Open Simultaneously ENS 509142015-03-21T05:30:00021 March 2015 05:30:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Both Secondary Containment Doors Opened Simultaneously ENS 505602014-10-23T06:07:00023 October 2014 06:07:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Inoperable Due to Both Airlock Doors Open Simultaneously ENS 503752014-08-15T17:18:00015 August 2014 17:18:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Standby Gas Treatment System Inoperable ENS 501532014-05-30T12:59:00030 May 2014 12:59:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Airlock Inoperable for 10 Seconds ENS 498382014-02-18T15:44:00018 February 2014 15:44:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Momentary Loss of Secondary Containment ENS 496572013-12-18T14:30:00018 December 2013 14:30:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Both Doors in Secondary Containment Airlock Opened Concurrently ENS 482122012-08-20T20:20:00020 August 2012 20:20:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Rwcu System Isolation Differential Flow - High Function Inoperable ENS 477092012-02-29T18:22:00029 February 2012 18:22:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Isolation Dampers Fail to Close During Quarterly Surveillance ENS 417852005-06-20T08:08:00020 June 2005 08:08:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Both Standby Gas Treatment Trains Briefly Inoperable During Testing 2018-07-09T05:00:00 | |