ENS 47448
ENS Event | |
|---|---|
22:22 Nov 16, 2011 | |
| Title | Rhr Capability Affected Due to Both Trains of River Water Supply Hvac Systems Inoperable |
| Event Description | At 1622 [CST] on November 16, 2011, NextEra Energy Duane Arnold declared the 'A' River Water Supply inoperable following discovery that the HVAC damper controller was installed in reverse. This would have closed the HVAC intake dampers on high temperature instead of opening them. At this time, the 'B' River Water Supply system was already inoperable for HVAC damper maintenance. This resulted in entering TS 3.7.2 Condition B for both River Water Supply systems inoperable [required action to restore a train or be shutdown in 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />s]. Both trains of River Water Supply inoperability potentially affect the plant capability to remove residual heat. Therefore, this event is being reported pursuant to the requirements of 10CFR 50.72(b)(3)(v)(B).
At 1735 [CST] on November 16, 2011 Post Maintenance testing on the 'B' River Water Supply HVAC Dampers was completed and 'B' River Water Supply was declared operable, restoring the capability to remove residual heat. The NRC Resident Inspector has been notified.
The licensee is retracting this report based on the following: The purpose of this notification is to retract a previous report made on 11/16/2011 at 19:04 (ET) (EN 47448). Notification of the event to the NRC was initially made as a result of declaring both trains of the River Water Supply (RWS) system inoperable following the discovery that the HVAC damper controller was installed incorrectly. Subsequent to the initial report, NextEra Energy Duane Arnold (NextEra) has determined that the RWS system was capable of performing its safety function and was fully operable during the period that the HVAC controller was incorrectly configured. Specifically, based on the environmental conditions that existed during the period from November 8, 2011 to November 16, 2011, the non-TS RWS Intake HVAC system was Functional, but Degraded. 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 10 CFR 50.73. The NRC Senior Resident Inspector has been notified. Notified R3DO (Orth). |
| Where | |
|---|---|
Duane Arnold  Iowa (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat | |
| Time - Person (Reporting Time:+-3.3 h-0.138 days <br />-0.0196 weeks <br />-0.00452 months <br />) | |
| Opened: | Kevin Huber 19:04 Nov 16, 2011 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Jan 16, 2012 |
| 47448 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 475112011-12-02T19:11:0002 December 2011 19:11:00
[Table view]10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Low Pressure Coolant Injection Inoperable ENS 474482011-11-16T22:22:00016 November 2011 22:22:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Rhr Capability Affected Due to Both Trains of River Water Supply Hvac Systems Inoperable ENS 471422011-08-11T08:27:00011 August 2011 08:27:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Initiation of Technical Specification Required Shutdown ENS 464102010-11-10T11:18:00010 November 2010 11:18:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Rhr Pump Tripped While Operating in Shutdown Cooling Mode ENS 431852007-02-24T23:56:00024 February 2007 23:56:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Loss of Normal Electrical Lineup Due to Grid Instability from Adverse Weather Conditions ENS 426802006-07-01T04:37:0001 July 2006 04:37:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Common Cause Degradation to Rhr Service Water Pump Motor Cooling Coils 2011-08-11T08:27:00 | |