ENS 50375
ENS Event | |
|---|---|
17:18 Aug 15, 2014 | |
| Title | Standby Gas Treatment System Inoperable |
| Event Description | On 8/15/2014 at 1218 CDT, the 'B' Standby Gas Treatment (SBGT) System was undergoing its monthly surveillance testing. With the 'B' fan running, as part of the surveillance, the 'A' Standby Gas Treatment Mode Select Switch was taken to Manual. This renders the 'A' SBGT subsystem inoperable. Almost simultaneously the 'B' fan Flow Indicating Controller went blank and flashed an error message although indicated flow through the 'B' train remained at 4073 SCFM. Based on the indication seen on 'B' controller, regardless of flow, the 'B' SBGT subsystem was also declared inoperable. In accordance with the surveillance the 'A' SBGT mode switch was placed back in the AUTO position on 8/15/2014 at 1220 CDT, restoring that train to operability. The 'B' SBGT was still considered inoperable based on its flow indicating controller being blank and flashing an error message. For a period of two minutes both SBGT subsystems were considered inoperable which is a condition that could have prevented the fulfillment of the safety function of SBGT system to control the release of radioactive material. This is considered a 8-hour reportable event per 50.72(b)(3)(v)(C) 'Any event or condition that at the time discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material.'
During the 2 minutes that 'A' SBGT was in Manual, the 'B' SBGT train maintained 4073 scfm train flow which is at the required flow rate per STP 3.6.4.3-01B. In addition, the 'A' train could have been initiated manually at any time during that 2 minutes by the operator who was stationed at the panel performing the surveillance. The licensee notified the NRC Resident Inspector.
The purpose of this notification is to retract a previous report made on 08/15/2014 at 1802 (EDT) (EN 50375). Notification of the event to the NRC was initially made as a result of declaring both trains of the Standby Gas Treatment (SBGT) System inoperable. Specifically, during performance of planned surveillance testing required by Technical Specification (TS) Surveillance Requirement (SR) 3.6.4.3.2, with the 'B' train of SBGT running as part of the testing, the 'A' SBGT train's mode switch was taken to manual. This action renders the 'A' train inoperable. Simultaneously with this action, the 'B' SBGT Flow Indicator Controller went blank and flashed an error message. This resulted in the 'B' train being declared inoperable. Subsequent to the initial report, NextEra Energy Duane Arnold (NextEra) has determined that TS SR 3.6.4.3.2 contains a note that states, 'When a SBGT subsystem is placed in an inoperable status solely for the performance of VFTP testing required by this Surveillance on the other subsystem, entry into associated Conditions and Required Actions may be delayed for up to 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.' The 'A' SBGT train mode switch was in manual for approximately 2 minutes; therefore, entry into the associated conditions and actions was not required. Therefore, this event is not considered a Safety System Functional Failure 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 (Dickson) |
| Where | |
|---|---|
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:+0.73 h0.0304 days <br />0.00435 weeks <br />9.99954e-4 months <br />) | |
| Opened: | Mark Gilbert 18:02 Aug 15, 2014 |
| NRC Officer: | Daniel Mills |
| Last Updated: | Sep 16, 2014 |
| 50375 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (95 %) |
| After | Power Operation (95 %) |
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 | |