ENS 53090
ENS Event | |
|---|---|
08:38 Nov 25, 2017 | |
| Title | Manual Reactor Scram During Startup |
| Event Description | At 0238 [CST] a manual reactor scram was inserted by placing the Reactor Mode Switch in Shutdown. At 0149 [CST], with reactor power just above the point of adding heat, IRM [Intermediate Range Monitor] channels A, C, and D received a spurious upscale trip signal which immediately cleared. Upon investigation, operability of RPS [Reactor Protection System] scram function for Intermediate Range Detectors was placed in question. This event is being reported under 10 CFR 50.72(b)(2)(iv)(B), as any event or condition that results in actuation of the Reactor Protection System (RPS), when the reactor is critical.
The licensee notified the NRC Resident Inspector.
At 0238 [CST] a manual reactor scram was inserted by placing the Reactor Mode Switch in Shutdown. At 0149 [CST], with reactor power just above the point of adding heat, Intermediate Range Monitor neutron flux detector (IRM) channels A, C, and D received a spurious Upscale Trip signal which immediately cleared. Upon investigation, IRM channels A, C, and D were declared Inoperable. IRM G was already Inoperable for another reason. RPS scram function from IRM channels B, E, F, and H was always Operable and available. That event is being reported under 10CFR 50.72(b)(2)(iv)(B), as any event or condition that results in actuation of the Reactor Protection System (RPS), when the reactor is critical. This Revised Statement to Event Notification # 53090 is being made to make it clear that only four IRM channels (A, C, D, G) were Inoperable and that the IRM RPS SCRAM function was still available from the four remaining Operable IRM channels (B, E, F, and H). The licensee notified the NRC Resident Inspector. Notified R4DO (O'Keefe)
On 11/25/17, at 0149 [CST], with reactor power just above the point of adding heat, Intermediate Range Monitor neutron flux detector (IRM) channels A, C, and D received a spurious Upscale Trip signal which immediately cleared. Upon investigation, IRM channels A, C, and D were declared Inoperable. IRM G was already Inoperable for another reason. At 0238 [CST] a manual reactor scram was inserted by placing the Reactor Mode Switch in Shutdown. RPS scram function from IRM channels B, E, F, and H was always Operable and available. That event was initially being reported under 10 CFR 50.72(b)(2)(iv)(B), as any event or condition that results in actuation of the Reactor Protection System (RPS), when the reactor is critical. After the trip alarms were received, the Operators spent approximately twenty minutes investigating possible causes and implications, and consulted with Reactor Engineering and the Shift Technical Advisor. The investigation showed that the plant was stable and the upscale IRM alarms were spurious. A review of plant technical specifications by the operators determined that a plant shutdown was not required. After further discussions, Operations concluded that a shutdown to allow further investigation of the issue was the prudent course of action. Prior to shutting down, Operations spent approximately twenty minutes reviewing procedures, notifying personnel to exit containment, and conducting a brief. The shutdown was then conducted by inserting a manual reactor scram by placing the reactor mode switch in SHUTDOWN. This was initially reported under 10 CFR 50.72(b)(2)(iv)(B) as an actuation of the RPS. Based on the sequence of events, and Operator actions in conducting the shutdown, the event is considered 'part of a pre-planned sequence during testing or reactor operation' as specified in 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.73(a)(2)(iv)(A). In accordance with NUREG-1022, Section 3.2.6, the event is not reportable as an actuation of RPS. The licensee notified the NRC Resident Inspector. Notified R4DO (Taylor). |
| Where | |
|---|---|
Grand Gulf  Mississippi (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation | |
| Time - Person (Reporting Time:+-2.6 h-0.108 days <br />-0.0155 weeks <br />-0.00356 months <br />) | |
| Opened: | David Burrus 06:02 Nov 25, 2017 |
| NRC Officer: | Dan Livermore |
| Last Updated: | Jan 16, 2018 |
| 53090 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Startup (0 %) |
| After | Hot Shutdown (0 %) |
WEEKMONTHYEARENS 568942023-12-16T09:50:00016 December 2023 09:50:00
[Table view]10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Scram Due to Turbine Trip ENS 562822022-12-20T03:01:00020 December 2022 03:01:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Scram Due to Loss of Feedwater Pump ENS 559732022-06-30T19:45:00030 June 2022 19:45:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Scram Due to Loss of Transformer ENS 550302020-12-11T18:04:00011 December 2020 18:04:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to Main Turbine / Generator Trip ENS 549862020-11-06T08:39:0006 November 2020 08:39:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to Turbine/Generator Trip ENS 548552020-08-25T04:05:00025 August 2020 04:05:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Scram After Loss of Feedwater - Grand Gulf ENS 548242020-08-08T06:27:0008 August 2020 06:27:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Scram Due to a Turbine High Pressure Control Valve Malfunction ENS 547252020-05-25T09:33:00025 May 2020 09:33:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to Main Turbine Trip ENS 540622019-05-12T15:39:00012 May 2019 15:39:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Reactor Scram Due to Partial Loss of Service Water ENS 538942019-02-23T20:58:00023 February 2019 20:58:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram After Turbine Control Valve Fast Closure ENS 537882018-12-12T06:00:00012 December 2018 06:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge En Revision Imported Date 12/17/2018 ENS 536082018-09-14T05:00:00014 September 2018 05:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram ENS 531882018-01-31T00:22:00031 January 2018 00:22:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Main Turbine Load Oscillations ENS 530902017-11-25T08:38:00025 November 2017 08:38:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram During Startup ENS 526632017-04-04T05:10:0004 April 2017 05:10:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Condensate Leak ENS 520442016-06-25T19:07:00025 June 2016 19:07:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram Due to Turbine Trip ENS 520122016-06-17T07:57:00017 June 2016 07:57:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram During Testing ENS 518272016-03-29T16:23:00029 March 2016 16:23:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram Due to Turbine Trip ENS 507952015-02-08T00:56:0008 February 2015 00:56:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram ENS 499722014-03-29T15:08:00029 March 2014 15:08:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to a Turbine Trip ENS 499202014-03-17T10:14:00017 March 2014 10:14:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Steam Leak in Low Pressure Turbine Line ENS 492252013-07-30T19:32:00030 July 2013 19:32:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram Due to Turbine Generator Trip ENS 486732013-01-15T00:05:00015 January 2013 00:05:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram from 100% Power Due to a Turbine/Generator Trip ENS 486522013-01-05T05:37:0005 January 2013 05:37:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to a Turbine/Generator Trip ENS 486372012-12-29T06:18:00029 December 2012 06:18:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to a Turbine/Generator Trip ENS 476792012-02-20T01:04:00020 February 2012 01:04:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram During Shutdown Due to Lowering Reactor Vessel Water Level (Rvwl) ENS 457532010-03-08T22:35:0008 March 2010 22:35:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram on Low Reactor Water Level ENS 446012008-10-26T16:25:00026 October 2008 16:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram and Isolation Due to Turbine Trip ENS 445952008-10-23T12:20:00023 October 2008 12:20:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram with Manual Rcic Initiation ENS 440862008-03-21T20:25:00021 March 2008 20:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram from a Main Turbine Trip ENS 438992008-01-12T22:26:00012 January 2008 22:26:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Degraded Cooling to Main Transformers ENS 435842007-08-21T19:15:00021 August 2007 19:15:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Scrammed Due to Reactor Water Level 3 Rps Actuation ENS 433762007-05-19T16:27:00019 May 2007 16:27:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram Due to Turbine Trip on Loss of Condenser Vacuum ENS 414052005-02-12T01:59:00012 February 2005 01:59:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Rps Actuation 2023-12-16T09:50:00 | |