ENS 43046
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ENS Event | |
|---|---|
14:07 Dec 12, 2006 | |
| Title | Manual Reactor Trip During Turbine Control System Maintenance |
| Event Description | At 0907 Calvert Cliffs Unit 1 experienced a manual reactor trip during turbine control maintenance. Maintenance was being performed on turbine control to replace circuit cards. This system is a two out of three logic system. Only one logic branch was being de-powered at a time. When the first logic branch was de-powered, the control room supervisor noticed a transient on the reactor coolant system and ordered a manual trip.
Decay heat is being removed via normal methods through the Turbine Bypass Valves to the condenser. At the time of the trip, 11 Auxiliary Feedwater (AFW) Pump was being tested but it was not feeding the steam generators. This was an uncomplicated trip. The plant responded normally to the event. All control rods fully inserted. The plant is stable and operators are maintaining the unit in Hot Standby. The licensee notified the NRC Resident Inspector. The trip had no effect on Unit 2, The licensee was in no significant safety system LCO action statement at the time (other than for the AFW 11 surveillance that was in progress at the time of the event.) The steam generators remained on normal feed throughout the event. No Porv's or safeties lifted during the transient. All systems functioned as required. The licensee is investigating how de-powering only one control system logic circuits resulted in the transient. |
| Where | |
|---|---|
Calvert Cliffs  Maryland (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation | |
| LER: | 05000317/LER-2006-004 |
| Time - Person (Reporting Time:+-2.83 h-0.118 days <br />-0.0168 weeks <br />-0.00388 months <br />) | |
| Opened: | Brian Hayden 11:17 Dec 12, 2006 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Dec 12, 2006 |
| 43046 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (100 %) |
| After | Hot Standby (0 %) |
WEEKMONTHYEARENS 569912024-02-24T20:46:00024 February 2024 20:46:00
[Table view]10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Steam Generator 22 Feed Pump Trip ENS 568562023-11-16T07:27:00016 November 2023 07:27:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip ENS 568392023-11-07T21:17:0007 November 2023 21:17:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip Due to NON-SAFETY Related Bus Under Voltage ENS 556842022-01-03T17:23:0003 January 2022 17:23:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip Due to Loss of Electrical Load ENS 555972021-11-21T15:46:00021 November 2021 15:46:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip and Automatic Auxiliary Feedwater Actuation ENS 551472021-03-22T02:16:00022 March 2021 02:16:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Due to Lowering Steam Generator Level ENS 524062016-12-04T03:24:0004 December 2016 03:24:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip Caused by Main Turbine Trip ENS 519672016-05-31T20:26:00031 May 2016 20:26:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Calvert Cliffs Loss of Load Turbine/Reactor Trip from 100 Percent Power ENS 516832016-01-25T08:15:00025 January 2016 08:15:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Elevated Condenser Sodium Levels ENS 515772015-12-01T23:20:0001 December 2015 23:20:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip After Steam Generator Feed Pump Trip ENS 509612015-04-07T16:45:0007 April 2015 16:45:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Dual Unit Automatic Reactor Trips Due to a Voltage Transient Resulting in Generator Trips ENS 500782014-05-01T14:16:0001 May 2014 14:16:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip ENS 497542014-01-22T02:25:00022 January 2014 02:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Dual Unit Trip on the Loss of the "21" 13Kv Bus ENS 490542013-05-21T09:33:00021 May 2013 09:33:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip After a Feed Pump Trip ENS 490122013-05-09T01:47:0009 May 2013 01:47:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip ENS 472082011-08-28T03:02:00028 August 2011 03:02:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unusual Event - Transformer Explosion Near Turbine Building ENS 459202010-05-12T17:51:00012 May 2010 17:51:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Rps Actuation - Load Reject ENS 457092010-02-18T13:24:00018 February 2010 13:24:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Dual Unit Automatic Reactor Trips Due to Partial Loss of Offsite Power ENS 430462006-12-12T14:07:00012 December 2006 14:07:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip During Turbine Control System Maintenance ENS 429952006-11-16T05:18:00016 November 2006 05:18:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip Due to Turbine Trip and Discovery of After-The-Fact Emergency Condition of an Unsual Event ENS 414522005-03-01T05:43:0001 March 2005 05:43:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram from 15% Power Due to High Turbine Vibration ENS 406012004-03-20T18:40:00020 March 2004 18:40:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip at Calvert Cliffs Unit 1 Due to a Loss of Feedwater ENS 404722004-01-23T20:29:00023 January 2004 20:29:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip with Safety Injection Actuation Signals 2024-02-24T20:46:00 | |
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