ENS 42966
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ENS Event | |
|---|---|
07:10 Nov 6, 2006 | |
| Title | Automatic Reactor Scram During Turbine Testing |
| Event Description | On 6 November 2006 at 0110 an automatic reactor scram was received. This report is being made under 10 CFR 50.72 (b)(2)(iv)(B), 'any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical.' The plant also received Group 2, 3 and 4 isolations from the low level signal as reactor water dropped due to the reactor scram. The isolations are being reported under 10 CFR 50.72 (b)(3)(iv)(A), 'any event or condition that results actuation of any of the systems listed in paragraph (b)(3)(iv)(B) of this section.' The scram is believed to be the result of a turbine trip but is currently being investigated further. Main Turbine surveillance testing was in progress at the time but it is not known if the testing caused the turbine trip and subsequent Reactor Scram. Reactor pressure is currently being controlled by the turbine bypass valves and steamline drains. No actuations of Safety Relief Valves were required or occurred. Both Reactor Recirculation pumps tripped as part of RPT. The 'B' Recirc pump has been restarted. Reactor level dropped following the scram resulting in the isolations but was recovered and is currently being maintained by the normal feedwater systems. All isolations went to completion and have been reset at this time. The plant electrical buses transferred without incident and are currently in a normal shutdown alignment.
The current plan is to remain in Mode 3 while investigations determine the cause of the turbine trip and reactor scram. All control rods fully inserted on the trip. Currently the plant is using offsite power but diesel generators are available. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
Duane Arnold  Iowa (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+-2.22 h-0.0925 days <br />-0.0132 weeks <br />-0.00304 months <br />) | |
| Opened: | Edward Harrison 04:57 Nov 6, 2006 |
| NRC Officer: | Pete Snyder |
| Last Updated: | Nov 6, 2006 |
| 42966 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | A/R |
| Before | Power Operation (98 %) |
| After | Hot Shutdown (0 %) |
Duane Arnold with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 540122019-04-20T10:07:00020 April 2019 10:07:00
[Table view]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 Both Reactor Feed Pumps Trip Causing Manual Reactor Scram and Eccs Injection ENS 536762018-10-19T05:00:00019 October 2018 05:00:00 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 Automatic Reactor Trip Due to Feedwater Regulating Valve Failing Closed ENS 514842015-10-20T23:00:00020 October 2015 23:00:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Diesel Generators Started After Transmission Line Lightning Strikes ENS 502462014-07-01T00:13:0001 July 2014 00:13:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Auto-Start of Standby Diesel Generators Due to a Grid Disturbance ENS 471432011-08-11T16:38:00011 August 2011 16:38:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unplanned Primary Containment Isolations ENS 458732010-04-26T08:00:00026 April 2010 08:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Scram Due to High Turbine Vibrations ENS 456032010-01-02T05:10:0002 January 2010 05:10:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Diesel Generator Auto Start Due to Failed Line Arrestor in Switchyard ENS 454212009-10-08T19:20:0008 October 2009 19:20:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram During Testing ENS 451542009-06-23T22:04:00023 June 2009 22:04:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Auto Start of Emergency Diesel Generators Due to Offsite Voltage Transient ENS 449652009-04-03T05:28:0003 April 2009 05:28:00 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 Increasing Reactor Water Level During Calibration ENS 448212009-02-02T00:00:0002 February 2009 00:00:00 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 Loss of Condenser Cooling ENS 438172007-12-01T20:35:0001 December 2007 20:35:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Edg Starts on 161 Kv Line Transient ENS 432712007-04-02T16:25:0002 April 2007 16:25:00 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 Lowering Reactor Vessel Water Level ENS 432472007-03-19T00:40:00019 March 2007 00:40:00 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 Coolant Chemistry Concerns ENS 432102007-03-03T05:32:0003 March 2007 05:32:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram Signal Due to High Discharge Volume Level 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 429662006-11-06T07:10:0006 November 2006 07:10:00 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 Turbine Testing ENS 403532003-11-25T21:22:00025 November 2003 21:22:00 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 Degrading Condenser Vacuum During Power Ascension ENS 403012003-11-07T07:34:0007 November 2003 07:34:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Scram at Duane Arnold Due to Hi Coolant Conductivity 2019-04-20T10:07:00 | |
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