ENS 43271
ENS Event | |
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16:25 Apr 2, 2007 | |
Title | Manual Reactor Scram Due to Lowering Reactor Vessel Water Level |
Event Description | This report is being made under 50.72(b)(2)(iv)(B) for inserting a manual scram due to lowering reactor pressure vessel level. The lowering level resulted from a loss of non-essential 4160 VAC bus 1A2 and subsequent loss of 'B' Reactor Feed Pump.
In addition this report is being made under 50.72(b)(3)(iv)(A), 'Any event or condition that results in valid actuation of any systems listed in paragraph (b)(3)(iv)(B) of this section due to PCIS groups 2, 3, and 4 being received when reactor water level dropped below 170". All isolations went to completion. The reactor water level drop is normal following a scram from full power due to void collapse in the reactor vessel. After the initial scram, vessel level rose to 211" causing the 'A' Reactor Feed Pump to trip. Before a Reactor Feed Pump could be restarted and adequate feed flow established, another scram signal and isolation occurred when vessel level dropped below 170". Control rods were already fully inserted and isolation valves in the isolated condition when this occurred. Reactor water level was restored to normal and the PCIS group isolations were reset. The current plan is to remain in Hot Standby (Mode 3) and determine the cause of the loss of 1A2 non-essential 4160 VAC bus. The licensee informed the NRC Resident Inspector.
This update is being added to clarify that the second scram on 170 " vessel level described in the original report also constituted a 50.72 (b)(3)(iv)(A) reportable event. The licensee notified the NRC Resident Inspector. Notified R3DO (Kozak) |
Where | |
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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 | |
LER: | 05000331/LER-2007-007 |
Time - Person (Reporting Time:+-3.62 h-0.151 days <br />-0.0215 weeks <br />-0.00496 months <br />) | |
Opened: | Mike Davis 12:48 Apr 2, 2007 |
NRC Officer: | Steve Sandin |
Last Updated: | Apr 2, 2007 |
43271 - NRC Website
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Unit 1 | |
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Reactor critical | Critical |
Scram | Yes, Manual Scram |
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 | |