ENS 44821
ENS Event | |
|---|---|
00:00 Feb 2, 2009 | |
| Title | Manual Reactor Scram Due to Loss of Condenser Cooling |
| Event Description | [The licensee manually inserted a reactor scram] due to imminent loss of heat sink (condenser). Circulating water to the condenser suffered an unisolable break resulting in loss of suction source to pumps with cavitation. [The] plant was stabilized per emergency operating procedures. Containment isolations signals operated per design with Groups 2, 3, and 4 received.
Plant response [was] complicated with [an] unexpected loss of one 161 KV bus in the switchyard. This was caused by a breaker failure lockout of the bus caused by signal from the output breaker. This output breaker did open. Cause of the breaker failure being investigated. [The] power loss [of the 161 KV bus] had minor plant effect. One power supply to essential service offsite transformer 1X3 [was] lost due to the bus lockout. [The] transformer and offsite circuit remained available. [The] plant did sustain a temporary loss of spent fuel pool cooling system. Cooling has been restored with no level or temperature complications. Essential power [remained] available with both onsite SBDG's (Standby Diesel Generators) and offsite circuits (current source). All ECCS available. All safety related equipment operat[ed] as designed, except Reactor Core Isolation Cooling (RCIC) turbine which had difficulty in automatic control. Manual control [of RCIC] was effective. This is not unexpected during the conditions it was operating (low flow). The licensee was shutting down to enter a refueling outage as the time of the event. Circulating water to one cooling tower had been isolated when a riser on the second cooling tower ruptured and resulted in loss of supply to the circwater pumps. All systems functioned as required except for the lockout of the 161KV bus and RCIC automatic control. Rods fully inserted. The plant is in a normal electrical configuration except for the loss of the 161 KV bus which does not supply any safety related busses. No safety relief valves lifted during the transient. Cooling is currently via HPCI and RCIC to the torus with torus cooling via essential service water. The plant is currently stable at 600 psi and being cooled-down to cold shutdown. The NRC Resident Inspector has been notified. |
| 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:+-2.53 h-0.105 days <br />-0.0151 weeks <br />-0.00347 months <br />) | |
| Opened: | Jeff Miell 21:28 Feb 1, 2009 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Feb 1, 2009 |
| 44821 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (53 %) |
| 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 | |