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Category:NRC Preliminary Notification of Event/Occurrence
MONTHYEARPNO-III-23-002B, Prairie Island Update to PNO-III-23-002 Declaration of an Unusual Event Following a Turbine Generator and Reactor Trip Due to Fault on Unit 2 Generator Main Transformer2023-06-0808 June 2023
PNO-III-23-002B Prairie Island Update to PNO-III-23-002 Declaration of an Unusual Event Following a Turbine Generator and Reactor Trip Due to Fault on Unit 2 Generator Main Transformer
PNO-III-23-002, Prairie Island Nuclear Power Station Declaration of an Unusual Event Following a Turbine Generator and Reactor Trip Due to Fault on Unit 2 Generator Main Transformer2023-06-0101 June 2023
PNO-III-23-002 - Prairie Island Nuclear Power Station Declaration of an Unusual Event Following a Turbine Generator and Reactor Trip Due to Fault on Unit 2 Generator Main Transformer
PNO-III-15-011, Prairie Island Nuclear Plant: Shutdown of Unit 2 and Notice of Unusual Event2015-12-18018 December 2015
PNO-III-15-011 - Prairie Island Nuclear Plant: Shutdown of Unit 2 and Notice of Unusual Event
PNO-III-15-008, Prairie Island Unit 2 Shutdown Due to Trip of Main Power Turbine2015-06-0909 June 2015
PNO-III-15-008: Prairie Island Unit 2 Shutdown Due to Trip of Main Power Turbine
PNO-III-15-003, A: Update: Shutdown of Prairie Island Unit 2 Due to Loss of Instrument Air to Containment Building2015-03-26026 March 2015
PNO-III-15-003A: Update: Shutdown of Prairie Island Unit 2 Due to Loss of Instrument Air to Containment Building
ML15069A1852015-03-10010 March 2015
PNO-III-15-003 Prairie Island Nuclear Plant: Shutdown of Prairie Island Unit 2 Due to Loss of Instrument Air to Containment Building and Notification of Unusual Event
PNO-III-15-001, A: Update: Shutdown of Prairie Island Unit 1 Due to Increasing Trend in Reactor Coolant System Leakage2015-02-17017 February 2015
PNO-III-15-001A: Update: Shutdown of Prairie Island Unit 1 Due to Increasing Trend in Reactor Coolant System Leakage
ML15028A0232015-01-27027 January 2015
PNO-III-15-001 - Shutdown of Prairie Island Unit 1 Due to Increasing Trend in Reactor Coolant System Leakage
PNO-III-14-012, A Update: Shutdown of Prairie Island Unit 1 Due to Increasing Trend in Reactor Coolant System Leakage2014-12-29029 December 2014
PNO-III-14-012A Update: Shutdown of Prairie Island Unit 1 Due to Increasing Trend in Reactor Coolant System Leakage
ML14346A4682014-12-12012 December 2014
PNO-III-14-012 Shutdown of Prairie Island Unit 1 Due to Increasing Trend in Reactor Coolant System Leakage
PNO-III-12-014, Notification of Unusual Event at Prairie Island Nuclear Generating Plant2012-11-0101 November 2012
PNO-III-12-014, Notification of Unusual Event at Prairie Island Nuclear Generating Plant
ML12234A6382012-08-20020 August 2012
Update to Prairie Island Unit 1 Unplanned Shutdown Due to Both Emergency Diesel Generators Being Declared Inoperable
ML12229A3572012-08-16016 August 2012
PNO-lll-12-008 - Prairie Island, Unit 1 Unplanned Shutdown Due to Both Emergency Diesel Generators Being Declared Inoperable
PNO-III-11-013, A, Prairie Island Unit 2 Unplanned Shutdown for Greater than 72 Hours (Update)2011-10-20020 October 2011
PNO-III-11-013A, Prairie Island Unit 2 Unplanned Shutdown for Greater than 72 Hours (Update)
ML1127804832011-10-0505 October 2011
PNO-III-11-013 - Prairie Island Unit 2 Unplanned Shutdown for Greater than 72 Hours
PNO-III-10-002, Prairie Island Units 1 and 2, Fire in a Nonsafety-Related Diesel Generator2010-01-21021 January 2010
PNO-III-10-002, Prairie Island Units 1 and 2, Fire in a Nonsafety-Related Diesel Generator
PNO-III-09-003, Prairie Island - Unplanned Unit 1 Shutdown Greater than 72 Hours2009-05-20020 May 2009
PNO-III-09-003: Prairie Island - Unplanned Unit 1 Shutdown Greater than 72 Hours
PNO-III-08-007, A - Prairie Island, Unplanned Unit 1 Shutdown Greater than 72 Hours (Update)/ Notification of Unusual Event Due to a Release of a Toxic Gas Deemed Detrimental to Normal Operation of the Plant2008-08-0404 August 2008
PNO-III-08-007A - Prairie Island, Unplanned Unit 1 Shutdown Greater than 72 Hours (Update)/ Notification of Unusual Event Due to a Release of a Toxic Gas Deemed Detrimental to Normal Operation of the Plant
ML0821408742008-08-0101 August 2008
PNO-III-08-007, Prairie Island Unit 1, Unplanned Unit 1 Shutdown Greater than 72 Hours/Special Inspection
PNO-III-07-016, Prairie Island, Unplanned Unit 1 Shutdown Greater than 72 Hours2007-12-26026 December 2007
PNO-III-07-016: Prairie Island, Unplanned Unit 1 Shutdown Greater than 72 Hours
PNO-III-07-005, Prairie Island Non-Credible Bomb Threat2007-03-20020 March 2007
PNO-III-07-005 - Prairie Island Non-Credible Bomb Threat
PNO-III-06-003, Prairie Island Technical Specification Required Shutdown of Unit 2 for Greater than 72 Hours2006-02-0606 February 2006
PNO-III-06-003, Prairie Island Technical Specification Required Shutdown of Unit 2 for Greater than 72 Hours
PNO-III-05-009, Technical Specification Required Shutdown of Prairie Island Unit 2 for Greater than 72 Hours2005-04-20020 April 2005
PNO-III-05-009, Technical Specification Required Shutdown of Prairie Island Unit 2 for Greater than 72 Hours
2023-06-08
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PRELIMINARY NOTIFICATION- REGION III August 4, 2008 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-III-08-007A This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region III staff on this date.
Facility Licensee Emergency Classification Prairie Island Unit 1 x Notification of Unusual Event Nuclear Management Company (NMC) Alert Welch, Minnesota Site Area Emergency Docket: 50-282 General Emergency License: DPR-42 _ Not Applicable
SUBJECT:
UNPLANNED UNIT 1 SHUTDOWN GREATER THAN 72 HOURS (UPDATE)/
NOTIFICATION OF UNUSUAL EVENT DUE TO A RELEASE OF A TOXIC GAS DEEMED DETRIMENTAL TO NORMAL OPERATION OF THE PLANT DESCRIPTION:
On July 31, 2008 at 8:17 a.m. (CDT), the Unit 1 reactor tripped due to a spurious overtemperature delta temperature signal concurrent with reactor trip system testing. After the reactor trip, the turbine driven auxiliary feedwater pump tripped on low discharge pressure. The reactor trip was due to a failed card in the reactor trip system during the system testing. The card was replaced and the system was returned to service. The turbine-driven auxiliary feedwater pump failure was due to an incorrect valve lineup associated with the pump discharge pressure instrumentation. Subsequently, the auxiliary feedwater pump lineup was corrected, and both the auxiliary feedwater pump and the installed card in the reactor trip system were successfully tested. A Special Inspection Team was dispatched to review the cause of the reactor trip and the auxiliary feedwater pump failure. The team also reviewed the licensees corrective actions prior to restart and found them appropriate.
On August 2, 2008, at 3:42 p.m. the licensee began startup activities in accordance with station procedures. Early the morning of August 3, 2008, while Unit 1 was holding at approximately 30 percent power for secondary chemistry to stabilize, a technician reported the smell of hydrazine. Subsequent air samples taken in the vicinity of the condenser pit were positive for hydrazine. The licensee took actions to control access to these areas and at 3:52 a.m. declared a Notification of Unusual Event (NOUE) in accordance with its emergency plan for the release of toxic gases deemed detrimental to normal operation of the plant. The gas was confined to a few areas in the Unit 1 Turbine Building, and did not affect any areas with equipment vital to the safe operation of the plant. Unit 2 was not affected by the event and remained at full power. The resident inspectors responded to the site, and the Regional staff assessed the situation in accordance with the Agencys Incident Response Program but did not change the Agency Response Mode.
The licensee utilized extra ventilation in the affected areas to reduce the hydrazine concentration. The licensee continued to sample plant areas over the next 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> with concentration levels decreasing over this time period. Based upon acceptable hydrazine levels
in the plant, the licensee exited the NOUE at 10:20 p.m. on August 3, 2008. The resident inspectors and Region III staff remained onsite or in contact with the licensee until the NOUE was exited. Although investigation by the licensee continues, the hydrazine event appears to have been caused by a larger than normal addition of hydrazine into the feedwater system to counteract oxygen introduced following the reactor trip. The cause of the hydrazine release will also be assessed by the Special Inspection Team.
The States of Minnesota and Wisconsin, Region 5 FEMA, and the Prairie Island Indian Community were informed of the NOUE.
The information in this preliminary notification has been reviewed with licensee management.
This information is current as of 1:30 p.m. on August 4, 2008.
CONTACTS: Richard Skokowski Karla Stoedter 630-829-9620 651-388-8209
