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Category:NRC Preliminary Notification of Event/Occurrence
MONTHYEARPNO-IV-07-011, Arizona Public Service Company, Palo Verde Nuclear Generating Station (PVNGS) Unit 1 Technical Specification Required Shutdown2007-11-26026 November 2007
PNO-IV-07-011, Arizona Public Service Company, Palo Verde Nuclear Generating Station (PVNGS) Unit 1 Technical Specification Required Shutdown
PNO-IV-07-007, Arizona Public Service Company, Palo Verde Nuclear Generating Station, Unit 1 Technical Specification Required Reactor Shutdown, 10/22/20072007-10-22022 October 2007
PNO-IV-07-007 - Arizona Public Service Company, Palo Verde Nuclear Generating Station, Unit 1 Technical Specification Required Reactor Shutdown, 10/22/2007
PNO-IV-06-003, A: Arizona Public Service Company, Update - Palo Verde Unit 1 Extended Shutdown to Repair Shutdown Cooling Valve Vibration, 07/07/20062006-07-0707 July 2006
PNO-IV-06-003A: Arizona Public Service Company, Update - Palo Verde Unit 1 Extended Shutdown to Repair Shutdown Cooling Valve Vibration, 07/07/2006
ML0608800902006-03-29029 March 2006
PNO-IV-06-003 - Palo Verde Nuclear Generating Station, Unit 1 Subject: Palo Verde Unit 1 Extended Shutdown to Repair Shutdown Cooling Valve Vibration
PNO-IV-06-001, Arizona Public Service Company - Followup for Tritium Contamination Found in Water Onsite2006-03-17017 March 2006
PNO-IV-06-001: Arizona Public Service Company - Followup for Tritium Contamination Found in Water Onsite
PNO-IV-05-016, Palo Verde Nuclear Generating Station, Units 2 and 3, Technical Specification Required Shutdown2005-10-12012 October 2005
PNO-IV-05-016, Palo Verde Nuclear Generating Station, Units 2 and 3, Technical Specification Required Shutdown
PNO-IV-05-015, Palo Verde Nuclear Generating Station, Unit 3, Shutdown to Repair Reactor Coolant Pump Oil Seal2005-10-0505 October 2005
PNO-IV-05-015: Palo Verde Nuclear Generating Station, Unit 3, Shutdown to Repair Reactor Coolant Pump Oil Seal
PNO-IV-05-011, Palo Verde Nuclear Generating Station, Unit 2, Shutdown to Repair Core Protection Calculators (Cpcs)2005-08-24024 August 2005
PNO-IV-05-011 Palo Verde Nuclear Generating Station, Unit 2, Shutdown to Repair Core Protection Calculators (Cpcs)
PNO-IV-05-010, A: Palo Verde Nuclear Generating Station, Unit 1, Update to Preliminary Notification PNO-IV-05-010, Shutdown to Repair Auto Voltage Regulator on Emergency Diesel Generator Train B2005-08-24024 August 2005
PNO-IV-05-010A: Palo Verde Nuclear Generating Station, Unit 1, Update to Preliminary Notification PNO-IV-05-010, Shutdown to Repair Auto Voltage Regulator on Emergency Diesel Generator Train B
PNO-IV-05-002, Palo Verde Nuclear Generating Station, Unit 1, Technical Specification Required Shutdown Due to a Partial Loss of Offsite Power2005-02-10010 February 2005
PNO-IV-05-002 Palo Verde Nuclear Generating Station, Unit 1, Technical Specification Required Shutdown Due to a Partial Loss of Offsite Power
PNO-IV-04-009, Palo Verde Unit 3: Shutdown of Unit 3 for Greater than 72 Hours2004-03-0202 March 2004
PNO-IV-04-009: Palo Verde Unit 3: Shutdown of Unit 3 for Greater than 72 Hours
PNO-IV-04-007, Palo Verde 2: Palo Verde Unplanned Reactor Shutdown to Exceed 72 Hours2004-02-20020 February 2004
PNO-IV-04-007 Palo Verde 2: Palo Verde Unplanned Reactor Shutdown to Exceed 72 Hours
PNO-IV-04-005, Arizona Public Service Co., Palo Verde, Technical Specification Required Shutdown to Exceed 72 Hours2004-02-0404 February 2004
PNO-IV-04-005 Arizona Public Service Co., Palo Verde, Technical Specification Required Shutdown to Exceed 72 Hours
PNO-IV-03-036, Palo Verde 1, 2, 3 - Automatic Reactor Trip of Unit 3 Due to Grid Perturbation2003-07-29029 July 2003
PNO-IV-03-036: Palo Verde 1, 2, 3 - Automatic Reactor Trip of Unit 3 Due to Grid Perturbation
PNO-IV-03-007, Arizona Public Service Co., Palo Verde, Ultralight Aircraft Flying Over Plant Site2003-01-31031 January 2003
PNO-IV-03-007 Arizona Public Service Co., Palo Verde, Ultralight Aircraft Flying Over Plant Site
2007-11-26
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March 17, 2006 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-IV-06-001 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 IV staff on this date.
Facility Licensee Emergency Classification Palo Verde Nuclear Generating Station Notification of Unusual Event Arizona Public Service Company Alert Tonopah, Arizona Site Area Emergency Docket: 50-528, 50-529, and 50-530 General Emergency License: NPF-41; NPF-51, and NPF-74 X Not Applicable
SUBJECT:
FOLLOWUP FOR TRITIUM CONTAMINATION FOUND IN WATER ONSITE DESCRIPTION:
On March 1, 2006, a water sample collected by the licensee from a test hole located within the licensees Unit 3 Protected Area identified tritium levels of 71,400 picocuries/Liter (pCi/L). On March 2, 2006, the licensee notified the Arizona Department of Environmental Quality (ADEQ) that a release of tritium had occurred that had the potential to cause the EPA drinking water limit (20,000 pCi/L) for tritium to be exceeded in a groundwater aquifer. As required by 10 CFR Part 50.72(b)(2)(xi) the licensee also notified the NRC (Event # 42381).
Since February 15, 2006, the licensee has been investigating the source of water leakage into an underground pipe tunnel located within the Protected Area of Units 2 and 3. Test holes were drilled inside the Protected Area in an area between all three Units power block and spray pond in an effort to find the source of the tritiated water. A water sample that contained the elevated tritium levels was from the Unit 3 test hole.
As part of the NRCs followup to the onsite elevated tritium levels, NRC Region IV obtained a split water sample from the Unit 3 test hole for the NRCs independent analysis on March 3, 2006. The NRCs independent laboratory analyzed the spilt sample for tritium and gamma radioactive isotopes and results were consistent with the 71,400 pCi/L value obtained by the licensee.
On March 6, 2006, NRC Region IV, dispatched a Senior Health Physicist to supplement the NRCs onsite resident staff and further review the licensee's actions. To date the NRCs review has determined: (1) The tritiated water at elevated levels is confined onsite; (2) No elevated levels have been found in wells located outside the Protected Area. From a review of the analyzed sample results from both onsite and offsite groundwater monitoring wells, the NRC has found no evidence of an offsite release of the radioactive water.
The apparent cause or source of the elevated tritium levels in the test holes has not been found/determined to date and is still under investigation by the licensee. NRC Region IV health physicists and the resident inspectors continue to monitor the licensees activities to address the source of the elevated tritium as well as and the licensees measures to ensure it will be confined onsite. NRC Region IV is in the process of obtaining additional environmental water samples from the Palo Verde site and surrounding areas.
The information presented herein has been discussed with the licensee and is current as of 11 a.m. (CST) on March 17, 2006.
ADAMS ACCESSION NUMBER: ML060760584 CONTACTS: Michael P. Shannon, Chief Louis C. Carson, II Plant Support Branch Senior Health Physicist 817-860-8215 817-860-8221 mps1@nrc.gov lcc1@nrc.gov
