ENS 42681
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ENS Event | |
|---|---|
02:28 Jul 2, 2006 | |
| Title | Manual Reactor Trip Following Large Leak in Condensate System |
| Event Description | On July 1, 2006, at approximately 19:28 MST Palo Verde Unit 3 experienced a manual reactor trip from approximately 100% rated thermal power due to a large leak in the condensate system. The sight glass for the 'A' condensate demin vessel blew out of the vessel creating an approximate 6 inch diameter hole. Several thousand gallons of condensate were discharged to the Turbine Building and the environment. Radiation Protection has sampled the condensate water and have verified no activity is present. Unit 3 was at normal operating temperature and pressure prior to the trip. The 'A' Main feedwater pump tripped on low suction pressure and a Reactor Power Cutback Signal was received. Condenser hotwell levels continued to decrease. When the main control board annunciator for the 'B' Main Feedwater Pump Trip Circuit Energized was received the reactor was manually tripped. All CEAs fully inserted into the reactor core. The event was diagnosed as an uncomplicated reactor trip. No ESF actuations occurred and none were required. Safety related buses remained energized during and following the reactor trip. The offsite power grid is stable. No significant LCOs have been entered as a result of this event. There was no loss of normal heat removal capabilities, or loss of any safety functions associated with this event. No major equipment was inoperable prior to the event that contributed to the event. No primary or secondary safety valves lifted during the event. The event did not result in any challenges to fission product barriers and there were no adverse safety consequences as a result of this event. The event did not adversely affect the safe operation of the plant or the health and safety of the public.
Unit 3 is stable at normal operating temperature and pressure in Mode 3. There is no estimated time and date for the Unit 3 restart at the time this call is being made. AFW is being used to feed the steam generators and is discharging steam to the main condenser. The licensee stated that the leak has been secured and that there is no significant standing water in the turbine building lower levels. All the water has drained into sumps or out doors. There does not appear to be any electrical or personnel safety hazards as a result of the water leak. The licensee notified the NRC Resident Inspector.
The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. This notification is a follow-up to the manually initiated reactor trip event reported on July 1, 2006 (ENS 42681). The notification indicated that the reactor was manually tripped from approximately 100% rated thermal power due to a large leak in the condensate system. Prior to the transient the unit was operating at approximately 100 % rated thermal power, however, the manual trip was actually initiated from approximately 55% rated thermal power following a reactor power cutback caused by the loss of the A train main feedwater pump on low suction pressure. In addition, the ENS report stated that Radiation Protection had sampled the condensate water and verified no activity is present. The condensate actually was found to contain tritium at a concentration of 1.22E-5 uCi/ml. The water from the spill flowed to the onsite storm drains, was captured behind dams, and transferred to the onsite retention basins. Samples of resin from the spill were also collected, analyzed by gamma spectroscopy, and found to not contain licensed radioactive material. The licensee notified the NRC Resident Inspector. Notified R4DO (Shannon) |
| Where | |
|---|---|
Palo Verde  Arizona (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation | |
| Time - Person (Reporting Time:+-1.08 h-0.045 days <br />-0.00643 weeks <br />-0.00148 months <br />) | |
| Opened: | James Blazek 01:23 Jul 2, 2006 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Jul 2, 2006 |
| 42681 - NRC Website
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Unit 3 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (100 %) |
| After | Hot Standby (0 %) |
WEEKMONTHYEARENS 565512023-06-02T11:05:0002 June 2023 11:05:00
[Table view]10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip ENS 564592023-04-09T04:44:0009 April 2023 04:44:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Loss of Reactor Coolant Pumps ENS 556262021-12-06T19:03:0006 December 2021 19:03:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Unit 3 Automatic Trip ENS 552652021-05-19T10:15:00019 May 2021 10:15:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip Due to High Pressurizer Pressure ENS 551142021-02-26T17:33:00026 February 2021 17:33:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Trip Due to Loss of Two Reactor Coolant Pumps ENS 545602020-03-04T03:50:0004 March 2020 03:50:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Trip Due to Low Steam Generator Level ENS 542242019-08-16T15:21:00016 August 2019 15:21:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Turbine Trip ENS 534772018-06-27T07:00:00027 June 2018 07:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip on Low Steam Generator Water Level ENS 534242018-05-23T18:28:00023 May 2018 18:28:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip on Low Departure from Nucleate Boiling Ratio ENS 532152018-02-16T04:53:00016 February 2018 04:53:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Automatic Reactor Trip Due to Low Departure from Nucleate Boiling Signal ENS 522262016-09-08T04:31:0008 September 2016 04:31:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Due to Stuck Open Pressurizer Main Spray Valve ENS 496002013-12-03T00:58:0003 December 2013 00:58:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip Following the Loss of the 1A Reactor Coolant Pump ENS 478372012-04-15T19:20:00015 April 2012 19:20:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Due to Control Rod Deviation During Startup ENS 474722011-11-23T02:25:00023 November 2011 02:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Due to Control Element Deviation ENS 471332011-08-06T18:19:0006 August 2011 18:19:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip Due to Dropped Control Element Assembly ENS 465562011-01-20T01:41:00020 January 2011 01:41:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip Due to Main Feedwater Pump Trip ENS 457482010-03-07T18:24:0007 March 2010 18:24:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Notification of Unusual Event Due to Electrical Fault Causing Damage to Equipment ENS 455372009-12-03T11:30:0003 December 2009 11:30:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip After Loss of Instrument Air to Containment ENS 449702009-04-04T06:54:0004 April 2009 06:54:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to High Vibrations in the Turbine ENS 445252008-09-28T04:51:00028 September 2008 04:51:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Unit 3 Reactor Manually Tripped Following Automatic Turbine Trip on High Vibration ENS 444962008-09-16T21:00:00016 September 2008 21:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip During Troubleshooting of Control Rod Drive Mechanism Motor Generators ENS 442462008-05-29T04:34:00029 May 2008 04:34:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Due to Improper Movement of Cea'S ENS 436972007-10-06T17:59:0006 October 2007 17:59:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Due to Condenser Tube Rupture ENS 429252006-10-21T22:48:00021 October 2006 22:48:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip Due to Control Element Assembly Position Transmitter Output Deviations ENS 429202006-10-19T18:47:00019 October 2006 18:47:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Following the Trip of Secondary Condensate Pumps ENS 427302006-07-26T14:35:00026 July 2006 14:35:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Variable Overpower Reactor Trip Following Turbine Control Valve Maintenance ENS 426812006-07-02T02:28:0002 July 2006 02:28:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Following Large Leak in Condensate System ENS 423872006-03-05T14:10:0005 March 2006 14:10:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip Due to Low Departure from Nucleate Boiling Ratio. ENS 419512005-08-27T01:24:00027 August 2005 01:24:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Rps Actuation - Reactor Scram on High Steam Generator Level ENS 408702004-07-14T08:35:00014 July 2004 08:35:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip Following a Main Generator Trip ENS 408162004-06-14T14:44:00014 June 2004 14:44:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unusual Event Due to Reactor Trip Due to Loss of Off Site Power ENS 408152004-06-14T14:44:00014 June 2004 14:44:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unusual Event Declared Due to Reactor Trip Due to Loss of Off Site Power ENS 408142004-06-14T14:44:00014 June 2004 14:44:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Alert Declared - Reactor Trip Due to Loss of Off Site Power ENS 407952004-06-07T21:58:0007 June 2004 21:58:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Trip Due to Main Turbine Electro-Hydraulic Control System Failure ENS 407372004-05-09T03:39:0009 May 2004 03:39:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip During Physics Testing Due to Control Element Assembly Slipping 6 Inches. 2023-06-02T11:05:00 | |
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