ENS 42468
ENS Event | |
|---|---|
03:54 Apr 3, 2006 | |
| Title | Emergency Diesel Trip During Testing |
| Event Description | 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.
On April 2, 2006 at approximately 20:54 Mountain Standard Time, Palo Verde Nuclear Generating Station Unit 3 experienced a valid Loss of Power (LOP) actuation on the Train 'B' 4.16 kV safety bus. The event occurred due to personnel error during performance of surveillance test 73ST-9DG02 (Class 1 E Diesel Generator and Integrated Safeguards Test Train B). EDG 'B' had been started In Emergency Mode per the surveillance test by opening the normal supply breaker to the associated 4.16 kV bus and initiating simulated Safety Injection Actuation System (SIAS) and Containment Isolation Actuation System (CIAS) signals. A subsequent portion of the surveillance test was in progress which demonstrates that the EDG 'test mode' trips are bypassed with the EDG operating in Emergency Mode. The step being performed was intended to simulate an Overcurrent (test mode) trip by installing a jumper at the Overcurrent relay. However the jumper was inadvertently installed at the Differential Current relay, which generated an 'Emergency Mode' trip of EDG 'B'. This resulted in the deenergization of the 4.16 kV bus. The operations staff entered Abnormal Operating Procedure (AOP) 40AO-9ZZ12 (Degraded Electrical) and reset EDG 'B'. Upon reset at approximately 21:26 MST, EDG 'B' automatically started in response to a valid Loss of Power (LOP) signal from the deenergized 4.16 kV bus. The EDG 'B' output breaker automatically closed to restore power to the Train 'B' 4.16 kV and equipment sequenced onto the 4.16 kV bus. Due to the loss of power on the Train 'B' 4.16 kV bus, the Train 'B' Control Room Essential Filtration System (CREFS) and Control Room Emergency Air Temperature Control System (CREATCS) were rendered inoperable and LCOs 3.7.11 Condition 'A' and 3.7.12 Condition 'A' were entered. Operability of Train 'B' CREFS and CREATCS was restored when the Train 'B' 4.16 kV bus was reenergized and these LCO Conditions were exited. Offsite power remained available to the Train 'A' 4.16 kV bus and EDG 'A' remained operable throughout the event. Shutdown Cooling was unaffected since it was being provided by the Train 'A' safety train, which was supplied by offsite power. The offsite electrical grid is stable. Palo Verde Unit 3 Is shutdown and in Mode 5 for its 12th refueling outage. No other ESF actuations occurred and none were required. There were no structures, systems, or components that were inoperable at the time of discovery that contributed to this condition. The event did not result in the release of radioactivity to the environment and did not adversely affect the safe operation of the plant or health and safety of the public. The NRC Resident Inspector has been notified of the ESF actuation and this ENS notification. The site performed a work stand down to discuss this event and prevent recurrence. |
| Where | |
|---|---|
Palo Verde  Arizona (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+0.03 h0.00125 days <br />1.785714e-4 weeks <br />4.1094e-5 months <br />) | |
| Opened: | Steve Smith 03:56 Apr 3, 2006 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Apr 3, 2006 |
| 42468 - NRC Website | |
Unit 3 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (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 560442022-08-15T00:02:00015 August 2022 00:02:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Actuations of Unit 1 and Unit 3 Emergency Diesel Generators and Unit 1 Auxiliary Feedwater Pump ENS 558782022-05-05T02:55:0005 May 2022 02:55:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Actuation of Unit 2 and Unit 3 Emergency Diesel Generators and Unit 3 Auxiliary Feedwater Pump ENS 555342021-10-20T21:46:00020 October 2021 21:46:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Specified System Actuations of Unit 1 and Unit 3 Emergency Diesel Generators 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 466332011-02-22T03:01:00022 February 2011 03:01:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Auto Start and Load of Edgs on Units 1&3 Following Loss of Start-Up Transformer 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 429382006-10-27T06:53:00027 October 2006 06:53:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Loss of Power to the Unit 1 and Unit 3 Train B Safety Buses with Emergency Diesel Generator Actuation ENS 426092006-05-30T15:13:00030 May 2006 15:13:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Loss of Power to Train "a" 4 Kv Safety Bus ENS 425592006-05-06T23:35:0006 May 2006 23:35:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Actuation of Emergency Diesel Generator Due to Low Voltage Condition ENS 424682006-04-03T03:54:0003 April 2006 03:54:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Emergency Diesel Trip During Testing ENS 413792005-02-07T05:19:0007 February 2005 05:19:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Emergency Diesel Start Due to Bus Deenergization ENS 413042004-12-31T17:42:00031 December 2004 17:42:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Plant Had Auto Start and Loading of Two Emergency Diesel Gererators 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 403492003-11-22T05:53:00022 November 2003 05:53:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Actuation of the "a" Emergency Diesel Generator During Testing 2023-06-02T11:05:00 | |