04-25-2006 | On March 18, 2005 at 15:00 Mountain Standard Time ( MST) Palo Verde Unit 1 was in Mode 1 (Power Operations), operating at approximately 100 percent power, when Control Room personnel commenced a reactor shutdown required by Technical Specification 3.8.1.
On March 17, 2005, at approximately 04:11 MST, Unit 1 Diesel Generator "A" failed to start during its post maintenance retest. The diesel generator (DG) tripped on incomplete sequence. Prior to tripping, the DG reached approximately 100 rpm for fifteen seconds. It has been determined that the cause of the DG failure was due to a governor failure, whose speed controller showed signs of oil contamination. The failed governor has been replaced. At 17:50 MST on March 17, 2005, DG "B" was tested satisfactorily to confirm there was no common cause failure. Unit 1 was shutdown because the load rejection retest of DG "A"which was required to be performed is prohibited from being performed in Modes 1 through 4. LCO 3.8.1 expired at 04:00 MST, March 19, 2005 requiring initiation of a shut down required by Technical Specifications. At 08:48 MST on March 19, 2005, Unit 1 entered Mode 5 (Cold Shutdown) and exited LCO 3.8.1.
In the past three years, Palo Verde reported reactor shutdowns required by Technical Specifications but none associated with the same root cause. |
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LER-2005-006, A subsidiary of Pinnacle West Capital Corporation
N
Palo Verde Nuclear
Generating Station
Cliff Eubanks Mail Station 7602
Vice President Tel (623) 393-6116 PO Box 52034
Nuclear Operations Fax (623) 393-6077 Phoenix, Arizona 85072-2034
102-05473-CE/SAB/DJS
April 25, 2006
ATTN: Document Control Desk
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001
Dear Sirs:
Subject:N Palo Verde Nuclear Generating Station (PVNGS)
Unit 1
Docket No. STN 50-528
License No. NPF 41
Licensee Event Report 2005-006-01
Attached please find a supplemental Licensee Event Report (LER) 50-528/2005-006-01
prepared and submitted pursuant to 10 CFR 50.73. This LER reports a shutdown required by
Technical Specifications (TS) based on the inability to return "A" Emergency Diesel Generator to
operable status following a failed routine surveillance test within the TS action completion time.
In accordance with 10 CFR 50.4, copies of this LER supplement are being forwarded to the
NRC Regional Office, NRC Region IV and the Senior Resident Inspector. If you have questions
regarding this submittal, please contact James Proctor, Section Leader, Regulatory Affairs, at
(623) 393-5730.
The corrective actions described in this LER are not necessary to maintain compliance with
regulations.
Arizona Public Service Company makes no commitments in this letter.
Sincerely,
CE/SAB/DJS/gt
Attachment
cc:N B. S. MallettN NRC Region IV Regional Administrator
M. B. FieldsN NRC NRR Project Manager
G. G. Wamick NRC Senior Resident Inspector for PVNGS
A member of the STARS (Strategic Teaming and Resource Sharing) Alliance
Callaway • Comanche Peak • Diablo Canyon • Palo Verde • South Texas Project • Wolf Creek
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007
(6-2004)
Estimated burden per response to comply with this mandatory collection
request 50 hours. Reported lessons learned are incorporated into the
licensing process and fed back to Industry. Send comments regarding burden
estimate to the Records and FOIA/Privacy Service Branch (T-5 F52), U.S.
LICENSEE EVENT REPORT (LER) Nuclear Regulatory Commission, Washington, DC 20555-0001, or by intemet
e-mail to Infocollects@nrc.gov, and to the Desk Officer, Office of Information
and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and
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not conduct or sponsor, and a person is not required to respond to, thedigits/characters for each block) Information collection.
1. FACILITY NAME 2. DOCKET NUMBER 3. PAGE
Palo Verde Nuclear Generating Station (PVNGS) Unit 1 05000528 1 OF 6
4. TITLE
TS Required Reactor Shutdown on EDG "A" Failure to Start During Post Maintenance TestingDocket Number |
Event date: |
03-18-2005 |
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Report date: |
04-25-2006 |
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Reporting criterion: |
10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown
10 CFR 50.73(a)(2)(v), Loss of Safety Function |
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Initial Reporting |
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ENS 41502 |
10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown |
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5282005006R01 - NRC Website |
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1. REPORTING REQUIREMENT(S):
This LER (50-528/2005-006-00) is being submitted pursuant to 10 CFR 50.73(a)(2)(i)(A), to report the completion of a reactor shutdown required by Technical Specifications. Specifically, on March 18, 2005 Control Room personnel completed a reactor shutdown because the load rejection retest of DG "A" is prohibited in Modes 1 through 4. LCO 3.8.1b which requires two Emergency Diesel Generators (EDG) — (EllS:EK), each capable of supplying one train of the onsite class 1E alternating current (ac) power distribution system, be operable. (Reference: ENS call # 41502)
2. DESCRIPTION OF STRUCTURE(S), SYSTEM(S) AND COMPONENT(S):
The standby power supply for each safety-related load group consists of one EDG, complete with its accessories and fuel storage and transfer systems. The standby power supply functions as a source of alternating current (ac) power for safe plant shutdown in the event of loss of preferred power and for post-accident operation of engineered safety feature (ESF) loads.
3. INITIAL PLANT CONDITIONS:
On March 18, 2005 Palo Verde Unit 1 was in Mode 1 (Power Operations), operating at approximately 100 percent power. At the start of the event EDG "A" was inoperable due to a pre-planned routine maintenance outage. No other major structures, systems, or components were inoperable at the start of the event that contributed to the event.
4.�EVENT DESCRIPTION:
Prior to the event, on March 16, 2005, at 04:00 MST Unit 1 entered LCO 3.8.1 to conduct pre-planned routine maintenance on EDG 'A.' On March 17, 2005 at 04:11 MST the Unit 1 EDG "A" failed to start during its post maintenance retest. The Diesel Generator tripped on incomplete sequence during an exception Test Mode start/run. Prior to tripping, an Area Operator reported that the diesel reached approximately 100 rpm for 15 seconds. The engine was quarantined for Root Cause Analysis. Subsequently, Unit 1 was shutdown because the load rejection retest of the replaced governor for DG "A" is prohibited in Modes 1 through 4. At that point in time, Unit l's only operable EDG was the "B" train EDG.
Technical Specification 3.8.1 condition "B" requires the following actions to be completed with one EDG inoperable:
"B.1 Perform SR 3.8.1.1 for the operable required offsite circuit(s) within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter and, B.2 Declare required feature(s) supported by the inoperable DG inoperable when its redundant required feature(s) is inoperable within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> from discovery of condition B concurrent with inoperability of redundant required feature(s) and, B.3.1 Determine OPERABLE DG is not inoperable due to common cause failure within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (or) B.3.2 Perform SR 3.8.1.2 for OPERABLE DG within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and, B.4 Restore DG to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and within 6 days from discovery of failure to meet LCO.
5. ASSESSMENT OF SAFETY CONSEQUENCES:
With one EDG inoperable, the remaining operable EDG and offsite circuits are adequate to supply electrical power to the onsite class lE ac power distribution system.
The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> completion time takes into account the capacity and capability of the remaining ac sources, a reasonable time for repairs, and the low probability of a Design Basis Accident (DBA) occurring during this period.
The event did not result in any challenges to the fission product barriers or result in the release of radioactive materials. Therefore, there were no adverse safety consequences or implications as a result of this event and the event did not adversely affect the safe operation of the plant or health and safety of the public.
The event did not result in a transient more severe than those analyzed in the updated Final Safety Evaluation Report Chapters 6 and 15. The event did not have any nuclear safety consequences or personnel safety impact.
The condition would not have prevented the fulfillment of any safety function and did not result in a safety system functional failure as defined by 10 CFR 50.73(a)(2)(v).
6. CAUSE OF THE EVENT:
The cause of the EDG "A" failure was due to a governor failure. The governor's speed controller showed signs of contaminated oil. The contamination was the result of water intrusion into the governor internals and an extended period of time in which this governor was stored in this condition. This led to the formation of rust particles which migrated to key internal components such as the servo piston, other tight tolerance areas, and internal pump check valves.
The cause of the late Licensee Event Report (LER) was cognitive error. The cognitive error appears to have been a "mental lapse," in that the LER requirement to report the completion of a shutdown was not recognized, even though ENS 41502 to report the initiation of a shutdown was recognized and performed.
Normally, the "POTENTIALLY SIGNIFICANT Maintenance Rule Functional Failure (MRFF)" Condition Reports/Disposition Request (CRDR) # 2782680 would be returned to the CRDR Review Committee for reclassification to "SIGNIFICANT" when the condition becomes reportable. A review of CRDR 2782680 determined that it was not reclassified until 04/01/2005 when it was determined to be (solely) a Maintenance Rule Functional Failure (MRFF) (SIGNIFICANT EQUIPMENT ROOT CAUSE OF FAILURE normal shutdown. A review of CRDR 2783081 determined that it was only classified as supporting the "mental lapse" theory.
7.�CORRECTIVE ACTIONS:
The governor on EDG "A" was replaced and all retests were completed satisfactorily.
The Unit was started and synchronized to the grid on March 21, 2005.
A significant investigation into the EDG "A" governor failure has been completed resulting in the following corrective actions:
- PVNGS changed governor vendors in the 4th quarter 2000. The failed governor was refurbished from the previous vendor (pre - 4th quarter 2000).
There have been no instances of water introduction noted with several governor actuators that have been refurbished by the new vendor.
- Governor oil samples were analyzed, for all three unit's diesel generators, with acceptable results.
- Receipt procedures have been written and implemented to put oil in new/refurbished speed regulating governor actuators and over speed governors as they are received in the warehouse to prevent water intrusion in the spare governors.
- Oil from the spare governors will be sampled before installation in an EDG.
- Master Instruction (WSLMI) 245877 has been revised to obtain two oil samples of speed regulating governors (one for water, and one for wear metals and other parameters) for the installation of a replacement governor.
- Since it could not be determined whether the water contamination of the oil occurred at PVNGS or at the vendor, the next vendor audit scope will include foreign material exclusion measures.
The late LER submittal was a cognitive error. All members of the Regulatory Affairs group were counseled regarding this omission to report the completion of a TS required plant shutdown.
8.�PREVIOUS SIMILAR EVENTS:
In the past three years, Palo Verde reported reactor shutdowns required by Technical Specifications but none associated with the same root cause.
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05000328/LER-2005-001 | Unit 2 Reactor Trip Following Closure of Main Feedwater Upon Inadvertent Opening of Control Breakers | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000388/LER-2005-001 | DDegradation of Primary Coolant Pressure Boundary due to Recirculation Pump Discharge Valve Bonnet Vent Connection Weld Flaw | 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded | 05000423/LER-2005-001 | | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000455/LER-2005-001 | Unit 2 Automatic Reactor Trip Due to Low Steam Generator Level resulting from a Software Fault on the Turbine Control Power Runback Feature | | 05000370/LER-2005-001 | Automatic Actuation of Motor Driven Auxiliary Feedwater Pumps During Outage | | 05000244/LER-2005-001 | Failure of ADFCS Power Supplies Results in Plant Trip | | 05000247/LER-2005-001 | 0Technical Specification Prohibited Condition Due to Exceeding the Allowed Completion Time for One Inoperable Train of ECCS Caused by an Inoperable Auxiliary Component Cooling Water Check Valve | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000529/LER-2005-001 | REACTOR HEAD VENT AXIAL INDICATIONS CAUSED BY DEGRADED ALLOY 600 COMPONENT | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded | 05000336/LER-2005-001 | | | 05000266/LER-2005-001 | | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition | 05000269/LER-2005-001 | | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000289/LER-2005-001 | | | 05000293/LER-2005-001 | | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000298/LER-2005-001 | Reactor Scram due to Reactor Level Transient and Inadvertent Rendering of High Pressure Coolant Injection Inoperable | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000331/LER-2005-001 | | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition | 05000315/LER-2005-001 | Reactor Trip Following Intermediate Range High Flux Signal | | 05000316/LER-2005-001 | Reactor Trip from RCP Bus Undervoltage Signal Complicated by Diesel Generator Output Breaker Failure | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000317/LER-2005-001 | Main Feedwater Isolation Valve Inoperability Due to Handswitch Wiring | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000323/LER-2005-001 | TS 3.4.10 Not Met During Pressurizer Safety Valve Surveillance Testing Due to Random Lift Spread | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000333/LER-2005-001 | Inoperable Offsite Circuit In Excess of Technical Specifications Allowed Out of Service Time | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000352/LER-2005-001 | Loss Of Licensed Material In The Form Of A Radiation Detector Calibration Source | | 05000353/LER-2005-001 | Core Alterations Performed With Source Range Monitor Alarm Horn Inoperable | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000306/LER-2005-001 | | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000361/LER-2005-001 | | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000362/LER-2005-001 | Emergency Diesel Generator (EDG) 3G003 Declared Inoperable Due to Loose Wiring Connection on Emergency Supply Fan | | 05000263/LER-2005-001 | | | 05000456/LER-2005-001 | Potential Technical Specification (TS) 3.9.4 Violation Due to Imprecise Original TS and TS Bases Wording | | 05000454/LER-2005-001 | Failed Technical Specification Ventilation Surveillance Requirements During Surveillance Requirement 3.0.3 Delay Period | | 05000282/LER-2005-001 | | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000286/LER-2005-001 | Plant in a Condition Prohibited by Technical Specifications due to Error Making Control Room Ventilation System Inoperable | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000400/LER-2005-001 | Reactor Auxiliary Building Emergency Exhaust System Single Failure Vulnerability | | 05000395/LER-2005-001 | Emergency Diesel Generator Start and Load Due To A Loss Of Vital Bus | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000382/LER-2005-001 | RCS Pressure Boundary Leakage Due to Primary Water Stress Corrosion Cracking of a Pressurizer Heater Sleeve | 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded | 05000305/LER-2005-001 | | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000369/LER-2005-001 | Reactor Coolant System Leakage Detection Instrumentation Inoperable | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000266/LER-2005-002 | | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition | 05000255/LER-2005-002 | | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000361/LER-2005-002 | Missing Taper Pins on CCW Valve Cause Technical Specification Required Shutdown | 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown | 05000370/LER-2005-002 | Ice Condenser Lower Inlet Door Failed Surveillance Testing | | 05000353/LER-2005-002 | High Pressure Coolant Injection System Inoperable due to a Degraded Control Power Fuse Clip | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000263/LER-2005-002 | | | 05000454/LER-2005-002 | One of Two Trains of Hydrogen Recombiners Inoperable Longer Than Allowed by Technical Specifications Due to Inadequate Procedure | | 05000244/LER-2005-002 | Emergency Diesel Generator Start Resulting From Loss of Off-Site Power Circuit 751 | | 05000362/LER-2005-002 | Emergency Containment Cooling Inoperable for Longer than Allowed by Technical Specifications | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000247/LER-2005-002 | DTechnical Specification Prohibited Condition Due to Exceeding the Allowed Completion Time for One Inoperable Train of ECCS Caused by Gas Intrusion from a Leaking Check Valve | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000306/LER-2005-002 | | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown | 05000265/LER-2005-002 | Main Steam Relief Valve Actuator Degradation Due to Failure to Correct Vibration Levels Exceeding Equipment Design Capacities | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown | 05000286/LER-2005-002 | • Entergy Nuclear Northeast Indian Point Energy Center 450 Broadway, GSB P.O. Box 249Entergy Buchanan. NY 10511-0249 Tel 914 734 6700 Fred Dacimo Site Vice President Administration July 5, 2005 Indian Point Unit No. 3 Docket Nos. 50-286 N L-05-078 Document Control Desk U.S. Nuclear Regulatory Commission Mail Stop O-P1-17 Washington, DC 20555-0001 Subject:L Licensee Event Report # 2005-002-00, "Automatic Reactor Trip Due to 32 Steam Generator Steam Flow/Feedwater Flow Mismatch Caused by Low Feedwater Flow Due to Inadvertent Condensate Polisher Post Filter Bypass Valve Closure." Dear Sir: The attached Licensee Event Report (LER) 2005-002-00 is the follow-up written report submitted in accordance with 10 CFR 50.73. This event is of the type defined in 10 CFR 50.73(a)(2)(iv)(A) for an event recorded in the Entergy corrective action process as Condition Report CR-IP3-2005-02478. There are no commitments contained in this letter. Should you or your staff have any questions regarding this matter, please contact Mr. Patric W. Conroy, Manager, Licensing, Indian Point Energy Center at (914) 734-6668. Sincerely, 4F-/t R. Dacimo Vice President Indian Point Energy Center Docket No. 50-286 NL-05-078 Page 2 of 2 Attachment: LER-2005-002-00 CC: Mr. Samuel J. Collins Regional Administrator — Region I U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission Resident Inspector's Office Resident Inspector Indian Point Unit 3 Mr. Paul Eddy State of New York Public Service Commission INPO Record Center NRC FORM 3660 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES: 06/30/2007 (6-2004) Estimated burden per response to comply with this mandatory collection request 50 hours.RReported lessons teamed are incorporated into the licensing process and fed back to Industry. Send comments regarding burden estimate to the Records and FOIA/Privacy Service Branch (T-5 F52), U.S. Nuclear Regulatory Commission, Washington, DC 29555-0001, or by InternetLICENSEE EVENT REPORT (LER) e-mail to Infocoilectsenrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-l0202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person Is not required to respond to, the Information collection. 1. FACIUTY NAME 2. DOCKET NUMBER 3. PAGE INDIAN POINT 3 05000-286 10OF06 4. TITLE Automatic Reactor Trip Due to 32 Steam Generator Steam Flow/Feedwater Flow Mismatch Caused by Low Feedwater Flow Due to Inadvertent Condensate Polisher Post Filter Bypass Valve Closure | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000287/LER-2005-002 | Unit 3 trip with ES actuation due to CRD Modification Deficiencies | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000336/LER-2005-002 | | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
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