04-14-2006 | in response to a turbine/generator load reject due to a trip of the main power transformer (MPT) 'B' phase differential overcurrent relay. The relay trip was caused by degraded wiring insulation, resulting in a ground in the current transformer 'C' phase wiring at a box mounted on the MPT. The degraded wiring insula.tion resulted in a direct short to ground and resultant trip of the protective differential overcurrent relay.
All control rods inserted to the full-in position. The reactor was brought to the hot shutdown condition using normal methods and was maintained in hot shutdown durinc investigation and repair of the MPT issue until the reactor was returned to power operation on February 24, 2006.
The degraded wiring insulation was caused by inadequate MPT wiring assembly design and installation. Corrective actions include repair of degraded wiring, inspection of accessible wiring and design changes. |
---|
FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6 PAGE (3) Quad Cities Nuclear Power Station Unit 1 05000254 NUMBER6 NUMBER (If more space is required, use additional copies of NRC Form 366A)(17)
PLANT AND SYSTEM IDENTIFICATION
General Electric - Boiling Water Reactor, 2957 Megawatts Thermal Rated Core Power Energy Industry Identification System (EIIS) codes are identified in the text as [XX].
EVENT IDENTIFICATION
Automatic Reactor Scram From Turbine/Generator Load Reject due to Degraded Current Transformer Wiring on the Main Power Transformer CONDITION PRIOR TO EVENT A.
Unit: 1 Event Date: February 22, 2006 Event Time: 0122 hours0.00141 days <br />0.0339 hours <br />2.017196e-4 weeks <br />4.6421e-5 months <br /> Power Level: 085% Reactcr Mode: 1 Mode Name: Power Operation DESCRIPTION OF EVENT B.C On February 22, 2006, at 0122 hours0.00141 days <br />0.0339 hours <br />2.017196e-4 weeks <br />4.6421e-5 months <br />, an automatic reactor scram occurred on Quad Cities Nuclear Power Station Unit 1 in response to a turbine/generator [TG] load reject.
The event was initiated by a trip of the main power transformer (MPT) [XFMR][EL] `B'phase differential overcurrent relay [87]. The relay trip was caused by degraded wiring insulation, resulting in a ground in the current transformer (CT) `C'phase wiring at a box mounted on the MPT. The degraded wiring insulation resulted in a direct short to ground at or near the box in the associated conduit run and a resultant trip of the protective differential overcurrent relay.
All control rods inserted to the full-in position. The reactor was brought to the hot shutdown condition using normal methods and was maintained in hot shutdown during investigation and repair of the MPT issue until the reactor was returned to power operation on February 24, 2006. The plant operated as designed with no abnormal issues or failures, with one exception. The fire deluge on the MPT, expected to actuate during a differential overcurrent trip, did not actuate.
CAUSE OF EVENT C.
The degraded wiring insulation in the CT was caused by the fact that the MPT wiring design and installation of the wiring assembly (interconnection boxes, conduit, pull-boxes, and wiring) was not adequate to support design life of the transformer.
Vibration of certain conduits, pull-boxes, interconnection boxes, and control boxes resulted in abnormal wear of the wiring insulation.
The failure of the MPT deluge to activate was due to a cross-threaded screw on the deluge contact on the differential overcurrent relay that had become loose over time.
FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6 PAGE (3) (If more space is required, use additional copies of NRC Form 366A)(17)
D. SAFETY ANALYSIS
The safety significance of this event was minimal. All control rods inserted to the full-in position. The reactor was brought to the hot shutdown condition using normal methods and was maintained in hot shutdown during investigation and repair of the MPT issue until the reactor was returned to power operation.
An Emergency Notification System call was made at 0351 hours0.00406 days <br />0.0975 hours <br />5.803571e-4 weeks <br />1.335555e-4 months <br /> on February 22, 2006, in accordance with 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System Actuation..
This report is being made in accordance with 10 CFR 50.73(a)(2)(iv)(A), as an event or condition that resulted in manual or automatic actuation of the reactor protection system.
E. CORRECTIVE ACTIONS
Corrective Actions Completed:
New external CT wiring was routed and tested prior to reactor startup.
The MPT sudden pressure relay (SPR) trip wiring was inspected to the extent: possible and practical, and insulation degradation identified was repaired.
The wiring for the MPT coolers was inspected to the extent possible and practical, and insulation degradation identified was repaired.
The differential overcurrent relay was replaced.
Corrective Actions to be Completed:
Unit 1 MPT SPR and cooler group wiring will be re-wired to bypass the suspect wirinc
- . A spare Unit 2 MPT of a different design has been installed during the recent spring refueling outage; therefore the condition of the wiring on the Unit 2 MPT is not in question.
The design specifications for the Unit 1 MPT will be upgraded to ensure the MPT electrical assembly will operate for its design life.
F. PREVICUS OCCURRENCES
No reportable instances of worn wiring on an MPT were identified at Quad CLties Nuclear Power Station for the last three years. However, there have been non-reportable instances of evidence of damaged or degraded wiring since the installation of the Unit 1 MPT in March 2005. These instances were primarily in three specific cooling banks, and corrective actions specific to the events were implemented.
G. COMPONENT FAILURE DATA
The Unit 1 MPT is a new transformer that was manufactured by ABB at the Cordoba, Spain, factory (serial # 63006, manufacturing date 2002), and was installed at Quad Cities Nuclear Power Station in March 2005.
|
---|
|
|
| | Reporting criterion |
---|
05000305/LER-2006-010 | | | 05000456/LER-2006-001 | Unit 1 Reactor Coolant System Pressure Boundary Leakage Due To Inter-Granular Stress Corrosion Cracking of a Pressurizer Heater Sleeve | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded | 05000454/LER-2006-001 | Technical Specification Required Action Completion Time Exceeded for Inoperable Containment Isolation Valves Due to Untimely Operability Determination | | 05000423/LER-2006-001 | Loss Of Safety Function Of The Control Room Emergency Ventilation System | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000369/LER-2006-001 | Ice Condenser and Floor Cooling System Containment Isolation Valve inoperable longer than allowed by Technical Specification 3.6.3. | | 05000353/LER-2006-001 | HPCI Ramp Generator Signal Converter Failure | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000352/LER-2006-001 | Loss Of One Offsite Circuit Due To Invalid Actuation Of Fire Suppression System | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000336/LER-2006-001 | | 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor | 05000316/LER-2006-001 | Failure to Comply with Technical Specification 3.6.2, Containment Air Locks | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000315/LER-2006-001 | Plant Shutdown Required by Technical Specification Action 3.6.5.B.1 | | 05000293/LER-2006-001 | | 10 CFR 50.73(a)(2)(iv), System Actuation | 05000289/LER-2006-001 | | | 05000287/LER-2006-001 | Actuation of Emergency Generator due to Spurious Transformer Lockout | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000251/LER-2006-001 | Turkey Point Unit 4 05000251 1 OF 6 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000247/LER-2006-001 | Manual Reactor Trip Due to Multiple Dropped Control Rods Caused by Loss of Control Rod Power Due to Personnel Error | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000440/LER-2006-001 | Incorrect Wiring in the Remote Shutdown Panel Results in a Fire Protection Program Violation | | 05000413/LER-2006-001 | | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000368/LER-2006-001 | Completion of a Plant Shutdown Required by Technical Specifications Due to Loss of Motive Power to Certain Containment Isolation Valves as a Result of a Phase to Ground Short Circuit in a Motor Control Cubicle | 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown | 05000306/LER-2006-001 | | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown | 05000298/LER-2006-001 | Cooper Nuclear Station 05000298 1 of 4 | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000286/LER-2006-001 | I | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000282/LER-2006-001 | | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000266/LER-2006-001 | | 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000261/LER-2006-001 | Manual Reactor Trip Due to Failure of a Turbine Governor Valve Electro-Hydraulic Control Card | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000255/LER-2006-001 | | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition | 05000461/LER-2006-002 | Turbine Bypass Function Lost Due to Circuit Card Maintenance Frequency | | 05000458/LER-2006-002 | Loss of Safety Function of High Pressure Core Spray Due to Manual Deactivation | | 05000456/LER-2006-002 | Units 1 and 2 Entry into Limiting Condition for Operation 3.0.3 due to Main Control Room Ventilation Envelope Low Pressure | | 05000443/LER-2006-002 | Noncompliance with the Requirements of Technical Specification 6.8.1.2.a | | 05000387/LER-2006-002 | DMissed Technical Specification surveillance requirement | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000362/LER-2006-002 | Unit 3 Shutdown to Inspect Safety Injection Tank Spiral Wound Gaskets | | 05000336/LER-2006-002 | Manual Reactor Trip Due To Trip Of Both Feed Pumps Following A Loss Of Instrument Air | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000316/LER-2006-002 | | 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000315/LER-2006-002 | Failure to Comply with Technical Specification Requirement 3.6.13, Divider Barrier Integrity | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000293/LER-2006-002 | | | 05000289/LER-2006-002 | | | 05000251/LER-2006-002 | Intermediate Range High Flux Trip Setpoint Exceeded Technical Specification Allowable Value | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000440/LER-2006-002 | Scaffold Built in the Containment Pool Swell Region | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition | 05000413/LER-2006-002 | Safe Shutdown Potentially Challenged by an External Flooding Event and Inadequate Design and Configuration Control | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000388/LER-2006-002 | Missed Technical Specification LCO 3.8.1 Entry for Unit 2 During Unit 1 ESS Bus Testing | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000348/LER-2006-002 | Main Steam Isolation Valve Failure to Close | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000305/LER-2006-002 | | 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 | 05000301/LER-2006-002 | | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000286/LER-2006-002 | 450 Broadway, GSB P.O. Box 249 Buchanan, N.Y. 10511-0249Entergy Tel (914) 734-6700 Fred Dacimo Site Vice President Administration September 13, 2006 Indian Point Unit No. 3 Docket No. 50-286 N L-06-084 Document Control Desk U.S. Nuclear Regulatory Commission Mail Stop O-P1-17 Washington, DC 20555-0001 Subject:L Licensee Event Report # 2006-002-00, "Manual Reactor Trip as a Result of Arcing Under the Main Generator Between Scaffolding and Phase A&B of the Isophase Bus Housing" Dear Sir: The attached Licensee Event Report (LER) 2006-002-00 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-IP3-2006-02255. 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. Fred R. Dacimo Site Vice President Indian Point Energy Center Docket No. 50-286 NL-06-084 Page 2 of 2 Attachment: LER-2006-002-00 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 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.DReported 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. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internetLICENSEE EVENT REPORT (LER) 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 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. FACILITY NAME 2. DOCKET NUMBER I 3. PAGE
INDIAN POINT 3 05000-286 1 OF 6
4.TITLE: Manual Reactor Trip as a Result of Arcing Under the Main Generator Between
Scaffolding and Phase A&B of the Iso-phase Bus Housing | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000282/LER-2006-002 | | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000269/LER-2006-002 | High Energy Line Breaks Outside Licensing Basis May Result in Loss of Safety Function | | 05000263/LER-2006-002 | | | 05000255/LER-2006-002 | | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000254/LER-2006-002 | Quad Cities Nuclear Power Station Unit 1 05000254 1 of 3 | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000483/LER-2006-003 | Unexpected Inoperability of the Emergency Exhaust System due to Inoperable Pressure Boundary | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
|