At 20:59 on October 14, 2008, Unit 2 Component Cooling Water ( CCW) Train A was discovered to be inoperable due to an inoperable level switch in the CCW surge tank. During surveillance testing of the low- low level switch, it did not respond as required. Troubleshooting identified the cause of the failure as a loose wire. Operability was restored at 01:58 on October 16, 2008.
Technical Specification 3.7.3 requires that if one train of CCW is inoperable in Modes 1, 2, 3, and 4, it is to be restored to operability within seven days or the unit is to be in at least hot standby within six hours. Previous maintenance that could have affected the wire was completed January 22, 2008. The allowed outage time expired on January 29, 2008. Because these components were inoperable longer than allowed under the Technical Specifications without taking the appropriate action, this event is reportable under 10 CFR 50.73(a)(2)(i)(B).
The root cause of the event was an inadequate calibration procedure. The procedure did not require a functionality check of the internal switch contacts after switch calibration restoration. Maintenance procedures for safety-related equipment will be reviewed to identify procedures that are not followed immediately by a functionality check, and will be corrected as necessary.
Only CCW Train A of Unit 2 was affected by this condition.. This event resulted in no personnel injuries, no offsite radiological releases, and no damage to other safety-related equipment. |
DESCRIPTION OF EVENT
A. REPORTABLE EVENT CLASSIFICATION
This event is reportable pursuant to 10 CFR 50.73(a)(2)(i)(B). South Texas Project (STP) Technical Specification 3.7.3 allows one train of Component Cooling Water (CCW) to be inoperable in Modes 1 through 4 for seven days before taking action to begin shutdown without extending the allowed outage time using the Configuration Risk Management Program. However, STP Unit 2 CCW Train A was determiried to have been inoperable longer than the allowed outage time. Consequently, STP Unit 2 was in a condition prohibited by Technical Specifications.
B. PLANT OPERATING CONDITIONS PRIOR TO EVENT
STP Unit 2 was in Mode 6 at 0% power.
C. STATUS OF STRUCTURES, SYSTEMS, AND COMPONENTS THAT WERE INOPERABLE
AT THE START OF THE EVENT AND THAT CONTRIBUTED TO THE EVENT
� No other inoperable structures, systems, or components contributed to the event.
D. NARRATIVE SUMMARY OF THE EVENT
At 20:59 on October 14, 2008, during a surveillance test, STP Unit 2 CCW Train A was found to be inoperable due to failure of system valves to actuate to their designated positions. This occurred during the component 18-month surveillance test conducted during the Unit 2 2RE13 refueling outage. This test is conducted in plant operating modes 5 or 6, or when the core is offloaded. The test was conducted on CCW surge tank low-low level switch A2CC-LSL-4503C which actuates valves required to mitigate a CCW system leak. Troubleshooting determined that a. loose wire on switch terminal 6 was the reason for the event. The wire was secured in place and Train A was returned to operable status at 01:58 on October 16, 2008.
The most recent maintenance performed on the switch occurred during a calibration procedure on January 22, 2008. The internal switch contacts were not functionally checked after restoration following calibration.
Initially, the condition was identified as being not reportable based on "time of discovery" as delineated in NUREG-1022. The condition would not have prevented fulfillment of a safety function. However, subsequent review determined that a functional check was not performed following restoration after the calibration on January 22, 2008. Because Train A was inoperable longer than the Technical Specification allowed outage time, a formal determination was made November 12, 2008, that the condition is reportable under 10 CFR 50.73(a)(2)(i)(B).
discovery. The instrumentation was confirmed to be operable.
E. METHOD 'OF DISCOVERY OF EACH COMPONENT FAILURE, SYSTEM FAILURE, OR
PROCEDURAL ERROR
This condition was identified during the 18-month surveillance of the Unit 2 Train A CCW surge tank low level actuation system.
IL EVENT-DRIVEN INFORMATION
A. SAFETY SYSTEMS THAT RESPONDED
No safety systems were required to respond during this event.
B. DURATION OF SAFETY SYSTEM INOPERABILITY
The CCW surge tank low-low level switch-was most recently calibrated on January 22, 2008.
The loose wire is presumed to have occurred at that time. Train A was declared inoperable October 14, 2008, and restored to operability October 16, 2008. The train was inoperable for 237 days.
Of the three trains of CCW, Trains B and C were unaffected by this condition. Low and low-low surge tank level monitors for Train B and Train C were confirmed as being operable.
At least one of the two remaining trains was operable while Train A was inoperable.
C. SAFETY CONSEQUENCES AND IMPLICATIONS OF THE EVENT
Technical Specification Requirements:
Technical Specification 3/.3 requires at least three independent CCW loops to be operable in Modes 1, 2, 3, and 4. With only two CCW loops operable, the inoperable loop is to be restored to operable status within seven days or the Configuration Risk Management Program applied to justify an extension. Otherwise, the unit is to be in at least hot standby within the next six hours and in cold shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
In addition to Technical Specification 3.7.3, Technical Specifications also include requirements for Residual Heat Removal System (RHR) operability. Some of these technical specifications are applicable in modes 5 and 6. CCW operability is required to support RHR operability; therefore, CCW must be operable during modes 5 and 6 in addition to modes 1 through 4 as required above.
Because Unit 2 CCW Train A was inoperable longer than allowed under the Technical Specifications without entering the appropriate action statements, this event is reportable pursuant to 10 CFR 50.73(a)(2)(i)(B).
Design Description:
The CCW surge tank is partitioned into three equal volumes by internal baffles. Each compartment is connected to the inlet piping of one of the CCW pumps. The internal baffles provide separation between redundant CCW trains, so that leakage from a pipe break in one train does not affect the operability of the other trains. Makeup to the CCW surge tank is added automatically from the Demineralized Water System (DWS). As a backup by manual valve alignment, makeup water can be obtained from the Reactor Makeup Water System (RMWS) which is a safety-related and seismic Category I makeup source. An alarm is indicated in the control room if the level in the surge tank decreases due to inadequate makeup. If the level in the surge tank continues to decrease, the non-safety header is isolated, followed by automatic isolation of each CCW train from the other trains by closing the motor-operated supply and return valves located upstream and downstream of the common supply and the return headers, respectively. Simultaneously, pneumatic cross-connect valves (FV-4656 and FV-4657) in the centrifugal charging pump and positive displacement pump coolers supply and return headers (CCW train A and CCW train B from CCW train C) and motor-operated valves MOV-0768 and MOV-0772 are closed to prevent loss of more than one CCW train at a time. As soon as the CCW common header is isolated, the low pressure switch located in the common header automatically starts the standby CCW pump(s).
Makeup to the system is automatic. The main plant computer and the Qualified Display Processing System monitor the surge tank level. When the valve providing tank makeup opens, the computer alarms to give an indication of system leakage. If the normal source of makeup (the Demineralized Water System) fails or is inadequate, it is alarmed in the control room by the surge tank level instrumentation. Surge tank level indication is displayed in the control room through indicators and the QDPS.
Risk Assessment:
This event resulted in no personnel injuries, no offsite radiological releases, and no damage to other safety-related equipment. The extended outage of CCW Train A was not risk significant and did not result in a net increase in the radiological risk to the public. Train A was still functional.� ; III' CAUSE OF THE EVENT , The root cause of the event was an inadequate calibration probedure. The procedure did not require a functionality check of the internal switch contacts after switch calibration restoration.
IV. CORRECTIVE ACTIONS
The surveillance procedure will be revised to require functional checks of switch contact actuation.
- Expected completion: 01/31/2009 Maintenance surveillance procedures will be reviewed to identify and correct as necessary those that do not have a functionality check prior to return-to-service.
- Expected completion: 04/09/2009
V. PREVIOUS SIMILAR EVENTS
On April 13, 2008, CCW surge tank for Train A low level switch LSL-4503B failed to actuate a non safety isolation valve during performance of the low level actuation surveillance procedure. A valve was found to be stuck, and Train A was returned to service after it was corrected.
VI. ADDITIONAL INFORMATION
None.
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05000413/LER-2008-001 | | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability | 05000334/LER-2008-001 | Control Room Envelope Air Intake During Normal Operation Higher Than Assumed In Design Basis Accident Dose Calculations | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000315/LER-2008-001 | Unit 1 Manual Reactor Trip due to Main Turbine Vibrations | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000272/LER-2008-001 | Inadvertent Start of an Emergency Diesel Generator During Testing | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000251/LER-2008-001 | Manual Reactor Trip due to High Level in the 4A Steam Generator | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000247/LER-2008-001 | Manual Reactor Trip Due to Decreasing Steam Generator Levels Caused by Loss of Feedwater Flow as a Result of Feedwater Pump Speed Control Malfunction | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000530/LER-2008-001 | Manual Reactor Trip when Removing a Degraded CEDM MG Set from Service | 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000457/LER-2008-001 | 2A Essential Service Water Train Inoperable due to Strainer Fouling from Bryozoa Deposition and Growth | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000454/LER-2008-001 | Technical Specification Non-Compliance of Containment Sump Monitor Due to Improper Installation During Oriainal construction | | 05000440/LER-2008-001 | ' Condition Prohibited by Technical Specifications Due to Unrecognized Reactor Core Isolation Cooling Inoperability | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000483/LER-2008-001 | Containment Cooler Inoperability | 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 | 05000412/LER-2008-001 | Unplanned Actuation of the Auxiliary Feedwater System During Plant Startup | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000374/LER-2008-001 | High Pressure Core Spray System Declared Inoperable Due to Failed Room Ventilation Supply Fan | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000323/LER-2008-001 | Reactor Trip Due to Main Electrical Transformer Failure | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000305/LER-2008-001 | Pressurizer PORV and Reactor Coolant System Vent Valves Appendix R Spurious Operation Concern | | 05000271/LER-2008-001 | Crane Travel Limit Stops not Installed as Required by Technical Specifications due to an Inadequate Procedure | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000269/LER-2008-001 | Gas Void Found in High Pressure Injection System Suction Piping | | 05000263/LER-2008-001 | | | 05000261/LER-2008-001 | Appendix R Pathway Impassable due to Lock Configuration | 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor | 05000361/LER-2008-001 | Valid actuation of Emergency Feedwater system following Main Feedwater pump trip | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000335/LER-2008-001 | Unattended Ammunition Discovered Inside Protected Area | | 05000456/LER-2008-001 | Technical Specification Non-Compliance Due to Inadequate Design of Auxiliary Feedwater (AF) Tunnel Access Covers Causing AF Valves Within the Tunnel to be Inoperable | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000423/LER-2008-001 | Postulated Fire Scenario Results in Unanalyzed Condition - Pressurizer Overfill | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition | 05000369/LER-2008-001 | Potential Failure of Containment Isolation Valves (CIV) to Remain Fully Closed and Ino erable loner than allowed bCTechnical S ecification 3.6.3. | | 05000220/LER-2008-002 | Manual Reactor Scram Due to Loss of Reactor Pressure Control | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000261/LER-2008-002 | Manual Reactor Trip due to High Turbine Vibrations | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000270/LER-2008-002 | Main Steam Relief Valves Exceeded Lift Setpoint Acceptance Band 050002 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000305/LER-2008-002 | 5 . Blocked Open Steam Exclusion Door Results in Postulated Inoperability of Safety Systems | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition | 05000336/LER-2008-002 | Unplanned LCO Entry - Three Charging Pumps Aligned for Injection With the Reactor Coolant System Temperature Less than 300 Degrees F. | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000354/LER-2008-002 | BLOWN lE INVERTER MAIN FUSE WITH ONE EMERGENCY DIESEL GENERATOR INOPERABLE CAUSES LOSS OF CONTROL ROOM EMERGENCY FILTRATION LOSS OF SAFETY FUNCTION | | 05000395/LER-2008-002 | Control Room Normal and Emergency Air Handling Systems Inoperable Due to Pressure Boundary Breach | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000382/LER-2008-002 | Inoperable Steam Generator Narrow Range Level Channels | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000369/LER-2008-002 | 'Energy® BRUCE H HAMILTON Vice President McGuire Nuclear Station Duke Energy Corporation MGOIVP 112700 Hagers Ferry Road Huntersville, NC 28078 704-875-5333 704-875-4809 fax bhhamilton@duke-energy.corn August 21, 2008
U.S. Nuclear Regulatory Commission
ATTENTION: Document Control Desk
Washington, D.C. 20555
Subject: Duke Energy Carolinas, LLC
McGuire Nuclear Station, Unit 1
Docket No. 50-369
Licensee Event Report 369/2008-02, Revision 0
Problem Investigation Process No.: M-08-03862
Pursuant to 10 CFR 50.73 Sections (a)(1) and (d), attached
is Licensee Event Report (LER) 369/2008-02, Revision 0,
regarding the Unit 1 Reactor trip on June 26, 2008 due to
the 1B Reactor Coolant Pump Motor trip which was caused by
a failed surge capacitor.
This report is being submitted in accordance with 10 CFR
50.73 (a)(2)(iv)(A). This event is considered to be of no
significance with respect to the health and safety of the
public. There are no regulatory commitments contained in
this LER.
If questions arise regarding this LER, contact Lee A. Hentz
at 704-875-4187.
Very truly yours,
Bruce H. Hamilton
Attachment
www. duke-energy. corn U.S. Nuclear Regulatory Commission
August 21, 2008
Page 2
cc: L. A. Reyes, Regional Administrator
U.S. Nuclear Regulatory Commission, Region II
Sam Nunn Atlanta Federal Center
61 Forsyth Street, SW, Suite 23T85
Atlanta, GA 30303
J. F. Stang, Jr. (Addressee Only)
Senior Project Manager (McGuire)
U.S. Nuclear Regulatory Commission
Mail Stop O-8G9A
Washington, DC 20555
J. B. Brady
Senior Resident Inspector
U.S. Nuclear Regulatory Commission
McGuire Nuclear Station
B. 0. Hall, Section Chief
Radiation Protection Section
1645 Mail Service Center
Raleigh, NC 27699
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVEDBYOMB:NO.3150-0104 EXPIRES: 08/31/2010 (9-2007) 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 ' LICENSEE EVENT REPORT (LER) 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 internet 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 (See reverse for required number of means used to impose an information collection does not display a currently valid OMB control digits/characters for each block) 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 05000- ' 1 8McGuire Nuclear Station, Unit 1 _ 0369' OF .4, TITLE . . Unit 1 Reactor Trip due to the 1B Reactor Coolant Pump Motor Trip which was caused by a
failed Surge Capacitor | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000440/LER-2008-002 | Inoperable Emergency Closed Cooling System Results In Condition Prohibited By Technical Specifications | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000454/LER-2008-002 | Technical Specification Non-Compliance Due to Inadequate Design of Auxiliary Feedwater (AF) Tunnel Access Covers Causing AF Valves Within the Tunnel to be Inoperable | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000298/LER-2008-002 | Technical Specification Prohibited Condition Due to Safety Relief Valve Test Failure | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000237/LER-2008-002 | Unit 2 High Pressure Coolant Injection System Declared Inoperable | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000272/LER-2008-002 | | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000361/LER-2008-002 | Disturbance on the Pacific DC Intertie cause offsite power frequency to dip below operability limits | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000362/LER-2008-003 | Missed TS completion time results in TS Violation | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000220/LER-2008-003 | Power Supplies for Drywell Pressure Indication not Qualified for Required Post-Accident Operating Duration | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000529/LER-2008-003 | Technical Specification - Limiting Condition for Operation 3.0.3 for Greater Than 1 Hour | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000293/LER-2008-003 | | | 05000263/LER-2008-003 | | | 05000423/LER-2008-003 | Automatic Reactor Trip During Shutdown for Refueling Outage 3R12 ., | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000251/LER-2008-003 | . Class 1 Weld Leak Due to Fatigue and Completion of Technical Specification Required Shutdown | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown | 05000282/LER-2008-003 | Loss of AFW Safety Function and Condition Prohibited by Technical Specifications Due to Mispositioned Isolation Valve | 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000286/LER-2008-003 | Automatic Actuation of Emergency Diesel Generator 33 During Surveillance Testing Caused by .Inadvertent Actuation of the Undervoltage Sensing Circuit on 480 Volt AC Safeguards Bus 5A | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000361/LER-2008-003 | Disturbance on the Pacific DC Intertie cause offsite power frequency to dip below operability limits | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000305/LER-2008-003 | Door Bottom Seal Failure Results in Inoperability of Control Room Ventilation System | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat |
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