05000277/LER-2003-004, Regarding Automatic Scrams Resulting from an Off-Site Electrical Grid Disturbance
| ML033230324 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 11/07/2003 |
| From: | Stone J Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 03-004-00 | |
| Download: ML033230324 (12) | |
| Event date: | |
|---|---|
| Report date: | |
| 2772003004R00 - NRC Website | |
text
Exek1nm Exelon Nuclear Telephone 717.456.7014 Nuclear Peach Bottom Atomic Power Station www.exeloncorp.com 1848 Lay Road Delta, PA 17314-9032 I OCFR 50.73 November 7, 2003 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Peach Bottom Atomic Power Station (PBAPS) Units 2 & 3 Facility Operating License Nos. DPR-44 and DPR-56 NRC Docket Nos. 50-277 & 50-278
Subject:
Licensee Event Report (LER) 2-03-04 This LER reports automatic scrams and other plant operational events for Units 2 and 3 that resulted from an off-site electrical grid disturbance that occurred approximately 35 miles away from the site. In accordance with NEI 99-04, the regulatory commitment contained in this correspondence is to restore compliance with the regulations. The specific methods that are planned to restore and maintain compliance are discussed in the LER. If you have any questions or require additional information, please do not hesitate to contact us.
Sincerely, ihn A. Stone ant Manager Peach Bottom Atomic Power Station JAS/djfICR 175737 Attachment cc:
PSE&G, Financial Controls and Co-owner Affairs R. R. Janati, Commonwealth of Pennsylvania INPO Records Center H. J. Miller, US NRC, Administrator, Region I R. l. McLean, State of Maryland C. W. Smith, US NRC, Senior Resident Inspector CCN 03-14091
bcc:
J. L. Skolds - Cantera 1 W. Levis - KSA 3-N C. G. Pardee - KSA 3-N Jeff Benjamin - Cantera 1 J. A. Stone - PB, A4-1S E. J. Eilola - PB, A4-1 S G. L. Stathes, PB, SMB 3-7 P. J. Davison - PB, A3-1S J. P. Grimes - KSA 2-N R. C. Braun - KSA 3-N R. A. Kankus - KSB 3-S J. L. Mallon - PB, TC E. P. Anderson - PB, SMB 4-1 M. P. Gallagher - KSA 3-E D. P. Helker - KSA 3-E K. Langdon - PB, SMB4-6 Commitment Coordinator - KSA 3-E Site Commitment Coordinator - A4-5S Correspondence Control Desk - KSA 1-N-1 DAC - KSA 1-N-1
SUMMARY OF EXELON NUCLEAR COMMITMENTS The following table identifies commitments made in this document by Exelon Nuclear.
(Any other actions discussed in the submittal represent intended or planned actions by Exelon Nuclear. They are described to the NRC for the NRC's information and are not regulatory commitments.)
Commitment
Committed Date or "Outage" In accordance with NEI 99-04, the In accordance with the Corrective Action regulatory commitment contained in this Program correspondence is to restore compliance with the regulations. The specific methods that are planned to restore and maintain compliance are discussed in the LER.
Abstract
At approximately.0132.on 9/15/03, Units 2 and' 3 'automatically scrammed and received Primary Containment Isolations as a result of an interruptionof power to -the 'Reactor Protection'System (RPS) and the Primary Containment Isolation System (PCIS)'logic circuits. This interruption of power was caused by a'brief loss of two,of the three PBAPSoff-site power sources,,caused by an electrical grid disturbance approximately 35 milesaway from the'site. The disturbance was the result of failure of off-site protective relaying during a lightning storm.
The Emergency Diesel Generators (EDGs) started' and provided on-site power. On Unit 3, 'one Safety 'Relief, Valve. (SRV) remained Open, after actuation. SIt subsequently closed,when reactor pressure was' reduced:'At approximately 0235 hours0.00272 days <br />0.0653 hours <br />3.885582e-4 weeks <br />8.94175e-5 months <br />, the E-2 EDG tripped on low, jacket coolant pressure., A discretionary
'Unusual Event was declared by the Shift Manager as a result of the E-2 EDG trip combined with'the off-sitegrid concerns.-The High Pressure Coolant Injection and Reactor Core'Isolation'.Cooling systems were used to provide reactor water level control.'Safety Relief'Valves were used for reactor pressure control. The Suppression Pool cooling system was used for containment heat removal. Normal power was restored to the on-site emergency busses and the Unusual Event was terminated at 1046 hours0.0121 days <br />0.291 hours <br />0.00173 weeks <br />3.98003e-4 months <br />. The cause of the event was due to less than adequate maintenance and testing on protective relaying on the off-site electrical distribution system. Appropriate maintenance, testing and other upgrades are being pursued.
NRC FORM 366 (7-2001)
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Cause of the Event, cont.
The failure of the 36D MSIV to close is being thoroughly investigated in accordance with the site Correctiye Action Program (CAP).
The valve was disassembled and thoroughly evaluated. It was determined that there were no in-body concerns with the valve and that the most likely failure cause was external to the valve (i.e. actuator or actuator sub-components such as solenoid valves, manifold, etc).
Corrective Actions '.
The protective relaying associated with---the off-site power. sources was repaired. Other design, maintenance and testing enhancements are being pursued to upgrade, the reliability of theIelectrical grid protective relaying in proximity to the PBAP!, station.
Repairs were made to the E-2 EDG to riepair the combustion gas leakage into the jacket water cooling system. Extensive. testing and analysis has been performed on all four EDGs at PBAPS. Enhancements have been made to the monitoring program for EDG performance. Improvements will be made to the EDG maintenance practices with regards to the installation of cylinder liner adapter seals. A formal root cause evaluation is in progress and other appropriate corrective actions will be performed in accordance with the Corrective Action Program.
The Unit 3 71D and 71G SRVs were removed and replaced with factory refurbished SRVs. Other SRVs on Unit 3 were 'also refurbished. An extent of condition review for other SRVs on both Units 2 and 3 was performed. It was determined that the PBAPS SRVs currently installed are highly reliable.
The actuating.control components of the 86D MSIV were replaced. An extent of condition review for other MSIVs on Units 2 and 3 was completed.
Previous Similar Occurrences There were no previous events identified involving a Peach Bottom dual unit scram initiated by an off-site grid disturbance issue.
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r(1-2001)
LICENSEE EVENT REPORT (LER)
FAILURE CONTINUATION FACILITY NAME (1)
DOCKET (2)
NUMBER (2)
LER NUMBER (6)
PAGE (3)
SEQUENTIAL l REVISION YEAR NUMBER NUMBER Peach Bottom Atomic Power Station, Units 2 (and 3) 05000277 03 04 00 9
OF 9
j COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
MANU-REPORTABLE MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT FACTURER TO EPIX
CAUSE
SYSTEM COMPONENT FACTURER TO EPIX X
SB T020 Y
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D SB
- RV,..
T020 Y. -:
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NRC FORM 3665 (1-2001)