ML033430360
| ML033430360 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 12/01/2003 |
| From: | Jennifer Davis Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 03-588 | |
| Download: ML033430360 (3) | |
Text
VIRGINIA ELECTRIC AND POWER CO'M PANY RICIIMOND, VIRGINIA 23261 December 1, 2003 United States Nuclear Regulatory Commission Serial No.03-588 Attention: Document Control Desk NAPS: MPW Washington, D.C. 20555 Docket Nos. 50-338/339 License Nos. NPF-4/7 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS I & 2 FIRE PROTECTION SYSTEM INOPERABLE SPECIAL REPORT On November 17, 2003, the Fire Protection System (FPS) was rendered inoperable for approximately thirty-six minutes, from 1250 hours0.0145 days <br />0.347 hours <br />0.00207 weeks <br />4.75625e-4 months <br /> to 1326 hours0.0153 days <br />0.368 hours <br />0.00219 weeks <br />5.04543e-4 months <br />, as a result of having all main FPS pumps isolated from the fire piping loops. This was done to decrease system pressure and flow enough to allow full closure of isolation valves in a portion of the FPS piping that had ruptured outside of the plant protected area.
The station FPS consists of two separate fire piping loops each supplied by two main fire pumps. One loop provides protection for the warehouses and the training facility that houses the Local Emergency Offsite Facility (LEOF) and the second loop provides protection for the plant. A cross-tie that is normally isolated is available between the two FPS piping loops to provide a backup water supply.
On November 17, 2003, at 1150 hours0.0133 days <br />0.319 hours <br />0.0019 weeks <br />4.37575e-4 months <br />, three fire pumps were observed to be operating.
At that time the fire alarm for the LEOF was alarming.
Maintenance soldering activities associated with the LEOF HVAC system in the LEOF caused a smoke detector to actuate. As a result, the pre-action sprinkler system isolation valve opened as designed allowing the fire protection piping to fill with water.
Since the cross-tie between the FPS piping loops was open both piping loops saw a decrease in pressure causing the fire pumps in both the warehouse and plant FPS piping loops to start. At that time the cross-tie between the warehouse FPS piping loop and the plant FPS piping loop was open due to the warehouse fire pump being tagged for maintenance. During this pressure transient a section of the plant FPS piping ruptured.
The rupture occurred in a section of piping outside of the station protected area on the north west side of the plant. Pressure and flow conditions were such that full closure of the plant FPS piping loop isolation valves could not be performed. Unable to isolate the leak completely, at 1250 hours0.0145 days <br />0.347 hours <br />0.00207 weeks <br />4.75625e-4 months <br />, two fire pumps were placed in off and the discharge valve for the third fire pump was then closed thus rendering the FPS inoperable. At 1313 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />4.995965e-4 months <br />, the ruptured portion of piping was isolated. At 1326 hours0.0153 days <br />0.368 hours <br />0.00219 weeks <br />5.04543e-4 months <br />, the discharge valve for fire pump 1-FP-P-1 was opened and FPS piping loop inventory was restored making the FPS operable.
The plant fire pumps were later placed in auto and associated actions were cleared.
A'ODCQ
The NRC Operations Center was notified, at 1003 hours0.0116 days <br />0.279 hours <br />0.00166 weeks <br />3.816415e-4 months <br />, on November 18, 2003, in accordance with Technical Requirements Manual (TRM) Section 7.1.1.D.2.1.
This Special Report is being submitted in accordance with TRM Section 7.1.1.D.2.3.
The section of the plant FPS piping loop that ruptured on November 17, 2003, has been replaced with ductile iron piping. Current evaluations are being performed to determine if additional actions are needed. During the FPS pipe rupture investigation it was noted that the rupture occurred in a portion of piping that had been installed as a temporary installation during construction activities in the late 1970s. Permanent piping that was to supply Units 3 and 4 was not installed due to the area being excavated where the pipe line was to be located. A temporary section of the piping was installed around the excavated area at a depth of approximately eighteen inches. Following the cancellation of construction on Units 3 and 4 the temporary piping was never removed and the permanent piping was never installed. The temporary piping is not installed to a depth required for the FPS piping loop missile protection. Contingency actions are in place for the temporary piping to fulfill missile protection criteria.
The Station Nuclear Safety and Operating Committee has reviewed this report and it will be provided to the Management Safety Review Committee. Should you have any questions regarding this report, please contact us.
Very truly yours, Davis Site Vice President Commitments made in this letter: None
cc:
U. S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center Suite 23T85 61 Forsyth St., SW, Atlanta, Georgia 30303 Mr. M. J. Morgan NRC Senior Resident Inspector North Anna Power Station