ML020500488
| ML020500488 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 01/25/2002 |
| From: | Heacock D Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 02-041 | |
| Download: ML020500488 (2) | |
Text
VIRGINiA ELECTRIC AND POWER COMPANY RICHMOXD,VIRGINIA 23261 January 25, 2002 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Serial No.02-041 NAPS: MPW Docket Nos. 50-338 License Nos. NPF-4 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 & 2 SPECIAL REPORT REGARDING REGULATORY GUIDE 1.97 VARIABLE On December 8, 2001, with Unit 1 in Mode 1, 100 percent power, the open red light indication for Phase B containment isolation valve (CIV) 1 -CC-TV-1 02A was determined to be inoperable.
This Regulatory Guide (RG) 1.97 CIV is located outside of containment in the component cooling (CC) water return line from the "C" reactor coolant pump (RCP). The closed green light indication was operable. The cause of the inoperable red open light indication is believed to be an electrical short.
At the time of discovery an information action was entered to assess RG 1.97 reportability if the component was not returned to service in 30 days. A visual cue was established to require local verification of the CIV in the closed position if a containment isolation signal is received. There has been no change in CC system flow from the "C" RCP to indicate any mechanical problem with the valve. The CIV cycled properly during its last valve position indication test completed on October 1, 2001.
If a containment depressurization accident (CDA) were to occur, both the inside and outside CIVs would receive a signal to close. The outside CIV would be verified closed locally. The CIV located inside containment also cycled properly during its last valve position indication test completed on October 1, 2001.
Plans are in progress to be prepared to perform corrective maintenance with the unit on-line, if required.
However, due to the inherent risks involved with performing maintenance on-line, repairs will be performed at the first entry into a unit condition of sufficient duration to allow the repair. The risks associated with performing repairs on-line include maintenance in a sensitive area (i.e., Control Room Safeguards Equipment Panel) and by-passing the air supply to the CIV to prevent the CIV from inadvertently closing requiring manually tripping the reactor and shutting down the running C RCP.
Initial conditions for the valve position indication periodic test require the unit to be in Modes 5, 6 or defueled with the RCP secured. Without knowing the exact root cause of the malfunction, actions to prevent recurrence can not be determined at this time.
Actions to prevent recurrence will be implemented, as appropriate, through the corrective action system following CIV repairs.
The Station Nuclear Safety and Operating Committee has reviewed this special 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, D. A. Heacock Site Vice President Commitments made in this letter:
- 1) Maintenance will be performed at the first entry into a unit condition of sufficient duration to allow the repair.
- 2) Implement actions to prevent recurrence as appropriate.
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