ML12107A008
| ML12107A008 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 04/03/2012 |
| From: | Gerald Bichof Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 12-231 | |
| Download: ML12107A008 (3) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 April 3, 2012 U.S. Nuclear Regulatory Commission Serial No.12-231 Attention: Document Control Desk NAPS: MPW Washington, D.C. 20555 Docket Nos. 50-339 License Nos. NPF-7 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
NORTH ANNA POWER STATION UNIT 2 POST ACCIDENT MONITORING (PAM) REPORT On February 26, 2012, with Unit 2 in Mode 1 at 100 percent power, the open red indication light for the Phase B containment isolation valve (CIV) 2-CC-TV-202A ("C" RCP CC Return Outside Isolation) was determined to be inoperable. This Regulatory Guide 1.97 CIV is located outside of containment in the component cooling (CC) water return line from the "C" reactor coolant pump (RCP). The cause of the inoperable red open light is a blown bulb.
Technical Specification (TS) 3.3.3 Condition A requires restoration of the CIV indication to operable within thirty days. If CIV indication is not returned to service within thirty days, a Post Accident Monitoring Report is required in accordance with TS 5.6.6. This letter provides the required report and includes our plan and schedule for restoring the CIV indication to service.
This is a valve position open indication operability issue only. The replacement of the bulb with the unit on-line can lead to grounding of the circuit due to possible separation of the bulb glass from its base. This could possibly result in the associated trip valve closing which would be detrimental to Unit 2 operation. Therefore, due to the inherent risks involved with performing maintenance on-line, repairs are scheduled to 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). Changing the light bulb could result in shorting the light circuit which would result in the CIV inadvertently closing, which may require 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 or 6 or defueled with the "C" RCP secured.
Continued operation with this valve open indication inoperable is permitted because there are several levels of alternate indication.
The Plant Computer System (PCS) provides an alternate reliable indication (PCS computer point S2CCO19D, "C" RCP Return Header Valve") to determine valve position.
Flow indicators will also indicate zero flow in the CC return line when 2-CC-TV-202A is closed. In addition, the closed green light indication is operable.
Serial No.12-231 Docket No. 339 PAM Report Page 2 of 3 The outside CIV cycled properly during its last valve position indication test completed on October 23, 2011.
Additionally, the CIV located inside containment on the same penetration was also cycled properly during the last valve position indicator test completed on October 24, 2011.
If a containment depressurization actuation (CDA) were to occur, both the inside and outside CIVs would receive a signal to close.
This report has been reviewed and approved by the Facility Safety Review Committee.
If you have any questions or require additional information, please contact Mr. Donald R. Taylor at (540) 894-2616.
Sincerely,
/Aa ZW S Gerald T. Bischof Site Vice President Commitments made in this letter: Replacement of the open red indication light for 2-CC-TV-202A during the next entry into a unit condition of sufficient duration to allow the repair.
Serial No.12-231 Docket No. 339 PAM Report Page 3 of 3 cc:
U.S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, Georgia 30303-1257 NRC Senior Resident Inspector North Anna Power Station Dr. V. Sreenivas NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G-9A 11555 Rockville Pike Rockville, Maryland 20852-2738 Ms. K. R. Cotton NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G-9A 11555 Rockville Pike Rockville, Maryland 20852-2738