ML061230672
| ML061230672 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 04/25/2006 |
| From: | Gordon Peterson Duke Energy Carolinas, Duke Power Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML061230672 (3) | |
Text
GARY R. PETERSON PVice President rEnergy' McGuire Nuclear Station Duke Energy Corporation MG01 VP / 12700 Hagers Ferry Rd.
Huntersville, NC 28078 704 875 5333 704 875 4809 fax grpeters@duke-energy. com April 25, 2006 United States Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, DC 20555-0001
Subject:
Duke Power Company LLC d/b/a Duke Energy Carolinas, LLC (Duke)
McGuire Nuclear Station Units 1 and 2 Docket Nos. 50-369 and 50-370 Update on Corrective Actions to Resolve the Auxiliary Feedwater System Air Entrainment Condition The purpose of this letter is to provide an update on Duke's plans for resolving an Operable But Degraded Non-conforming (OBDN) condition which currently exists on the Auxiliary Feedwater system at McGuire Nuclear Station (McGuire).
Due to changes in the corrective action plan, McGuire will not resolve the OBDN condition on the schedule previously determined. Changes in the corrective action plan have become necessary due to the complexity of the OBDN condition, limited options available for resolution, and the extensive modifications of safety related piping necessary for resolution.
McGuire Engineering has been working diligently for over a year to resolve this condition.
In July of 2004, McGuire determined that the operator manual alignments put in place in 1993 to prevent air entrainment of the Auxiliary Feedwater (CA) system pumps were outside the licensing basis and represented an Operable But Degraded Non-conforming (OBDN) condition.
This condition is documented in the McGuire Corrective Action Program (M 03803) and applies to both units.
This condition is also documented in the McGuire NRC Integrated Inspection Report dated October 8, 2004.
This condition only arises when the
'A' Trains of the Nuclear Service Water (RN) system on each unit, which supply an assured source of water to the 'A' Motor Driven and Turbine Driven CA pumps, are aligned to the Standby Nuclear Service Water Pond.
www. duke-energy. corn
U.S. Nuclear Regulatory Commission April 25, 2006 Page 2 Manual alignments of the RN system are utilized to preclude air entrainment of the CA pumps.
These manual alignments are proceduralized, time critical, and have been validated on the McGuire simulator and by in-plant walk downs.
In addition, a Probabilistic Risk Assessment (PRA) was performed on this condition and it was determined that it involves no significant increase in core damage frequency (CDF) or large early release frequency (LERF).
Extensive modifications of safety related piping on both units are under development to resolve this condition.
Because of the complexity of the issue, full scale model testing by an independent vendor will be performed to validate the design.
In addition, critical system tie-ins can only be performed during outages of sufficient length contingent upon design completion, material availability, and resources.
Upon completion of vendor testing and design validation, McGuire will provide a committed schedule for implementing the corrective actions to resolve the 'A' Train RN system to CA system air entrainment OBDN condition on both units.
Testing and design validation is expected to be complete in June, 2006.
This letter has been discussed with John Stang, NRR Project Manager and Michael Ernstes, NRC Region II Branch Chief for McGuire.
Please contact Lee Hentz at 704-875-4187 if any questions arise.
Sincerely, Gary R. Peterson
4 a
U.S. Nuclear Regulatory Commission April 25, 2006 Page 3 xc:
W. D. Travers Regional Administrator, Region II U. S. Nuclear Regulatory Commission Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, GA 30303 J. F. Stang, Jr. (addressee only)
Project Manager U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Mail Stop 8-H4A Washington, D.C. 20555 J. B. Brady Senior Resident Inspector U. S. Nuclear Regulatory Commission McGuire Nuclear Station