ML021690204
| ML021690204 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 06/06/2002 |
| From: | Mccollum W Duke Energy Corp |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML021690204 (3) | |
Text
SDuke Duke Energy Energy Oconee Nuclear Station 7800 Rochester Highway Seneca, SC 29672 W R. McCollum, Jr.
(864) 885-3107 OFFICE Vice President (864) 885-3564 FAX June 6, 2002 U.
S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION:
Document Control Desk
SUBJECT:
Duke Energy Corporation Docket No(s).
50-269,
-270,
-287 Oconee Nuclear Station Units 1, 2, and 3 Discrepancies between Duke Energy Automatic Feedwater Isolation System (AFIS) submittal and Nuclear Regulatory Commission Safety Evaluation Report dated September 26, 2001 The NRC advised Duke Energy Corporation (Duke) during an April 10, 2002, telephone conference call held between Messrs.
L.
Olshan, J.
Tatum, and W. LeFave of NRC NRR Staff and Messrs.
B.
Shingleton, J.
Burchfield, L. Nicholson, and R.
Gambrell of Duke that they may need to issue a revision to the Safety Evaluation Report (SER) for Amendment Nos.
- 320, 320,
& 320.
This SER addresses Technical Specification Change (TSC) 99-10 associated with the AFIS modification.
During the call it became apparent that there was not a clear understanding of the basis for crediting the Main Feedwater (MFW) control valves to isolate MFW for the Main Steam Line Break (MSLB) accident analyses.
Duke credits MFW isolation using the control valves for MSLB analyses regarding containment response and steam generator (SG) tube loads.
The revised methodology for determining SG tube loads was addressed in previous Technical Specification Change (TSC) 99-01 (April 26, 1999),
which requested NRC to review and approve the analytical details regarding the revised methodology.
One of the key assumptions of the revised analysis is that the MSLB detection and FW isolation instrumentation trips both MFW pumps, isolates the flow of the MFW to both SGs, and inhibits auto-start of or auto-stops the Turbine-Driven
NRC Letter dated June 6, 2002 Page 2 of 4 Emergency Feedwater Pump.
The NRC staff approved this TSC by letter dated September 18, 2000 (Amendment Nos.
- 315, 315,
& 315).
The revised methodology approved by the SER was not affected by the requested changes made by TSC 99-10.
TSC 99-10 was submitted to support installation of the AFIS modification.
AFIS replaces the MSLB detection circuitry and actuates the same components that were actuated by the MSLB circuitry.
AFIS provides automatic termination of EFW to a faulted SG thereby eliminating manual operator action for isolating EFW flow to a faulted SG.
Duke indicated in TSC 99-10 that the analysis presented in TSC 99-01 was bounding with respect to implementation of the AFIS modification.
Duke advised NRC by letter dated July 26, 2001 that the more conservative SG tube tensile stress values developed in TSC 99-01 would be used as the basis for SG tube inspection and plugging criteria until the MSLB and Main Feedwater Line Break (MFLB) analyses associated with the AFIS modification are completed.
Inquiries on this matter should be directed to Boyd Shingleton at (864) 885-4716.
Very t uly yours, W.
ollum, Jr., Site Vice President Oconee uclear Site
NRC Letter dated June 6, 2002 Page 3 of 4 L.
A. Reyes U. S. NRC Regional Administrator, Region II Atlanta Federal Center 61 Forsyth St.,
SW, Suite 23T85 Atlanta, GA 30303 L.
N. Olshan NRC Senior Project Manager (ONS)
U.
S. Nuclear Regulatory Commission Mail Stop O-14H25 Washington, DC 20555-0001 M. C.
Shannon Senior Resident Inspector (ONS)
U.
S. Nuclear Regulatory Commission Oconee Nuclear Site V.
R. Autry, Director Division of Radioactive Waste Management Bureau of Land & Waste Management Department of Health & Environmental Control 2600 Bull Street
- Columbia, SC 29201