ML101520241
| ML101520241 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 05/26/2010 |
| From: | Baxter D Duke Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML101520241 (4) | |
Text
Duke DAVE BAXTER EnergyVice President
- Energy, Oconee Nuclear Station Duke Energy ON01 VP / 7800 Rochester Highway Seneca, SC 29672 864-873-4460 864-873-4208 fax dabaxter@dukeenergy. corn May 26, 2010 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
SUBJECT:
Duke Energy Carolinas, LLC (Duke)
Oconee Nuclear Station, Unit 2 Docket Number 50-270 Relief Request 09-ON-003 On March 20, 2009 Duke Energy submitted Relief Request 09-ON-003 (ADAMS ML090830726) pursuant to 10 CFR 50.55a(a)(3)(i), requesting NRC approval to use alternatives to the American Society of, Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), Section Xl inservice inspection (ISI) requirements for the Oconee Nuclear Station, Unit 1, 2, & 3. This alternative approach is to support application of full structural weld overlays on several welds in the Reactor Coolant System for all three Oconee units.
On October 16, 2009 the NRC granted verbal approval for the portion of Relief Request 09-ON-003 applicable to the Unit 1 Letdown nozzle welds. By letter dated March 31, 2010 (ADAMS ML100880286), the NRC provided written approval for all three Oconee Units. The request committed to provide a report to summarize the results of ultrasonic examinations of the weld overlays within
.14 days of completion of those examinations. In accordance with that commitment, the summary report for Unit 2 is attached.
If you have any questions or require additional information, please contact Randy Todd at (864)-873-3418.
Sincerely, Dave axter Site Vice President Oconee Nuclear Station Attachment CA I www. duke-energy, com
Nuclear Regulatory Commission May 26, 2010 Page 2 XC with
Attachment:
Luis Reyes Region II Administrator U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, GA 30303-1257 John Stang Project Manager (ONS)
U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Rockville, MD 20852-2738 XC w/o
Attachment:
Andy Sabisch NRC Senior Resident Inspector Oconee Nuclear Station Susan Jenkins, Section Manager, Division of Waste Management Bureau of Land and Waste Management SC Dept. of Health & Environmental Control 2600 Bull St.
Columbia, SC 29201
Attachment Summary of Weld Overlay Ultrasonic Examination for Letdown Line Drain Nozzle-to-Safe End and Safe End-to-Elbow Welds at Oconee Nuclear Station, Unit 2 Attachment to 0900082.407, Rev. 0 1 of 2 Structural Integrity Associates, Inc.
Ultrasonic Examination Procedure SI-UT-145, Revision 0, Procedure for Manual PhasedArray Ultrasonic Examination of Weld Overlaid Similar and Dissimilar Metal Piping Welds, EPRI-WOL-PA-1, was used for examination of the Letdown Line Drain Nozzle weld overlay (WOL). This procedure, and the examiner who applied the procedure, are qualified through the PDI Program at the EPRI NDE Center.
Letdown Drain Nozzle Weld Overlay Examination Component Identification: Letdown Drain Weld Overlay 2-51A-0035-01-136V Examination Date: 05/12/10 Examination Time: 1144 to 1210 Weld Overlay Regions Examined: Overlay, Nozzle-to-Safe End Dissimilar Metal (DM) Weld
- 2-PIBI-1 1 / Base Material (Outer 25%) and Safe End-to-Elbow Weld #2-51A-0035-01-15A /
Base Material (Outer 25%)
Axial Examination Angles: 00 through 850 Circumferential Examination Angles: 0' through 85' Examination Summary: No suspected flaw indications were observed during the examinations. The examination gain was adjusted to maintain the procedure-specified baseline noise level from 5% to 20% of full screen height. The examination coverage achieved of the Code-required volumes during the examinations is provided below:
" Coverage of Weld Overlay 2-51A-0035-01-136V Material: 100%
" Coverage of Outer 25% of Nozzle-to-Safe End DM Weld #2-PIBI-1I1 & Adjacent Base Material: 100%
" Coverage of Safe End-to-Elbow Weld #2-51A-0035-01-15A & Outer 25% Adjacent Base Material: 93%
Attachment to 0900082.407, Rev. 0 2 of 2 Structural Integrity Associates, Inc.