ET 07-0002, Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds
| ML070430455 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 01/31/2007 |
| From: | Garrett T Wolf Creek |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| ET 07-0002 | |
| Download: ML070430455 (3) | |
Text
W4LF CREEK NUCLEAR OPERATING CORPORATION January 31, 2007 Terry J. Garrett Vice President, Engineering ET 07-0002 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
Reference:
- 3) Letter ET 06-0042, dated September 27, 2006, from T. J.
Subject:
Docket No. 50-482: Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds Gentlemen:
In October 2006, while performing examinations of Alloy 82/182 pressurizer butt welds at Wolf Creek Generating Station (WCGS) in accordance with Materials Reliability Program - 139 (MRP-139),
Wolf Creek Nuclear Operating Corporation (WCNOC) discovered several circumferential indications in the pressurizer Surge, "C" Safety, and Relief nozzle to safe-end dissimilar metal (DM) butt welds.
The examinations were performed prior to the planned installation and examination of full structural weld overlays for repairing/mitigating pressurizer nozzle to safe-end DM butt welds in accordance with WCNOC 10 CFR 50.55a Request 13R-05, as described in References 1, 2, 3, and 4.
WCNOC's resolution for these circumferential P.O. Box 411 / Burlington, KS 66839 / Phone: (620) 364-8831 70 An Equal Opportunity Employer M/F/HCNET
ET 07-0002 Page 2 of 2 flaw indications was to install the previously planned full structural weld overlays. Reference 5 provided additional information requested by the Nuclear Regulatory Commission (NRC) concerning the results of the pre-weld overlay examinations. Reference 6 provided the results of the ultrasonic examinations of the full structural weld overlays on the pressurizer nozzle welds. Due to the potential importance of the discovered circumferential indications, this letter is being submitted as part of an industry initiative to notify the NRC of actions planned and taken for inspecting and repairing/mitigating Alloy 600/82/182 butt welds on pressurizer spray, surge, safety and relief lines.
As stated above, pressurizer Alloy 82/182 butt welds at WCGS have been inspected and repaired/mitigated.
Attached is a summary of the pre-weld overlay locations inspected and repaired/mitigated, and the results of those inspections. Additional details concerning the pre-weld overlay inspection methods, PDI qualification, coverage obtained and results can be found in Reference 5 of this submittal.
There are no commitments contained within this letter. If you have any questions concerning this matter, please contact me at (620) 364-4084, or Mr. Kevin Moles at (620) 364-4126.
Very truly yours,
.erry J. Garrett TJG/rlt Attachment cc:
J. N. Donohew (NRC), w/a V. G. Gaddy (NRC), w/a B. S. Mallett (NRC), w/a Senior Resident Inspector (NRC), w/a
Attachment to ET 07-0002 Page 1 of 1 Inspection and Mitigation Summary for Wolf Creek Generating Station Alloy 82/182 Pressurizer Nozzle to Safe-End Dissimilar Metal Butt Welds MRP-139 Volumetric Mitigation Nozzle Inspection Requirement Completed or to Met or to be Met be Completed Results/Comments SucMaterial Outage Start Date Outage Designation Description Designation (MM/YYYY)
Designation Alloy 82/182 Met in 10/2006 Completed in No indications found. Full structural Spray nozzle to safe-RF1 5 RF15 weld overlay was installed.
end weld Alloy 82/182 Met in 10/2006 Completed in Three (3) circumferential indications Surge nozzle to safe-RF15 RF15 found (Reference 5). Full structural end weld weld overlay was installed.
Alloy 82/182 Met in 10/2006 Completed in No indications found. Full structural "A" Safety nozzle to safe-RF15 RF15 weld overlay was installed.
end weld Alloy 82/182 Met in 10/2006 Completed in No indications found. Full structural "B" Safety nozzle to safe-RF15 RF15 weld overlay was installed.
end weld Alloy 82/182 Met in 10/2006 Completed in One (1) circumferential indication "C" Safety nozzle to safe-RF15 RF15 found (Reference 5). Full structural end weld weld overlay was installed.
Alloy 82/182 Met in 10/2006 Completed in One (1) circumferential indication Relief nozzle to safe-RF15 RF15 found (Reference 5). Full structural end weld weld overlay was installed.