ML071150426
| ML071150426 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 05/03/2007 |
| From: | Donohew J NRC/NRR/ADRO/DORL/LPLIV |
| To: | Muench R Wolf Creek |
| Donohew J N, NRR/DORL/LP4, 415-1307 | |
| References | |
| TAC MC3526 | |
| Download: ML071150426 (5) | |
Text
May 3, 2007 Mr. Rick A. Muench President and Chief Executive Officer Wolf Creek Nuclear Operating Corporation Post Office Box 411 Burlington, KS 66839
SUBJECT:
WOLF CREEK GENERATING STATION - CLOSEOUT OF BULLETIN 2004-01, INSPECTION OF ALLOY 82/182/600 MATERIALS USED IN THE FABRICATION OF PRESSURIZER PENETRATIONS AND STEAM SPACE PIPING (TAC NO. MC3526)
Dear Mr. Muench:
On May 28, 2004, the U.S. Nuclear Regulatory Commission (NRC) issued Bulletin 2004-01, Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping, to the industry. The purpose of the Bulletin is to (1) inform the pressurized-water reactor licensees that current methods of inspecting the pressurizer penetrations and steam-space piping fabricated from Alloy 82/182/600 materials may need to be supplemented with additional measures (e.g., bare-metal visual inspections) to detect pressurizer penetration and steam-space piping flaws or leakage, and (2) request these licensees to provide the NRC with information related to the materials of construction and inspections that have been and will be performed to verify the integrity of the pressurizer penetrations and steam-space piping. The request for information included a report after the plant restart following the next inspection of the Alloy 82/182/600 pressurizer penetrations and steam-space piping connections.
By letters dated July 27, 2004 (WO 04-0039), and July 14, 2005 (ET 05-0015) (Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML042190154 and ML052080155, respectively), Wolf Creek Nuclear Operating Company (the licensee) provided its response to Bulletin 2004-01 for Wolf Creek Generating Station, Unit 1 (WCGS).
In its letter dated July 27, 2004, the licensee provided its responses to items 1a, 1b, 1c, and 1d of the Bulletin. These responses described the materials used in the fabrication of the pressurizer penetrations and steam-space piping at WCGS. In its response to item 1a, the licensee reported that there are Alloy 82/182/600 components in only five pressurizer steam-space piping connections (the pressurizer spray, relief, safety, and surge nozzle safe-ends) with the pressurizer penetrations and J-groove welds being stainless steel. In its response to item 1b, the licensee provided a table of prior inspections and inspection results of these piping connections, stated that its risk-informed inservice inspection program (implemented in Period 2 of the second 10-year interval) includes these piping connections, and provided its basis for concluding that these piping connections comply with the applicable regulatory requirements.
In its response to item 1c, the licensee provided a description of the Alloy 82/182/600 pressurizer steam-space piping connection inspection program that will be implemented at WCGS during the next and subsequent refueling outages until mitigative actions are taken or
R. A. Muench an industry recommended inspection program is issued. The description included the items to be inspected; the percent coverage that would be performed at each location; the inspection methods to be used; the qualification standards for the inspection methods and personnel; the process used to resolve any inspection indications; the inspection documentation to be generated; and the statement that WCGS has met and will continue to meet the regulatory requirements of Section 50.55a of Part 50 of Title 10 to the Code of Federal Regulations (10 CFR 50.55a). The licensee also provided its plans for expansion of the scope of nondestructive examination to be performed if leaks are found in any portion of these pressurizer steam-space piping connections. In its response to item 1d, the licensee explained why the inspection program identified in the response to item 1c in the bulletin is adequate for the purpose of maintaining the integrity of the reactor coolant pressure boundary at WCGS.
In its letter dated July 14, 2005, in its response to item 2a of the Bulletin, the licensee stated that in Refueling Outage 14 (spring 2005) it performed a direct bare-metal visual inspection on all five steam-space piping connections on the pressurizer and found no relevant indications of through-wall leakage on these connections.
In Refueling Outage 15 (fall 2006), the licensee performed full-structural weld overlays on the five pressurizer steam-space piping connections after having inspected the piping connections.
The American Society of Mechanical Engineers Boiler and Pressure Vessel (ASME) Code requires that unacceptable crack indications in these piping connections be corrected either by repair or replacement of the affected components. By letter dated May 19, 2006 (ET 06-0021, ADAMS Accession No. ML061450319), the licensee requested relief from certain ASME Code,Section XI, requirements at WCGS. In its application, the licensee submitted Relief Request (RR) I3R-05 and proposed alternatives to the ASME Code requirements in (1) Code Cases N-504-3 and N-638-1, and (2) Appendix VIII, Supplement 11, for the purpose of performing pre-emptive or repair full-structural weld overlays on the pressurizer spray, relief, safety, and surge nozzle safe-ends at WCGS. RR I3R-05 was verbally authorized by the NRC staff in a conference call on October 5, 2006, and the structural weld overlays were performed on the pressurizer spray, relief, safety, and surge nozzle safe-ends during Refueling Outage 15.
The NRC staff issued its letter authorizing RR I3R-05 in its letter dated April 3, 2007 (ADAMS Accession No. ML070670514).
The licensee also provided (1) the results of the ultrasonic examinations of the full-structural weld overlays on the pressurizer nozzle welds and (2) its response to a request for additional information related to the pre-weld overlay examination of the pressurizer nozzle to safe-ends dissimilar metal welds. These were provided in its letters dated (1) November 17, 2006 (ET 06-0055, ADAMS Accession No. ML063330060) and January 31, 2007 (ET 07-002, ADAMS Accession No. ML070430455), and (2) November 29, 2006 (ET 06-0049, ADAMS Accession No. ML063380456), respectively.
The NRC staff has completed its activities associated with the review of the licensees responses to Bulletin 2004-01. Based on the licensees responses in its letters dated July 27, 2004, and July 14, 2005, and the pre-emptive or repair full-structural weld overlays performed in Refuel Outage 15, the NRC staff finds that the licensees responses for WCGS are acceptable.
It should be noted that industry commitments or NRC staff regulatory actions may result in actions beyond those that were implemented in Refueling Outage 15 on the pressurizer steam-space piping connections discussed in Bulletin 2004-01. For example, specific actions
R. A. Muench addressed in topical report MRP-139, "Materials Reliability Program: Primary System Piping Butt Weld Inspection and Evaluation Guideline," may exceed the scope of actions performed in the refueling outage. It is the NRC staffs expectation that you will address whatever additional scope of actions are in the industry commitments or NRC staff regulatory actions, and determine why the additional scope of actions should not be performed at a later refueling outage.
This letter closes the NRC staffs efforts with regard to its review of the licensees response to Bulletin 2004-01 for WCGS and the subject TAC number. If you have any questions on this letter, contact me at (301) 415-1307.
Sincerely,
/RA/
Jack Donohew, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-482 cc: See next page
R. A. Muench May 3, 2007 addressed in topical report MRP-139, "Materials Reliability Program: Primary System Piping Butt Weld Inspection and Evaluation Guideline," may exceed the scope of actions performed in the refueling outage. It is the NRC staffs expectation that you will address whatever additional scope of actions are in the industry commitments or NRC staff regulatory actions, and determine why the additional scope of actions should not be performed at a later refueling outage.
This letter closes the NRC staffs efforts with regard to its review of the licensees response to Bulletin 2004-01 for WCGS and the subject TAC number. If you have any questions on this letter, contact me at (301) 415-1307.
Sincerely,
/RA/
Jack Donohew, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-482 cc: See next page DISTRIBUTION PUBLIC LPLIV r/f RidsNrrDorl RidsOgcRp RidsNrrDorlLpl4 RidsAcrsAcnwMailCenter RidsNrrDorlDpr RidsRgn4MailCenter RidsNrrPMJDonohew RidsNrrDciCpnb (TChan)
RidsNrrLALFeizollahi JODriscoll, NRR RidsNrrDciCvib (MMitchell) EAndruszkiewicz, NRR ACCESSION NO.: ML071150426 NRR-106 OFFICE NRR/LPL4/PM NRR/LPL4/LA CVIB/BC NRR/LPL4/BC NAME JDonohew LFeizollahi MMitchell THiltz DATE 5/1/07 5/3/07 5/3/07 5/3/07 OFFICIAL RECORD COPY February 2006
Wolf Creek Generating Station cc:
Jay Silberg, Esq. Chief, Radiation and Asbestos Control Pillsbury Winthrop Shaw Pittman LLP Section 2300 N Street, NW Kansas Department of Health Washington, D.C. 20037 and Environment Bureau of Air and Radiation Regional Administrator, Region IV 1000 SW Jackson, Suite 310 U.S. Nuclear Regulatory Commission Topeka, KS 66612-1366 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 Vice President Operations/Plant Manager Wolf Creek Nuclear Operating Corporation Senior Resident Inspector P.O. Box 411 U.S. Nuclear Regulatory Commission Burlington, KS 66839 P.O. Box 311 Burlington, KS 66839 Supervisor Licensing Wolf Creek Nuclear Operating Corporation Chief Engineer, Utilities Division P.O. Box 411 Kansas Corporation Commission Burlington, KS 66839 1500 SW Arrowhead Road Topeka, KS 66604-4027 U.S. Nuclear Regulatory Commission Resident Inspectors Office/Callaway Plant Office of the Governor 8201 NRC Road State of Kansas Steedman, MO 65077-1032 Topeka, KS 66612 Attorney General 120 S.W. 10th Avenue, 2nd Floor Topeka, KS 66612-1597 County Clerk Coffey County Courthouse 110 South 6th Street Burlington, KS 66839 February 2006