ML070780503
| ML070780503 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 03/20/2007 |
| From: | Dyer J Office of Nuclear Reactor Regulation |
| To: | Lash J FirstEnergy Nuclear Operating Co |
| Morgan N, NRR/DORL, 415-3650 | |
| References | |
| TAC MD4132, NRR-07-011 | |
| Download: ML070780503 (6) | |
Text
March 20, 2007 CAL No. NRR-07-011 Mr. James H. Lash Site Vice President FirstEnergy Nuclear Operating Company Beaver Valley Power Station Mail Stop A-BV-SEB1 P.O. Box 4, Route 168 Shippingport, PA 15077
SUBJECT:
CONFIRMATORY ACTION LETTER - BEAVER VALLEY POWER STATION, UNIT NO. 1 (TAC NO. MD4132)
Dear Mr. Lash:
This letter confirms commitments by FirstEnergy Nuclear Operating Company (FENOC) regarding Alloy 82/182 butt welds in the pressurizer at Beaver Valley Power Station (BVPS),
Unit 1.
The discovery, in October 2006, of five circumferential indications in three dissimilar metal (DM) welds on the pressurizer at the Wolf Creek Generating Station (Wolf Creek) raised safety concerns based on the size and location of the indications. At Wolf Creek, three indications were in the pressurizer surge nozzle-to-safe end weld, and two separate indications were in the safety and relief nozzle-to-safe end welds. These findings also indicated that significant concerns might exist with the inspection schedules for addressing the pressurizer weld concerns issued by the industry-sponsored Materials Reliability Program (MRP), in Primary System Piping Butt Weld Inspection and Evaluation Guideline (MRP-139).
The Nuclear Regulatory Commission (NRC) is concerned about the pressurizer surge nozzle-to-safe end weld indications, as this is the first time that multiple circumferential primary water stress-corrosion cracking (PWSCC) indications have been identified in a weld. This condition calls into question the degree of safety margin present in past structural integrity evaluations for flawed DM welds susceptible to PWSCC, since multiple stress-corrosion cracking flaws may grow independently and ultimately grow together, significantly reducing the time from flaw initiation to leakage or rupture. The size of the relief nozzle-to-safe end flaw is also of concern, as this flaw has a much larger aspect ratio than those assumed in the estimates used to establish the basis for completing the baseline inspections required by the industry-sponsored MRP. Larger aspect ratios could result in achieving a critical flaw size and rupture before the onset of detectable leakage.
The long-term resolution of this issue is expected to involve changes to the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), and will involve changes to the NRC regulations in Title 10 of the Code of Federal Regulations (10 CFR),
Part 50, Section 50.55a, Codes and standards. The development of the NRC regulations, whether the rule adopts the ASME Code standards or defines separate requirements, will likely
J. Lash benefit from additional operating experience, continuing assessments, and analysis being conducted by the NRC and the MRP.
Until NRC regulations are revised, it is necessary to establish a minimum set of enhanced reactor coolant system (RCS) DM butt weld inspection expectations for nickel-based Alloy 82/182 pressurizer surge, spray, safety, and relief nozzle butt welds, including safe end welds, to supplement existing inspection and other requirements of the ASME Code and NRC regulations. In addition, enhanced monitoring of RCS leakage is needed to promptly identify any through-wall flaws in the pressurizer surge, spray, safety, or relief nozzle DM butt welds or safe end DM butt welds to prevent additional degradation from occurring. The above actions provide reasonable assurance that there is no undue risk to the health and safety of the public while the NRC regulations are revised.
The NRC communicated the need for near-term enhancements to the industry through public meetings held on November 30, 2006, December 20, 2006, and February 2, 2007. Licensees submitted letters voluntarily committing to the enhanced inspection and leakage monitoring requirements. After teleconferences with specific licensees held between February 12 through February 23, 2007, the licensees submitted supplemental commitment letters addressing the NRC staffs concerns regarding inspection, compensatory actions, and reporting.
In your letter dated February 23, 2007, (Agencywide Documents Access & Management System (ADAMS) Accession Number ML070640092) you described actions you will take at BVPS, Unit 1 for the pressurizer dissimilar metal butt welds containing Alloy 82/182 material.
These commitments address: 1) completion schedules for inspection/mitigation of the welds; 2)
RCS leak monitoring frequency, action levels, and actions; 3) reporting requirements, and
- 4) reinspection frequencies.
The NRC staff has reviewed these actions and commitments and agree the actions and commitments are appropriate to address the potential of PWSCC of the applicable pressurizer dissimilar metal butt welds containing Alloy 82/182 material with clarification on one of the commitments as indicated in bold below regarding RCS leak monitoring and actions.
- Once a 72-hour evaluation period i.e. the period of sustained leakage increase is complete, and leak rate is still elevated, place the unit in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 within the next 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />, and perform bare metal visual inspections of unmitigated pressurizer spray, safety and relief nozzle butt welds and safe-end butt welds containing Alloy 82/182 material.
This clarification was discussed with and agreed upon by your staff during a telephone discussion on March 19, 2007, between Greg Halnon, FENOC Fleet Regulatory Affairs Director and Michele Evans, Director-Division of Component Integrity.
Pursuant to Section 182 of the Atomic Energy Act, 42 U.S.C. 2232, you are required to:
- 1) Notify me immediately if your understanding differs from that set forth above;
- 2) Notify me if for any reason you cannot complete the actions and commitments within the specified schedule and advise me in writing of your modified schedule in advance of the change; and
J. Lash 3) Notify me in writing when you have completed the actions and commitments addressed in this Confirmatory Action Letter.
Issuance of this Confirmatory Action Letter does not preclude issuance of an Order formalizing the above commitments or requiring other actions on the part of the licensee; nor does it preclude the NRC from taking enforcement action for violations of NRC requirements that may have prompted the issuance of this letter. In addition, failure to take the actions addressed in this Confirmatory Action Letter may result in enforcement action.
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and your response will be made available electronically for public inspection in the NRC Public Document Room or from the NRCs ADAMS, accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html. To the extent possible, your response should not include any personal privacy, proprietary, or safeguards information so that it can be made available to the Public without redaction. If personal privacy or proprietary information is necessary to provide an acceptable response, then please provide a bracketed copy of your response that identifies the information that should be protected and a redacted copy of your response that deletes such information. If you request withholding of such material, you must specifically identify the portions of your response that you seek to have withheld and provide in detail the bases for your claim of withholding (e.g., explain why the disclosure of information will create an unwarranted invasion of personal privacy or provide the information required by 10 CFR 2.390(b) to support a request for withholding confidential commercial or financial information). If safeguards information is necessary to provide an acceptable response, please provide the level of protection described in 10 CFR 73.21.
Sincerely,
/RA/
J. E. Dyer, Director Office of Nuclear Reactor Regulation Docket No. 50-334 License No. DPR-66 cc: See next page
ML070780503 OFFICE CPNB DCI LPL1-1/PM LPL1-1/LA LPL1-1/BC (A) TECH ED DIRS/TA NAME KHoffman ESullivan NMorgan SLittle DPickett HChang RPascarelli DATE 3/20/07 3/20/07 3/19/07 3/19/07 3/19/07 2/28/07 3/20/07 OFFICE CPNB/BC DRP/D RGN1 DORL/D DCI/D AD:DES NRR/D NAME TChan DLew CHaney MEvans JGrobe JDyer DATE 3/20/07 3/16/07 3/20/07 3/20/07 3/20/07 3/20/07 Beaver Valley Power Station, Unit Nos. 1 and 2 cc:
Gary R. Leidich Director, Fleet Regulatory Affairs President and Chief Nuclear Officer FirstEnergy Nuclear Operating Company FirstEnergy Nuclear Operating Company Mail Stop A-GHE-315 Mail Stop A-GO-19 395 Ghent Road 76 South Main Street Akron, Ohio 44333 Akron, OH 44308 Manager, Site Regulatory Compliance Joseph J. Hagan FirstEnergy Nuclear Operating Company Senior Vice President of Operations Beaver Valley Power Station and Chief Operating Officer Mail Stop A-BV-A FirstEnergy Nuclear Operating Company P.O. Box 4, Route 168 Mail Stop A-GO-14 Shippingport, PA 15077 76 South Main Street Akron, OH 44308 Richard Anderson Vice President, Nuclear Support Danny L. Pace FirstEnergy Nuclear Operating Company Senior Vice President, Fleet Engineering Mail Stop A-GO-14 FirstEnergy Nuclear Operating Company Akron, Ohio 44308 Mail Stop A-GO-14 76 South Main Street Commissioner James R. Lewis Akron, OH 44308 West Virginia Division of Labor 749-B, Building No. 6 Jeannie M. Rinckel Capitol Complex Vice President, Fleet Oversight Charleston, WV 25305 FirstEnergy Nuclear Operating Company Mail Stop A-GO-14 Director, Utilities Department 76 South Main Street Public Utilities Commission Akron, OH 44308 180 East Broad Street Columbus, OH 43266-0573 David W. Jenkins, Attorney FirstEnergy Corporation Director, Pennsylvania Emergency Mail Stop A-GO-18 Management Agency 76 South Main Street 2605 Interstate Dr.
Akron, OH 44308 Harrisburg, PA 17110-9364 Manager, Fleet Licensing FirstEnergy Nuclear Operating Company Mail Stop A-GHE-115 395 Ghent Road Akron, OH 44333 Ohio EPA-DERR ATTN: Zack A. Clayton P.O. Box 1049 Columbus, OH 43266-0149
Beaver Valley Power Station, Unit Nos. 1 and 2 (continued) cc:
Dr. Judith Johnsrud Environmental Coalition on Nuclear Power Sierra Club 433 Orlando Avenue State College, PA 16803 Director Bureau of Radiation Protection Pennsylvania Department of Environmental Protection Rachel Carson State Office Building P.O. Box 8469 Harrisburg, PA 17105-8469 Mayor of the Borough of Shippingport P.O. Box 3 Shippingport, PA 15077 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 298 Shippingport, PA 15077