ML082280165
| ML082280165 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 08/28/2008 |
| From: | Geoffrey Miller NRC/NRR/ADRO/DORL/LPLI-2 |
| To: | St.Pierre G Florida Power & Light Energy Seabrook |
| Miller G, NRR/DORL, 415-2481 | |
| References | |
| TAC MD5947 | |
| Download: ML082280165 (7) | |
Text
August 28, 2008 Mr. Gene St. Pierre, Site Vice President c/o Michael OKeefe Seabrook Station FPL Energy Seabrook, LLC PO Box 300 Seabrook, NH 03874
SUBJECT:
REVIEW OF STEAM GENERATOR TUBE INSPECTION REPORT FOR FALL 2006 - SEABROOK STATION, UNIT NO. 1 (TAC NO. MD5947)
Dear Mr. St. Pierre:
By letter dated October 26, 2006 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML063040324), and May 23, 2007 (ADAMS Accession No. ML071510197) FPL Energy Seabrook, LLC (FPLE) submitted information summarizing the steam generator (SG) tube inspections performed at Seabrook Station, Unit No. 1 (Seabrook) during the fall 2006 refueling outage (OR11). FPLE provided additional information regarding the SG inspections in letters dated June 18, 2008 (ADAMS Accession No. ML081750527), and August 8, 2008 (ADAMS Accession No. ML082260306).
The Nuclear Regulatory Commission staff has completed its review of your submittals as documented in the enclosed evaluation. The staff concludes that FPLE has provided the information required by the Technical Specifications and that no additional follow-up is required at this time. This completes the NRC staff efforts for TAC No. MD5947.
If you have any questions regarding this matter, I may be reached at 301-415-2481.
Sincerely,
/ra/
G. Edward Miller, Project Manager Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-443
Enclosure:
As stated cc w/encl: See next page
ML071510197) FPL Energy Seabrook, LLC (FPLE) submitted information summarizing the steam generator (SG) tube inspections performed at Seabrook Station, Unit No. 1 (Seabrook) during the fall 2006 refueling outage (OR11). FPLE provided additional information regarding the SG inspections in letters dated June 18, 2008 (ADAMS Accession No. ML081750527), and August 8, 2008 (ADAMS Accession No. ML082260306).
The Nuclear Regulatory Commission staff has completed its review of your submittals as documented in the enclosed evaluation. The staff concludes that FPLE has provided the information required by the Technical Specifications and that no additional follow-up is required at this time. This completes the NRC staff efforts for TAC No. MD5947.
If you have any questions regarding this matter, I may be reached at 301-415-2481.
Sincerely,
/ra/
G. Edward Miller, Project Manager Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-443
Enclosure:
As stated cc w/encl: See next page DISTRIBUTION:
PUBLIC RidsAcrsAcnw_MailCTR Resource LPL1-2 Reading RidsRgn1MailCenter Resource RidsNrrDorlLpl1-2 Resource RidsNrrDciCsgb Resource RidsNrrLAABaxter Resource KKarwoski, DCI/CSGB RidsNrrPMGMiller Resource AJohnson, DCI/CSGB RidsOgcRp Resource ADAMS Accession No.: ML082280165 OFFICE LPL1-2/PM LPL 1-2/LA CSGB/BC LPL1-2/BC NAME G. E. Miller ABaxter AHiser HChernoff DATE 8/20/08 8/21/08 8/27/08 8/28/08
Seabrook Station, Unit No. 1 cc:
Mr. J. A. Stall Senior Vice President, Nuclear and Chief Nuclear Officer Florida Power & Light Company P.O. Box 14000 Juno Beach, FL 33408-0420 Mr. Peter Brann Assistant Attorney General State House, Station #6 Augusta, ME 04333 Resident Inspector U.S. Nuclear Regulatory Commission Seabrook Nuclear Power Station P.O. Box 1149 Seabrook, NH 03874 Town of Exeter 10 Front Street Exeter, NH 03823 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Office of the Attorney General One Ashburton Place, 20th Floor Boston, MA 02108 Board of Selectmen Town of Amesbury Town Hall Amesbury, MA 01913 Mr. Robert Poole Federal Emergency Management Agency Region I 99 High Street, 6th Floor Boston, MA 02110 Mr. Tom Crimmins Polestar Applied Technology One First Street, Suite 4 Los Altos, CA 94019 John Giarrusso Massachusetts Emergency Management Agency 400 Worcester Road Framingham, MA 01702-5399 Ms. Kelly Ayotte, Attorney General Mr. Orvil Fitch, Deputy Attorney General 33 Capitol Street Concord, NH 03301 Mr. Christopher M. Pope, Director Homeland Security & Emergency Mgmt.
New Hampshire Department of Safety Bureau of Emergency Management 33 Hazen Drive Concord, NH 03301 Mr. M. S. Ross, Managing Attorney Florida Power & Light Company P.O. Box 14000 Juno Beach, FL 33408-0420 Mr. Rajiv S. Kundalkar Vice President - Nuclear Technical Services Florida Power & Light Company P.O. Box 14000 Juno Beach, FL 33408-0420 Michael OKeefe Licensing Manager FPL Energy Seabrook, LLC PO Box 300 Seabrook, NH 03874 Ms. Marjan Mashhadi Senior Attorney Florida Power & Light Company 801 Pennsylvania Ave., NW Suite 220 Washington, DC 20004
Seabrook Station, Unit No. 1 cc:
Mr. Joseph Roy Director of Operations Massachusetts Municipal Wholesale Electric Company Moody Street Ludlow, MA 01056 Mr. Paul Freeman Plant General Manager FPL Energy Seabrook, LLC P.O. Box 300 Seabrook, NH 03874
EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION STEAM GENERATOR TUBE INSPECTION REPORT FOR FALL 2006 SEABROOK STATION, UNIT NO. 1 DOCKET NO. 50-443
1.0 INTRODUCTION
By letter dated October 26, 2006 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML063040324), and May 23, 2007 (ADAMS Accession No. ML071510197) FPL Energy Seabrook, LLC (FPLE) submitted information summarizing the steam generator (SG) tube inspections performed at Seabrook Station, Unit No. 1 (Seabrook) during the fall 2006 refueling outage (OR11). FPLE provided additional information regarding the SG inspections in letters dated June 18, 2008 (ADAMS Accession No. ML081750527), and August 8, 2008 (ADAMS Accession No. ML082260306).
2.0 BACKGROUND
Seabrook has four Westinghouse Model F SGs, each of which contain 5,626 thermally treated Alloy 600 tubes. Each tube has a nominal outside diameter of 0.688 inches and a nominal wall thickness of 0.040 inches. During SG fabrication, the tubes were hydraulically expanded, at both ends, over the full length of the tubesheet. Type 405 stainless steel support plates, which have broached quatrefoil holes, support the vertical section of the tubes, and anti-vibration bars support the U-bend section of the tubes.
FPLE provided the scope, extent, methods, and results of their SG tube inspections in the documents referenced above. The licensee also described corrective actions in the form of tube plugging and tube stabilization taken in response to the inspection findings.
At the time of inspection, the SGs had accumulated approximately 165.6 Effective Full Power Months (EFPM) of operation. At the time of the inspection, the SGs had experienced approximately 34.7 EFPM of operation in the second sequential period, which is 90 EFPM in duration.
3.0 EVALUATION Based on the Nuclear Regulatory Commission (NRC) staffs review of the information submitted by FPLE, the NRC staff has the following observations and comments:
No crack-like indications were detected during this outage (OR11);
Inspections of the tube support plate quatrefoils were performed in previous outages and they showed insignificant blockage in the tube support plate quatrefoil area. Seabrook has started Advanced Scale Conditioning Agent (ASCA) treatment to reduce the total scale loading in the SGs. In OR12 (2008), a full bundle copper ASCA was performed.
Pressure Pulse Cleaning was performed on the Seabrook SGs during OR04 and OR05.
This cleaning process resulted in wear indications in several tubes. These indications have been tracked since that time with no change in the depth of the indications.
In SG-C, 14 tubes were preventatively plugged (but not stabilized) in an area where a loose part could not be retrieved. Because the loose part had caused wear in two tubes, FPLE plugged 14 tubes around the two tubes that showed wear, in order to box in the tubes affected by the wear. FPLE indicated that tube severance from the object is extremely unlikely and that a postulated severed tube is constrained from further propagation by the surrounding tubes that were plugged. The NRC staff notes that, at another plant, a cascading failure of plugged tubes has led to a tube rupture in the past, and, depending on the nature of the loose part and the thermal hydraulic conditions in the region where the loose part is located, continued wear of a plugged tube can lead to its failure (severance) and this type of failure can continue unnoticed on other plugged tubes. In addition, new loose parts in this region would also potentially go unnoticed.
This sequence may be mitigated through periodic inspection of the region (e.g., through visual or eddy current inspection of the plugged tubes) or stabilizing the tubes surrounding the loose part.
The licensee performed upper-bundle in-bundle tube support plate inspections of the SGs as a part of foreign object search and retrieval (FOSAR) in 2000 (during OR07) and in 2002 (during OR08).
4.0 CONCLUSION
The NRC staff concludes that the licensee provided the information required by the Seabrook Technical Specifications and that no additional follow-up is required at this time. The inspections appear to be consistent with the objective of detecting potential tube degradation and the inspection results appear to be consistent with industry operating experience at similarly designed and operated units.
Principal Contributor: A. B. Johnson Date: August 28, 2008