ML063380188
| ML063380188 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 12/13/2006 |
| From: | Milano P NRC/NRR/ADRO/DORL/LPLI-1 |
| To: | Spina J Calvert Cliffs |
| Milano P, NRR/DORL/LPLA, 415-1457 | |
| References | |
| TAC MD0542 | |
| Download: ML063380188 (5) | |
Text
December 13, 2006 Mr. James A. Spina, Vice President Calvert Cliffs Nuclear Power Plant, Inc.
Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702
SUBJECT:
CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NO. 2 - REVIEW OF STEAM GENERATOR TUBE INSPECTION
SUMMARY
REPORT FOR THE SPRING 2005 OUTAGE (TAC NO. MD0542)
Dear Mr. Spina:
By letter dated February 27, 2006, Calvert Cliffs Nuclear Power Plant, Inc. (the licensee),
submitted its steam generator (SG) tube inspection summary report for the spring 2005 outage at Calvert Cliffs Nuclear Power Plant, Unit No. 2 (Calvert Cliffs 2).
The Nuclear Regulatory Commission staff has completed its review of the SG tube inspection report. The staff concluded that the licensee provided the information required by the Calvert Cliffs Technical Specifications and that no additional follow-up is required at this time. The staffs review of the report is enclosed.
If you have any questions, please contact me at 301-415-1457.
Sincerely,
/RA/
Patrick D. Milano, Senior Project Manager Plant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-318
Enclosure:
As stated cc w/encl: See next page
December 13, 2006 Mr. James A. Spina, Vice President Calvert Cliffs Nuclear Power Plant, Inc.
Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702
SUBJECT:
CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NO. 2 - REVIEW OF STEAM GENERATOR TUBE INSPECTION
SUMMARY
REPORT FOR THE SPRING 2005 OUTAGE (TAC NO. MD0542)
Dear Mr. Spina:
By letter dated February 27, 2006, Calvert Cliffs Nuclear Power Plant, Inc. (the licensee),
submitted its steam generator (SG) tube inspection summary report for the spring 2005 outage at Calvert Cliffs Nuclear Power Plant, Unit No. 2 (Calvert Cliffs 2).
The Nuclear Regulatory Commission staff has completed its review of the SG tube inspection report. The staff concluded that the licensee provided the information required by the Calvert Cliffs Technical Specifications and that no additional follow-up is required at this time. The staffs review of the report is enclosed.
If you have any questions, please contact me at 301-415-1457.
Sincerely,
/RA/
Patrick D. Milano, Senior Project Manager Plant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-318
Enclosure:
As stated cc w/encl: See next page DISTRIBUTION:
PUBLIC K. Karwoski LPLI-1 Reading File Y. Díaz-Castillo R. Laufer RidsNrrDorlLplI-1 OGC RidsOgcRp S. Little RidsNrrLASLittle ACRS RidsAcrsAcnwMailCenter P. Milano RidsNrrPMPMilano B. McDermott, R-I RidsRgn1MailCenter A. Hiser RidsNrrDciCsgb Accession Number: ML063380188 OFFICE LPLI-1\PM LPLI-1\LA CSGB\BC LPLI-1\BC NAME PMilano SLittle AHiser RLaufer DATE 12/12/06 12/12/06 08/14/06 12/13/06 OFFICIAL RECORD COPY
Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 cc:
President Ms. Patricia T. Birnie, Esquire Calvert County Board of Co-Director Commissioners Maryland Safe Energy Coalition 175 Main Street P.O. Box 33111 Prince Frederick, MD 20678 Baltimore, MD 21218 Mr. Carey Fleming, Esquire Mr. Roy Hickok Sr. Counsel - Nuclear Generation NRC Technical Training Center Constellation Generation Group, LLC 5700 Brainerd Road 750 East Pratt Street, 17th floor Chattanooga, TN 37411-4017 Baltimore, MD 21202 Mr. Jay S. Gaines Director, Licensing Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702 Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 287 St. Leonard, MD 20685 Mr. R. I. McLean, Manager Nuclear Programs Power Plant Research Program Maryland Department of Natural Resources 580 Taylor Avenue (B wing, 3rd floor)
Tawes State Office Building Annapolis, MD 21401 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Ms. Kristen A. Burger, Esquire Maryland People's Counsel 6 St. Paul Centre Suite 2102 Baltimore, MD 21202-1631
STAFF REVIEW OF THE 2005 STEAM GENERATOR TUBE INSPECTION REPORT CALVERT CLIFFS NUCLEAR POWER PLANT, INC.
CALVERT CLIFFS NUCLEAR POWER PLANT DOCKET NO. 50-318 By letter dated February 27, 2006 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML060610081), Calvert Cliffs Nuclear Power Plant, Inc. (the licensee),
submitted information pertaining to the steam generator (SG) tubing inspections performed at Calvert Cliffs Nuclear Power Plant, Unit No. 2 (Calvert Cliffs 2), performed during the 2005 refueling outage.
Calvert Cliffs Unit 2 has two Babcock and Wilcox International (BWI) replacement SGs, each containing 8471 tubes that are made of thermally-treated Alloy 690 material. The tubes have an outside diameter of 0.75 inch and a nominal wall thickness of 0.042 inch. The SGs have a triangular tube pitch arrangement with 1-inch spacing between tube centers. The tubes are hydraulically expanded through the entire depth of the tubesheet in both the hot-leg and cold-leg. The tubesheet is 21.875 inches thick without accounting for the clad thickness. The austenitic stainless steel tubesheet cladding has a minimum thickness of 0.375 inch. The lattice grid tube support structures and the U-bend supports are made of 410 stainless steel.
The smallest radii for the U-bend is 3.5 inches in Row 1. The tubes in Rows 1 through 18 of the U-bend received a stress relief treatment after bending.
During the 2005 refueling outage (the first outage following SG replacement at Calvert Cliffs 2),
100% of the tubes in each of the two SGs were inspected for the full length with an eddy current testing (ECT) bobbin coil. In addition, a rotating probe equipped with a +PointTM ECT coil was used to inspect any bobbin coil indications. As a result of these inspections, several indications of wear at the fan bars were identified and several possible loose part indications were found.
A number of fan bar wear indications were observed during the 2005 outage. The wear is considered typical fan bar wear, caused by thermal hydraulic conditions and tube-to-support clearances, which can vary because of manufacturing tolerances. Although the number of wear indications is more than that observed at similarly designed operational units, the size and type of wear is consistent with that observed at these units. There are no major design differences between the replacement SGs at Calvert Cliffs Unit 2 and other BWI replacement SGs that would account for the larger number of fan bar wear indications. All wear indications were inspected with a rotating probe, and no anomalies were detected.
A conference call was held with the licensee on March 7, 2005, to discuss concerns over the finding of several indications of wear from loose parts during the SG inspection. During this call, the licensee confirmed the presence of one loose part in SG No. 22. The licensee stated that the part was retrieved and identified and all affected tubes would be left in service. Other indications were also present in SG No. 22, but given the location of the tubes with indications, attempts to visually inspect the location of these indications were unsuccessful. Since the presence of a part (or parts) could not be confirmed visually and the part (or parts) could not be Enclosure
removed, the licensee plans to plug and stabilize several (29 in all) tubes in the area of the indications. Further detials of the telephone conference, as well as the specific information provided by the licensee, can be found in a summary of the telephone conference (see ADAMS Accession No. ML052410150).
The licensee provided the scope, extent, methods, and results of their SG tube inspections in the February 27, 2006, letter. In addition, the licensee described corrective actions (e.g., tube plugging or repair) taken in response to the inspection findings. Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by its Technical Specifications. In addition, the staff concludes that there are no technical issues that warrant follow-up action at this time because 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 plants.