ML051890278

RAI MC6764, SL1-19 Steam Generator Tube Inservice Inspection Special Report

ML051890278
Person / Time
Site:	Saint Lucie
Issue date:	07/12/2005
From:	Moroney B NRC/NRR/DLPM/LPD2
To:	Stall J Florida Power & Light Co
Moroney B, NRR/DLPM, 415-3974
References
Download: ML051890278 (5)

Text

July 12, 2005 Mr. J. A. Stall Senior Vice President, Nuclear and Chief Nuclear Officer Florida Power and Light Company P.O. Box 14000 Juno Beach, Florida 33408-0420

SUBJECT:

ST. LUCIE PLANT, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION REGARDING STEAM GENERATOR TUBE INSERVICE INSPECTION SPECIAL REPORT (TAC NO. MC6764)

Dear Mr. Stall:

By letter dated April 8, 2005, Florida Power and Light Company submitted the steam generator tube inservice inpection special report required by Sections 4.4.5.5.b and 6.9.2 of the St. Lucie Unit 1 Technical Specification (TS) for the SL1-19 refueling outage.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed your submittal and finds that a response to the enclosed Request for Additional Information (RAI) is needed before we can complete the review. Question No. 1 of the RAI asks for information that was omitted from the special report. The remaining questions seek additional information that will enable the NRC staff to better understand the design features of the St. Lucie Unit 1 steam generators and to evaluate whether there is atypical wear or indication of problems that have been identified in other steam generators.

This request was discussed with your staff on July 7, 2005, and Mr. Ken Frehafer indicated that a response would be provided within 90 days of this request.

If you have any questions, please feel free to contact me at 301-415-3974.

Sincerely,

/RA/

Brendan T. Moroney, Project Manager, Section 2 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-335

Enclosure:

Request for Additional Information cc w/encl: See next page

ML051890278 NRR-088 OFFICE PDII-2/PM PDII-2/LA EMCB-C/SC PDII-2/SC NAME BMoroney BClayton LLund by MMarshall memo DATE 07/12/05 07/12/05 5/9/05 07/18/05 REQUEST FOR ADDITIONAL INFORMATION SL1-19 STEAM GENERATOR TUBE INSERVICE INSPECTION SPECIAL REPORT ST. LUCIE NUCLEAR PLANT, UNIT 1 DOCKET NUMBER 50-335

1. St. Lucie Unit 1 Technical Specification (TS) 4.4.5.5.b requires the licensee to provide the location and percent of wall thickness penetration for each indication of an imperfection. This technical specification also requires identification of tubes plugged.

Please provide the location of the three tubes that were plugged in steam generator A (i.e., row, column, and axial location of the flaw). In addition provide the location and percent of wall thickness penetration for each indication of an imperfection in both steam generators.

2. Your report identifies the population of tubes that are experiencing wear at U-bend support structure locations. There are different types of wear mechanisms, which behave differently and may present challenges to tube integrity. To help the NRC staff in understanding the identified indications of wear, please discuss the extent to which these wear indications are considered typical fan bar wear, atypical U-bend wear, or localized U-bend wear. Typical fan bar wear refers to wear caused by the thermal hydraulic conditions and tube-to-support clearances, which can vary because of manufacturing tolerances. Atypical U-bend wear refers to pit-like indications found at flat-bar supports and theorized to be the result of asperities on the flat bars introduced during fabrication. Localized U-bend wear refers to wear localized to specific columns of tubes and possibly the adjacent column as a result of arch-bar distortion instead of a more random manufacturing tolerance issue (which causes typical fan bar wear).

Please discuss how the nature of the wear detected during this outage compares to the wear indications detected in 1999 (i.e., what was the cause of wear indications in 1999).

3. In several Babcock and Wilcox replacement steam generators currently in service, tube-to-tube contact or tubes in close proximity have been observed. For St. Lucie Unit 1, please discuss how many tubes are currently considered to be in close proximity and whether any tube wear has been observed at the locations of close proximity. In addition, please discuss whether the number of tubes in close proximity has increased, decreased, or remained the same since the steam generators were installed. If the number of tubes in close proximity is increasing with time, please discuss the cause (the staff understands that the tube proximity issue is a result of manufacture and that it was expected that the condition may correct itself with time).

4. There is limited steam generator design information in the St. Lucie Updated Final Safety Analysis Report. In order for the staff to better understand the design of your steam generators and the location of the indications described in your reports, please provide the following design information for St. Lucie Unit 1: (a) the manufacturers model number for the replacement steam generators, (b) tube manufacturer, (c) outer diameter and nominal wall thickness of tubes, (d) number of tubes in each steam generator, (e) tube pitch and pattern ( e.g., 0.95" triangular), (f) tubesheet thickness (with and without clad), (g) a sketch depicting the tube support structure naming ENCLOSURE

conventions, (h) anti-vibration bar (fan bar) design, (i) tube support material (e.g., 410 Stainless Steel), (j) a sketch of a tubesheet map which depicts the rows and columns of the tubes in the steam generators, (k) smallest U-bend radius in the steam generator and the radii of the row 1 tubes, (l) stress relief after bending of tubes (e.g., stress relief of the entire tube length for the tubes in rows 1 through 27).

5. Steam generator inspections may not be required each refueling outage to meet TS requirements. To ensure NRC staff records are accurate, please confirm that no tube inspections were performed during the fall 2002 refueling outage (SL1-18).

Mr. J. A. Stall ST. LUCIE PLANT Florida Power and Light Company cc:

Senior Resident Inspector Mr. G. L. Johnston St. Lucie Plant Plant General Manager U.S. Nuclear Regulatory Commission St. Lucie Nuclear Plant P.O. Box 6090 6351 South Ocean Drive Jensen Beach, Florida 34957 Jensen Beach, Florida 34957 Craig Fugate, Director Mr. Terry Patterson Division of Emergency Preparedness Licensing Manager Department of Community Affairs St. Lucie Nuclear Plant 2740 Centerview Drive 6351 South Ocean Drive Tallahassee, Florida 32399-2100 Jensen Beach, Florida 34957 M. S. Ross, Managing Attorney Mark Warner, Vice President Florida Power & Light Company Nuclear Operations Support P.O. Box 14000 Florida Power and Light Company Juno Beach, FL 33408-0420 P.O. Box 14000 Juno Beach, FL 33408-0420 Marjan Mashhadi, Senior Attorney Florida Power & Light Company Mr. Rajiv S. Kundalkar 801 Pennsylvania Avenue, NW. Vice President - Nuclear Engineering Suite 220 Florida Power & Light Company Washington, DC 20004 P.O. Box 14000 Juno Beach, FL 33408-0420 Mr. Douglas Anderson County Administrator Mr. J. Kammel St. Lucie County Radiological Emergency 2300 Virginia Avenue Planning Administrator Fort Pierce, Florida 34982 Department of Public Safety 6000 Southeast Tower Drive Mr. William A. Passetti, Chief Stuart, Florida 34997 Department of Health Bureau of Radiation Control 2020 Capital Circle, SE, Bin #C21 Tallahassee, Florida 32399-1741 Mr. William Jefferson, Jr.

Site Vice President St. Lucie Nuclear Plant 6351 South Ocean Drive Jensen Beach, Florida 34957-2000