ML062910261
| ML062910261 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 10/24/2006 |
| From: | Moroney B NRC/NRR/ADRO/DORL/LPLD |
| To: | Stall J Florida Power & Light Co |
| Moroney B, NRR/DORL, 415-3974 | |
| References | |
| TAC MC9192 | |
| Download: ML062910261 (5) | |
Text
October 24, 2006 Mr. J. A. Stall Senior Vice President, Nuclear and Chief Nuclear Officer Florida Power and Light Company P.O. Box 14000 Juno Beach, FL 33408-0420
SUBJECT:
ST. LUCIE NUCLEAR PLANT, UNIT NO. 2 - REVIEW OF THE STEAM GENERATOR TUBE INSPECTIONS DURING THE SPRING 2005 OUTAGE (TAC NO. MC9192)
Dear Mr. Stall:
By letters dated February 11, 2005, June 15, 2005, November 28, 2005, and June 28, 2006, Florida Power & Light Company (FPL) submitted reports summarizing the steam generator (SG) tube inspections performed during the spring 2005 refueling outage (SL2-15) at St. Lucie Unit 2. The results of the U.S. Nuclear Regulatory Commission (NRC) staff review of these documents is enclosed.
Based on a review of the information provided, the NRC staff concludes that FPL provided the information required by the St. Lucie Unit 2 technical specifications. In addition, the staff concludes that there are no technical issues that warrant follow-up action since 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.
This completes NRC staffs efforts under TAC No. MC9192. If you have any questions regarding this matter, please contact me at 301-415-3974.
Sincerely,
/RA/
Brendan T. Moroney, Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-389
Enclosure:
Review of SG Inspection Summary cc: See next page
ML062910261 NRR-106 OFFICE LPL2-2/PM LPL2-2/LA CSGB/BC LPL2-2/BC NAME BMoroney BClayton AHiser by memo dated LRaghavan DATE 39008 39008 09/25/06 39013
Enclosure REVIEW OF STEAM GENERATOR INSPECTION
SUMMARY
REPORT 2005 STEAM GENERATOR TUBE INSPECTIONS AT ST. LUCIE UNIT 2 By letters dated February 11, 2005 (Agencywide Documents Access and Management System Accession Number ML050550032), June 15, 2005 (ML051720461), November 28, 2005 (ML053410482), and June 28, 2006 (ML061870466), Florida Power and Light Company (the licensee) submitted information summarizing the results of the 2005 steam generator (SG) tube inspections at St. Lucie Unit 2. These inspections were performed during the fifteenth refueling outage (SL2-15). In addition to these reports, the U.S. Nuclear Regulatory Commission (NRC) staff participated in a conference call concerning the 2005 SG tube inspections at St. Lucie Unit 2. This conference call was summarized by the staff in a letter dated April 8, 2005 (ML051030078).
Based on a review of these documents, the NRC staff prepared a request for additional information (RAI) that was forwarded to the licensee around the time of their subsequent (2006)
SG tube inspections. Given that the 2006 SG tube inspections would be conducted prior to the licensee being able to respond to this RAI, the NRC staff factored these questions into the discussions it had with the licensee regarding the results of their 2006 tube inspections. These discussions were documented in a letter dated August 3, 2006 (ML062060255). The licensee subsequently responded to the RAI on the 2005 outage by letter dated August 29, 2006 (ML062490426).
St. Lucie Unit 2 has two Combustion Engineering Model 3410 SGs. The mill-annealed Alloy 600 SG tubes have an outside diameter of 3/4 inch and a nominal wall thickness of 0.048 inch. The tubes are explosively expanded for the full depth of the tubesheet at each end and are supported by a number of carbon steel lattice grid (i.e., eggcrate) tube supports, diagonal bars, and vertical straps.
During the 2005 SG tube inspections, a number of indications were coded as retest for clarification (RCL) because they were identified with a rotating probe as it was being removed from the tube at a rate greater than the rate at which the probe is qualified. The indications in question had not been identified during bobbin coil inspection. The NRC staff discussed these indications with representatives from St. Lucie during conference calls at the time of the outage.
During the call the staff made several observations concerning the disposition of these flaws (refer to pages 5 and 6 of the conference call summary dated April 8, 2005). In its August 29, 2006, letter the licensee addressed the NRCs observations. The licensee compared the results of the 2005 tube inspections with the 2003 inspection results and with a predictive code.
The licensee concluded that it had adequately dispositioned the RCL indications identified during the 2005 SG tube inspections. This conclusion was supported during the 2006 SG tube inspections, since no significant degradation was identified during this inspection (see call summary dated August 3, 2006).
By letter dated June 28, 2006, the licensee indicated that an error was made during the 2005 SG eddy current testing at St. Lucie Unit 2. During the 2005 SG inspections, a diagnostic inspection of an indication identified with a bobbin coil was performed using a rotating +Point' coil. No defect was detected during the +Point' coil examination and the tube was left in service. During the 2006 SG inspections, the licensee again performed a +Point' coil inspection after the indication was again detected during the bobbin coil examination. During the 2006 inspection, the +Point' coil inspection confirmed the presence of a defect in the tube.
A review of the 2005 data (in 2006) indicated that the +Point' coil inspection did not include the entire target area and, therefore, confirm the presence of the flaw. This tube was in situ pressure tested and passed without any leakage or burst. The tube containing the flaw was plugged during the 2006 outage and a full review of the 2005 eddy current test data was performed. The full review of the 2005 data also identified one other flaw that was not fully inspected by +Point' coil during the 2005 inspections. This tube was also plugged in 2006, and the licensee determined that there were no structural or leakage integrity issues associated with the tube being in service prior to the 2006 inspection. As a result of these findings, the 2006 rotating probe data were reviewed and no additional incomplete +Point' coil tests were observed. The licensee determined that the incomplete tests were limited to one calibration group of the 2005 data.
The licensee provided the scope, extent, methods and results of their SG tube inspections in the documents referenced above. 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 the St. Lucie Unit 2 technical specifications. In addition, the staff concludes that there are no technical issues that warrant follow-up action since 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.
Mr. J. A. Stall ST. LUCIE PLANT Florida Power and Light Company cc:
Mr. William E. Webster Vice President, Nuclear Operations Florida Power & Light Company P.O. Box 14000 Juno Beach, FL 33408-0420 Senior Resident Inspector St. Lucie Plant U.S. Nuclear Regulatory Commission P.O. Box 6090 Jensen Beach, Florida 34957 Craig Fugate, Director Division of Emergency Preparedness Department of Community Affairs 2740 Centerview Drive Tallahassee, Florida 32399-2100 M. S. Ross, Managing Attorney Florida Power & Light Company P.O. Box 14000 Juno Beach, FL 33408-0420 Marjan Mashhadi, Senior Attorney Florida Power & Light Company 801 Pennsylvania Avenue, NW.
Suite 220 Washington, DC 20004 Mr. Douglas Anderson County Administrator St. Lucie County 2300 Virginia Avenue Fort Pierce, Florida 34982 Mr. William A. Passetti, Chief Department of Health Bureau of Radiation Control 2020 Capital Circle, SE, Bin #C21 Tallahassee, Florida 32399-1741 Mr. Gordon L. Johnston Site Vice President St. Lucie Nuclear Plant 6351 South Ocean Drive Jensen Beach, Florida 34957-2000 Mr. Christopher R. Costanzo Plant General Manager St. Lucie Nuclear Plant 6351 South Ocean Drive Jensen Beach, Florida 34957 Mr. Terry Patterson Licensing Manager St. Lucie Nuclear Plant 6351 South Ocean Drive Jensen Beach, Florida 34957 Mark Warner, Vice President Nuclear Operations Support Florida Power & Light Company P.O. Box 14000 Juno Beach, FL 33408-0420 Mr. Rajiv S. Kundalkar Vice President - Nuclear Engineering Florida Power & Light Company P.O. Box 14000 Juno Beach, FL 33408-0420 Mr. J. Kammel Radiological Emergency Planning Administrator Department of Public Safety 6000 Southeast Tower Drive Stuart, Florida 34997 Mr. Bill Parks Operations Manager St. Lucie Nuclear Plant 6351 South Ocean Drive Jensen Beach, Florida 34957-2000 Mr. Seth B. Duston Training Manager St. Lucie Nuclear Plant 6351 South Ocean Drive Jensen Beach, Florida 34957-2000