ML15058A884

Review of the 2013 Steam Generator Tube Inservice Inspection Report During Refueling Outage 1-25

ML15058A884
Person / Time
Site:	Saint Lucie
Issue date:	03/09/2015
From:	Farideh Saba Plant Licensing Branch II
To:	Nazar M Florida Power & Light Co
Tam P
References
TAC MF4404
Download: ML15058A884 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 March 9, 2015

SUBJECT:

ST. LUCIE PLANT, UNIT NO. 1 - REVIEW OF THE 2013 STEAM GENERATOR TUBE INSERVICE INSPECTION REPORT DURING REFUELING OUTAGE 1-25 (TAC NO. MF4404)

Dear Mr. Nazar:

By letter dated April 29, 2014, Florida Power & Light Company (the licensee) submitted information summarizing the results of the fall 2013 steam generator tube inspections at the St. Lucie Plant, Unit No. 1. These inspections were performed during Refueling Outage 1-25.

The U.S. Nuclear Regulatory Commission (NRC) staff discussed the inspection results with licensee personnel in a public meeting (conference call) on August 21, 2014, and documented the meeting by a summary dated September 18, 2014. By letter dated October 20, 2014, the licensee provided additional information.

The NRC staff has completed its review of the licensee's submittals and concludes that the licensee has provided the information required by the St. Lucie Plant, Unit No. 1, Technical Specifications, and that no additional follow-up is required at this time. The NRC staff's review of the report is set forth in the enclosed Safety Evaluation.

If you have any questions, please contact me at 301-415-1447 or Farideh.Saba@nrc.gov.

Sincerely, fA., -~1L Farideh E. Saba. Senior Project Manager Plant Licensing Branch 11-2 Division of Operator Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-335

Enclosure:

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REVIEW OF THE FALL 2013 STEAM GENERATOR TUBE INSPECTION SPECIAL REPORT ST. LUCIE PLANT. UNIT NO. 1 DOCKET NO. 50-335

1.0 INTRODUCTION

By letter dated April 29, 2014 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML14127A008), Florida Power & Light Company (the licensee) submitted information summarizing the results of the fall 2013 steam generator (SG) tube inspections at the St. Lucie Plant, Unit No. 1. These inspections were performed during Refueling Outage 1-25.

As part of its review efforts, the U.S. Nuclear Regulatory Commission (NRC) staff discussed the licensee's inspection results with licensee staff in a public meeting held by telephone on August 21, 2014. The licensee provided slides to support this meeting (ADAMS Accession No. ML14232A067) and the NRC staff documented the meeting in a summary dated September 18, 2014 (ADAMS Accession No. ML14240A558). The licensee provided additional information in a letter dated October 20, 2014 (ADAMS Accession No. ML14321A412).

2.0 TECHNICAL EVALUATION

St. Lucie Plant, Unit No. 1, has two recirculating SGs designed and fabricated by Babcock and Wilcox International. Each SG has 8523 thermally-treated Alloy 690 tubes that have a nominal outside diameter of 0.75 inch and a nominal wall thickness of 0.045 inch. The tubes are arranged in a triangular pattern with a pitch of approximately 1.0 inch. The tubes were hydraulically expanded at each end for the full depth of the tubesheet. The tubesheet is 21.5 inches thick; with the cladding, the tubesheet is 21.875 inches thick. The tubes are supported by lattice grid tube supports and fan bars. The lowest fan bar is also referred to as a collector bar, since all other fan bars connect to it. All supports are constructed from type 410 stainless steel. The U-bend region of the tubes in rows 1 through 20 was stress-relieved after bending. The smallest U-bend radius occurs in row 3 and is 3.905 inches. The row 1 U-bend radius measures 4.272 inches.

This was the fifth inservice inspection for the replacement SGs. At the end of Refueling Outage 1-25 in fall 2013, the replacement SGs had accumulated 166.20 effective full-power months of operation.

Enclosure

The licensee provided the scope, extent, methods, and results of its SG tube inspections in the documents referenced above. In addition, the licensee described corrective actions, such as tube plugging, taken in response to the inspection findings. The tubes in both SGs were inspected during Refueling Outage 1-25.

Based on its review of the reports submitted, the NRC staff has the following observations and comments:

• There were 215 new fan bar wear indications identified during this outage. This increase in the number of fan bar wear indications is attributed to operation at power uprate conditions. For the 150 tubes plugged since replacement, 135 were plugged during Refueling Outage 1-25. All tubes with wear at the fan bars were plugged during Refueling Outage 1-25. The licensee plans to monitor wear at future inspections. The licensee normally inspects tubes every three cycles; however, the licensee plans to perform the next SG tube inspections after two cycles of operation.

3.0 CONCLUSION

Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by the Unit 1 Technical Specifications. In addition, the NRC staff concludes there are no technical issues that warrant follow-up action at this time. The inspections appear to be consistent with the objective of detecting potential tube degradation, and inspection results appear to be consistent with industry operating experience at similarly designed and operated units.

Principal Contributors: Andrew B. Johnson Alan Huynh Date: March 9, 2015

March 9, 2015 Mr. Mano Nazar President and Chief Nuclear Officer Nuclear Division NextEra Energy P.O. Box 14000 Juno Beach, FL 33408-0420

SUBJECT:

ST. LUCIE PLANT, UNIT NO. 1 - REVIEW OF THE 2013 STEAM GENERATOR TUBE INSERVICE INSPECTION REPORT DURING REFUELING OUTAGE 1-25 (TAC NO. MF4404)

Dear Mr. Nazar:

By letter dated April 29, 2014, Florida Power & Light Company (the licensee) submitted information summarizing the results of the fall 2013 steam generator tube inspections at the St. Lucie Plant, Unit No. 1. These inspections were performed during Refueling Outage 1-25.

The U.S. Nuclear Regulatory Commission (NRC) staff discussed the inspection results with licensee personnel in a public meeting (conference call) on August 21, 2014, and documented the meeting by a summary dated September 18, 2014. By letter dated October 20, 2014, the licensee provided additional information.

The NRC staff has completed its review of the licensee's submittals and concludes that the licensee has provided the information required by the St. Lucie Plant, Unit No. 1, Technical Specifications, and that no additional follow-up is required at this time. The NRC staff's review of the report is set forth in the enclosed Safety Evaluation.

If you have any questions, please contact me at 301-415-1447 or Farideh.Saba@nrc.gov.

Sincerely, IRA/

Farideh E. Saba, Senior Project Manager Plant Licensing Branch 11-2 Division of Operator Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-335

Enclosure:

Safety Evaluation cc w/

Enclosure:

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