ML090430253

Summary of Nrc'S Review of the 2007 Steam Generator Tube Inspections

ML090430253
Person / Time
Site:	Turkey Point
Issue date:	03/05/2009
From:	Siva Lingam Plant Licensing Branch II
To:	Nazar M Florida Power & Light Co
Paige, Jason, NRR,301-415-5888
References
TAC MD9234
Download: ML090430253 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 March 5, 2009 Mr. Mano Nazar Senior Vice President Nuclear and Chief Nuclear Officer Florida Power and Light Company P.O. Box 14000 Juno Beach, FL 33408-0420 SUB.JECT: TURKEY POINT NUCLEAR GENERATING UNIT 3 - REVIEW OF THE 2007 STEAM GENERATOR TUBE INSPECTION REPORT (TAC NO. MD9234)

Dear Mr. Nazar:

By letters dated April 3, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession No. IVIL081 050248), and January 30, 2009 (ADAMS Accession No. ML090570046), Florida Power & Light Company (the licensee) submitted information to the U.S. Nuclear Regulatory Commission (NRC) pertaining to the 2007 steam generator tube inspections performed at Turkey Point Unit 3.

Based on a review of the material provided by the licensee, the NRC staff concludes that the licensee provided the information required by their technical specifications. In addition, the staff did not identify any issues that warrant additional follow-up at this time. The staff's review of the licensee's report is enclosed.

Sincerely,

~~'~

Siva P. Lingam, Project Manager Plant Licensing Branch 11-2 Division of Operator Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-250

Enclosure:

NRC Review cc w/enclosures: Distribution via Listserv

REVIEW OF 2007 STEAM GENERATOR TUBE INSPECTION REPORT TURKEY POINT U!'JIT 3 DOCKET NO. 50-250 By letters dated April 3, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML081050248), and January 30, 2009 (ADAMS Accession No. ML090570046), Florida Power & Light Company (the licensee) submitted information pertaining to the 2007 steam generator tube inspections performed at Turkey Point Unit 3 in accordance with the plant's Technical Specifications.

Turkey Point Unit 3 has three Westinghouse Model 44F steam generators (SGs). The SGs have tubes that were hydraulically expanded into the tubesheet. The tubes are supported by Type 405 stainless steel tube support plates with broached quatrefoil holes. The Unit 3 SGs began operation in 1982, and have thermally treated Alloy 600 tubing.

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 (i.e.,

tube plugging or repair) taken in response to the inspection findings.

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

• The SGs have operated for 233.3 effective full power months (EFPM). At the time of the 2007 SG inspection, the SGs had operated for 6.9 EFPM in the 60 EFPIVI sequential period.

• There are 8 tubes that are not expanded for the full length of the tube sheet on the hot-leg. There is 1 in SG 3A, 2 in SG 3B and 5 in SG 3C. Also, 1 tube in SG 3B is not expanded for the full length of the tubesheet on the cold-leg.

• The licensee indicated that the volumetric indication in R20 C67 in SG 3C is considered to be manufacturing related since the indication is located on the outer diameter surface of the tube between the tube and the tubesheet bore hole, 6-inches below the top of the tubesheet, and this area is not exposed to the secondary side impurities that can cause corrosion degradation. This indication was the only one of its kind detected of all tubes and was not previously detected since this area had not been previously inspected with a +Point probe. This tube with the volumetric indication was the only tube plugged in the 2007 outage.

• In 2001, 18 high row (i.e., non stress relieved) tubes were identified that had an eddy current offset in the u-bend that was less than 2 volts. These tubes are potentially more susceptible to stress corrosion cracking. In 2004, a new screening criteria (i.e., a voltage offset less than the mean minus two times the standard deviation) was applied to the eddy current data, and a total of 59 tubes were identified as having an eddy current offset (i.e., non-optimal tube processing). No cracking was found in any of these tubes.

Enclosure

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• The licensee provided several figures that contained the structural limits for various degradation mechanisms. The staff did not review these structural limits in detail; however, these limits appeared reasonable.

• Secondary side inspections o In the upper bundle regions in SG 3A, a thin layer of deposits was observed and all the tube support flow holes were observed to be fully open. No abnormal conditions or degradation was observed.

o In SG 3B, the steam drum area was inspected. This included visual inspections of the steam separation equipment, feedring, j-tubes and j-tube bore holes.

Ultrasonic inspections of the feedring and feedring distribution box were also performed with no abnormal conditions nor degradation reported.

o Eddy current testing of R7 C45 in SG 3B at the second cold leg support reported a small wear mark with a possible small object present. This location could not be visually inspected due to its location within the tube bundle. This indication was determined to be present as early as 1990, measured 12 percent through-wall in 2007 and has changed little in 17 years. All adjacent tubes were tested with the -Point probe and no additional wear was present. Based on the shallow measured depth, long service history without significant change and no evidence of wear on adjacent tubes, the licensee left this tube in service and will track it during future examinations.

Based on a review of the information provided, the staff concludes that the licensee provided the information required by their technical specifications. In addition, the staff concludes that there are no technical issues that warrant follow-up action at this time 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.

ML090570046), Florida Power & Light Company (the licensee) submitted information to the U.S. Nuclear Regulatory Commission (NRC) pertaining to the 2007 steam generator tube inspections performed at Turkey Point Unit 3.

Based on a review of the material provided by the licensee, the NRC staff concludes that the licensee provided the information required by their technical specifications. In addition, the staff did not identify any issues that warrant additional follow-up at this time. The staff's review of the licensee's report is enclosed.

Sincerely,

/raJ Siva P. Lingam, Project Manager Plant Licensing Branch 11-2 Division of Operator Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-250

Enclosure:

NRC Review cc w/enclosures: Distribution via Listserv DISTRIBUTION:

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