ML14147A034

Review of the 2013 Steam Generator Tube Inspections

ML14147A034
Person / Time
Site:	Point Beach
Issue date:	06/06/2014
From:	Beltz T Plant Licensing Branch III
To:	Mccartney E Point Beach
Beltz T
References
TAC MF2800
Download: ML14147A034 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 June 6, 2014 Mr. Eric McCartney Site Vice President NextEra Energy Point Beach, LLC Point Beach Nuclear Plant 661 0 Nuclear Road Two Rivers, WI 54241

SUBJECT:

POINT BEACH NUCLEAR PLANT, UNIT 1 - REVIEW OF THE SPRING 2013 REFUELING OUTAGE STEAM GENERATOR TUBE INSPECTION RESULTS (TAC NO. MF2800)

Dear Mr. McCartney:

By letter dated September 24, 2013, as supplemented by letter dated March 3, 2014, NextEra Energy Point Beach , LLC (NextEra) submitted information summarizing the results of its steam generator tube inspections performed at the Point Beach Nuclear Plant, Unit 1, during the spring 2013 refueling outage.

The U.S. Nuclear Regulatory Commission (NRC) staff has completed its review of the submittals and concludes that NextEra provided the information required by its technical specifications. No additional follow-up is required at this time. The results of the NRC staff's review and observations are enclosed.

Please direct any inquiries to me at 301-415-3049 , or Terry .Beltz@nrc.gov.

Terry A. Beltz, Senior Project Manager Plant Licensing Branch 111-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-266

Enclosure:

Review of Spring 2013 Steam Generator Tube Inspection Results cc w/encl: Distribution via Listserv

SUMMARY

OF THE U.S. NUCLEAR REGULATORY COMMISSION STAFF'S REVIEW OF THE STEAM GENERATOR TUBE INSPECTIONS PERFORMED DURING THE SPRING 2013 REFUELING OUTAGE POINT BEACH NUCLEAR PLANT, UNIT 1 DOCKET NO. 50-266 (TAC NO. MF2800)

By letter dated September 24, 2013 (Agencywide Documents Access Management System (ADAMS) Accession No. ML13268A108), as supplemented by letter dated March 3, 2014 (ADAMS Accession No. ML14062A047), NextEra Energy Point Beach, LLC (NextEra, the licensee), submitted information summarizing the results of its spring 2013 steam generator (SG) tube inspections performed during refueling outage 34 for Unit 1 (U1 R34) at the Point Beach Nuclear Plant (Point Beach).

Point Beach, Unit 1, has two Westinghouse 44F SGs each containing 3,214 thermally-treated Alloy 600 tubes. Both SGs were installed during refueling outage 11 in 1983. The tubes have a nominal outside diameter of 0.875 inches, and a nominal wall thickness of 0.050 inches. The tubes are supported by six stainless steel tube support plates and a baffle plate. The tube support plate holes are quatrefoil shaped. The U-bend region of the tubes in rows one through eight was stress relieved after bending.

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) taken in response to the inspection findings. The tubes in both SGs (A and B) were inspected during the outage.

After reviewing the information provided by the licensee, the U.S. Nuclear Regulatory Commission (NRC) staff has the following comments/observations:

• During U 1R33 in 2011, two circumferential crack indications were identified near the hot-leg tube ends in two tubes in SG B. These two tubes were plugged during U1 R33 .

During U1 R34 in 2013, no crack-like indications were detected near the hot-leg tube ends.

In SG B, 100 percent of the hot-leg tube ends (from the tube end to 3 inches above the top of the tubesheet) were inspected with a rotating probe equipped with a +Point' coil in U1R34.

In SG A, 50 percent of the hot-leg tube ends (from the tube end.to 3 inches above the top of the tubesheet) were inspected in U1 R33 , and the remaining 50 percent of the hot-Enclosure

leg tube ends were inspected in U1 R34. Although no tube end cracks have been observed in SG A , the NRC staff notes that a sampling approach may have limitations when only a few indications may be present.

• NextEra stated that the combined primary-to-secondary leak rate from both SGs is in the range of 0.0 to 0.2 gallons per day, the leak rate has remained constant, and the leakage has been evident since prior to the spring 1991 outage. The leak rate is too low to allow accurate differentiation between the SGs. One-hundred percent of the tubes in both SGs have been tested several times since leakage was detected, and no degradation that would lead to leakage has been identified. Although leakage was previously reported in the range of 0.2 to 0.4 gallons per day (in U1 R33), the licensee considers the current leak rate consistent with past reports .

• No indication of cladding degradation was identified in the SG A channel head; however, discoloration was observed around the hot-leg manway in SG B. This discoloration was initially observed in U1 R30, and showed no indication of further degradation during the U1 R34 inspections.

• Weld "burn-through" has been observed in J-nozzles 2, 3, and 28 in SG A, and J-nozzles 7, 11 , and 14 in SG B. The licensee indicated that the burn-through does not affect J-nozzle operation.

• In SG A, a 50-percent sample of the U-bends in rows 1 and 2 in U1 R34 did not include tubes inspected during U1 R33; however, for SG B, the 50-percent sample of the U-bends in rows 1 and 2 in U1 R34 were the same tubes inspected in RF033.

• Monitoring of the steam drum components, following a second cycle of operation under extended power uprate conditions , is scheduled for U1 R35.

Based on a review of the information provided, the NRC staff concludes that NextEra 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 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.

ML14147A034

• via memorandum dated 05/22/14 OFFICE NRR/LPL3-1/PM NRR/LPL3-1 /LA NRR/DE/ESGB/BC NRR/LPL3-1/BC NRR/LPL3-1/PM NAME TBeltz MHenderson GKulesa

• RCarlson TBeltz DATE 05/27/14 06/02/13 05/22/14 06/05/13 06/6/13