L-2007-172, In-Service Inspection Plans Response to Request for Additional Information Re Third Ten-Year Interval Unit 2 Relief Request 10

In-Service Inspection Plans Response to Request for Additional Information Re Third Ten-Year Interval Unit 2 Relief Request 10

ML073020660
Person / Time
Site:	Saint Lucie
Issue date:	10/24/2007
From:	Johnston G Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-2007-172
Download: ML073020660 (2)

Text

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Florida Power & Light Company, 6501 S. Ocean Drive, Jensen Beach, FL 34957 October 24, 2007 FPL L-2007-172 10 CFR 50.4 10 CFR 50.55a U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Re: St. Lucie Unit 2 Docket No. 50-3 89 In-Service Inspection Plans Reponse to Request for Additional Information Third Ten-Year Interval Unit 2 Relief Request 10 Pursuant to the provisions of 10 CFR 50.55a(a)(3)(i), via letter L-2007-045 dated March 29, 2007, as supplemented by L-2007-148 dated September 24, 2007, Florida Power &

Light (FPL) requested approval to use structural weld overlays (SWOLs) as an alternative repair method. Relief was requested on the basis that the relief request provides an acceptable level of quality.and safety.

On October 12, 2007, FPL and NRC held a teleconference on the submittals, and this letter contains the FPL response to the NRC request for additional information.

FPL requests approval of the relief request prior to entering Mode 4 during the fall 2007 St. Lucie Unit 2 refueling outage, SL2-17, tentatively scheduled for Early December.

Please contact Ken Frehafer at (772) 467-7748 if there are any questions about this submittal.

Very truly yours, Site Vice President St. Lucie Plant Attachment GLJ/KWF r7 an FPL Group company

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St. Lucie Unit 2 L-2007-172 Third Inspection Interval Attachment Relief Request Number 10 Page 1 of I Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(i)

Alternative Provides Acceptable Level of Quality and Safety USE OF WELD OVERLAYS AS AN ALTERNATIVE REPAIR TECHNIQUE The purpose of this document is to provide weld overlay thickness and reduction in ultrasonic testing volume coverage information for the weld overlaid locations which involve cast stainless steel safe-ends at the St. Lucie Unit 2 Nuclear Power plant. This information is provided in response to the NRC request received during the conference call between the NRC and FPL on October 12, 2007.

FPL Response The following information is summarized in the table below:

• Minimum analyzed weld overlay thickness in inches for each weld overlay design at the nozzle side of the weld overlay.

• Barrier layer thickness in inches.

• Thickness of the associated pipe in inches

• Approximate percent (%) reduction in Ultrasonic (UT) coverage of the ISI volume due to the cast stainless steel safe-ends.

Weld Location Minimum Barrier Nominal Reduction in UT Analyzed Layer Pipe coverage due to Thickness Thickness Thickness cast safe-end Note (1)

Pressurizer Surge Line 0.54" 0.065" 1.312" <10%

Hot Leg Surge Line 0.68" 0.065" 1.312" <10%

Shutdown Cooling to A 0 0.065" 1.312" <10%

RCS I _ __ _ I _ __ _ I _ __ _ I _ _ __

Shutdown CoolingtoB 0.50" 0.065" 1.312" <10%

RCS I I I I Note 1: Barrier layer is not credited in the analysis of the Structural Weld Overlay (SWOL).