ML102090662

Request for Additional Information Regarding Relief Request Vegp-ISI-Alt-03, Version 2.0

ML102090662
Person / Time
Site:	Vogtle
Issue date:	07/30/2010
From:	Martin R Plant Licensing Branch II
To:	Ajluni M Southern Nuclear Operating Co
Martin R, NRR/DORL, 415-1493
References
TAC ME3752, TAC ME3753
Download: ML102090662 (3)

Text

UNITED NUCLEAR REGULATORY WASHINGTON, D.C. 20555-0001 July 30,2010 Mr. M. J. Ajluni Nuclear Licensing Director Southern Nuclear Operating Company, Inc. P.O. Box 1295 Bin -038 Birmingham, Alabama 35201-1295

SUBJECT:

VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2, REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST VEGP-ISI-ALT-03, VERSION 2 (TAC NOS. ME3753 AND ME3752)

Dear Mr. Ajluni:

By letter to the U.S. Nuclear Regulatory Commission (NRC) dated April 7, 2010, Southern Nuclear Operating Company, Inc. (SNC), submitted a proposed alternative, VEGP-ISI-AL 1-03, Version 2, for the Vogtle Electric Generating Plants, Units 1 and 2, from certain examination qualification requirements of the American Society of Mechanical Engineers, Boiler and Pressure Vessel Code (ASME Code),Section XI. SNC proposes the use of alternate root mean square error (RMSE) values of 0.189 inch for Supplement 10 and 0.245 inch for Supplements 10 and 2 combined.

We have reviewed the April 7, 2010, submittal and have determined that additional information is necessary as follows. VEGP-ISI-ALT-03, Version 2 states that "In the event that an indication is detected that requires depth sizing, a process will be used where the difference between the required RMSE and vendor-demonstrated RMSE will be added to the measured through-wall depth for comparison with the Section IWB-3500 acceptance criteria." More specifically, the acceptance criteria specified for Class 1, Category R-A, Item R1.15, Reactor Pressure Vessel (RPV) nozzle-to-safe-end dissimilar metal (DM) butt welds and the adjacent Category R-A, Item B1.20, austenitic safe-end welds is IWB-3514.

However, the 2007 Edition of the ASME Code with 2009 Addenda, no longer permits the use of IWB-3514 for pressurized-water reactors with nickel alloy welds that are susceptible to primary water stress corrosion cracking (PWSCC) for planar, surface-connected flaws that are in contact with the reactor coolant environment during normal operation.

Additionally, MPR-139, Section 7, Evaluation Methodologies, specifies that "any flaw attributed to PWSCC, regardless of depth, will be evaluated even if it meets the IWB-3500 requirements." As such, please justify the use of IWB-3514 acceptance criteria when the flaw is determined to be surface-connected.

M. Ajluni -2 Please provide a response within thirty (30) days of the date of this letter. Sincerely, Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424 and 50-425 cc: Distribution via Listserv M. Ajluni -Please provide a response within thirty (30) days of the date of this letter. Sincerely, IRA! Robert E. Martin, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424 and 50-425 cc: Distribution via Listserv DISTRIBUTION:

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