ML080370026

Request for Additional Information Requests for Alternative ANO1-R&R-011 for Unit 1 and ANO2-R&R-005 for Unit 2, Structural Weld Overlay Repairs to Improve Dissimilar Metal Weld Integrity

ML080370026
Person / Time
Site:	Arkansas Nuclear
Issue date:	02/13/2008
From:	Wang A NRC/NRR/ADRO/DORL/LPLIV
To:	Mitchell T Entergy Operations
Wang, A B, NRR/DORL/LPLIV, 415-1445
References
TAC MD4974, TAC MD6958
Download: ML080370026 (5)

Text

February 13, 2008 Mr. Timothy G. Mitchell Vice President, Operations Arkansas Nuclear One Entergy Operations, Inc.

1448 S. R. 333 Russellville, AR 72802

SUBJECT:

ARKANSAS NUCLEAR ONE - REQUEST FOR ADDITIONAL INFORMATION REGARDING REQUESTS FOR ALTERNATIVE ANO2-R&R-005 (UNIT 2) AND ANO1-R&R-011 (UNIT 1), WELD OVERLAY OF DISSIMILAR METAL WELDS (TAC NOS. MD4907 AND MD6958)

Dear Mr. Mitchell:

By letters dated March 21, and October 8, 2007, Entergy Operations, Inc. (the licensee) submitted requests for alternative ANO2-R&R-005 (Unit 2) and ANO1-R&R-011 (Unit 1),

respectively, to the requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, for mitigating primary water stress-corrosion cracking on dissimilar metal welds using full structural weld overlays at Arkansas Nuclear One.

The U.S. Nuclear Regulatory Commission staff has reviewed the requests, and determined that we require additional information to complete our review. A request for additional information is enclosed. This request was discussed with David Bice of your staff on January 30, 2008, and it was agreed that a response would be provided within 30 days of receipt of the request.

If you or your staff have any questions concerning the resolution of this matter, please contact me at (301) 415-1445.

Sincerely,

/RA/

Alan B. Wang, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-313 and 50-368

Enclosure:

Request for Additional Information cc w/encl: See next page

ML080370026 OFFICE DORL/LPL4/PM DORL/LPL4/PM DORL/LPL4/PM NAME AWang JBurkhardt THiltz DATE 2/8/08 2/8/08 2/13/08 Arkansas Nuclear One (November 2007) cc:

Senior Vice President Senior Manager, Nuclear Safety Entergy Nuclear Operations & Licensing P.O. Box 31995 Entergy Operations, Inc.

Jackson, MS 39286-1995 1340 Echelon Parkway Jackson, MS 39213-8298 Senior Vice President

& Chief Operating Officer Manager, Licensing Entergy Operations, Inc. Entergy Operations, Inc.

P.O. Box 31995 Arkansas Nuclear One Jackson, MS 39286-1995 1448 SR 333 Russellville, AR 72802 Vice President, Operations Support Entergy Operations, Inc. Section Chief, Division of Health P.O. Box 31995 Radiation Control Section Jackson, MS 39286-1995 Arkansas Department of Health and Human Services Site Vice President 4815 West Markham Street, Slot 30 Entergy Operations, Inc. Little Rock, AR 72205-3867 Arkansas Nuclear One 1448 S.R. 333 Section Chief, Division of Health Russellville, AR 72802 Emergency Management Section Arkansas Department of Health and General Manager Plant Human Services Operations 4815 West Markham Street, Slot 30 Entergy Operations, Inc. Little Rock, AR 72205-3867 Arkansas Nuclear One 1448 SR 333 Pope County Judge Russellville, AR 72802 Pope County Courthouse 100 W. Main Street Director, Nuclear Safety & Licensing Russellville, AR 72801 Entergy Services, Inc.

440 Hamilton Avenue Senior Resident Inspector White Plains, NY 10601 U.S. Nuclear Regulatory Commission P.O. Box 310 Director, Nuclear Safety Assurance London, AR 72847 Entergy Operations, Inc.

Arkansas Nuclear One Regional Administrator, Region IV 1448 SR 333 U.S. Nuclear Regulatory Commission Russellville, AR 72802 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064

REQUEST FOR ADDITIONAL INFORMATION REQUEST FOR ALTERNATIVE ANO1-R&R-011 AND ANO2-R&R-005 WELD OVERLAY OF DISSIMILAR METAL WELDS ARKANSAS NUCLEAR ONE, UNITS 1 AND 2 ENTERGY OPERATIONS, INC.

By letters dated March 21, and October 8, 2007 (Agencywide Documents Access and Management System Accession Nos. ML070860369 and ML072910042, respectively), Entergy Operations, Inc. (the licensee) submitted requests for alternative ANO2-R&R-005 (Unit 2) and ANO1-R&R-011 (Unit 1), respectively, to the requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), for mitigating primary water stress-corrosion cracking on dissimilar metal welds using full structural weld overlays at Arkansas Nuclear One (ANO). To complete its review, the NRC staff is requesting the following additional information:

Unit 1, ANO1-R&R-011

1. What are the beginning and end dates for the fourth 10-year inservice inspection (ISI) interval at Unit 1?

2. On page 4 of 14 of the October 8, 2007, submittal, the licensee stated that it will apply a butter (transitional) layer of austenitic stainless steel filler metal across the austenitic stainless steel base metal.

a. Discuss whether paragraph (e) of Code Case N-504-2 is applicable to the butter layer if austenitic stainless steel filler metal is applied.

Paragraph (e) requires existence of certain delta ferrite content in the welded metal when austenitic stainless steel weld metal is used.

b. Identify the austenitic stainless steel weld filler metal that will be used for the butter layer.

c. Confirm that the Certified Material Test Report (CMTR) for the austenitic stainless steel filler wire shows a minimum delta ferrite of a specified amount. Provide the maximum and minimum delta ferrite content for the heat of austenitic stainless steel filler wire to be used, as stated on the CMTR.

Unit 2, ANO2-R&R-011

1. In the March 21, 2007, letter, the licensee requested U.S. Nuclear Regulatory Commission (NRC) approval of Request for Alternative ANO2-R&R-005 to support the 19th refueling outage at Unit 2 currently scheduled for the spring 2008. However, the duration of the proposed alternative is not specified in the

March 21, 2007, submittal other than for the spring 2008 refueling outage.

Please confirm/clarify the duration of the proposed alternative.

2. In Section V.A.3.c of Request for Alternative ANO2-R&R-005, the licensee discussed the inspection issues regarding cast austenitic stainless steel (CASS) safe ends of the surge and hot-leg shutdown cooling nozzles. The licensee stated correctly that the ultrasonic examination (UT) has not been qualified in accordance with Appendix VIII, Supplement 11 of the ASME Code,Section XI, in the examination of cast austenitic stainless steel. The licensee stated further that a flaw with a depth of 75 percent of pipe thickness and circumference of 360 degrees will be assumed in the crack-growth calculation for the cast stainless steel safe ends. In light of the limiting capability of the current UT technology in the CASS examination, the postulated 75 percent depth flaw may not be adequate to assess the structural integrity of the CASS component.

Pending the qualified UT for the CASS material, the licensee might consider other options such as:

a. Option (1). Size the initial flaw depth at 100 percent through-wall for the crack-growth calculations.

b. Option (2). If the 100 percent through-wall flaw is impractical or creates a hardship in the overlay design or installation, an initial flaw with a 75 percent through-wall depth may be assumed in the crack-growth calculation. However, with this option the required inspection volume needs to be examined at a higher frequency than the requirements in proposed alternative ANO2-R&R-005.

The licensee is requested to provide an approach to resolve the CASS issue in Alternative ANO2-R&R-005.

3. On page 5, first paragraph, of the March 21, 2007, submittal, the licensee stated that it may apply a butter (transitional) layer of austenitic stainless steel filler metal across the austenitic stainless steel base metal.

a. Discuss whether paragraph (e) of Code Case N-504-2 is applicable to the butter layer if austenitic stainless steel filler metal is applied.

Paragraph (e) requires existence of certain delta ferrite content in the welded metal when austenitic stainless steel weld metal is used.

b. Identify the austenitic stainless steel weld filler metal that will be used for the butter layer.

c. Confirm that the CMTR for the austenitic stainless steel filler wire shows a minimum delta ferrite of a specified amount. Provide the maximum and minimum delta ferrite content for the heat of austenitic stainless steel filler wire to be used, as stated on the CMTR.