ML16308A401

Followup Request for Additional Information (CAC Nos. MF8061 and MF8062)

ML16308A401
Person / Time
Site:	Vogtle
Issue date:	11/16/2016
From:	Martin R Plant Licensing Branch II
To:	Pierce C Southern Nuclear Operating Co
Martin R, NRR/DORL/LPL2-1
References
CAC MF8061, CAC MF8062
Download: ML16308A401 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 16, 2016 Mr. Charles R. Pierce Regulatory Affairs Director Southern Nuclear Operating Co., Inc.

P.O. Box 1295, Bin 038 Birmingham, AL 35201-1295

SUBJECT:

VOGTLE ELECTRIC GENERATING PLANT, UNITS 1AND2, AND JOSEPH M.

FARLEY NUCLEAR PLANT, UNIT 1 - FOLLOWUP REQUEST FOR ADDITIONAL INFORMATION (CAC NOS. MF8061 AND MF8062)

Dear Mr. Pierce:

By application dated August 4, 2016 (Agencywide Documents Access and Management System (ADAMS) Package Accession No. ML16221A072), Southern Nuclear Operating Company, Inc. (SNC, the licensee) submitted Request for Alternative VEGP-ISl-ALT-11, Version 2.0, for the Vogtle Electric Generating Plant, Units 1 and 2, and Alternative FNP-ISl-ALT-19, Version 2.0, for the Joseph M. Farley Nuclear Plant, Unit 1. Alternatives VEGP-ISl-ALT-11, Version 2.0, and FNP-ISl-ALT-19, Version 2.0, propose to eliminate the reactor pressure vessel (RPV) threads-in-flange examination requirement as an alternative to certain requirements of Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code for inservice inspection of RPV components.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the licensee's previous responses, dated October 24, 2016 (ADAMS Accession No. ML16298A049), to the NRC staff's Request for Additional Information (RAI) (ADAMS Accession No. ML16298A049), and has determined that the enclosed followup RAI is needed to complete its review. Please provide responses to these questions within 30 days of the date of this letter.

Sincerely,

(_.,/; ll/ 1VJJ::{-'

b Mahin, Senior Project Manager nt Licensing Branch, 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424, 50-425, and 50-348

Enclosure:

Followup Request for Additional Information

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 FOLLOWUP REQUEST FOR ADDITIONAL INFORMATION ALTERNATIVE REQUESTS VEGP-ISl-ALT-11, VERSION 2.0 AND FNP-ISl-ALT-19, VERSION 2.0 REACTOR PRESSURE VESSEL FLANGE BOLT HOLE THREAD EXAMINATION SOUTHERN NUCLEAR OPERATING COMPANY, INC.

VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 JOSEPH M. FARLEY NUCLEAR PLANT, UNIT 1 SOUTHERN NUCLEAR OPERATING COMPANY DOCKET NOS. 50-424, 50-425, 50-348 By application dated August 4, 2016 (Agencywide Documents Access and Management System (ADAMS) Package Accession No. ML16221A072), Southern Nuclear Operating Company, Inc. (SNC, the licensee) submitted Request for Alternative VEGP-ISl-ALT-11, Version 2.0, for the Vogtle Electric Generating Plant, Units 1 and 2, and Alternative FNP-ISl-ALT-19, Version 2.0, for the Joseph M. Farley Nuclear Plant, Unit 1. Alternatives VEGP-ISl-ALT-11, Version 2.0, and FNP-ISl-ALT-19, Version 2.0, propose to eliminate the reactor pressure vessel (RPV) threads-in-flange examination requirement as an alternative to certain requirements of Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code for inservice inspection of RPV components.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the licensee's previous responses, dated October 24, 2016 (ADAMS Accession No. ML16298A049), to the NRC staff's Request for Additional Information (RAI) (ADAMS Accession No. ML16298A049), and has determined that the following questions are needed to complete its review.

Followup RAl-1 (Related to NRC RAl-5, Question 2a)

The licensee's response to the previous RAl-5, Question 2a, indicated that, "Thermal loads are applied as uniform surface convection on the inside surface only." This response did not clarify how the heatup transient was applied. Please provide: (a) the thermal boundary conditions for the top, bottom, and RPV flange outer surfaces to confirm that this part of modeling is appropriate, and (b) a revision of the response to this RAI regarding how the heatup transient was applied to the thermal model since the application of thermal loads was not answered clearly.

Enclosure

Followup RAl-2 (Related to Previous RAl-5, Question 3)

Regarding selection of the heatup transient instead of the cooldown transient in the finite element method (FEM) analysis, the licensee's response to previous RAl-5, Question 3, states that, "Since heatup and cooldown have the same temperature change rate, in linear elastic analysis they will produce identical maximum and minimum stress range for crack growth calculation, despite an opposite time history." The above description of stresses does not appear to be consistent with the similar pressure-temperature (PT) limits application (ignoring the crack growth part because it does not apply to the PT limit application), wherein the cooldown transient will create tensile stresses in the RPV inner wall and compressive stresses in the outer wall, and vice versa for the heatup transient. Please provide additional discussion on your response to previous RAl-5, Question 3, to justify that heatup and cooldown transients will produce identical maximum and minimum stress ranges.

Followup RAl-3 (Related to Previous RAl-5, Question 4a)

The licensee's response to previous RAl-5, Question 4a, indicated that, " ... the FEM model for the applied K determination is the same as the FEM model for the stress determination."

Please clarify how loads are applied to both the FEM model for the stress determination and the FEM model for the applied K determination.

Followup RAl-4 (Related to Previous RAl-5, Question 6)

The licensee's response to previous RAl-5, Question 6, indicated that, " ... the maximum calculated Kat any crack depth is about 20ksi"in. This requires a Kie of 20*"10 = 3.2ksi"in."

The Kie of 3.2 ksi"in may be a misprint of 63.2 ksi"in. Please provide the operating temperature at the time when K is 20 ksi"in to justify that "an RT NDT of up to 70°F will not affect the results."

ML16298A049), to the NRC staff's Request for Additional Information (RAI) (ADAMS Accession No. ML16298A049), and has determined that the enclosed followup RAI is needed to complete its review. Please provide responses to these questions within 30 days of the date of this letter.

Sincerely, IRA/

Bob Martin, Senior Project Manager Plant Licensing Branch, 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424, 50-425, and 50-348

Enclosure:

Followup Request for Additional Information DISTRIBUTION:

PUBLIC LPL2-1 R/F RidsNrrDorllpl2-1 Resource RidsNrrPMVogtle Resource RidsNrrDeEvib Resource RidsRgn2MailCenter Resource SSheng, NRR RidsNrrLALRonewicz Resource RidsACRS_MailCTR Resource SWilliams, NRR RidsNrrPMFarley Resource ADAMS A ccess1on No.: ML16308A401 *b1y e-ma1*1 OFFICE DORL/LPL2-1 /PM DORL/LPL2-1 /LA DE/EVIB/BC* DORL/LPL2-1 /BC DORL/LPL2-1 /PM NAME BMartin LRonewicz DRudland MMarkley BMartin DATE 11/16/2016 11/4/2016 11/02/2016 11/16/2016 11/16/2016