ML16333A007

Response to Request for Additional Information Regarding Proposed Inservice Inspection Alternatives N1-I4-NDE-008 and N2-I4-NDE-003

ML16333A007
Person / Time
Site:	North Anna
Issue date:	11/22/2016
From:	Mark D. Sartain Virginia Electric & Power Co (VEPCO)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
N1-I4-NDE-008, N2-I4-NDE-003
Download: ML16333A007 (4)

Text

VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 November 22, 2016

,,/

U. S. Nuclear Regulatory Commission Serial No. 16-266A Attention: Document Control Desk NRA/DEA RO Washington, DC 20555-0001 Docket Nos.: 50-338/339 License Nos.: NPF-4/7 VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 & 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION PROPOSED INSERVICE INSPECTION ALTERNATIVE N1-14-NDE-008 PROPOSED INSERVICE INSPECTION ALTERNATIVE N2-14-NDE-003 In a July 27, 2016 letter (Serial No.16-266), Virginia Electric and Power Company (Dominion) submitted a request for Nuclear Regulatory Commission (NRC) approval of inservice inspection (ISi) alternative N1-14-NDE-008 and N2-14-NDE-003. Specifically, Dominion requested to extend the interval for reactor vessel Examination Category B-A and B-D pressure retaining welds from 10 years to 20 years in accordance with WCAP-16168-NP, Risk-Informed Extension of Reactor Vessel In-Service Inspection Interval.

lq an email dated November 2, 2016, the Nuclear Regulatory Commission (NRC) transmitted a request for additional information (RAI) related to inservice inspection (ISi) alternative N1-14-NDE-008 and N2-14-NDE-003. The response to the RAI is provided in Attachment 1.

Should you have any questions in regard to this submittal, please contact Ms. Diane E.

Aitken at (804) 273-2694.

Sincerely,

~cv.t-Mark D. Sartain Vice President - Nuclear Engineering Commitments made in this letter: None

Serial No. 16-266A Docket Nos.: 50-338/339 Response to RAI - Proposed ISi Alternative N1-14-NDE-008 & N2-14-NDE-003 Page 2 of 2

Attachment:

1. Response to Request for Additional Information for Proposed lnservice Alternative N1-14-NDE-008 and Proposed lnservice Alternative N2-14-NDE-003 Commitments made in this letter: None.

cc: U.S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, GA 30303-1257 Ms. K. R. Cotton-Gross NRC Project Manager U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 08 G-9A Rockville, MD 20852-2738 Dr. V. Sreenivas NRC Project Manager U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 08 G-9A Rockville, MD 20852-2738 Mr. J. E. Reasor, Jr.

Old Dominion Electric Cooperative Innsbrook Corporate Center 4201 Dominion Blvd.

Suite 300 Glen Allen, VA 23060 NRC Senior Resident Inspector North Anna Power Station

Serial No. 16-266A Docket Nos.: 50-338/339 ATTACHMENT 1 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION PROPOSED INSERVICE INSPECTION ALTERNATIVE N1-14-NDE-008 PROPOSED INSERVICE INSPECTION ALTERNATIVE N2-14-NDE-003 Virginia Electric and Power Company {Dominion)

North Anna Power Station Units 1 and 2

Serial No. 16-266A Docket Nos.: 50-338/339 Attachment 1 Page 1 of 1

., Response to Request for Additional Information CRAil Proposed lnservice Alternative N1-14-NDE-008 Proposed lnservice Alternative N2-14-NDE-003 Table 1 of both attachments state that North Anna Units 1 and 2 are bounded by 7 heatuplcooldown cycles per year. Please cite the plant design basis for heatuplcooldown cycles per year.

RAI RESPONSE:

Attachments 1 and 2 of the original lnservice Inspection Program proposed inspection alternative, dated July 27, 2016, each contained a Table 1 that listed the critical parameters investigated in WCAP-16168-NP-A and compared the results of the Westinghouse pilot plant to those of North Anna Power Station (NAPS) Units 1 and 2, respectively. The WCAP parameter, "Frequency and Severity of Design Basis Transients," in Table 1 of Attachments 1 and 2 was shown as, "Bounded by 7 heatup/cooldown cycles per year," for NAPS Units 1 and 2, respectively.

Seven heatup/cooldown cycles per year was the bounding criteria used in WCAP-16168-NP-A, and corresponds to the bounding criteria all Westinghouse plants must meet. Dominion does not have a plant specific design basis for heatup/cooldown cycles per year.

WCAP-16168-NP-A specifies a limit of 200 transient (heatup/cooldown) cycles as the design basis for the Westinghouse pilot plant. The NAPS design basis for plant I

heatup/cooldown cycles is identical to the Westinghouse pilot plant from WCAP-16168-NP-A; a limit of 200 heatup/cooldown cycles. As indicated in the WCAP, "it is unlikely that most plants will reach 200 design transients by end of life (80 years) based on operational histories".

Operational data as of November 3, 2016, indicates NAPS Unit 1 has had 58 heatups and 57 cooldowns of the reactor coolant system, and NAPS Unit 2 has had 54 heatups and 53 cooldowns of the reactor coolant system.