ML17051A001

Summary of the NRC Staff'S Review of the Spring 2015 Steam Generator Tube Inservice Inspections

ML17051A001
Person / Time
Site:	Millstone
Issue date:	02/27/2017
From:	Richard Guzman Plant Licensing Branch 1
To:	Stoddard D Dominion Nuclear
Guzman R
References
CAC MF8507
Download: ML17051A001 (3)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 27, 2017 Mr. Daniel G. Stoddard Senior Vice President and Chief Nuclear Officer Dominion Nuclear Connecticut, Inc.

Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711

SUBJECT:

MILLSTONE POWER STATION, UNIT NO. 2 -

SUMMARY

OF THE U.S. NUCLEAR REGULATORY COMMISSION'S STAFF'S REVIEW OF THE SPRING 2015 STEAM GENERATOR TUBE INSERVICE INSPECTIONS (CAC NO. MF8507)

Dear Mr. Stoddard:

By letters dated December 14, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15356A375) and January 31, 2017 (ADAMS Accession No. ML17038A005), Dominion Nuclear Connecticut, Inc. (the licensee) submitted information summarizing the results of the spring 2015 steam generator tube inspections performed at the Millstone Power Station, Unit No. 2 (MPS2). These inspections were performed during the MPS2 Refueling Outage 23.

The U.S. Nuclear Regulatory Commission (NRC) staff has completed its evaluation of the steam generator tube inspection summary report and concludes that the licensee provided the information required by the MPS2 Technical Specifications, and no additional followup is required at this time. The results of the NRC staff's review of the report submitted by the licensee are summarized in the enclosed NRC staff's evaluation.

If you have any questions regarding this matter, please contact me at 301-415-1030 or Richard.Guzman@nrc.gov.

Sincerely, Richard V. Guzman, Senior Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-336

Enclosure:

Steam Generator Tube Inspection Report Summary cc w/enclosure: Distribution via Listserv

REVIEW

SUMMARY

OF THE SPRING 2015 STEAM GENERATOR TUBE INSERVICE INSPECTIONS MILLSTONE POWER STATION, UNIT NO. 2 DOCKET NO. 50-336 By letter dated December 14, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15356A375), Dominion Nuclear Connecticut, Inc. (the licensee) submitted information summarizing the results of its 2015 steam generator (SG) tube inspections performed during Refueling Outage 23 at the Millstone Power Station, Unit No. 2 (MPS2). By letter dated January 31, 2017 (ADAMS Accession No. ML17038A005), the licensee provided additional information regarding the 2015 report.

MPS2 has two replacement SGs manufactured by Babcock and Wilcox that were installed in 1992. Each SG contains 8,523 thermally treated Alloy 690 tubes. Each tube has a nominal outside diameter of 0.75 inches and a nominal wall thickness of 0.0445 inches. The tubes were hydraulically expanded at both ends for the full depth of the tubesheet. The tubes are supported by type 410 stainless steel lattice grids.

The licensee provided the scope, extent, methods, and results of its SG tube inspections in the documents referenced above. In addition, the licensee described corrective actions (i.e., tube plugging) taken in response to the inspection findings. Only the tubes in SG 1 were inspected this outage.

Based on a review of the information provided by the licensee, the staff concludes that the licensee provided the information required by its technical specifications. The SG tube inspections at MPS2 appear to be consistent with the objective of detecting potential tube degradation, and the inspection results appear to be consistent with industry operating experience at similarly designed and operated units. Therefore, the NRC staff concludes that there are no technical issues that warrant followup action at this time Principal Contributor: A. Huynh Date: February 27, 2017 Enclosure

SUBJECT:

MILLSTONE POWER STATION, UNIT NO. 2 -

SUMMARY

OF THE U.S. NUCLEAR REGULATORY COMMISSION'S STAFF'S REVIEW OF THE SPRING 2015 STEAM GENERATOR TUBE INSERVICE INSPECTIONS (CAC NO. MF8507) DATED FEBRUARY 27, 2017 DISTRIBUTION:

Public LPL 1 R/F RidsACRS_MailCTR Resource RidsNrrDeEsgb Resource RidsNrrDorlLpl1 Resource RidsNrrPMMillstone Resource RidsNrrLALRonewicz RidsRgn1 MailCenter Resource AHuynh, NRR AJohnson, NRR PKlein, NRR ADAMS A ccess1on N um b er: ML17051A001 *b>Y e-ma1 **b>Y memoran d um OFFICE DORL/LPL 1/PM* DORL/LPL 1/LA DE/ESGB/BC(A)** DORL/LPL 1/BC(A) DORL/LPL 1/PM NAME RGuzman LRonewicz EWong SKoenick RGuzman (AJohnson for)

DATE 02/24/2017 02/24/2017 02/10/2017 02/24/2017 02/27/2017 OFFICIAL RECORD COPY