ML17004A017

Review of Steam Generator Tube Inspection Report for the 19th Refueling Outage in October 2015

ML17004A017
Person / Time
Site:	Diablo Canyon
Issue date:	01/10/2017
From:	Balwant Singal Plant Licensing Branch IV
To:	Halpin E Pacific Gas & Electric Co
Singal B
References
CAC MF7649
Download: ML17004A017 (3)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 January 10, 2017 Mr. Edward D. Halpin Senior Vice President, Generation and Chief Nuclear Officer Pacific Gas and Electric Company Diablo Canyon Power Plant P.O. Box 56, Mail Code 104/6 Avila Beach, CA 93424

SUBJECT:

DIABLO CANYON POWER PLANT, UNIT 1 - REVIEW OF THE STEAM GENERATOR TUBE INSPECTION REPORT FOR THE 19rH REFUELING OUTAGE IN OCTOBER 2015 (CAC NO. MF7649)

Dear Mr. Halpin:

By letter dated May 2, 2016 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML16123A333), Pacific Gas and Electric Company (the licensee) submitted information summarizing the results of the steam generator tube inspections for the 19th refueling outage in October 2015 at Diablo Canyon Power Plant, Unit 1.

The U.S. Nuclear Regulatory Commission staff has completed its review of this report and concludes that the licensee provided the information required by its technical specifications.

The NRC staff's review of the reports is enclosed.

If you have any questions, please contact me at 301-415-3016 or via e-mail at Balwant. Singal@nrc.gov.

Sincerely,

~~4-t2,~~

~ant K. Singal, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-275

Enclosure:

Review of the Steam Generator Tube Inspection Report cc w/encl: Distribution via Listserv

REVIEW OF THE STEAM GENERATOR TUBE INSPECTION REPORT FOR THE 19rH REFUELING OUTAGE IN OCTOBER 2015 PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON POWER PLANT. UNIT 1 DOCKET NO. 50-275 By letter dated May 2, 2016 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML16123A333), Pacific Gas and Electric Company (the licensee) submitted information summarizing the results of the steam generator (SG) tube inspections for the 19th refueling outage in October 2015 at Diablo Canyon Power Plant (DCPP), Unit 1. The licensee provided additional information regarding these SG inspections on August 25, 2016 (ADAMS Accession No. ML16242A012).

DCPP, Unit 1, has four recirculating Westinghouse Model Delta 54 replacement SGs. Each SG has 4,444 tubes with a nominal outside diameter of 0. 75 inches and a nominal tube wall thickness of 0.043 inches. The tubes are hydraulically expanded for the full depth of the tubesheet, with the end of each tube expanded using a urethane plug expansion process.

Tubes in rows 1 through 16 were full-length stress relieved following bending. Row 1 has the smallest U-bend radius of 3.25 inches. The eight tube support plates (TSPs) are stainless steel (Type 405) and are 1.125 inches thick. All TSPs have broached trefoil-shaped holes.

The licensee provided the scope, extent, methods, and results of the SG tube inspections in the document referenced above. In addition, the licensee described the tube plugging taken in response to the inspection findings.

Based on a review of the information provided, the U.S. Nuclear Regulatory Commission staff concludes that the licensee provided the information required by the Technical Specifications.

In addition, the staff concludes that there are no technical issues that warrant follow-up action at this time since the inspections 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.

Enclosure

..* ML17004A017 *memo dated December 30, 2016 OFFICE NRR/DORL/LPL4/PM NRR/LPL4/DORL/LA NRR/DE/ESGB/BC(A) NRR/DORL/LPL4/BC NRR/DORL/LPL4/PM NAME BSingal PBlechman EWong* RPascarelli BSingal DATE 01/10/2017 01/10/2017 12/30/16 01/10/2017 01/10/2017