ML17258A020

Review of the Steam Generator Tube Inspection Report for the 2016 Refueling Outage No. 21

ML17258A020
Person / Time
Site:	Callaway
Issue date:	09/28/2017
From:	Klos L Plant Licensing Branch IV
To:	Diya F Union Electric Co
Klos L, 415-5136
References
CAC MF8474
Download: ML17258A020 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 28, 2017 Mr. Fadi Diya Senior Vice President and Chief Nuclear Officer Union Electric Company P.O. Box 620 Fulton, MO 65251

SUBJECT:

CALLAWAY PLANT, UNIT NO. 1 - REVIEW OF THE STEAM GENERATOR TUBE INSPECTION REPORT FOR THE 2016 REFUELING OUTAGE NO. 21 (CAC NO. MF8474)

Dear Mr. Diya:

By letters dated October 11, 2016 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML16286A547), February 28, 2017 (ADAMS Accession No. ML17060A349), and March 23, 2017 (ADAMS Accession No. ML17082A580), Union Electric Company, dba Ameren Missouri (the licensee), submitted information to the U.S.

Nuclear Regulatory Commission (NRC) summarizing the results of the 2016 steam generator tube inservice inspections performed at Callaway Plant, Unit No. 1 (Callaway) during the 21st refueling outage in accordance with Callaway Technical Specification (TS} 5.6.10, "Steam Generator Tube Inspection Report."

Based on its review, the NRC staff concludes that the licensee has provided the information required by TS 5.6.10. There are no technical issues and no followup actions are required at this time. A summary of the NRC staff's review is enclosed.

If you have any questions, please contact me at 301-415-5136 or via e-mail at John.Klos@nrc.gov.

SincereL ~ 4!~

L. John Kio

• roject Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-483

Enclosure:

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

SUMMARY

REVIEW OF THE 2016 REFUELING OUTAGE 21 STEAM GENERATOR TUBE INSPECTION REPORT UNION ELECTRIC COMPANY CALLAWAY PLANT, UNIT 1 DOCKET NO. 50-483 By letters dated October 11, 2016 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML16286A547), February 28, 2017 (ADAMS Accession No. ML17060A349), and March 23, 2017 (ADAMS Accession No. ML17082A580), Union Electric Company, dba Ameren Missouri (the licensee), submitted information to the U.S.

Nuclear Regulatory Commission summarizing the results of the 2016 steam generator (SG) tube inservice inspections performed at Callaway Plant, Unit No. 1 (Callaway) during the 21st refueling outage.

During its review of the submitted report by letter dated October 11, 2016, the NRG staff determined that a request for additional information was needed to complete its review. The licensee's response by letter dated February 28, 2017, was originally designated as proprietary by the provider, and accordingly, it was requested that the information enclosed be withheld from public disclosure pursuant to Title 1O of the Code of Federal Regulations (1 O CFR)

Section 2.390, "Public inspections, exemptions, requests for withholding." Subsequent to that submittal, however, and after consultation with the licensee's provider, it was determined that the provided information did not need to be considered proprietary and that withholding, per 10 CFR 2.390, was unnecessary. Consequently, a fully nonproprietary version of the requested information was submitted by letter dated March 23, 2017. The only change required to be made for the nonproprietary version was removal of the proprietary information notice that appeared as a note on the grid map pages included in the enclosure.

Callaway has four Framatone-designed 73/19T SGs, which was installed at the plant in 2005.

Each SG has 5872 thermally treated Alloy 690 tubes, which have a nominal outside diameter of 0.75 inches and a nominal wall thickness of 0.043 inches. The tubes are hydraulically expanded throughout the entirety of the tubesheet. The U-bend region of the tubes in rows 1 through 18 was stress relieved after bending. The tubes are supported by eight Type 41 o stainless steel tube support plates (TSPs) and anti-vibration bars. The holes in the TSPs are trifoil shaped.

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.

Based on the NRC staff's review of the reports submitted by the licensee, the staff has the following observations and comments:

• The four SGs contain 33 tubes that have been identified as having non-nominal tubesheet drill hole diameters. All these tubes were inspected during the preservice inspection. For Refueling Outage 21, 1O tubes on the cold leg of SG A (7 tubes) and SG D (3 tubes) were examined with an array probe.

Enclosure

Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by its technical specifications. In addition, the staff concludes that there are no technical issues that warrant followup 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.

SUBJECT:

CALLAWAY PLANT, UNIT NO. 1 - REVIEW OF THE STEAM GENERATOR TUBE INSPECTION REPORT FOR THE 2016 REFUELING OUTAGE NO. 21 (CAC NO. MF8474) DATED SEPTEMBER 28, 2017 DISTRIBUTION:

PUBLIC RidsNrrDorllpl4 Resource RidsRgn4MailCenter Resource LPL4 Reading RidsNrrPMCallaway Resource AJohnson, NRR/DLR/RCCB RidsACRS_MailCTR Resource RidsNrrLAPBlechman Resource RidsNrrDlrRasb Resource AD AM S Accession No.: ML 1725SA020 *by memo dated OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL4/LA NRR/DLR/RCCB* NRR/DORL/LPL4/BC NRR/DORL/LPL4/PM NAME JKlos PBlechman SB loom RPascarelli JKlos DATE 09/19/17 09/18/17 07/17/17 09/25/17 09/28/17 OFFICIAL RECORD COPY