ML18012A148

Review of the Fall 2016 Steam Generator Tube Inspections During Refueling Outage 1R26 (CAC No. MF9493; EPID L-2017-LRO-0007)

ML18012A148
Person / Time
Site:	Arkansas Nuclear
Issue date:	01/18/2018
From:	Wengert T J Plant Licensing Branch IV
To:	Entergy Operations
Wengert T J
References
CAC MF9493, EPID L-2017-LRO-0007
Download: ML18012A148 (3)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 ANO Site Vice President Arkansas Nuclear One Entergy Operations, Inc. 1448 S.R. 333 Russellville, AR 72802 January 18, 2018

SUBJECT:

ARKANSAS NUCLEAR ONE, UNIT 1 -REVIEW OF THE FALL 2016 STEAM GENERATOR TUBE INSPECTIONS DURING REFUELING OUTAGE 1R26 (CAC NO. MF9493; EPID L-2017-LR0-0007)

Dear Sir or Madam:

By letter dated March 22, 2017 (Agencywide Documents Access and Management System Accession No. ML 17081A486), Entergy Operations, Inc. (the licensee) submitted information to the U.S. Nuclear Regulatory Commission (NRC) summarizing the results of the fall 2016 steam generator tube inspections performed during refueling outage 1 R26 at Arkansas Nuclear One, Unit 1. The NRC staff has completed its review of the submittal and concludes that the licensee provided the information required by its technical specifications.

No additional followup is required at this time. The results of the NRC staff's review are enclosed.

If you have any questions, please contact me at (301) 415-4037 or by e-mail at Thomas.Wengert@nrc.gov.

Docket No. 50-313

Enclosure:

Review of the Steam Generator Tube Inspection Report cc: Listserv Sincerely, Thomas J. Wengert, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation STAFF REVIEW OF FALL 2016 STEAM GENERATOR TUBE INSERVICE INSPECTIONS PERFORMED DURING REFUELING OUTAGE 1R26 ENTERGY OPERATIONS, INC. ARKANSAS NUCLEAR ONE, UNIT 1 DOCKET NO. 50-313 By letter dated March 22, 2017 (Agencywide Documents Access and Management System Accession No. ML 17081A486), Entergy Operations, Inc. (the licensee) submitted information summarizing the results of the fall 2016 steam generator (SG) tube inspections performed during refueling outage 1 R26 at Arkansas Nuclear One, Unit 1 (AN0-1 ). The SGs at AN0-1 are Enhanced Once-Through Steam Generators (EOTSG) manufactured by AREVA. The EOTSG is a straight shell-and-tube type heat exchanger installed in a vertical position.

The Alloy 690 thermally treated tubing has a 0.625-inch diameter and a 0.037-inch wall thickness.

The tubes were hydraulically expanded for the full depth of the tubesheet and are supported by 15 Type 410 stainless steel tube support plates (TSPs) with broached trefoil-shaped holes. The licensee provided the scope, extent, methods, and results of its SG tube inspections in the submittal dated March 22, 2017. In addition, the licensee described corrective actions (i.e., tube plugging) taken in response to the inspection findings.

The tubes in both SGs A and B were inspected during this outage. After reviewing the information provided by the licensee, the U.S. Nuclear Regulatory Commission (NRC) staff has the following comments/observations:

• The licensee detected two new tie-rods that experienced bowing in SG B during the previous cycle. No new tie-rod bowing was detected in SG A. The licensee stated that a pattern is developing in SG A, in which the tie-rods bow to a point and then stagnate.

This pattern is most evident in the first span tie-rods.

The NRC staff notes that this pattern is not present in SG B; however, the tie-rod bowing in SG B appears to have initiated several cycles later than the tie-rod bowing in SG A and, as a result, this pattern may manifest in SG B over the next several cycles.

• There were 536 and 531 new TSP wear indications in SG A and SG B, respectively.

The largest TSP wear indications detected were 41 percent and 44 percent through-wall in SG A and SG B, respectively.

Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by the AN0-1 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 (with the exception of tie-rod bowing) appear to be consistent with industry operating experience at similarly designed and operated units. Enclosure

SUBJECT:

ARKANSAS NUCLEAR ONE, UNIT 1 -REVIEW OF THE FALL 2016 STEAM GENERATOR TUBE INSPECTIONS DURING REFUELING OUTAGE 1R26 (CAC NO. MF9493; EPID L-2017-LR0-0007)

DATED JANUARY 18, 2018 DISTRIBUTION:

PUBLIC PM File Copy RidsACRS_MailCTR Resource RidsNrrDorlLpl4 Resource RidsNrrLAPBlechman Resource RidsNrrPMANO Resource RidsRgn4MailCenter Resource RidsNrrDmlrMccb Resource A. Huynh, NRR ADAMS Accession No. ML 18012A148 OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL4/LA NAME TWengert PBlechman DATE 1/17/2018 1/12/2018 OFFICE NRR/DORL/LPL4/BC NRR/DORL/LPL4/PM NAME RPascarelli TWengert DATE 1/18/2018 1/18/2018 OFFICIAL RECORD COPY *via memorandum NRR/DMLR/MCCB/BC*

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