ML22088A197

Summary of March 11, 2022, Call Regarding the Spring 2022 Steam Generator Tube Inspections

ML22088A197
Person / Time
Site:	Davis Besse
Issue date:	03/30/2022
From:	Blake Purnell Plant Licensing Branch III
To:	Brown T Energy Harbor Nuclear Corp
Purnell B
References
EPID L-2022-NFO-0000
Download: ML22088A197 (3)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON , D.C. 20555-0001 March 30, 2022 Mr. Terry J. Brown Site Vice President Energy Harbor Nuclear Corp.

Mail Stop P-DB-3080 5501 North State Route 2 Oak Harbor, OH 43449-9760

SUBJECT:

DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO. 1 -

SUMMARY

OF MARCH 11, 2022, CALL REGARDING THE SPRING 2022 STEAM GENERATOR TUBE INSPECTIONS (EPID L-2022-NFO-0000)

Dear Mr. Brown:

On March 11, 2022, the U.S. Nuclear Regulatory Commission (NRC) staff participated in a conference call with Energy Harbor Nuclear Corp. (the licensee) regarding the steam generator (SG) tube inspection activities at Davis-Besse Nuclear Power Station, Unit No. 1 (Davis-Besse),

during refueling outage 22. By email dated February 24, 2021 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22055B038), the NRC staff provided the licensee with a list of discussion points to facilitate the call. The purpose of this letter is to provide a summary of the call.

Davis-Besse has two once-through SGs designed by Babcock and Wilcox that were installed in 2014. Each SG contains 15,607 thermally treated Alloy 690 tubes. The tubes were hydraulically expanded for part of the length of the tubesheet and are supported by 16 carbon-steel tube support plates (TSPs). There are 66 stainless steel tie rods between each TSP. Tube support plate 15S is below the auxiliary feedwater nozzle and has drilled holes in the periphery through which the tubes pass. The remaining portion of TSP 15S and the other TSPs in the SGs have trefoil broached holes. The trefoil holes of the even numbered TSPs are offset from centerline to minimize tube wear at the TSP elevations.

The NRC staff notes that the inspection information provided during the call was preliminary and is subject to change upon final data analysis. Preliminary information presented by the licensee during the March 11, 2022, conference call is available in ADAMS under Accession No. ML22081A147. Additional clarifying information provided during the call is summarized below.

At the time of the call, approximately 95 percent of the eddy current data acquisition had been completed and eddy current analysis was close behind.

Array probe examinations were performed on all proximity indications identified as having zero gap with an adjacent tie-rod or tube. The licensee did not have the exact number of new proximity indications available during the call, but they stated that the number of new proximity indications was small compared to the last SG tube inspection.

The licensee stated that prior to the start of the current outage, there were 69 tubes plugged in SG 1B and 105 tubes plugged in SG 2A.

The licensee reported that there were no eddy current indications of loose parts or degradation from loose parts, no parts have been found or removed, and there is no history of loose parts in either SG.

The NRC staff did not identify any issues that required follow-up action at this time. If you have any questions, please contact me at 301-415-1380 or via e-mail at Blake.Purnell@nrc.gov.

Sincerely,

/RA/

Blake Purnell, Project Manager Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-346 cc: Listserv

ML22088A197 OFFICE NRR/DORL/LPL3/PM NRR/DORL/LPL3/LA NRR/DNRL/NCSG/BC NAME BPurnell SRohrer SBloom DATE 3/30/22 3/30/22 3/22/22 OFFICE NRR/DORL/LPL3/BC NRR/DORL/LPL3/PM NAME NSalgado (SWall for) BPurnell DATE 3/30/22 3/30/22