ML21070A002

Upcoming Steam Generator Tube Inservice Inspection

ML21070A002
Person / Time
Site:	Catawba
Issue date:	03/16/2021
From:	Cotton K Plant Licensing Branch II
To:	Simril R Duke Energy Carolinas
Cotton K
References
EPID L-2021-NFO-0004
Download: ML21070A002 (4)

Text

March 16, 2021 Mr. Robert T. Simril Site Vice President Catawba Nuclear Station Duke Energy Carolinas, LLC 4800 Concord Road York, SC 29745

SUBJECT:

CATAWBA NUCLEAR STATION, UNIT 2 - UPCOMING STEAM GENERATOR TUBE INSERVICE INSPECTION (EPID L-2021-NFO-0004)

Dear Mr. Simril:

Inservice inspections of steam generator (SG) tubes play a vital role in assuring SG tube integrity. A telephone conference call has been arranged with members of your staff to discuss the ongoing results of the SG tube inspections to be conducted during the upcoming Catawba Nuclear Generating Station Unit 2 refueling outage. This call will occur after the majority of the tubes have been inspected, but before the SG inspection activities have been completed.

Enclosed is a list of discussion points to facilitate this call.

The NRC staff will document a publicly available summary of the conference call, including any material that you provide to the NRC staff in support of the call.

If you have any questions, please contact me at 301-415-1438 or via e-mail at Karen.Cotton@nrc.gov.

Sincerely,

/RA/

Karen Cotton, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-414

Enclosure:

Steam Generator Tube Inspection Discussion Points cc: Listserv

ML21070A002 OFFICE NRR/DORL/LPLII-1/PM NRR/DORL/LPLII-1/LA NRR/DORL/LPLII-1/BC NRR/DORL/LPLII-1/PM NAME KCotton KGoldstein MMarkley KCotton DATE 03/15/2021 03/11/2021 03/15/2021 03/15/2021

Enclosure STEAM GENERATOR TUBE INSPECTION DISCUSSION POINTS DUKE ENERGY CAROLINAS, LLC CATAWBA NUCLEAR STATION, UNIT 2 DOCKET NO. 50-414 The following discussion points have been prepared to facilitate the conference call arranged with the licensee to discuss the results of the steam generator tube inspections to be conducted during the upcoming spring 2021, Unit 2 refueling outage. This conference call is scheduled to occur toward the end of the planned SG tube inspections, but before the unit completes the inspections and repairs.

The NRC staff plans to document a publicly available summary of the conference call, as well as any material that is provided in support of the call.

1.

Discuss any trends in the amount of primary-to-secondary leakage observed during the recently completed cycle.

2.

Discuss whether any secondary-side pressure tests were performed during the outage and the associated results.

3.

Discuss any exceptions taken to the industry guidelines.

4.

For each steam generator, provide a description of the inspections performed including the areas examined and the probes used (e.g., dents/dings, sleeves, expansion-transition, U-bends with a rotating probe), the scope of the inspection (e.g., 100% of dents/dings greater than 5 volts and a 20% sample between 2 and 5 volts), and the expansion criteria.

5.

For each area examined (e.g., tube supports, dent/dings, sleeves, etc), provide a summary of the number of indications identified to-date for each degradation mode (e.g., number of circumferential primary water stress corrosion cracking indications at the expansion transition). For the most significant indications in each area, provide an estimate of the severity of the indication (e.g., provide the voltage, depth, and length of the indication). In particular, please address whether tube integrity (structural and accident induced leakage integrity) was maintained during the previous operating cycle.

In addition, discuss whether any location exhibited a degradation mode that had not been observed previously at the subject location (e.g., observed circumferential primary water stress corrosion cracking at the expansion transition for the first time at this unit).

6.

Describe repair/plugging plans.

7.

Describe in-situ pressure test and tube-pull plans and results (as applicable and if available).

8.

Discuss the following regarding loose parts:

inspections that were performed to detect loose parts a description of any loose parts detected and their location within the SG (including the source or nature of the loose part, if known) loose parts that were removed from the SG indications of tube damage associated with the loose parts

9.

Discuss the scope and results of any secondary-side inspection and maintenance activities (e.g., in-bundle visual inspections, feed ring inspections, sludge lancing, assessing deposit loading, etc).

10.

Discuss any unexpected or unusual results.

11.

Provide the schedule for steam generator-related activities during the remainder of the current outage.

12.

Summarize any secondary-side chemical cleaning plans or results during the current outage.