ML22069A719

E-mail from R. Guzman to S. Sinha - Millstone Unit 3 Steam Generator Outage Conference Call

ML22069A719
Person / Time
Site:	Millstone
Issue date:	03/10/2022
From:	Richard Guzman NRC/NRR/DORL/LPL1
To:	Sinha S Dominion Energy Nuclear Connecticut
Guzman R
References
Download: ML22069A719 (3)

Text

{{#Wiki_filter:From: Guzman, Richard To: Shayan.Sinha@dominionenergy.com Cc: Bloom, Steven; Johnson, Andrew; Klein, Paul; Terry, Leslie; Makar, Gregory; Gray, Mel; Cataldo, Paul; Turilin, Andrey

Subject:

Millstone Power Station, Unit No. 3 - Steam Generator Outage Conference Call Date: Thursday, March 10, 2022 11:31:59 AM

Mr. Sinha,

Inservice inspections of steam generator (SG) tubes play a vital role in assuring SG tube integrity. A telephone conference call will be arranged with members of Dominion Energy staff (the licensee for Millstone Power Station) to discuss the ongoing results of the SG tube inspections to be conducted during the upcoming spring 2022 refueling outage for Millstone Power Station, Unit 3 (Millstone 3). This call will occur after the majority of the Millstone 3 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 U.S. Nuclear Regulatory Commission (NRC) staff will document a publicly available summary of the conference call, including any material that the licensee provides to the NRC staff in support of the call. The NRC staff will await the licensees availability for the conference call, then schedule the call in TEAMS.

This e-mail communication will be entered into ADAMS and made publicly available as an official agency record. Should you have any questions, please contact me at 301-415-1030.

Thanks,

Richard V. Guzman, Senior Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Docket No. 50-423

Enclosure:

Steam Generator Tube Inspection Discussion Points

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Enclosure

STEAM GENERATOR TUBE INSPECTION DISCUSSION POINTS

The following discussion points have been prepared to facilitate the conference call arranged with the licensee to discuss the results of the steam generator (SG) tube inspections to be conducted during the upcoming spring 2022 Millstone Power Station, Unit 3 (Millstone 3), refueling outage. This conference call is scheduled to occur towards the end of the planned SG tube inspections, but before Millstone 3 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 percent of dents/dings greater than 5 volts and a 20 percent sample between 2 and 5 volts), and the expansion criteria.

5. For each area examined (e.g., tube supports, dent/dings, sleeves, etc.), provide the following:

a. 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).

b. For the most significant indications in each area, provide an estimate of the severity of the indication (e.g., voltage, depth, and length of the indication),

including whether tube integrity (structural and accident induced leakage integrity) was maintained during the previous operating cycle. In addition, discuss any analyses performed specifically for the most significant indications to demonstrate tube integrity.

c. Discuss whether any location exhibited a degradation mode that had not previously been observed at this location at this unit (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:

a. The inspections performed to detect loose parts.

b. A description of any loose parts detected and their location within the SG (including the source or nature of the loose part, if known).

c. If the loose parts were removed from the SG.

d. 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, feedring 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.

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