ML24053A030

NRR E-mail Capture - Request for Steam Generator (SG) Tube Inspection Call for Sequoyah, Unit 1

ML24053A030
Person / Time
Site:	Sequoyah
Issue date:	02/21/2024
From:	Perry Buckberg NRC/NRR/DORL/LPL2-2
To:	Baron J Tennessee Valley Authority
Buckberg P
References
L-2024-LRO-0008
Download: ML24053A030 (3)

Text

From: Perry Buckberg Sent: Wednesday, February 21, 2024 8:22 AM To: Baron, Jesse Shawn Cc: Taylor, Andrew Charles; McNeil, Andrew Clair; Bowman, Scott Travis; Spencer, Ryan Sean

Subject:

Sequoyah Unit 1 Spring Outage - Steam Generator Tube Inspections

Jesse Baron,

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 your staff to discuss the ongoing results of the SG tube inspections to be conducted during the upcoming Spring 2024, Sequoyah Unit 1 refueling outage. This call will occur after the majority of the tubes have been inspected, but before the SG inspection activities have been completed.

Below 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 you provide to the NRC staff in support of the call.

Please contact me with any questions.

Thanks, Perry Buckberg Senior Project Manager / Agency 2.206 Petition Coordinator U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation office: (301)415-1383 perry.buckberg@nrc.gov Mail Stop O-8B1a, Washington, DC, 20555-0001

STEAM GENERATOR TUBE INSPECTION DISCUSSION POINTS The following discussion points have been prepared to facilitate the conference call to be arranged with TVA to discuss the results of the steam generator tube inspections to be conducted during the upcoming Spring 2024, Unit 1 refueling outage This conference call will be scheduled to occur towards 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 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.

12. Please describe the tube degradation that is closest to the condition monitoring limit and the approximate margin to the condition monitoring limit.

Hearing Identifier: NRR_DRMA Email Number: 2408

Mail Envelope Properties (SA1PR09MB76792CBFD97B5CD3AC6C49BE9A572)

Subject:

Sequoyah Unit 1 Spring Outage - Steam Generator Tube Inspections Sent Date: 2/21/2024 8:21:54 AM Received Date: 2/21/2024 8:21:00 AM From: Perry Buckberg

Created By: Perry.Buckberg@nrc.gov

Recipients:

"Taylor, Andrew Charles" <actaylor@tva.gov>

Tracking Status: None "McNeil, Andrew Clair" <acmcneil@tva.gov>

Tracking Status: None "Bowman, Scott Travis" <stbowman@tva.gov>

Tracking Status: None "Spencer, Ryan Sean" <rsspencer@tva.gov>

Tracking Status: None "Baron, Jesse Shawn" <jsbaron@tva.gov>

Tracking Status: None

Post Office: SA1PR09MB7679.namprd09.prod.outlook.com

Files Size Date & Time MESSAGE 4355 2/21/2024 8:21:00 AM

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