ML21064A034

NRR E-mail Capture - Wolf Creek Generating Station Upcoming Steam Generator Tube Inservice Inspection

ML21064A034
Person / Time
Site:	Wolf Creek
Issue date:	03/04/2021
From:	Samson Lee NRC/NRR/DORL/LPL4
To:	Joseph Turner Wolf Creek
References
Download: ML21064A034 (3)

Text

From: Lee, Samson Sent: Thursday, March 4, 2021 3:23 PM To: Joshua Turner Cc: Bloom, Steven; Makar, Gregory; Taylor, Nick; Drake, James; O'Keefe, Neil; Henderson, Christopher; Vera, John

Subject:

Wolf Creek Generating Station Upcoming Steam Generator Tube Inservice Inspection 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 Wolf Creek Nuclear Operating Corporation (the licensee) staff to discuss the ongoing results of the SG tube inspections to be conducted during the upcoming Wolf Creek Generating Station refueling outage. This call will occur after the majority of the tubes have been inspected, but before the SG inspection activities have been completed.

The call supports the regional inspection and is non-public. The 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. Please contact Samson Lee, NRC Project Manager, at 301-415-3168 with any questions.

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 refueling outage.

STEAM GENERATOR TUBE INSPECTION DISCUSSION POINTS

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, 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 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:

• what inspections are 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)

• if the loose parts 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.

Docket No. 50-482

Hearing Identifier: NRR_DRMA Email Number: 1058 Mail Envelope Properties (DM8PR09MB618383B05BA03C5F86E6B7499A979)

Subject:

Wolf Creek Generating Station Upcoming Steam Generator Tube Inservice Inspection Sent Date: 3/4/2021 3:22:44 PM Received Date: 3/4/2021 3:22:44 PM From: Lee, Samson Created By: Samson.Lee@nrc.gov Recipients:

"Bloom, Steven" <Steven.Bloom@nrc.gov>

Tracking Status: None "Makar, Gregory" <Gregory.Makar@nrc.gov>

Tracking Status: None "Taylor, Nick" <Nick.Taylor@nrc.gov>

Tracking Status: None "Drake, James" <James.Drake@nrc.gov>

Tracking Status: None "O'Keefe, Neil" <Neil.O'Keefe@nrc.gov>

Tracking Status: None "Henderson, Christopher" <Christopher.Henderson@nrc.gov>

Tracking Status: None "Vera, John" <John.Vera@nrc.gov>

Tracking Status: None "Joshua Turner" <Josh.Turner@evergy.com>

Tracking Status: None Post Office: DM8PR09MB6183.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 3549 3/4/2021 3:22:44 PM Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: