ML25175A120
| ML25175A120 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 06/24/2025 |
| From: | Boyce M Wolf Creek |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| 001027 | |
| Download: ML25175A120 (1) | |
Text
P.O. Box 411 l Burlington, KS 66839 l 620-364-8831 Michael T. Boyce Vice President Engineering June 24, 2025 001027 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-001
References:
- 1) Letter 000685, dated November 1, 2024, from M. T. Boyce, WCNOC, to USNRC, Results of the Steam Generator Tube Inservice Inspection During the 26th Refueling Outage to Reflect TSTF-577 Reporting Requirements (ADAMS No. ML24306A219)
- 2) Electronic mail dated June 11, 2025, from S. S. Lee, USNRC, to J. K.
Turner, WCNOC, Request for Additional Information - Wolf Creek Results of Steam Generator Tube Inservice Inspection During the 26th Refueling Outage (ADAMS No. ML25162A255)
Subject:
Docket No. 50-482: Response to Request for Additional Information (RAI)
Regarding Steam Generator Tube Inspection Report RF26 Commissioners and Staff:
In accordance with the Wolf Creek Generating Station (WCGS) Technical Specification (TS) 5.6.10, Steam Generator Tube Inspection Report, in Reference 1, Wolf Creek Nuclear Operating Corporation (WCNOC) provided the Steam Generator Tube Inspection Report detailing the results of WCGSs steam generator (SG) tube in-service inspection performed during Refueling Outage 26 (RF26).
By electronic mail dated June 11, 2025, the U.S. Nuclear Regulatory Commission (NRC) indicated the staff had reviewed the information WCGS provided and determined that additional information is required to complete their review of the inspections (Reference 2). The attachment to this letter provides the questions contained in Reference 2, as well as WCNOCs responses.
This letter contains no commitments. If you have any questions concerning this matter, please contact me at (620) 364-8831 x8687, or Dustin Hamman at (620) 364-4204.
001027 Page 2 of 2 Sincerely, Michael T. Boyce MTB/jkt
Attachment:
Wolf Creek Nuclear Operating Corporation (WCNOC), Unit 1 Response to Request for Additional Information (RAI) Regarding Steam Generator Tube Inspection Report RF26 cc:
A. N. Agrawal (NRC), w/a S. S. Lee (NRC), w/a J. D. Monninger (NRC), w/a Senior Resident Inspector (NRC), w/a WC Licensing Correspondence, w/a - ET 25-001027
Attachment to 001027 Page 1 of 2 WOLF CREEK NUCLEAR OPERATING CORPORATION (WCNOC), UNIT 1 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING STEAM GENERATOR TUBE INSPECTION REPORT RF26
Background:
By letter dated November 1, 2024 (Agencywide Documents Access System (ADAMS) Accession Number ML24306A219), Wolf Creek Nuclear Operating Corporation (the licensee), submitted information summarizing the results of the 2024 steam generator (SG) tube inspections performed at Wolf Creek Generating Station (Wolf Creek) during refueling outage 26 (RF26).
Based on its review of the submittal, the U.S. Nuclear Regulatory Commission (NRC) staff determined that, to complete its review, it needs a response to its request for additional information (RAI) below.. The licensee staff requested, and NRC agreed, to an RAI response by June 30, 2025.
The NRC staff considers that timely responses to RAIs help ensure sufficient time is available for staff review and contribute toward the NRCs goal of efficient and effective use of staff resources.
Regulatory Basis:
The submittal is based on Section 5.6.10 in the Wolf Creek Technical Specifications, which requires that a report be submitted within 180 days after the initial entry into hot shutdown (MODE 4) following completion of an inspection of the SGs.
The NRC staff of the Chemical, Corrosion, and Steam Generator Branch of the Division of License Renewal has reviewed the information the licensee provided and determined that additional information is required to complete its review of the inspections. Therefore, the NRC staff requests the following additional information:
Question:
- 1. The RF26 SG tube inspection report states in the table on page 1 that the inspection addresses degradation mechanism sub-populations, such as potential high residual stress tubes and outside diameter stress corrosion cracking (ODSCC) at dings/dents. However, the report does not indicate whether the tube in SG A that was found with axial ODSCC at a dent/ding was a tube with potentially high residual stress.
- a. Provide the residual stress status of the tube in Row 55 Column 46 of SG A (i.e., whether it is a tube with potentially high residual stress).
- b. Provide the number and location of in-service tubes in each SG that have potentially high residual stress.
WCNOC, Response to Request for Additional Information (RAI):
- a. Provide the residual stress status of the tube in Row 55 Column 46 of SG A (i.e., whether it is a tube with potentially high residual stress).
This tube did not have high residual stress.
- b. Provide the number and location of in-service tubes in each SG that have potentially high residual stress.
Attachment to 001027 Page 2 of 2 The table below identifies the tubes with high residual stress.
Wolf Creek Ranking of Minus 2-Sigma High Stress Tubes SG A
SG B
SG C
SG D
No.
Row Col Row Col Row Col Row Col 1
18 4
18 31 20 11 19 21 2
18 5
32 41 17 22 25 33 3
18 6
24 45 20 22 17 40 4
36 15 26 46 24 26 26 42 5
18 19 25 53 27 26 17 70 6
17 21 12 63 28 34 19 89 7
19 22 17 66 26 38 42 102 8
20 27 11 80 17 60 9
18 28 20 81 25 84 10 21 29 14 88 18 109 11 19 30 28 110 12 18 33 13 18 34 14 17 36 15 21 39 16 17 40 17 21 40 18 27 46 19 53 46 20 17 47 21 22 69 22 17 91 23 38 92 24 21 106 25 19 107 26 16 109 27 16 112 28 16 115 29 24 115 30 16 116 31 16 117 Total 31 11 10 7