ML25338A253
| ML25338A253 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 12/09/2025 |
| From: | Wetzel B Plant Licensing Branch III |
| To: | Paulhardt W Northern States Power Co |
| Ballard, Brent | |
| References | |
| EPID L-2025-LRO-0034 | |
| Download: ML25338A253 (0) | |
Text
December 9, 2025 Mr. Werner Paulhardt Site Vice President Northern States Power Company - Minnesota Prairie Island Nuclear Generating Plant 1717 Wakonade Drive East Welch, MN 55089
SUBJECT:
PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT 1 - REVIEW OF THE 2024 STEAM GENERATOR TUBE INSPECTION REPORT (EPID L-2025-LRO-0034)
Dear Mr. Paulhardt:
By letter dated May 21, 2025 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25141A100), Northern States Power Company, doing business as Xcel Energy (the licensee) submitted information summarizing the results of the 2024 steam generator (SG) inspections for the Prairie Island Nuclear Generating Plant (PINGP), Unit 1. This report was submitted in accordance with Technical Specification (TS) 5.6.7, Steam Generator Tube Inspection Report.
The U.S. Nuclear Regulatory Commission (NRC) staff has completed its review of the 2024 SG tube inspection for PINGP, Unit 1. Based on this review, the NRC staff concludes that the information required by TS 5.6.7 has been provided and no additional follow-up action is required at this time. A summary of the NRC staffs review is enclosed.
If you have any questions, please contact me at 301-415-5223 or via e-mail at Beth.Wetzel@nrc.gov.
Sincerely,
/RA/
Beth Wetzel, Project Manager Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-282
Enclosure:
Review of the Fall 2024 Steam Generator Tube Inspection Report cc: Listserv
Enclosure REVIEW OF THE FALL 2024 STEAM GENERATOR TUBE INSPECTION REPORT NORTHERN STATES POWER COMPANY - MINNESOTA PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 DOCKET NO. 50-282 By letter dated May 21, 2025 (ADAMS Accession No. ML25141A100), Northern States Power Company, doing business as Xcel Energy (the licensee), submitted information summarizing the results of the fall 2024 steam generator (SG) inspections at Prairie Island Nuclear Generating Plant (Prairie Island), Unit 1. These inspections were performed during the 34th refueling outage (1R34). This report was submitted in accordance with Technical Specification (TS) 5.6.7, Steam Generator Tube Inspection Report.
Prairie Island, Unit 1, has two Framatome/AREVA model 56/19 replacement recirculating SGs.
Each SG has 4,868 thermally treated Alloy 690 tubes, which have a nominal outside diameter of 0.750 inches and a nominal wall thickness of 0.043 inches. The tubes were hydraulically expanded at each end for the full depth of the tubesheet. The tubes are supported by stainless steel tube support plates (TSPs) and anti-vibration bars (AVBs). The TSPs have a minimum thickness of 1.18 inches and have quatrefoil-shaped holes through which the tubes pass and the AVBs are rectangular in cross section (0.5 inches by 0.3 inches).
The licensee provided the scope, extent, methods, and results of the SG tube inspections in the letter referenced above. In addition, the licensee described corrective actions (e.g., tube plugging), if any were taken in response to the inspection findings.
After reviewing the information provided by the licensee, the staff has the following comments/observations:
The licensee reported that during the 1R34 SG tube inspections, the upper 95th percentile growth rates increased slightly for AVB wear and decreased slightly for TSP wear, as compared to the previous inspections in 1R31 (2018), and the actual number of indications reported in 1R34 was less than the number projected in the 1R31 Operational Assessment.
The licensee reported that secondary side inspections were performed during 1R34, and no degradation or loose parts intrusion was detected. A top of tubesheet deposit cleaning process was performed in both SGs during 1R34. The dry mass of removed deposit material was reported as 11.6 pounds from SG11 and 15.2 pounds from SG12.
The subsequent secondary side visual inspections showed the tubesheet to be essentially free of deposits with only limited hard sludge piles.
Based on a review of the information provided, the staff concludes that the licensee provided the information required by their technical specifications. In addition, the staff concludes that there are no technical issues that warrant follow-up action currently, since the inspections appear to be consistent with the objective of detecting potential tube degradation and the inspection results appear to be consistent with industry operating experience at similarly designed and operated units.
ML25338A253 OFFICE NRR/DORL/LPL3/PM NRR/DORL/LPL3/LA NRR/DNRL/NCSG/BC NAME BWetzel SLent SBloom DATE 12/04/2025 12/04/2025 11/24/2025 OFFICE NRR/DORL/LPL3/BC (A)
NRR/DORL/LPL3/PM NAME IBerrios BWetzel DATE 12/05/2025 12/09/2025