05000263/LER-2025-001, Automatic Reactor Scram on Low Water Level
| ML25136A306 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 05/16/2025 |
| From: | Brown G Northern States Power Co, Xcel Energy |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-MT-25-021 LER 2025-001-00 | |
| Download: ML25136A306 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 2632025001R00 - NRC Website | |
text
(l Xcel Energy*
May 16, 2025 ATTN : Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Monticello Nuclear Generating Plant Docket No. 50-263 Subsequent Renewed Facility Operating License No. DPR-22 Monticello Nuclear Generating Plant Licensee Event Report 2025-001-00 2807 West County Road 75 Monticello, MN 55362 L-MT-25-021 10 CFR 50.73 Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter "NSPM"), hereby submits Licensee Event Report (LER) 50-263/2025-001-00 in accordance with 10 CFR 50.73(a)(2)(iv)(A).
If you have any questions about this submittal, please contact Rick Loeffler, Senior Nuclear Regulatory Engineer, by email at rick.a.loeffler@xcelenergy.com, or by phone at 612-539-3370.
Summary of Commitments This letter makes no new commitments and no revisions to existing commitments.
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Plant Manager, Monticello Nuclear Generating Plant Northern States Power Company - Minnesota Enclosure cc:
Administrator, Region Ill, USNRC Project Manager, Monticello, USNRC Resident Inspector, Monticello, USNRC State of Minnesota
ENCLOSURE MONTICELLO NUCLEAR GENERATING PLANT LICENSEE EVENT REPORT 50-263/2025-001-00 (5 pages follow)
Abstract
On March 19, 2025, at 1136 Central Daylight Time (CDT), an automatic reactor scram occurred due to low reactor pressure vessel (RPV) water level due to a trip of the 11 Reactor Feedwater Pump (RFP). This event is reportable pursuant to 10 CFR 50.73(a)(2)(iv)(A) as an automatic actuation of the Reactor Protection System and due to primary containment isolation valves closure on a Group 2 isolation signal.
The cause of the scram was low RPV water level due to the trip of the 11 RFP. The 11 RFP tripped on low suction pressure due to low water level within the Condenser Hotwell and air binding in the Circulating Water System. The Condenser tube sheets were cleaned, the eight vacuum air release valves were replaced, and the Hotwell Makeup Level Controller was replaced. All nuclear safety systems functioned as designed. A supplement to this LER is planned to allow additional time to complete the cause evaluation.
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- 3. LER NUMBER YEAR SEQUENTIAL NUMBER REV NO.
052 050 Following the repairs and cleaning of the Condenser the reactor was restarted and synced to the electrical grid on March 22, 2025.
B. Corrective Actions to Prevent Recurrence or to reduce the probability of similar events occurring in the future
A supplement to this Licensee Event Report is planned to allow additional time to complete the cause evaluation.
VII. Previous Similar Events at the Same Site
A search of LERs for the MNGP identified no previous similar events in the past three years.
VIII. Additional Information
There is no additional information.
Energy Industry Identification System (EIIS) codes are identified in the text as [XX].
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Monticello Nuclear Generating Plant 263 2025 001 00
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