ENS Event | |
|---|---|
21:45 Jul 30, 2025 | |
| Title | Potential Inoperability of Residual Heat Removal (RHR) System |
| Event Description | The following information was provided by the licensee via phone and email:
At 1645 CDT on July 30, 2025, it was discovered that the single train of the ultimate heat sink was inoperable. Due to this inoperability, the system was in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(B). There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The proximal cause of the inoperability was due to a buildup of grasses in the crib house from the river. Operators were able to clear the crib house bar rack intake and restore operability within eight minutes. |
| Where | |
|---|---|
Dresden  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat | |
| LER: | 05000237/LER-2025-001 Ultimate Heat Sink Inoperable Due to River Grass Accumulation |
| Time - Person (Reporting Time:+2.93 h0.122 days <br />0.0174 weeks <br />0.00401 months <br />) | |
| Opened: | Bora Tuncer 00:41 Jul 31, 2025 |
| NRC Officer: | Jordan Wingate |
| Last Updated: | Jul 31, 2025 |
| 57841 - NRC Website
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WEEKMONTHYEARENS 578412025-07-30T21:45:00030 July 2025 21:45:00
[Table view]10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Potential Inoperability of Residual Heat Removal (RHR) System ENS 560232022-07-30T03:17:00030 July 2022 03:17:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat RHR Capability Lost Due to Suction Bay Level ENS 480802012-07-10T07:36:00010 July 2012 07:36:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Invalid Group 5 Isolation Due to Failed Test Switch During Surveillance ENS 468572011-05-17T15:30:00017 May 2011 15:30:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Temporary Blockage of Suction Source for Containment Cooling Service Water ENS 454722009-11-02T12:12:0002 November 2009 12:12:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Loss of Shutdown Cooling ENS 446262008-11-03T12:52:0003 November 2008 12:52:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Recirc Loop Temperature Element Failed ENS 444702008-09-07T13:05:0007 September 2008 13:05:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Isolation Condenser Declared Inoperable Following Surveillance Testing ENS 441402008-04-15T12:00:00015 April 2008 12:00:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection Declared Inoperable ENS 413702005-02-04T01:15:0004 February 2005 01:15:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 4160 Volt Relaying and Metering Single Failure Vulnerability ENS 407032004-04-24T15:50:00024 April 2004 15:50:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Isolation Condenser Declared Inoperable 2025-07-30T21:45:00 | |