ENS 56023
ENS Event | |
|---|---|
03:17 Jul 30, 2022 | |
| Title | RHR Capability Lost Due to Suction Bay Level |
| Event Description | The following information was provided by the licensee via email:
At 2217 CDT on 7/29/22, cribhouse suction bay levels were reported less than 501.5 feet due to buildup of grass on bar racks. Ultimate Heat Sink (UHS) is INOPERABLE due to Surveillance Requirement 3.7.3.1 not met. ENTER Technical Specification (TS) 3.7.3 condition A (Required Action (RA) A.1 mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, RA A.2 mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />). Dresden Lockmaster reports river level normal at 504.89 feet. Commenced trash rake operations to clear grass debris off of intake bar racks. At 0135 CDT on 7/30/22, cribhouse suction bay levels were reported at greater than 501.5 feet. Exit TS 3.7.3 condition A. 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 on the health and safety of the public or plant personnel. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The licensee notified the NRC Resident Inspector.
At 1116 CDT on 7/30/22, a repeat condition occurred where cribhouse suction bay levels were reported < 501.5 feet due to buildup of grass on bar racks. Entered TS 3.7.3 condition A (RA A.1 mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, RA A.2 mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />). Actions are in-progress to clear grass debris off the intake bar racks. 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). At 1745 CDT on 7/30/22, cribhouse suction bay levels were reported at >501.5 feet. Exit TS 3.7.3 condition A. The station continues to monitor for intake grass buildup and taking appropriate actions to maintain UHS operability. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The licensee notified the NRC Resident Inspector. Notified R3DO (Peterson). |
| 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-2022-002 Ultimate Heat Sink Declared Inoperable Due to River Grass Accumulation 05000237/LER-2022-002-01 Ultimate Heat Sink Declared Inoperable Due to River Grass Accumulation |
| Time - Person (Reporting Time:+0.72 h0.03 days <br />0.00429 weeks <br />9.86256e-4 months <br />) | |
| Opened: | Collin Grischott 04:00 Jul 30, 2022 |
| NRC Officer: | Bethany Cecere |
| Last Updated: | Jul 30, 2022 |
| 56023 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 3 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
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 | |