The Reactor Water Cleanup (RWCU) is the filtration system for the reactor vessel. (Its kinda like a pool filter) Its primary safety function is to isolate if needed. Filtering is not needed for safe shutdown but it is good to keep clean water in the vessel to avoid contaminates that may become radioactive or mitigating corrosion on various components.
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| | Site | Start date | Title | Description |
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| IR 05000298/2026002 | Cooper | 12 August 2026 | Integrated Inspection Report 05000298/2026002 | | | IR 05000331/2026001 | Duane Arnold | 3 August 2026 | Restart Inspection Report 05000331/2026001 | | | NMP1L3706, Supplement No. 1 - Changes to the Subsequent License Renewal Application Dated March 25, 2026 | Nine Mile Point | 30 July 2026 | Supplement No. 1 - Changes to the Subsequent License Renewal Application Dated March 25, 2026 | | | RS-26-086, License Amendment Request to Adopt TSTF-584, Eliminate Automatic RWCU System Isolation on SLC Initiation, Revision 0 | Dresden
Peach Bottom
Clinton
Quad Cities
FitzPatrick
LaSalle | 22 July 2026 | License Amendment Request to Adopt TSTF-584, Eliminate Automatic RWCU System Isolation on SLC Initiation, Revision 0 | | | ML24341A154 | | 14 July 2026 | Draft Regulatory Guide DG-1428 (RG 1.258, Rev. 0), Plant-Specific Applicability of the Transition Break Size | | | IR 05000259/2026002 | Browns Ferry | 13 July 2026 | Integrated Inspection Report 05000259/2026002, 05000260/2026002, 05000296/2026002, and 07200052/2026001 | | | RS-26-101, License Amendment Request to Reinstate and Apply Risk-Informed Completion Time (RICT) Applications | Limerick | 1 July 2026 | License Amendment Request to Reinstate and Apply Risk-Informed Completion Time (RICT) Applications | | | PLA-8220, Proposed Amendment to Licenses NPF-14 and NPF-22: Application to Revise Technical Specifications to Adopt TSTF-596, Expand the Applicability of the Surveillance Frequency Control Program (SFCP) | Susquehanna | 17 June 2026 | Proposed Amendment to Licenses NPF-14 and NPF-22: Application to Revise Technical Specifications to Adopt TSTF-596, Expand the Applicability of the Surveillance Frequency Control Program (SFCP) | | | 05000259/LER-2026-002, Technical Specifications Required Shutdown Due to Reactor Water Cleanup System ASME Code Class 1 Leak | Browns Ferry | 11 June 2026 | Technical Specifications Required Shutdown Due to Reactor Water Cleanup System ASME Code Class 1 Leak | | | ENS 58388 | Columbia | 8 June 2026 19:59:00 | Invalid Specified System Actuation | The following information was provided by the licensee via phone and email:
On June 8, 2026, at 1259 PDT, Columbia Generating Station's leak detection monitor '1A' (LD-MON-1A) caused an isolation of RWCU-V-4 (reactor water cleanup outboard isolation valve) and RCIC-V-8 (reactor core isolation cooling outboard steam supply isolation valve).
Based on a review of available information by engineering, the actuations were determined to be invalid and likely the result of an intermittent nuclear measurement analysis and control (NUMAC) bus communication fault as plant conditions for a valid actuation did not exist.
The actuation was not initiated in response to actual plant conditions, this was not an intentional manual initiation, and there were no parameters satisfying the requirements for initiation. Therefore, this event has been determined to be an invalid actuation.
As indicated in 10 CFR 50.73(a)(1), in the case of an invalid actuation reported under 10 CFR 50.73(a)(2)(iv)(A), the licensee may, at its option, provide a telephonic notification to the NRC Operations Center within 60 days of discovery of the event instead of submitting a written licensee event report. This 60-day telephone notification is being made in accordance with 10 CFR 50.73(a)(1) for invalid actuations reported under 10 CFR 50.73 (a)(2)(iv)(A).
There was no impact on the health and safety of the public or plant personnel.
The following information is provided as specified in NUREG-1022:
(a) Containment Isolation Valves RWCU-V-4 and RCIC-V-8 isolated.
(b) All expected isolations based on the as-found condition of the leak detection monitor were completed.
(c) The isolation of RWCU-V-4 and RCIC-V-8 completed successfully.
The NRC Resident Inspector has been notified. |
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