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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| ENS 54016 | Brunswick | 22 April 2019 03:07:00 | Automatic Reactor Trip and Specified System Actuation | At 2307 EDT on April 21, 2019, in Mode 1 at approximately 100 percent reactor power, Unit 1 automatically tripped due to a Main Turbine Trip. The Main Turbine Trip was a result of two out of three level instruments sensing a false high reactor water level. All control rods inserted as expected during the scram. Safety Relief Valves G and K lifted per design. The same level instruments that failed also tripped both Reactor Feed Pumps. As a result, reactor water level dropped below the Low Level 1 and 2 actuation setpoints. Per design, the Low Level 1 signal resulted in Group 2 (i.e., floor and equipment drain isolation valves), Group 6 (i.e., monitoring and sampling isolation valves) and Group 8 (i.e., shutdown cooling isolation valves) isolations. The Low Level 2 signals resulted in Group 3 (i.e. Reactor Water Cleanup) isolation, a secondary containment isolation signal, and an auto start of Standby Gas Treatment and Control Room Emergency Ventilation. Also, the Low Level 2 resulted in (high pressure coolant injection) HPCI and (reactor core isolation cooling system) RCIC automatically starting and injecting into the vessel.
All systems responded as designed.
This event is being reported in accordance with 10 CFR 50.72(b)(2)(iv)(B) for RPS actuation and 10 CFR 50.72(b)(3)(iv)(A) as an event that results in valid actuations of the Primary Containment Isolation System.
There was no impact on the health and safety of the public or plant personnel.
The NRC Resident Inspector has been notified.
Decay heat is currently being removed via the turbine bypass valves. Condensate and feed water are maintaining water level. The reactor is still at saturation temperature and 475 psi, lowering slowly. The reactor is still in a normal electrical lineup.
There was no impact to Unit 2 as a result of this event.
- * * UPDATE ON 04/22/19 AT 0220 EDT FROM ALAN SCHULTZ TO JEFFREY WHITED * * *
The licensee updated the event report to include a 4-Hr Non-Emergency Notification in accordance with 10 CFR 50.72(b)(2)(iv)(A) for Emergency Core Cooling System, HPCI, Discharge to the Reactor Coolant System. | | ML19092A159 | Clinton | 3 April 2019 | Transmittal of Final Clinton Power Station Accident Sequence Precursor Report (Licensee Event Report 461 2017 010) | | | NL-19-0317, Submittal of Fifth Ten-Year Interval Lnservice Testing Program Update | Hatch | 2 April 2019 | Submittal of Fifth Ten-Year Interval Lnservice Testing Program Update | | | IR 05000277/2019011 | Peach Bottom | 14 March 2019 | Design Bases Assurance Inspection (Programs) Report 05000277/2019011 and 05000278/2019011 | | | IR 05000352/2019011 | Limerick | 14 March 2019 | Triennial Fire Protection Inspection Report 05000352/2019011 and 05000353/2019011 | | | ML19078A211 | Susquehanna | 6 March 2019 | Technical Specifications Bases, Manual | | | ML19078A210 | Susquehanna | 6 March 2019 | Technical Specification Bases, Manual | | | NRC-19-0001, License Amendment Request to Revise Technical Specification 3.3.5.3, Reactor Pressure Vessel (RPV) Water Inventory Control Instrumentation | Fermi | 27 February 2019 | License Amendment Request to Revise Technical Specification 3.3.5.3, Reactor Pressure Vessel (RPV) Water Inventory Control Instrumentation | | | IR 05000333/2018004 | FitzPatrick | 11 February 2019 | Integrated Inspection Report 05000333/2018004 | | | ML18353A229 | Quad Cities | 28 January 2019 | Issuance of Amendment Nos. 273 and 268 Regarding Adoption of TSTF-542, Reactor Pressure Vessel Water Inventory Control | |
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