Emergency Core Cooling System (ECCS) is a set of systems designed to react to postulated design basis accidents. In combination they automatically bring the reactor to a safe shutdown condition.
Includes
see also
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| | Site | Start date | Title | Description |
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| ENS 57021 | Hatch | 11 March 2024 17:37:00 | Manual Reactor Trip | The following information was provided by the licensee via phone and email:
On March 11, 2024, at 1337 EDT, with Unit 1 in Mode 1 at 35 percent power performing power ascension activities, the reactor was manually tripped due to the 'A' reactor feed pump (RFP) tripping on low suction pressure. Due to the power level at the time, the 'B' RFP had not been placed in service. Closure of containment isolation valves (CIVs) in multiple systems and actuation of high-pressure coolant injection (HPCI) and reactor core isolation cooling (RCIC) occurred as a result of reaching the actuation setpoint on reactor water level as designed. The trip was not complex, with all safety systems responding normally post-trip. Operations responded and stabilized the plant. The 'B' RFP was placed in service and is controlling reactor water level. Decay heat is being removed by discharging steam to the main condenser using turbine bypass valves. Unit 2 is not affected.
Due to the emergency core cooling system (ECCS) discharging into the reactor, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(A). Also, the Reactor Protection System actuation while critical is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). Additionally, it is reportable under 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of CIVs, RCIC and HPCI.
There was no impact on 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 cause of the 'A' RFP is under investigation. The reactor electric plant remains in a normal lineup with both emergency diesel generators available. There were no temperature or pressure technical specification limits approached. | | ENS 56989 | Cooper | 22 February 2024 17:03:00 | Accident Mitigation - High Pressure Coolant Iinjection Declared Inoperable | The following information was provided by the licensee via email:
At 1103 CST on February 22, 2024, a potential through-wall steam leak was identified on the high pressure coolant injection (HPCI) steam supply 1-inch drain line. As a result, HPCI was declared inoperable. Since HPCI is a single-train system, this is 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)(D). Reactor core isolation cooling (RCIC) and low pressure emergency core cooling systems (ECCS) remain operable.
Additional investigation is in progress.
There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | | IR 05000220/2023004 | Nine Mile Point | 1 February 2024 | Integrated Inspection Report 05000220/2023004 and 05000410/2023004 | | | IR 05000317/2023004 | Calvert Cliffs | 1 February 2024 | Integrated Inspection Report 05000317/2023004 and 05000318/2023004 | | | ML24003A763 | | 31 January 2024 | Mug 2024 MOV Regulatory Activity (Scarbrough) Final | | | NUREG-2194 Volume 2, Rev. 1, Standard Technical Specifications, Westinghouse Advanced Passive 1000 (AP1000) Plants, Volume 2: Bases | | 31 January 2024 | NUREG-2194, Vol. 2, Rev. 1, Standard Technical Specifications, Westinghouse Advanced Passive 1000 (AP1000) Plants, Volume 2: Bases | | | IR 05000382/2023010 | Waterford | 31 January 2024 | Comprehensive Engineering Team Inspection Report 05000382/2023010 | | | ML23319A245 | Watts Bar
Sequoyah | 29 January 2024 | Issuance of Amendment Nos. 366 and 360; 164 and 71 Regarding the Adoption of TSTF-567, Revision 1, Add Containment Sump TS to Address GSI-191 Issues | | | NMP1L3569, CFR 50.46 Annual Report | Nine Mile Point | 26 January 2024 | CFR 50.46 Annual Report | | | L-2024-003, NextEra Energy Seabrook, LLC - 10 CFR 50.46 - Emergency Core Cooling System LBLOCA 30-Day Report | Seabrook | 11 January 2024 | NextEra Energy Seabrook, LLC - 10 CFR 50.46 - Emergency Core Cooling System LBLOCA 30-Day Report | |
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