ENS 55975
ENS Event | |
|---|---|
06:04 Jul 4, 2022 | |
| Title | Reactor Manual Scram Due to Lowering Reactor Water Level |
| Event Description | The following information was received from the licensee via facsimile:
On July 4, 2022 at 0104 CDT, with Unit 2 in Mode 1 at 100 percent power, a manual scram was inserted on U2 due to lowering reactor water level, which occurred following an unexpected closure of the 2A Feedwater Regulating Valve. Following the reactor scram, reactor water level decreased to approximately minus 16 inches, which resulted in an automatic Group II and Group III isolation (expected response). Following the scram, reactor water level rose to plus 75 inches resulting in a trip of all three Reactor Feedwater Pumps. At 0114 CDT, Reactor Water Level lowered to less than the Feedwater Pump High Level Trip setpoint and the 2C Reactor Feedwater Pump was restarted. Reactor Water Level control has been established in a normal band. The cause and details of the event are under investigation. The Unit 2 scram was not complicated. Operations responded using the Emergency Operating Procedure and stabilized the plant in mode 3. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 was unaffected by the event and remains at 100 percent power. Due to the Reactor Protection System actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). 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 licensee will notify the Illinois Emergency Management Agency. |
| Where | |
|---|---|
Quad Cities  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation | |
| LER: | 05000265/LER-2022-002 Manual Scram Due to Feedwater Regulator Valve Failure Decreasing Reactor Water Level |
| Time - Person (Reporting Time:+-0.12 h-0.005 days <br />-7.142857e-4 weeks <br />-1.64376e-4 months <br />) | |
| Opened: | Mike Maclennan 05:57 Jul 4, 2022 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Jul 4, 2022 |
| 55975 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (100 %) |
| After | Hot Standby (0 %) |
WEEKMONTHYEARENS 571412024-05-23T16:46:00023 May 2024 16:46:00
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