21:16 May 23, 2022
Automatic Reactor SCRAM
The following information was provided by the licensee via email:
At 1716 hours EDT on May 23, 2022, Susquehanna Steam Electric Station Unit 1 reactor automatically scrammed.
Unit 1 reactor was being operated at approximately 100 percent [Rated Thermal Power] RTP. The Control Room received indication that both divisions of [Reactor Protection System] RPS actuated from [Reactor Pressure Vessel] RPV high pressure signals and all control rods fully inserted. The Main Turbine bypass valves opened automatically to control reactor pressure. Reactor water level lowered to -42 inches causing Level 3 and Level 2 isolations. [High Pressure Coolant Injection] HPCI [Emergency Core Cooling System] ECCS actuation occurred as designed at -38 inches and injected to the Reactor Vessel. No other ECCS system actuations occurred. [Reactor Core Isolation Cooling] RCIC automatically initiated as designed at -30 inches. The Operations crew subsequently maintained reactor water level at the normal operating band using Feedwater pumps.
The reactor is currently stable in Mode 3. An investigation is in progress into the cause of the Automatic SCRAM.
The NRC Senior Resident Inspector was notified. A voluntary notification to [Pennsylvania Emergency Management Agency] PEMA will be made.This event requires a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> ENS notification in accordance with 10 CFR 50.72(b)(2)(iv)(A) & 10 CFR 50.72(b)(2)(iv)(B) and an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> ENS notification in accordance with 10 CFR 50.72(b)(3)(iv)(A).
Pennsylvania (NRC Region 1)
|10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge|
|Time - Person (Reporting Time:+-0.25 h-0.0104 days <br />-0.00149 weeks <br />-3.4245e-4 months <br />)|
21:01 May 23, 2022
|NRC Officer:||Karen Cotton-Gross|
|Last Updated:||May 23, 2022|
|55909 - NRC Website|