Peach Bottom - AUTOMATIC SCRAM DUE TO ELECTRICAL TRANSIENTS

U.S. Nuclear Regulatory Commission

Operations Center

EVENT REPORTS FOR

05/17/2022 - 05/18/2022

55899

Power Reactor

Event Number: 55899

Facility: Peach Bottom

Region: 1     State: PA

Unit: [2] [] []

RX Type: [2] GE-4,[3] GE-4

NRC Notified By: Linell, Bill

HQ OPS Officer: Brian P. Smith Notification Date: 05/16/2022

Notification Time: 19:51 [ET]

Event Date: 05/16/2022

Event Time: 15:52 [EDT]

Last Update Date: 05/16/2022 Emergency Class: Non Emergency

10 CFR Section:

50.72(b)(2)(iv)(B) - RPS Actuation - Critical

50.72(b)(3)(iv)(A) - Valid Specif Sys Actuation Person (Organization):

Lilliendahl, Jon (R1DO)

Power Reactor Unit Info

Unit SCRAM Code  RX Crit  Initial PWR Initial RX Mode Current PWR  Current RX Mode

2 A/R Y 100 Power Operation 0 Hot Standby

Event Text

AUTOMATIC SCRAM DUE TO ELECTRICAL TRANSIENTS

The following information was provided by the licensee via fax:

"Unit 2 experienced multiple electrical transients resulting in a Group I Primary Containment Isolation Signal (PCIS) isolation and subsequent unit reactor scram. Low reactor water level during the automatic scram caused PCIS Group II and III isolation signals. Following the PCIS Group I isolation, all main steam lines isolated. All control rods inserted and all systems operated as designed."

The following additional information was obtained from the licensee via phone in accordance with Headquarters Operations Officers Report Guidance:

Peach Bottom Unit 2 automatically scrammed from 100 percent power due to an electrical transient and subsequent PCIS Group I isolation (Main Steam Isolation Valve closure). Unit 2 lost main feedwater due to the PCIS Group I isolation, however, all other systems responded as expected following the scram. High Pressure Coolant Injection is maintaining pressure control while Condensate Pumps are maintaining inventory. The unit is currently stable and in Mode 3. Peach Bottom Unit 3's Adjustable Speed Drives were impacted by the electrical transients and the unit reduced power to 98 percent power.

The NRC Resident Inspector was notified.