06:18 Nov 9, 2012
Unit 2 Manual Scram Due to Loss of the Integrated Control System
At approximately 0118 hours0.00137 days <br />0.0328 hours <br />1.951058e-4 weeks <br />4.4899e-5 months <br /> [EST] on November 9, 2012, Susquehanna Steam Electric Station Unit Two reactor was scrammed by plant operators due to a loss of ICS (Integrated Control System; which controls the reactor feed and reactor recirculation systems). The reactor operator placed the mode switch in shutdown when reactor water level reached +25 inches and lowering. All control rods inserted and both reactor recirculation pumps tripped at -38 inches. Reactor water level lowered to -52 inches causing Level 3 (+13 inches) and level 2 (-38 inches) isolations. HPCI and RCIC both automatically initiated. HPCI was overridden prior to injection and RCIC was utilized to restore reactor water level to the normal band. All isolations and initiations at this level occurred as expected. No steam relief valves opened. Pressure was controlled via turbine bypass valve operation. All safety systems operated as expected.
The [Unit 2] reactor is currently stable in Mode 3. An investigation into the cause of the loss of ICS is underway.
Unit One continued power operation [at 78% power].
The NRC Resident Inspectors were notified. A press release will occur.
The licensee will inform the State of Pennsylvania.Decay heat removal is being maintained through the main condenser. On-site electrical power is in the normal configuration.
Pennsylvania (NRC Region 1)
|10 CFR 50.72(b)(2)(iv)(B), RPS Actuation|
10 CFR 50.72(b)(3)(iv)(A), ECCS Actuation
10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge
|Time - Person (Reporting Time:+-3.25 h-0.135 days <br />-0.0193 weeks <br />-0.00445 months <br />)|
03:03 Nov 9, 2012
|NRC Officer:||Vince Klco|
|Last Updated:||Nov 9, 2012|
|48496 - NRC Website|
Yes, Manual Scram
Power Operation (90 %)
Hot Shutdown (0 %)