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MANUAL
REACTOR SCRAM DUE TO PARTIAL LOSS OF
OFFSITE POWER DURING WINTER STORM
"On January 4, 2018, at 1410 hours EST, with the reactor at
approximately 100 percent power and steady state conditions, the winter storm
across the Northeast caused the loss of offsite 345 kV Line 342. Reactor
power was reduced to approximately 81 percent and a procedurally required
manual reactor scram was initiated. All control rods fully inserted.
"As a result of the reactor scram, indicated reactor water level decreased, as expected, to less than +12 inches resulting in automatic
actuation of the Primary Containment Isolation Systems for Group II - Primary
Containment Isolation and Reactor Building Isolation System, and Group VI -
Reactor Water Cleanup System.
"Reactor Water Level was restored to the normal operating band. The
Primary Containment Isolation Systems have been reset. The Reactor Protection
System signal has been reset.
"Following the reactor scram, the non-safety related Control Rod Drive
Pump "B" tripped on low suction pressure. Control Rod Drive Pump
"A" was placed in service. All other systems operated as expected,
in accordance with design.
"This event is reportable per the requirements of Title 10, Code of
Federal Regulations (CFR) 50.72 (b)(2)(iv)(B) - "RPS Actuation" and
10 CFR 50.72 (b)(3)(iv)(A) - "Specified System Actuation."
"This event had no impact on the health and/or safety of the public.
"The NRC Resident Inspector has been notified."
The main steam isolation valves are open with decay heat
being removed via steam to the main condenser.
Offsite power is still available from 345kV line 355. As a contingency, emergency diesel generators are running and powering safety
busses per licensee procedure.
The licensee notified the Commonwealth of Massachusetts. The licensee will be
notifying the town of Plymouth as part of their local notifications. The
licensee will be issuing a press release.
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