Vogtle (USA)

Map of Vogtle

Map Loading...

2 * 1100 MW PWR units; constructed by Westinghouse; grid connection in 1987/89

Facilities in Vogtle

plantreactor typconstruction startoperation startshut down

PLEX of Vogtle 1 and 2

The Plant Lifetime Extension of Vogtle 1 and 2 has been accepted by the NRC. The new licences will expire in 2047 and 2049 respectively.


During refueling outage, false readings from water level instruments prompted operators to lower the water level in the reactor too far, causing the water to heat up 30°C, because water has fallen below RHR pump's suction leve. Operators shut the pump because of cavitation and pumped water back into the reactor.


On 20 March 1990, the Alvin W. Vogtle Unit 1 pressurized water reactor was in the
25th day of a refueling outage. The reactor coolant system was drained for mid-loop
operation. In this configuration, the upper portions of the reactor vessel and the steam
generators were emptied of water to allow inspections and maintenance on
components such as the steam generators and pressurizer. The reactor core in the
lower portion of the reactor vessel remained covered with water. A single residual heat
removal pump circulated water through the reactor core to remove decay heat,
maintaining the water temperature at approximately 90ºF. One of the two main power
transformers and one of the two emergency diesel generators were out of service for
maintenance. The containment equipment hatch was open.
A truck in the plant’s electrical switchyard backed into a support column for a
transmission line providing power to the in-service transformer. A phase-to-ground electrical fault de-energized the transformer and disconnected the reactor from its
electrical grid.
The only available emergency diesel generator automatically started on the loss of
offsite power, but it shut down about 80 seconds later due to sensor problems in its
control circuit. The operators declared a Site Area Emergency when ac power had not
been restored 15 minutes into the event.
About 18 minutes into the event, operators manually restarted the available emergency
diesel generator, but it shut down about 70 seconds later. About 36 minutes into the
event, operators manually restarted the available emergency diesel generator in
emergency mode, which bypassed most of the protective trips for the diesel generator.
They connected the emergency diesel generator to its electrical bus and restarted the
residual heat removal pump to re-established reactor core cooling. In the 41 minutes it
took to restore reactor cooling, the reactor water temperature increased from 90ºF to
Workers closed the containment equipment hatch about 80 minutes into the event.
Their efforts were slowed by lack of procedural guidance.
The interruption of reactor core cooling coupled with delay in re-establishing
containment integrity represented a risky situation because things could have led to a
reactor meltdown without a barrier against release of radioactivity to the environment.
The NRC calculated the severe core damage risk from this event to be 1 x 10-3 or 0.1%
per reactor year. The event was not rated on the INES scale.

(source: Residual Risk May 2007)


LOCA precursor: 2 RHR cold leg injection valves failed during startup with a flow path to RWST open, the incident could have exposed the RHR system and piping to operating pressures - first step to severe accident sequence (PWR-5) under that sequence, failure of check valves separating the primary circuit from the LPCI system could result in a LOCA that discharges into LPCI and breaks LPCI piping at a point which bypasses containment.