Westinghouse 3-loop PWRs

rmattila

Would anybody happen to have at hand the water volume of the secondary side of Westinghouse 3 loop PWR steam generators?

Regarding the loss of external grid incident at North Anna, it would be nice to have a rough estimate of how long the plants could survive a total blackout by boiling off water from the SG:s.

Astronuc

Earthquake was about 8-9 miles from the plant, although some info indicates 1 mile. They lost off-site power and the EDGs started up. Both units shutdown.

I'm sure they'll have an interesting Event Report out soon.

QuantumPion

With a loss of feedwater flow, PWR steam generators boil dry in minutes.

North Anna has a terry turbine (steam-powered pump) to provide feedwater flow in the case of loss of total electrical power failure, as well as a station blackout diesel (in addition to the regular backup diesels).

rmattila

If the steam generators are similar to Ringhals 4, which is a 935 MWe Westinghouse 3-loop PWR, their secondary side inventory would appear to be some 40 m³ or 30 t per SG, which would 1 hour after scram be enough for approximately 1.5 h, if I got the figures correct.

However, the existence of a steam driven auxiliary pump and an SBO diesel make the situation appear quite non-problematic.