All of the discussion in other posts about emergency power ignores things like steam-driven emergency feedwater pumps. Those safety systems are very common in the US, and something like them exist in PWRs as well as BWRs. Steam is produced in either the steam generators or reactor. The steam goes to drive a small turbine connected to a pump. The pump then delivers cooling water back to the steam generators or reactor. No outside power is needed drive the pump. There might be a small amount of electricity needed to run the control systems for the pump and regulation valves, but that is a small draw.
- Pete
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This is a complex Mickey Mouse way to recover from a Station Blackout. It did not work at Fukushima. Most operators do not know how to do all this reconfiguration during a Station Blackout. It was does not provide any electricity to monitor the status of the reactor, the containment, and many other safety systems. It is not part of any design basis accident procedure authorized by NRC.
Jaak