http://en.wikipedia.org/wiki/Lead-bismuth_cooled_fast_reactor
So there's no way that lead media(#7 birdshot?) could be pumped in to the reactor to displace all the water?
It seems like you could put a 75ATM boiler on top like an hour glass and then let gravity do the rest.
My understanding of the problem:
-Since SCAM, the reactor has stopped generating heat.
-without circulation of coolant, the latent heat of the fuel rods is causing the coolant to boil and increase the pressure inside of the reactor.
-if the coolant boils away without being replaced with fresh...