Quote:
Originally Posted by cmac2012
I was a little apprehensive about the liquid sodium coolant thing but they practically won’t work w/o it. The history of sodium cooled reactors is a checkered one. Numerous lengthy plant closures - permanently in some cases - have resulted from water somehow mixing with sodium in the heat exchanger.
But the more I look at that, the more manageable the sodium thing seems. One possible solution is to use CO2 or even helium at high pressure as the expansive medium in the turbine. Just take water out of the picture.
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Actually, back in the 80's before they closed the site down, there was a helium cooled prototype test reactor out at Hanford in WA state. Difference was , from what I understand, was that helium was the coolant in the PRIMARY loop - what was actually circulated thru the reactor - and they still used water on the secondary side to run steam turbines. Back in '88, an old Navy Nuke friend was living in Benson City and had gotten a job there with a waste disposal company, gave me something of a mini-tour and described some of what was going on at the site, including the helium cooled test unit. One of the problems he mentioned was that they were having a deuce of a time designing pump and valve seals that wouldn't continually leak a small amount of helium.
If they could finally figure out a way to make it work, a Colliding Beam Reactor (CBR) using aneutronic fission (fission without neutrons) would be almost ideal from the standpoint of essentially no radiation or spent fuel/waste/radioactive byproducts. The idea is to cross over multiple particle streams of lithium, such that at the point of intersection the particle density is so high that particle collisions and fission of the lithium nuclei occur. Result is charged particles that can be converted to electricity, and little if any radiation.