For a sensible air cooled heatsink, what is the maximum wattage a nuclear reactor could be?
Apparently they can be quite large. Google 'air cooled condenser'. One hit shows "World's largest natural draft dry cooling system, 6 x 690 MW kendal power station, south africa"
Seems to me a smaller unit could be designed to condense the steam relief flow and send it back to the (turbine driven) auxiliary feedwater pump for post-trip decay heat removal. If they're really natural draft this could even work indefinitely during a station blackout, without sending river or ocean water into your SGs.
Interesting, so what about for a mobile application on land, where access to water is nonexistent?
I believe the Palo Verde units use air cooled condensers. They are in the middle of the desert in Arizona, west of Phoenix. Each unit is 3800 MWt, and they have to reject ~ 0.66 of the thermal energy directly to the environment.
So for example a modular reactor of, say, 40 MW needs a heat exchanger capable of sinking 26.4 MW thermal? In an air cooled solution that would seem to be too large to fit on a large semi truck or something.
EDIT: Is is possible to use an air cooled modular reactor to power something like a piece of heavy earthmoving equipment?
There is the shielding and containment as well.
Consider the size of a 40 MW gas turbine, and whether or not that would be mobile. Or consider the size of a 4400 HP (3.3 MW) diesel electric locomotive.
Palo Verde has 'regular' condensers rejecting heat via wet (forced draft) cooling towers. The make-up to the towers is waste water from Phoenix, piped out to the site.
Well clearly the power output wouldnt be 40 MW, more like 1/10th of that at best.
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