Reply To: NIMBY FUD

[zapkitty]

(Major edit … no biggie, what’s a wrong answer 19.7 times smaller than the actual answer between friends?)

The discussion seems to be overlooking the matter of scale. It’s the amount of He per FF unit that matters most.

The cooling bottleneck is in the confined volume of the anode, specifically the part of the anode nearest the focus point. Thus the advantage of helium for that purpose. But that helium loop needs only to be long enough to reach from the anode tip to the anode base.

Once the heat is out of the anode then standard cooling techniques can take over without strain.

And the pB11 unit would requiire a much smaller anode than even what LPP is currently working with.

So from dimensions LPP gave previously for a production FF unit we’re talking about something less than a hundred or so cubic centimeters.

Estimates for helium as reactor coolant quote from 2-7 megapascals… for now I’ll guess at 2 MPa for something like a DPF…

edit: forgot to multiply from atmospheric to MPa… lets try that again..

So say 150 cubic centimeters of He @ 2 MPa x 462,280,000,000 FF units for current global electrical generation

He is 0.0001786 grams per cc at 101325 Pa… at 2 MPa thats 0.0035253 g per cc… times 150 cc per dpf core that’s 0.52879349 g per dpf… times
462280000000 units gives 244450650000 grams He for global FF power or ~244451 tons…

So, even though that’s 19.7 times my original estimate, that is still feasible given that it will take years to build up to that point and that this He used for dpf coolant would still be recycled.

But Earthside supply limitations will have to be considered along the way, what with our wise and benevolent elites deliberately shaping a helium shortage to further entrench their fossil-derived power (and further enrich themselves, natch).

… and re lunar He: we’d only have to mine ~729 sq km of regolith at a 4 meter depth to cover the current projection of global FF helium needs…