[md2020]

Recently on a podcast John Carmack said somebody should look into building small fission fragment direct energy conversion reactors, since despite their lower efficiency, they’re apparently much cheaper to build. Since Carmack is a software guy (albeit a very good one) I’m somewhat skeptical, since it seems like if it’s not that complicated a design somebody would have tried it already and found good reasons why it doesn’t work. The only resources I could find on such a thing was a DoE paper about some prototypes Sandia and General Atomics built. Does anyone know more about the merits of this idea?

[lambdatronics]

Good question. I think historical designs supported the fuel elements on material structures that ended up absorbing a large fraction of the fragments, leading to inefficiency & overheating the fuel. Here's an outside-of-the-box idea, using a dusty plasma cloud. [0] In this case, I'd be concerned about a criticality accident if the fuel dust containment failed & all the dust landed in a pile.

[0] www.rbsp.info/rbs/PDF/aiaa05.pdf