May need to revisit nuclear methane

After reading Zubrin's book, I ran the numbers on the 100 kw nuclear reactor that he proposes to land on Mars to make methane and lox for the return to Earth.  The numbers look like an order of magnitude on the high side, so that puts me in a bit of a pickle.  I hoped to use this information to calibrate my own, but there's so much of a discrepancy, this goes by the wayside.

A quick, but perhaps delusional idea, is that it is an electrical kw rating and not a thermal one.  If so, and if that is how it operates, that could explain it.  If not, another explanation is needed, and that may not be good for the nuclear methane idea.

Losses can add up pretty quickly.  Even if you can produce dirt cheap process heat, all of it could be eaten up pretty fast by other inefficiencies.

Need more info.