Probably a stupid car question...

[Lissa]

Yeah, their present tendency to go unstable and wipe out a whole city leaves a little to be desired.

And, the glass is still half full.

But... it is kind of true that we have the technology to create millions of small scale power reactors that would be emissions free, however, the powers that be don't want to allow such devastating power into the hands of consumers, even if it were affordable. If they were designed to be modular and portable, they would survive multiple vehicle shells before running out of power.

The problem isn't so much minaturizing, it's shielding. To give you an idea, the TRIGA that the University of Arizona had (the decommissioned and pulled it out this year) used 20 feet of water to shield people from the radiation. While in a shutdown state, the radioactivity in the reactor room was at background levels, but when the reactor was powered up, you were still taking about 10 mRem/hr.

So, in order to properly shield a reactor core, you would need a dense material for the gammas (tungsten, lead, uranium - yes, it's a great gamma shielder) and something loaded with hydrogen (water, parafin wax) for the neutrons. This so called minature reactor would actually be about the size of the car itself with the power transformation equipment (turbines, generators, pumps/compressor depending on the cooling fluid for the reactor) in order to properly shield it from the gamma rays and neutrons it was producing.