FYI: unprocessed uranium isn't radioactive enough to do a lot of harm. At least as eaten. BUT uranium is incredibly toxic as a heavy metal so it'd still kill you quickly.
Meme is referring to nuclear reactors, not complete antimatter annihilation.
Nuclear reactors don't "burn" everything --- most of the matter stays (this is what nuclear waste is). So you can only apply E=mc^2 to the difference in mass, not the mass of the fuel.
Well, its an Actinium (94), but it works better than Uranium. Alternatively you can also use Polonium to eliminate the need to eat for the rest of your life, it was even tested
None of that wimpy and watered-down regular bleach, though. Go for the liquid chlorine used in pools, it's typically about twice as strong. You can get it at Walmart (or Lowes} when it is in-season.
This just gives me spec-evo ideas for a person who does the shin-godzilla schtick where they ingest radioactive material and then use their inner fluids, either blood or some secondary circulatory system, as a coolant for the internal bio-reactor digestive system.
Either developing sail-hawks and sail-backs to expose as much surface area as possible, or Kit-Fisto style tail-locks with the same purpose.
Maybe a mix of both with the sail fans migrating to be like bat wings for that extra surface area cooling combined with high altitude chill.
Surprisingly I'd actually imagine this creature getting smaller, more use out of every bit of material they can find, and smaller creatures radiate heat more quickly than larger ones, so even more bio-coolant features to keep the reactor from making biological corium.
I think a gram of uranium will be able to pass through your digestive system without killing you. I wouldn't call it safe but that ammount of radiation isn't lethal. I don't know if it'd be poison, though.