!!~Don't Try This It's Illegal~!!
Just about every household in America has a small amount of radioactive material, Americium-241, the key component in all smoke detectors. Americium is a fissile element which means that it can sustain a nuclear chain reaction. It emits alpha and gamma radiation and has a half life of over 400 years. There is a phenomenally small amount of Am-241 in smoke detectors though, small enough for the department of defense to rest easy at night. Still, Americium is fissile so someone could build a nuclear device for shits and giggles if they wanted to. Theres about 1/5000th of a gram of Am-241 in a single smoke detector so I figure using mass-energy equivalence relation you could get about 60 joules of energy for every smoke detector you have. which is enough to throw a 100 gram object 60 meters in the air or heat one gram of air by 60 degrees Celsius. A basic smoke detector will cost about 6 bucks. $6 for 60 joules of nuclear energy isn't exactly efficient, but its fucking fun.

Congratulations, you're a fucking retard.

Americium is not an appreciable gamma emitter, for starters. Secondly, one joule is the energy expended by a force of one newton moving an object one metre along the direction of the force. Try doing that against gravity, and see how far you get. You're also assuming a perfect transition of mass-to-energy from the radioisotope, which is pretty much what every nuclear physicist on the planet has been trying to do for the past sixty years.

Finally, critical mass for Americium-241 is roughly sixty kilos. So, for .002g of useable isotope per smoke detector, you'd need thirty million of them. At $6 each, you're looking at roughly the national debt of the Soviet Union to make just ONE of your shitty weapons. Not even counting the cost of, say, the massive blocks of tungsten carbide you'd need as neutron reflectors, or complex slapper detonators.

Aside from that, Americium is a shitty weapons fuel because of it's poor neutron density.

All in all, I give you an F. nice try, though.

IMO.. Even if 1 smoke det. could give you enough for a small 3 ft explosion or w/e. Who would want a 3 foot radioactive hot spot anywhere for 400 years?

Dose not sound to thrilling at all.

Food for thought. We don't get enough of it these days and when we do its shit, and I'm not about to go eating shit.

End this shit.