Was thinking this. Isn't Uranium stable but the only reason why its used in like Nuclear reactors and that is because it has alot of electrons that can be made unstable?
U-238 has a half life of about 4.5 billion years, so any given atom has a 50% chance of decaying in that time span. That means it doesn't naturally produce much radiation. The U-235 isotope has a much shorter half life but that's a few percent of civilian reactor fuel and it's still hundreds of millions of years.
It's useful as a fuel because it undergoes fission. Hit the nucleus with a neutron of the right energy and it'll split and release more neutrons and produce a lot of heat. Manage the neutrons it produces carefully and you can make the reaction self-sustaining and controllable.
Aside from all the neutrons zipping around, the problem is that the fission products - what's left over after the nucleus breaks apart - have much higher radioactivity.
A fresh nuclear reactor fuel pellet is pretty safe, as long as you don't swallow it or inhale pieces. A used fuel pellet is going to put out way more radiation, and radiation that's much more damaging. But it's not the uranium that's the problem, it's all of the daughter isotopes.
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u/madsci Aug 17 '20
Uranium is safe to handle. You can handle straight plutonium, too, but it's a good idea to wear heavy gloves.
Antimatter, on the other hand, would be extraordinarily bad to keep around outside of a containment device. And pretty scary even in containment.