And that's where all of our helium actually comes from. Any radioactive decay that emits alpha particles generates helium, since alpha particles are just helium nuclei. When that happens underground, the helium can get trapped. It tends to get trapped in the same places that natural gas gets trapped, so natural gas extraction often encounters helium as well.

Similar to oil and gas (although a completely different mechanism), it takes deep time to accumulate, but can be extracted much, much faster. So although new helium is being generated underground all the time, we can still run out in a practical sense.

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BobaFloutist 2 hours ago | parent [-]

Dumb question, but is there any world where a fission reactor could reasonably genrate waste with a short enough half-life to produce meaningful amounts of helium as a side-gig?

	▲	wat10000 an hour ago \| parent [-]
		I'd say no, although the amount of helium that's produced is small enough that it's not quite as absurd as I would have thought. Worldwide helium production is something around 25,000 tons/year. A nuclear power plant produces about 25 tons of waste per year. There are about 440 nuclear power plants in the world. If their waste consisted entirely of helium, that would be roughly 44% of total world helium production. More than I guessed! But, of course, only a tiny, tiny, tiny fraction of that waste ever turns into helium, so even if you somehow made it decay all at once, it would be be pretty insignificant on a world scale.