it's removed from "natural gas" when they make LNG. the amount generated by nuclear reaction byproducts is trivial by comparison. See https://www.sciencedirect.com/science/article/pii/0022311570...

So it'll be running out of helium that will make it finally cost effective? /s

You're thinking of He3 isotopes. Standard He4 is a byproduct from natural gas extraction.