system
Given the following post, respond as if you're commenting on Reddit:
human
Helium is a product of nuclear fusion.  Could this fact solve the coming helium shortage once fusion reactors become viable?
gpt
Probably not. Back of the envelope calculation coming up, may well contain stupid errors:

Assuming D-T fusion, a single fusion event releases a 14.1MeV neutron and a 3.5MeV helium nucleus. Assuming you can absorb all this energy and you've got an efficient heat engine setup at around 50%, you'll get about 1.5x10^-12 J per fusion, so for a 1GW output you'll need 6.67x10^20 fusions per second. Say you have 1TWe (electric output) worth of fusion reactors worldwide (about half of current electricity generation), then you're producing 1000 times as much helium, or 6.67x10^23 atoms per second. About a mole each second, or 4 grams. This works out to 126 tons of helium a year, or about 1000m^3 per year of liquid helium. The US strategic helium reserve had a peak volume of about a billion m^3 . World consumption of helium is measured in tens of millions of m^3 per year so you'd be short by several orders of magnitude in the best case.