I’ve just been swallowed by a rabbit hole on heavy hydrogen, the Norwegian hydro plant used to make fertiliser by splitting water and D being left behind, then them realising they could sell D₂O.
It being used in some medicines, and in semiconductor processes, then in preserving Blue OLED for longer.
from the article:
Stable, NON radioactive isotope of hydrogen with one proton and one neutron in its nucleus. Natural abundance of 0.015% of hydrogen atoms on Earth
It looks interesting, but the article has too few details. Some more info in the first reference https://pmc.ncbi.nlm.nih.gov/articles/PMC11936013/ Anyway, IIUC it discuss a research lab method, that may be hard to escale to factory production.