Talk:Volatiles Refinery/@comment-25153693-20140708133430/@comment-24951265-20140708145050

Well, no particular isotope is truly *essential* for fusion - H3 and He3 just happen to be useful for some of the easier to handle reaction paths. In RL, H3 is highly useful as a tracer for a number of purposes, though limited because it's mass is so low, and yet still 3 times that of H1, that its chemical properties actually are affected fairly significantly - enough so that either H2 or H3 can mess up enzymatic pathways and cause poisoning.