[CosmosGP]

Is the Tritium needed for HYdrogen fusion?

Is using Lithium the only way to get tritium?

[azmanam]

Dunno about the hydrogen fusion, but lithium is not the only way to get tritium, though it does seem common in nuclear reactors.  It seems to be naturally occurring through cosmic ray interaction with atmospheric nitrogen.

http://en.wikipedia.org/wiki/Tritium
http://www.physics.isu.edu/radinf/tritium.htm