Title is extremely misleading.

> "Right now, the tritium used in fusion experiments like ITER, and the smaller JET tokamak in the UK, comes from a very specific type of nuclear fission reactor called a heavy-water moderated reactor."

You litterally just need to make more of these heavy-water moderated reactors, which are rare and approaching end of life, but certainly you can build more of them if it was the difference between having endless energy or not.