Deuterium and tritium are both forms of hydrogen. Tritium is radioactive, however, and using it in a reactor will spread the radiation to other components. The “different fuel” mentioned is probably helium-3, which can be used in place of tritium and is non-radioactive. The problem is that it’s extremely rare and can’t be made artificially like tritium can. The movie “Moon” was about harvesting helium-3 from the moon because there’s more of it there.
Tritium decay is beta - no big deal. It’s the neutrons from fusion that will make the reactor vessel radioactive, if this works. Still, after a 30 year life, one radioactive reactor vessel is not much of a price to pay for all that energy.
Note: If true (a HUGE “if”), this will change the world’s economy and eliminate OPEC’s power.