Apparently it's helium cooled (woah) and a shipping container sized unit can "operate continuously for 20 years without refueling, generating 3-10 MW of electricity."

Their marketing materials imply the system is mostly hands-free and you just drop the container where you need power.

After the fuel is spent they claim it can be "decommissioned in two years" by which I'm guessing they mean the waste is ready to be stored somewhere.