Here they say that there is no waste per se only that some parts can become contaminated and they'll refurbish them onsite. The rest will be handed over to the authorities.
The Hot Cell Facility will be necessary at ITER to provide a secure
environment for the processing, repair or refurbishment, testing, and
disposal of components that have become activated by neutron exposure.
Although no radioactive products are produced by the fusion reaction
itself, energetic neutrons interacting with the walls of the vacuum
vessel will 'activate' these materials over time. Also, materials can
become contaminated by beryllium and tungsten dust, and tritium.
This one is about how much fuel is needed for the reaction(s). Based on how little is being used you could deduce on how little waste is being produced.
In fact, a fusion reaction is about four million times more energetic
than a chemical reaction such as the burning of coal, oil or gas.
While a 1,000 MW coal-fired power plant requires 2.7 million tons of
coal per year, a fusion plant of the kind envisioned for the second
half of this century will only require 250 kilos of fuel per year,
half of it deuterium, half of it tritium.
In addition, fusion emits no pollution or greenhouse gases. Its major
by-product is helium: an inert, non-toxic gas. There is no possibility
of a "runaway" reaction because the conditions for fusion are
precise—any alteration in these conditions and the plasma cools within
seconds and the reaction stops. Fusion has the capacity to furnish
large-scale quantities of energy, with a low burden of waste for
Also a relevant link posted by anna_v in a comment is:
Proponents believe that much of the ITER criticism is misleading and
inaccurate, in particular the allegations of the experiment's
"inherent danger." The stated goals for a commercial fusion power
station design are that the amount of radioactive waste produced
should be hundreds of times less than that of a fission reactor, and
that it should produce no long-lived radioactive waste, and that it is
impossible for any such reactor to undergo a large-scale runaway chain