Arguments about technical "Show-Stoppers" will never satisfy people who have the philosophy, "nothing is impossible". A different approach is to ask the question: why bother with fusion power at all? The answer, given loudly by advocates of fusion, is that there are major advantages of fusion over fission, however, this website has examined many of the claimed advantages of fusion and found them lacking. The current page summarizes these comparisons and concludes there is no sensible reason to bother with fusion.
It is well known, or at least should be, that nuclear fission is one of the cleanest and safest forms of electricity production. This is clearly shown in the plot below from Our World in Data. An essential advantages of nuclear fission over wind and solar is due to reliability, wind and solar are weather dependent and so unreliable, requiring storage or back-up. As explained on the pages: Wind Intermittency and Solar Mismatch with Demand .
For the 7 Advantages of fusion listed on the ITER website, this website considers that 5 are invalid as summarized below with links to the pages which make the arguments. Of the 2 considered valid, fission has the same characteristics and so fusion has no advantage over fission.
1) Abundant energy: Fusing atoms together in a controlled way releases nearly four million times more energy than a chemical reaction such as the burning of coal, oil or gas and four times as much as nuclear fission reactions (at equal mass).
2) Sustainability: Fusion fuels are widely available and nearly inexhaustible. Deuterium can be distilled from all forms of water, while tritium will be produced during the fusion reaction as fusion neutrons interact with lithium.
3) No CO₂: Fusion doesn't emit harmful toxins like carbon dioxide or other greenhouse gases into the atmosphere.
4) No long-lived radioactive waste: Nuclear fusion reactors produce no high activity, long-lived nuclear waste. The activation of components in a fusion reactor is low enough for the materials to be recycled or reused within 100 years.
5) Limited risk of proliferation: Fusion doesn't employ fissile materials like uranium and plutonium. (Radioactive tritium is neither a fissile nor a fissionable material.) There are no enriched materials in a fusion reactor like ITER that could be exploited to make nuclear weapons.
6) No risk of meltdown: A Fukushima-type nuclear accident is not possible in a tokamak fusion device. It is difficult enough to reach and maintain the precise conditions necessary for fusion—if any disturbance occurs, the plasma cools within seconds and the reaction stops.
7) Cost: The power output of the kind of fusion reactor that is envisaged for the second half of this century will be similar to that of a fission reactor, (i.e., between 1 and 1.7 gigawatts). The average cost per kilowatt of electricity is also expected to be similar ... slightly more expensive at the beginning, when the technology is new, and less expensive as economies of scale bring the costs down.
With the arguments given on this website, no advantage of fusion over fission remains except the weak and rather bizarre, "Non-Proliferation" argument. The argument is not in a true disadvantage of fission and in fact plutonium can be produces, by neutron activation, in a fusion reactor.
This website concludes commercial tokamak fusion power stations, following the technology style of machines like ITER, will never happen. Copious reasons have been set out: ranging from the lack of tritium to their enormous cost, size and complexity. Furthermore, even if all the difficulties could be overcome, they would have no significant advantages over nuclear fission.