We’re talking about ‘hot’ fusion here. The BBC has published a report on the current state of the Iter project in Provence, France where there is ongoing construction of a Tokamak reactor. The article discusses the delays that have held up progress on the project, but says that some of the problems have been resolved with better coordination between the participating countries.
Here’s a brief explanation of what they are trying to do from the BBC
There are however still problems projecting a completion date. Parts for the reactor need to be built to very exact specifications, and shipped to France from all over the world in a strict sequence. Once on site, all these parts have to be assembled to very tight specifications:
The 28 magnets that will create the field containing the plasma have to be machined to a very demanding level of accuracy. And each part must be structurally sound and then welded together to ensure a totally tight vacuum – without which the plasma cannot be maintained. A single fault or weakness could jeopardise the entire project.
Assuming Iter does succeed in proving that fusion can produce more power than it consumes, the next step will be for the international partners to follow up with a technology demonstration project – a test-bed for the components and systems needed for a commercial reactor.
It’s a major undertaking, and there still seems to be much uncertainty in terms of project completion, and whether the reactor will work as planned. So why are governments willing to expend so much effort and spend so much money on the project? There is the hope that we could one day replicate something like the energy of the sun at a high COP (this article mentions production of 500 MW at a COP of 10 ) from a cheap fuel, with no greenhouse emissions and ‘relatively little’ radioactive waste.
For a long time, without any alternative way to reach these goals, such a project may have made sense, but it seems to me the plan is now quite outdated since it appears that now E-Cat has demonstrated that it can meet these objectives in a much cheaper and easier way.