So quietly a really big news item is slipping by in this year of horror.
I’m not educated enough to do this news justice but roughly SPARC is an MIT led project. It is a compact, high-field, DT burning tokamak. Talk is a working reactor that is stable and produces more energy than it uses could well be running by 2025 and from there electrical generation could be a real thing in another 5-10 years.
Hopefully this post, gets our more knowledgeable physics people to comment and explain.
Nuclear fusion has been 10-15 years away for decades. I predict this is just another step in the chain of promising breakthroughs leading to failure.
I very much enjoyed “Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking” by Charles Seife
I would be happy to be proved wrong.
Weird, for my readings, Fusion has been 30 years aways since I was a kid. This is the most promising milestone I’ve seen.
It’s a milestone, but it’s breathlessly optimistic about commercially viable fusion power. In particular, three major practical roadblocks that contradict the ‘limitless, waste-free energy’ claims aren’t addressed by the experiment at all.
The first is that of fuel - a D-T reactor (which it looks like this is from a quick google) requires Deuterium and Tritium. Deuterium is pretty easy to collect, but Tritium decays quickly so isn’t found in the wild. Currently tritium is made by processes in fission reactors and harvested from there - which is a problem for the various ‘limitless, waste-free energy’ claims as with current processes. Also, worldwide production of tritium is around 20kg per year, while an estimate for a single commercial fusion reactor is that it would need roughly 250kg of fuel per year split between deuterium and tritium, so production would need to be massively increased. One solution that is floated for this problem is to use the neutron flux from fusion reactions to breed tritium from a blanket of lithium around the reactor. This could generate more tritium than is used in reactions, but whether it could all be collected is a difficult practical problem, as is keeping tritium from escaping the reactor. Even if the experiment created a reactor that works to produce significantly more energy than it consumes in 2025, producing enough fuel for electrical generation appears to be a problem that would take more than 5-10 years to solve.
And the fact that there is significant neutron flux which you could use for creating tritium brings us to the second problem, the fact that the reactor and/or it’s housing will become radioactive because of the release of neutrons from fusion. This both damages the structural integrity of the reactor and produces waste in shielding materials. While the waste produced will have lower rates of radioactivity than fission waste, it will likely be a much higher volume. And the third problem is that the neutron flux that could be used to breed tritium for peaceful fusion fuel can more easily breed weapons-grade fission material. This is trivial to do - all you do is put (non-enriched) uranium oxide in the area of neutron flux, and a portion of it will be transmuted to plutonium, which is then easily chemically separated from the rest of the ore. This is a major political issue with actually putting fusion power into widespread use, and I’m not sure how it will be solved.
This article below is a good reference to fusion issues written by a PhD who worked in the field for 25 years. While I think it’s overly pessimistic in tone, the issues raised are very real, and generally just get glossed over by fusion proponents.
From the technical standpoints, better superconductors and more powerful computing have made achieving fusion a more viable proposal.
As @Pantastic points out, there are still a number of logistics to be worked out.
I am not personally all that worried about waste, as that is manageable and not going to be all that great a volume, and I’m also not all that worried about proliferation, as any entity that can build and operate a fusion reactor can also enrich uranium or create plutonium.
But the tritium is a bit of a problem. Maybe not an unsolvable one, but it’s going to be a tough challenge.
Wow, that is incredibly exciting. I’ve been following the progress of the one in Europe for years now.
I don’t think it’s reasonable to tout fusion as the energy source of the future if most countries aren’t going to be able to use it. If fusion reactors are so difficult to maintain that it’s not reasonable for a country like Iran, Brazil or South Africa to operate them, then they’re not really as universal and easy of a power source as they’re being touted as.
I deliberately mention South Africa because they did have a nuclear weapons program from the 60s to the 80s that produced half a dozen bombs with help from Israel, they can’t make weapons grade materials today without importing a lot of (highly watched) equipment. And Iran similarly has the technical base to create a bomb, but not the actual expertise and equipment to do so. The problem with a fusion reactor is that, instead of a long, difficult process with a lot of easily traceable steps and requiring a lot of easily traceable machinery, creating plutonium is a matter of setting uranium ore near where the reaction takes place for a while, then taking the whole lump out and chemically separating it later. It turns something that takes decades of work and usually involves collaboration with other nuclear powers into something that pretty much just happens.
The best case scenario for fusion is that the reactors are treated like fission reactors today, and subject to frequent inspections from nuclear regulatory bodies. But that still puts them in a similar risk category to fission plants rather than the extremely safe facilities their proponents present them as.
I understand that they killed their nuclear weapons program when apartheid ended.
A few years earlier, actually, although it’s possible that the events were connected.
I heard they just cut it back, since now they wouldn’t need separate bombs…
Both Apartheid and the refusal to sign the Nuclear Non-Proliferation Treaty were causing them a plethora of foreign policy issues. The ending of Apartheid took place with negotiations that ran from 1987 to 1993, with Apartheid legislation repealed in 1991 and the 1994 elections set as the first with universal suffrage. The nuclear program ended in 1989 and South Africa signed the nuclear non-proliferation treaty in 1991, with inspectors confirming that they had no nuclear weapons capability by 1994. It looks to me like South Africa was tired of being a pariah state by the late 80s and ending both programs was part of a general program of getting on better terms with the Western world that happened at about the same time, though I’m no expert on it.