Even if fusion is an expensive power source, it may still be desirable in areas which aren’t well suited to wind or solar.
To move that "plausibly" into "actually" you have to have very careful design review by regulators. Very careful review of construction to make sure what is constructed is what was designed. And so on and so forth. It's a lot of friction that skyrockets costs. Legitimately. People inevitably attempt to cut corners, and there's no way to make sure they aren't on the safety parts without checking. Actual currently regulatory costs seem to bear out the difference between these, with SMR people spending large amounts of money to convince regulators they didn't screw up, vs Helion fusion being "regulated like a hospital".
I'm not saying fusion has no proliferation concerns. But it's the difference between "low grade nuclear waste, or a very high tech very advanced program to weaponize a working reactor" and "even a broken reactor can be strapped to some explosives to make a dirty bomb". I can't say I'm very aware of how much proliferation concerns drive costs.
Public sentiment also helps.
I was thinking more of large scale D-T fusion, e.g. the tokamak design, which requires breeding tritium & is expected to create a lot of neutron activated waste. The tritium is especially concerning, as it's roughly as deadly as polonium-210 & highly bioavailable in the form of super heavy water.
You're probably right for smaller aneutronic designs like Helion's. If they can actually be made to work, they'll be much safer.
Every schemer I have ever seen is quite a bit more complex than a fission reactor. Often, designs will depend on materials that do not yet exist.
That said there is a tremendous variety of techniques that fit under the umbrella term of "fusion," so I'm hoping to learn something more.
I've looked a lot into this in terms of how to get a project like Georgia's Vogtle to have cost less, or Olkioluoto in Finland, or Flamanville 3 in France. Big complex construction projects are expensive, and it's not clear at all to me that fusion would be simpler or smaller, or escape the rest of Baumol's cost disease that has been plaguing fission in highly developed economies.
(and other than that I echo elcritch's comments)
I still think its worth researching and we'll get there at some point, but I'm not holding my breath-- the whole industry has overpromised in the past, continues to overpromise now and will be probably be irrelevant for de-carbonizing the grid by the time the technology is actually ready at an industrial scale.
Mass media reporting on the whole sector is admittedly even worse; especially for uninformed readers without an engineering background.
I believe the current timetable is no longer contingent upon funding (since they've got the funding they think they need). It's no doubt still an optimistic startup timeline, a target, that they might well fail to achieve (even without the startup failing, just being late).
It's a cool concept, but probably not gonna be viable anytime soon (if ever!).
Does the physics change as they scale up the field strength? No one is really going to know until they try (unless we get a lot better at simulating plasma real fast). If not, they lost a bet, but they lost it honestly and as far as I can tell (not a physicist) it was a reasonably good bet to make.
Can they physically build the bigger magnets they need fast enough to meet their timelines (and everything else. I understand they are currently bottlenecked on capacitors)? Apart from normal "startups are overly optimistic" issues I don't see any reason to think that they shouldn't be able to reliably predict how fast they can scale magnet size, or be limited to a linear rate. While they are big magnets, it's not exactly new physics.
I'm not sure I'd say they are "probably going to be viable" anytime soon either. I think they have a good chance, but "probably" as in ">50%" is probably pushing it. (Also depends on where you put the goalposts of course)
FWIW I believe that 2018 report was for a high gain low pulse rate plan that Helion rejected, and they are aiming for substantially lower strength magnets as a result. I can't find anything more than rumors to confirm that though.
It's just that from everything I know about the project, they still have a long way to go, and there are a lot of milestones to hit that are just pipe dreams for now (actually fusing He3, breeding it, net-gain energy extraction, ...).
I would expect progress to slow down significantly as the scale of prototypes and their complexity increases (like what happens for basically every engineering project ever)-- but progress is already slow/behind schedule to begin with...
Though I guess some of that infrastructure could be overbuilt due to excessive regulation.
Also much of the concrete and steel is needed for the containment domes. Fusion power likely wouldn’t require nearly as much protection. Perhaps just a fairly standard industrial building.
Helion's reactor, if it works, could become a source of the cheapest neutrons on the planet. It would greatly enable nuclear proliferation by providing neutrons for breeding of fissionable material for bombs.
A 50 MW DD reactor would produce enough neutrons to make half a ton of plutonium per year. Remember, none of these neutrons have to be turned around to make tritium, as they would have to be in a DT reactor.
Easy to find research showing the detrimental effects of masks on communication, etc: https://pmc.ncbi.nlm.nih.gov/articles/PMC10321351/