Comment by gpm
5 days ago
Without any of the meltdown concerns a fusion powerplant is a lot simpler to actually build than a fission plant. It has a small fraction of the security, reliability, regulatory, etc concerns (not none, just way way less). Unless it's so marginal that it's barely producing electricity I'd be pretty surprised to find out we had Q>1 fusion and yet it couldn't out compete fission anywhere fission is practical.
Modern fission designs mitigate meltdown concerns well enough that I'm not sure the safety & security around a fusion plant would actually be any better/cheaper, although public sentiment may be enough of an advantage. Tritium & neutron activated metals are dangerous enough to require keeping the traditional nuclear plant safeguards IMO. As far as proliferation concerns go, I don't see any reason you couldn't breed plutonium in the neutron flux of a fusion reactor, & the tritium is clearly viable for boosted warheads.
Modern fission designs plausibly mitigate meltdown concerns well enough...
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.
A lot depends on the actual reactor design.
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.
That's astounding, I've never heard anybody claim that the reactors would be simpler before! Do you have any estimates of anybody working on the problem that thinks that?
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.
Not simpler in terms of technology, but simpler in terms of deployment, regulation, and security. Those are the majority of costs in fission power plants.
The majority of the cost in fission is in the massive construction build, change orders, logistics, massive concrete pours, welding, etc.
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.
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I think that it will depend on economies of scale.