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billdietrich1 t1_j0batwi wrote

Fusion probably will be an incremental improvement (in cost and waste) over fission. Not game-changing.

Fusion probably won't be viable economically, by the time we get it.

"Big" (thermal) fusion will be similar to today's fission plants, as far as I can tell, minus the fuel costs. Still a big complicated reactor, actually MORE complicated than a fission reactor. Tons of electronics and high-power electrical and electromagnets and maybe superconductors to control and confine and heat a plasma, or drive lasers to ignite pellets. You get a thermal flux (neutrons) to drive a big steam plant that drives a generator. So lots of high pressures and temperatures to control, lots of pumps and turbines and other moving parts. Still some radiation. No need for a sturdy containment vessel. Still a terrorist target, still need security.

Fuel cost is about 30% of operating cost [not LCOE, I don't know how that translates; some say fuel is more like 10%] of today's fission reactors. Subtract that, so I estimate cost of energy from fusion will be 70% of today's fission cost. Renewables PLUS storage are going to pass below that level soon, maybe in the next 5 years. [Edit: maybe I'm wrong about fuel for fusion, see https://thequadreport.com/is-tritium-the-roadblock-to-fusion-energy/ ]

And "big" fusion really isn't "limitless" power, either. All of the stuff around the actual reaction (vessel, controls, coolant loop, steam plant, grid) is limited in various ways. They cost money, require maintenance, impose limits, and scale in certain ways. You can't just have any size you want, for same cost or linear cost increase.

Also, ITER (one of the flagship fusion projects) isn't going to start real fusion experiments until 2035, and the machine planned after ITER is the one that will produce electricity in an experimental situation, not yet commercial. So you might be looking at 2070 for commercial "big" fusion ? ITER is not the only game in town, but ...

Now, if we get a breakthrough and someone invents "small" fusion, somehow generating electricity directly from some simple device, no huge control infrastructure, no tokamak or lasers, no steam plant and spinning generator, etc, that would be a different story.

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Arackels t1_j0c5yyy wrote

You are missing the point. ☢️. Remove this from the equation. Source: I worked in nuclear power. 😂

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billdietrich1 t1_j0c6ipk wrote

Yes, fusion will have a lot less waste and radiation than fission. Not zero, but much less. And will the public understand the delta ? Maybe not, they're both "nuclear".

It is cost that will mostly kill fission, and probably consign fusion to niches once we do get it working.

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ItsAConspiracy t1_j0cqrut wrote

ITER is the world's slowest fusion project. CFS is doing the same thing with a reactor a tenth the size, because unlike ITER they're using modern superconductors. They'll be starting fusion experiments a decade earlier.

For your "small fusion breakthrough," Helion seems to have a good shot at it. They're building their seventh reactor, for a net power attempt in 2024 with advanced fuel and direct electricity extraction.

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A1_B t1_j0bif25 wrote

It all kind of depends on what investment is put into fusion in the next couple of years, historically investment into fusion is slow and so progress is slow, as the needed legwork on R&D can only be done with a new flagship experiment every one to two decades.

Science advances, to make such conclusions using now for then is kind of moot.

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billdietrich1 t1_j0bj125 wrote

Many of the costs and constraints on fission and fusion plants have nothing to do with nuclear or new tech. It's the "heat engine", all the heat transfer and cooling and steam turbine and spinning generator etc. That stuff is OLD and mature. Throwing more money at it is not going to change it. That's why fusion is not going to be a big change relative to fission. And why renewables and storage are going to dominate.

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A1_B t1_j0bjhrk wrote

I'm not so sure about the idea that steam turbine = old mature, therefore unscalable, kind of goes against reality where Nuclear is in use and how much power it generates.

What do you specifically mean with the generalization "renewables?"

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billdietrich1 t1_j0c4pvs wrote

> old mature

Certainly it is old and mature: it has been optimized to the max because it is in so many power plants and industrial processes. Don't expect some large improvement in steam tech.

> therefore unscalable

Again a matter of steam and temperatures and cooling etc. Scaling nuclear large is less of a problem than scaling small. I doubt SMR nuclear will go very small or be successful. Whereas some renewables scale down to the level of a single house.

> What do you specifically mean with the generalization "renewables?"

The usual definition: solar, wind, tidal, wave, geothermal, hydro.

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