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Nuclear fusion has encountered a shortage of tritium

wired.co.uk

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Re: Nuclear fusion has encountered a shortage of tritium

#101

Post by willis936 »

perihelions wrote: post #79
theptip wrote: post #58

> “It would be an absurdity to use dirty fission reactors to fuel ‘clean’ fusion reactors,” This seems like a non-sequitur. If we need to keep around (or even build) a few heavy-water fission plants to enable the fusion industry, what's the problem? The simple phrasing of fission as "dirty" really shows the quotee's biases. You could easily envision a stable energy mix with a few percent of fission, the rest fusion a…

- "a few heavy-water fission plants" It's actually tilted very far in the opposite direction. The ratio is something like 600:1 heavy-water fission to fusion. A mix of 99.8% fission and 0.2% fusion, if your fusion is relying on that as its sole source of tritium. - "Small quantities of tritium are also produced by CANDU-type nuclear reactors—on the order of 100 grams per year for a 600 MW reactor," https://www.iter.o…

No tritium producing facility separates out nearly all tritium. Tritium separation and handling systems are expensive and demand has been low. It is not that more reactors are needed to meet demand. If demand ramps then the untapped supply can simply be tapped.

Re: Nuclear fusion has encountered a shortage of tritium

#103

Post by meowkit »

toomuchtodo wrote: post #64
fallingknife wrote: post #62

Earlier quoted context omitted.

Intel has a capex budget of $27 billion just for 2022, so you don't really understand scale or have a point.

Intel has working products, customers, shareholders, and fundamentally, accountability for that research spend. Results driven research funding is not unreasonable, unless you want to classify this research in the same vein as particle accelerators and a curiosity with no expectation of success (which is fine; just don’t sell as an energy silver bullet where there’s no evidence it can be delivered on). Hope is not a…

Just because the semiconductor's productivity gains have been massive on a short term time horizon, does not mean that fusion research has been a waste, or that is not on track to "deliver". Fusion as a technology is a long term bet and requires much more capital expenditure, for little short term return, then even semi fabs (which are notorious capital sinks).

Your mention of cost justification is ignoring the bigger picture that our economic system is setup to benefit public companies like Intel, and not grand research endeavors.

As an exercise to the reader, imagine what organizations/companies would exist if the contemporary economic incentive structures were different.

Re: Nuclear fusion has encountered a shortage of tritium

#104

Post by perihelions »

willis936 wrote: post #101
perihelions wrote: post #79

Earlier quoted context omitted.

- "a few heavy-water fission plants" It's actually tilted very far in the opposite direction. The ratio is something like 600:1 heavy-water fission to fusion. A mix of 99.8% fission and 0.2% fusion, if your fusion is relying on that as its sole source of tritium. - "Small quantities of tritium are also produced by CANDU-type nuclear reactors—on the order of 100 grams per year for a 600 MW reactor," https://www.iter.o…

No tritium producing facility separates out nearly all tritium. Tritium separation and handling systems are expensive and demand has been low. It is not that more reactors are needed to meet demand. If demand ramps then the untapped supply can simply be tapped.

I'm not a domain expert, but I believe that figure is the total amount that's created, not separated.

I.e. this language:

- "Ni et al (1) estimate that one CANDU 6 reactor can produce 130 g of tritium per year, but this is based on physics, not actual production data."

https://scientific-publications.ukaea.uk/wp-content/uploads/...

ref. (1) is https://sci-hub.se/http://dx.doi.org/10.1016/j.fusengdes.201...

It's just not a physically efficient process. Heavy-water reactors weren't optimized to produce tritium; it was an unwanted contaminant.

Re: Nuclear fusion has encountered a shortage of tritium

#105

Post by ncmncm »

Ironically, this is perhaps the smallest problem facing practical civil fusion power.

Probably the biggest problem is wasting time and budget on such dead-end technology as Tokamak, which can never in anybody's wildest dream be competitive with renewables, even given abundant tritium. But the conceivably useful D-3He aneutronic fusion depends on a supply of 3He, which is uniquely a product of tritium decay, and thus also depends on a tritium supply.

Thus D-3He would not be useful for baseload civil power, either. But it could be the only useful power source for projects in the outer solar system, for which a much smaller amount of 3He would suffice. It is hard to imagine another power source adequate in the outer solar system (aside from pB11 fusion which would be super if it is actually possible at all).

(No, mining 3He from the moon would totally not work at all.)

Re: Nuclear fusion has encountered a shortage of tritium

#106

Post by ncmncm »

zitterbewegung wrote: post #76
99_00 wrote: post #67

Earlier quoted context omitted.

There's a lot of bad thinking in that one sentence. All or nothing. We must have completely clean power or it has no value. Not using comparison. How does it compare to other sources of energy, (including solar which is built in facilities using coal power).

Fission is much cleaner than coal power plants in the Nuclear isotopes that are released into the air and we can contain nuclear waste pretty well.

Coal is on its way out, so is not a sensible standard of comparison.

Re: Nuclear fusion has encountered a shortage of tritium

#107

Post by perihelions »

jszymborski wrote: post #17

I'm not sure about the scale here, but is it really as crazy as the article says to use tritium that is formed from fission? What's the ratio of fusion:fission energy you'd need? I can't imagine even if it was 50% or 25% that it wouldn't be worth doing seeing as you'd just be fuelling a clean energy source from the waste stream of another energy source that doesn't produce CO2.

In my sibling comment, I calculate 600:1 fission:fusion, for the heavy water reactors they're talking about.

(I think it could be somewhat better if it were a fission reactor optimized for tritium, but I don't know the numbers for that. I think that would entail fast-neutron reactors with enriched ⁶Li blankets -- analagous to what the fusion reactors are planning to do).

Re: Nuclear fusion has encountered a shortage of tritium

#108

Post by ncmncm »

jszymborski wrote: post #54
marcosdumay wrote: post #29

Earlier quoted context omitted.

The reaction is supposed to be self-sustaining. The reactor walls are supposed to emit more than enough tritium to satisfy your needs. Whatever you bring from outside is just to bootstrap it once you turn it on. (I imagine they are not collecting the tritium between runs, but it's something you are expected to do.)

Wait, so then at _whatever_ cost, the cost of producing Tritium is sorta moot, right? Whether it's building reactors or investing a tonne of energy, the cost of creating the amount of tritium needed is met with theoretically infinite profits?

There will never be any marketable fusion power at all, never mind "infinite". Power from Tokamaks necessarily costs at least 10x power from fission, and fission is already not competitive, and gets less so each year.

Re: Nuclear fusion has encountered a shortage of tritium

#109

Post by ncmncm »

adrian_b wrote: post #78
ASalazarMX wrote: post #48

Earlier quoted context omitted.

> The reactor walls are supposed to emit more than enough tritium to satisfy your needs. Didn't know that fusion generators produced its own fuel! If it produces more than enough, then the excess tritium is considered radioactive waste?

The kinds of fusion generators that are considered for the near future produce most of their energy as kinetic energy of neutrons. The energy of the neutrons is transformed into heat by adsorbing them into some shielding walls. The materials for those walls will be chosen to minimize the quantity of radioactive waste that is produced by the extremely intense neutron irradiation, but it is impossible to avoid complete…

You could absorb neutron flux in a thousand tons of molten 6Li/7Li, and then try to separate grams of tritium from that thousand tons of molten, extremely inflammable metal, on a continuous basis. Good luck with that.

Renewables do not incur such operating expenses. Put renewables and a fusion reactor on the grid, and fusion would never, ever win a bid.

"Fusion .. will generate ... less ... than fission"? The whole damn ten-thousand-ton reactor becomes radioactive waste in short order. Fortunately, none will be built, so it is only a theoretical problem.

Re: Nuclear fusion has encountered a shortage of tritium

#110

Post by ncmncm »

gitfan86 wrote: post #69
westcort wrote: post #59

My key takeaways: * In a perfect world, there would be a more ambitious program developing the breeding technology in parallel to ITER, Willms says, so that by the time ITER has perfected the fusion reactor there’s still a fuel source to run it * Like many of the most prominent experimental nuclear fusion reactors, ITER relies on a steady supply of both deuterium and tritium for its experiments * When it’s finally fu…

Last week Elon explained that the problem of fusion is that it will be more expensive than solar and wind.

Like the stopped clock, even Elon is right once in a long while.
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