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> “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

> “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 and storage/peaking power, and that would be far, far cleaner than our current GHG/pollutant-heavy mix of fossil fuels. It seems quite premature to call this a "crisis" since we already have proven ways of manufacturing the required ingredient. I suppose the risk is just that this pushes up the price of fusion in the initial phases of deployment, providing an "activation cost" that delays fusion from taking over, but that's quite a speculative concern at this point.

99_00 4y ago
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).
- zitterbewegung 4y ago
  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.
  - ncmncm 4y ago
    Coal is on its way out, so is not a sensible standard of comparison.
- JimTheMan 4y ago
  At some point, we will have enough solar/hydro/wind etc that they won't be built using coal power... Right now it's a necessary yes, in the future no. In a way, that last (...) is also a very black and white way of viewing things.
  - 99_00 4y ago
    >In a way In what way is it black and white view of things? Solar energy production is not 100% clean. It never will be regardless if coal is used or not. That doesn't mean it's bad. The goal isn't purely clean energy. The goal is improved sources of energy. Hopefully coal isn't used in the future. But things don't appear to be on track. https://www.carbonbrief.org/china-briefing-17-march-2022-beijing-doubling-down-on-fossil-fuels-chinas-co2-emissions-increase-coal-production-growth/ https://www.carbonbrief.org/china-briefing-17-march-2022-bei... Unfortunately, because black and white thinking and evaluating energy sources without comparing them has resulted in a shortage of natural gas (thanks to fossil fuel divestment and ESG) and energy producers falling back to coal. The worst possible source of energy.
- c7DJTLrn 4y ago
  It's just shit popsci journalism. Better off reading The Register.
perihelions 4y ago
- "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.org/mag/8/56 https://www.iter.org/mag/8/56 You'd need 60 kg/year for a 600 MW D+T fusion reactor.
- theptip 4y ago
  Fair enough, perhaps I was oversimplifying with my example. It seems from the OP the plan is to transition to breeding the tritium in fusion reactors, and that we currently have enough fission-produced tritium to plausibly bridge to those fusion-based processes. And the concern is that the fission reactors might shut down before we bootstrap the fusion reactors. Still, as I said originally, it sounds like keeping our current level of fission reactors around should solve the bootstrapping problem.
- willis936 4y ago
  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.
  - perihelions 4y ago
    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/CCFE-PR1767-1.pdf https://scientific-publications.ukaea.uk/wp-content/uploads/... ref. (1) is https://sci-hub.se/http://dx.doi.org/10.1016/j.fusengdes.2013.05.043 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.
robonerd 4y ago
> The simple phrasing of fission as "dirty" really shows the quotee's biases. And I think their failure to really understand fusion power either. The sort of fusion reactors we build first will produce tons of neutron radiation, which over time will turn the whole reactor itself into radioactive nuclear waste.
IAmEveryone 4y ago
Being triggered by the use of the word "dirty" for fission reactors, in comparison with fusion reactors no less, is far more telling than the use of the word. It creates radioactive waste. Creating waste is dirty. The promise of fusion is not to do this. Requiring the former for the latter is a strange proposition when viewed threw the only lense that makes sense for fusion power: cleanliness, the absence of dirtiness. The love for nuclear power some internet communities exhibit has far left the realm of the science people often invoke as their reason and gone into full-on scientism. Nuclear scientists have respect for radiation. They wouldn't take offense with the mere mention that it has unwanted byproducts. They built and ran a couple hundred reactors for a few decades, and only two of them managed to render large swaths of the landscape into uninhabitable wastelands, which is quite a feat. But it was only possible because they didn't minimize the danger with the sort of I-would-love-a-reactor-in-my-backyard attitude that seems to be prevalent now. Which is, by the way, not only getting the science wrong, but also the politics: nuclear power is out not because it is dangerous, but because it is too expensive and, at this point, too slow to build. While science bros have been huffing isotopes, actual scientists, with the help of some eerily effective subsidies, have improved solar and wind power and battery technology to the point where it is competitive and scalable not just to replace nuclear power, but even coal. Why people keep making the same arguments as they did a decade ago, a time span in which those technologies became 80-90% cheaper and more efficient, cannot be explained by the natural sciences.

99_00 4y ago

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).

zitterbewegung 4y ago
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.
- ncmncm 4y ago
  Coal is on its way out, so is not a sensible standard of comparison.
JimTheMan 4y ago
At some point, we will have enough solar/hydro/wind etc that they won't be built using coal power... Right now it's a necessary yes, in the future no. In a way, that last (...) is also a very black and white way of viewing things.
- 99_00 4y ago
  >In a way In what way is it black and white view of things? Solar energy production is not 100% clean. It never will be regardless if coal is used or not. That doesn't mean it's bad. The goal isn't purely clean energy. The goal is improved sources of energy. Hopefully coal isn't used in the future. But things don't appear to be on track. https://www.carbonbrief.org/china-briefing-17-march-2022-beijing-doubling-down-on-fossil-fuels-chinas-co2-emissions-increase-coal-production-growth/ https://www.carbonbrief.org/china-briefing-17-march-2022-bei... Unfortunately, because black and white thinking and evaluating energy sources without comparing them has resulted in a shortage of natural gas (thanks to fossil fuel divestment and ESG) and energy producers falling back to coal. The worst possible source of energy.
c7DJTLrn 4y ago
It's just shit popsci journalism. Better off reading The Register.

perihelions 4y ago

- "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.org/mag/8/56 https://www.iter.org/mag/8/56 You'd need 60 kg/year for a 600 MW D+T fusion reactor.

theptip 4y ago
Fair enough, perhaps I was oversimplifying with my example. It seems from the OP the plan is to transition to breeding the tritium in fusion reactors, and that we currently have enough fission-produced tritium to plausibly bridge to those fusion-based processes. And the concern is that the fission reactors might shut down before we bootstrap the fusion reactors. Still, as I said originally, it sounds like keeping our current level of fission reactors around should solve the bootstrapping problem.
willis936 4y ago
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.
- perihelions 4y ago
  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/CCFE-PR1767-1.pdf https://scientific-publications.ukaea.uk/wp-content/uploads/... ref. (1) is https://sci-hub.se/http://dx.doi.org/10.1016/j.fusengdes.2013.05.043 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.

robonerd 4y ago

> The simple phrasing of fission as "dirty" really shows the quotee's biases. And I think their failure to really understand fusion power either. The sort of fusion reactors we build first will produce tons of neutron radiation, which over time will turn the whole reactor itself into radioactive nuclear waste.

IAmEveryone 4y ago

Being triggered by the use of the word "dirty" for fission reactors, in comparison with fusion reactors no less, is far more telling than the use of the word. It creates radioactive waste. Creating waste is dirty. The promise of fusion is not to do this. Requiring the former for the latter is a strange proposition when viewed threw the only lense that makes sense for fusion power: cleanliness, the absence of dirtiness. The love for nuclear power some internet communities exhibit has far left the realm of the science people often invoke as their reason and gone into full-on scientism. Nuclear scientists have respect for radiation. They wouldn't take offense with the mere mention that it has unwanted byproducts. They built and ran a couple hundred reactors for a few decades, and only two of them managed to render large swaths of the landscape into uninhabitable wastelands, which is quite a feat. But it was only possible because they didn't minimize the danger with the sort of I-would-love-a-reactor-in-my-backyard attitude that seems to be prevalent now. Which is, by the way, not only getting the science wrong, but also the politics: nuclear power is out not because it is dangerous, but because it is too expensive and, at this point, too slow to build. While science bros have been huffing isotopes, actual scientists, with the help of some eerily effective subsidies, have improved solar and wind power and battery technology to the point where it is competitive and scalable not just to replace nuclear power, but even coal. Why people keep making the same arguments as they did a decade ago, a time span in which those technologies became 80-90% cheaper and more efficient, cannot be explained by the natural sciences.