3 ms·

- "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 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.

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.