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> breeder reactors are still a technology under development It's been 40 years we know how to build breeder reactors. And there are already been multiple comm

by Kuinox 4y ago

> breeder reactors are still a technology under development It's been 40 years we know how to build breeder reactors. And there are already been multiple commercial fast breeder reactor. But like regular nuclear reactors, yes it is a technology under development. But we also have more than 100 years to figure out the rest. > The "at scale" argument is flaccid. It's feckless unless you can give a reason why the technology would not scale. Cost, and cost. Power2Gaz already exists, you never showed how it was inferior to your tech. But in both case, there is an enormous problem you never mentioned: the efficiency of power2gas is currently of 60% at most, hydrogen included. Without including the equipement cost needed, stored solar electricity is suddendly costlier than nuclear.

pfdietz 4y ago
There have been no successful commercial fast breeder reactors (that is, competitive with existing burner reactors, especially when the cost of reprocessing is included.) France has mothballed their entire fast reactor effort, not even building another prototype. Fast breeders have grave safety issues inherent in their physics. The delayed neutron fraction of plutonium (or U-233) is about half that of U-235. This means any breeder is skating closer to prompt supercriticality. If a fast reactor goes prompt supercritical, it will explode more violently than Chernobyl, since the time for the neutron population to double (for a given value of k) will be orders of magnitude shorter. Worst case, it would be an actual nuclear explosion. Fast breeders also present proliferation concerns. To get a good breeding ratio, a blanket of fertile material is placed around the fissioning core, so the neutrons escaping the core are efficiently utilized. If this is U-238, the Pu produced in the blanket will be "superweapon grade", with very low concentrations of higher Pu isotopes. Thorium breeders also have proliferation concerns, from the need to separate Pa-231 and allow it to decay before. This produces essentially pure U-233 outside the core. > cost and cost Let's look at a simple model to see how using hydrogen affects cost. https://model.energy/ https://model.energy/ Try Germany using 2011 or 2012 weather data and 2030 cost assumptions (note the cost of electrolysers in China is already half the number assumed there.) The overall cost of providing a steady 100 MW output is not bad, lower than what one would pay from a newly constructed nuclear plant including the cost of construction and financing. Hydrogen helps reduce the cost here, not increase it. Even very slight amounts of hydrogen noticeably help, covering for rare prolonged dark/calm periods.
- Kuinox 4y ago
  > France has mothballed their entire fast reactor effort, not even building another prototype. Yes due to public pressure/antinuclear lobby. > Fast breeders have grave safety issues inherent in their physics. Yet there has been a dozen of fast breeders reactors, and somes are still operating today. I trust way more the IPCC forecast on the subjects, than yours. The fully renewable path was rated "very uncertain, very risky" for the exact point I told you. The fully nuclear path for France was also uncertain and risky, but for another reason, they are uncertain we can build nuclear plant fast enough, which is understandable because they recommand a 2x increase in electricity production.
  - pfdietz 4y ago
    France abandoned their fast breeder effort because of serious technical and economic problems. There was no good prospect that anyone would want one, including France. BTW, this shows that for all the talk, France doesn't see nuclear as the global solution to CO2 emissions. Nor does Japan (whose fast breeder program was even more a fiasco) or the US (where we abandoned fast breeders even earlier, after massive cost overruns.) Fast reactors are like ordinary nuclear, only with even more ludicrousness. As for safety, the person to listen to is Edward Teller. He famously and publicly (in 1967) brought up the safety issue I mentioned. Because of that safety issue, I seriously doubt if any heterogenous fast reactor (with conventional fuel elements) would be licensed in the West today. That leaves molten salt fast reactors, but no one has ever built on of those, and they'd have serious problems with neutron damage to reactor structural materials.

by Kuinox 4y ago

pfdietz 4y ago

There have been no successful commercial fast breeder reactors (that is, competitive with existing burner reactors, especially when the cost of reprocessing is included.) France has mothballed their entire fast reactor effort, not even building another prototype. Fast breeders have grave safety issues inherent in their physics. The delayed neutron fraction of plutonium (or U-233) is about half that of U-235. This means any breeder is skating closer to prompt supercriticality. If a fast reactor goes prompt supercritical, it will explode more violently than Chernobyl, since the time for the neutron population to double (for a given value of k) will be orders of magnitude shorter. Worst case, it would be an actual nuclear explosion. Fast breeders also present proliferation concerns. To get a good breeding ratio, a blanket of fertile material is placed around the fissioning core, so the neutrons escaping the core are efficiently utilized. If this is U-238, the Pu produced in the blanket will be "superweapon grade", with very low concentrations of higher Pu isotopes. Thorium breeders also have proliferation concerns, from the need to separate Pa-231 and allow it to decay before. This produces essentially pure U-233 outside the core. > cost and cost Let's look at a simple model to see how using hydrogen affects cost. https://model.energy/ https://model.energy/ Try Germany using 2011 or 2012 weather data and 2030 cost assumptions (note the cost of electrolysers in China is already half the number assumed there.) The overall cost of providing a steady 100 MW output is not bad, lower than what one would pay from a newly constructed nuclear plant including the cost of construction and financing. Hydrogen helps reduce the cost here, not increase it. Even very slight amounts of hydrogen noticeably help, covering for rare prolonged dark/calm periods.

Kuinox 4y ago
> France has mothballed their entire fast reactor effort, not even building another prototype. Yes due to public pressure/antinuclear lobby. > Fast breeders have grave safety issues inherent in their physics. Yet there has been a dozen of fast breeders reactors, and somes are still operating today. I trust way more the IPCC forecast on the subjects, than yours. The fully renewable path was rated "very uncertain, very risky" for the exact point I told you. The fully nuclear path for France was also uncertain and risky, but for another reason, they are uncertain we can build nuclear plant fast enough, which is understandable because they recommand a 2x increase in electricity production.
- pfdietz 4y ago
  France abandoned their fast breeder effort because of serious technical and economic problems. There was no good prospect that anyone would want one, including France. BTW, this shows that for all the talk, France doesn't see nuclear as the global solution to CO2 emissions. Nor does Japan (whose fast breeder program was even more a fiasco) or the US (where we abandoned fast breeders even earlier, after massive cost overruns.) Fast reactors are like ordinary nuclear, only with even more ludicrousness. As for safety, the person to listen to is Edward Teller. He famously and publicly (in 1967) brought up the safety issue I mentioned. Because of that safety issue, I seriously doubt if any heterogenous fast reactor (with conventional fuel elements) would be licensed in the West today. That leaves molten salt fast reactors, but no one has ever built on of those, and they'd have serious problems with neutron damage to reactor structural materials.