4 ms·

> Well, excepting oceanic extraction which has vast supplies, but the extraction costs there would also send its price to the Moon. There are also unclear envir

by xvilka 3y ago

> Well, excepting oceanic extraction which has vast supplies, but the extraction costs there would also send its price to the Moon. There are also unclear environmental implications there. Uranium is only present in something like 3 parts per billion in saltwater. Extracting meaningful quantities there would be a tremendous undertaking. Or just build breeders. There's plenty of thorium and it's dirt-cheap.

littlestymaar 3y ago
There's also plenty of depleted uranium and we don't know what to do with it anyway. The problem is that there no simple “just build breeder reactors” plan. Breeder reactors are complex and have completely different safety concerns than regular reactors (mostly because the coolant cannot be water) so it's actually a lot of work to make one.
- PaulHoule 3y ago
  The worst problem facing breeders, I think, is fuel fabrication. France has developed a process that uses a high energy ball mill to “alloy” plutonium and uranium oxides to make very high quality fuel. The trouble is this also makes carcinogenic plutonium nano particles and protecting workers from them is problematic because workers need to pick up plutonium pellets up with gloves and stuff them in a tube. The factory Karen Silkwood worked at made excellent quality fuel for the FFTF with something like the French process but had trouble controlling plutonium dust. The U.S. wanted to build a MOX fab with help from the French for destruction of weapons grade plutonium but construction was halted not long after studies shown that workers in French fuel fabs were getting lung cancer (at a low enough rate thar French and Russian regulators seem sanguine about it.) Some other process like what https://www.moltexenergy.com/ https://www.moltexenergy.com/ uses might address the occupational safety problems plus the high capital costs that have affected breeders. If a breeder could replace the steam turbine with a supercritical CO2 or some other high temperature heat acceptor, capital costs could possibly be less than the LWR.
  - littlestymaar 3y ago
    I wasn't aware of that issue, thanks. That's yet another example of what it takes to switch to a radically new tech. (I'm not convinced with the assessment as being the “worst problem” though, as not using water as a coolant forces you to rethink nuclear safety from the ground up in a way that makes “controlling dust in the manufacturing process” sounds like an easy problem in comparison)
    - PaulHoule 3y ago
      In some ways breeders might be safer. There is no risk of a steam explosion. The core shuts itself if it overheats so it has been demonstrated that reactivity insertions and loss of cooling can be resolved passively https://gain.inl.gov/Shared%20Documents/Fast%20Flux%20Test%20Facility%20Documents/03%20Passive%20Safety-FFTF-LMR%20Designs-IAEA-CN-245-14PSTFR17.pdf https://gain.inl.gov/Shared%20Documents/Fast%20Flux%20Test%2... There was fear in the early days that in a meltdown the core might become denser and produce a small nuclear explosion but after thinking through the problem for years and a lot of experience it seems the core disperses in a worst cast. Dangerous iodine isotopes dissolve in the coolant and are trapped in case of fuel damage. Potentially a fast reactor can capture almost all the tritium produced for use. You can have a sodium fire but most sodium fires are pool fires which aren’t very dangerous. Fires happen all the time in industrial facilities, you detect them and put them out. They aren’t necessarily a big problem.
      - littlestymaar 3y ago
        It's not about which one is safer. At this point we have a deep understanding of what can go wrong in a PWR or BWR, with part of this knowledge deriving from accidents (TMI and Fukuahima) and smaller incidents. And we've developed a significant amount of mitigations and operators training to cope with these potential failures. Doing the same thing for breeder isn't trivial at all. I studied nuclear engineering ( before changing path in 2011 due to Fukushima) with one of my teacher having worked on SuperPhénix, and my wife is a nuclear engineer specializing in accident scenarios and operators training at EDF, so I'm actually pretty familiar with the topic.
pentae 3y ago
Australia has worlds largest uranium deposits, they can just buy it from us

by xvilka 3y ago

littlestymaar 3y ago

There's also plenty of depleted uranium and we don't know what to do with it anyway. The problem is that there no simple “just build breeder reactors” plan. Breeder reactors are complex and have completely different safety concerns than regular reactors (mostly because the coolant cannot be water) so it's actually a lot of work to make one.

PaulHoule 3y ago
The worst problem facing breeders, I think, is fuel fabrication. France has developed a process that uses a high energy ball mill to “alloy” plutonium and uranium oxides to make very high quality fuel. The trouble is this also makes carcinogenic plutonium nano particles and protecting workers from them is problematic because workers need to pick up plutonium pellets up with gloves and stuff them in a tube. The factory Karen Silkwood worked at made excellent quality fuel for the FFTF with something like the French process but had trouble controlling plutonium dust. The U.S. wanted to build a MOX fab with help from the French for destruction of weapons grade plutonium but construction was halted not long after studies shown that workers in French fuel fabs were getting lung cancer (at a low enough rate thar French and Russian regulators seem sanguine about it.) Some other process like what https://www.moltexenergy.com/ https://www.moltexenergy.com/ uses might address the occupational safety problems plus the high capital costs that have affected breeders. If a breeder could replace the steam turbine with a supercritical CO2 or some other high temperature heat acceptor, capital costs could possibly be less than the LWR.
- littlestymaar 3y ago
  I wasn't aware of that issue, thanks. That's yet another example of what it takes to switch to a radically new tech. (I'm not convinced with the assessment as being the “worst problem” though, as not using water as a coolant forces you to rethink nuclear safety from the ground up in a way that makes “controlling dust in the manufacturing process” sounds like an easy problem in comparison)
  - PaulHoule 3y ago
    In some ways breeders might be safer. There is no risk of a steam explosion. The core shuts itself if it overheats so it has been demonstrated that reactivity insertions and loss of cooling can be resolved passively https://gain.inl.gov/Shared%20Documents/Fast%20Flux%20Test%20Facility%20Documents/03%20Passive%20Safety-FFTF-LMR%20Designs-IAEA-CN-245-14PSTFR17.pdf https://gain.inl.gov/Shared%20Documents/Fast%20Flux%20Test%2... There was fear in the early days that in a meltdown the core might become denser and produce a small nuclear explosion but after thinking through the problem for years and a lot of experience it seems the core disperses in a worst cast. Dangerous iodine isotopes dissolve in the coolant and are trapped in case of fuel damage. Potentially a fast reactor can capture almost all the tritium produced for use. You can have a sodium fire but most sodium fires are pool fires which aren’t very dangerous. Fires happen all the time in industrial facilities, you detect them and put them out. They aren’t necessarily a big problem.
    - littlestymaar 3y ago
      It's not about which one is safer. At this point we have a deep understanding of what can go wrong in a PWR or BWR, with part of this knowledge deriving from accidents (TMI and Fukuahima) and smaller incidents. And we've developed a significant amount of mitigations and operators training to cope with these potential failures. Doing the same thing for breeder isn't trivial at all. I studied nuclear engineering ( before changing path in 2011 due to Fukushima) with one of my teacher having worked on SuperPhénix, and my wife is a nuclear engineer specializing in accident scenarios and operators training at EDF, so I'm actually pretty familiar with the topic.

pentae 3y ago

Australia has worlds largest uranium deposits, they can just buy it from us