4 ms·

There is about 40,000,000kg of accessible fissile material (U235, Pu239) on earth. Each kg can produce about 30-70TJ of energy with existing nuclear technology

There is about 40,000,000kg of accessible fissile material (U235, Pu239) on earth. Each kg can produce about 30-70TJ of energy with existing nuclear technology. Primary energy is about 17TW Please explain how you can get 17TWy of energy per year from a sum total of <80TWy of fuel.

sidewndr46 4y ago
There is some degree of agreement that nuclear fuel cycles exist for fissionable fuel. In other words, the waste from one reactor can simply be used as fuel for the next. There are already some niche uses for reactor waste, up until recently the decommissioned reactor in Chernobyl was actually still in use for some stuff like this. How many steps there are in this cycle and if actually is a net positive in energy production has not been born out by any research I am aware of. So your skepticism is warranted.
- Schroedingersat 4y ago
  One other note is that reprocessing is distinct from breeding. Reprocessing doesn't create new fissile material. You're stuck with the small fraction of Pu239 in the waste (which is about a 7th of the original U235). It buys you very little extra energy at huge financial cost and in the current form releases more radiation than the rest of the nuclear industry combined if you exclude weapons tests and chernobyl -- it even rivals coal in terms of radiation released per joule. Plus there is a hidden amount of CFCs and other extremely potent greenhouse gases involved in the process. Breeding to close the fuel cycle would be great (if it could be done economically and safely), but there is a laundry list of reasons why it may never happen, and every tonne of fissile material used before it happens is 200GW that can't be produced until a decade is spent breeding it back.
  - sidewndr46 4y ago
    There might actually be an interesting opportunity to use excess solar & wind power during some times to do the reprocessing.

sidewndr46 4y ago

There is some degree of agreement that nuclear fuel cycles exist for fissionable fuel. In other words, the waste from one reactor can simply be used as fuel for the next. There are already some niche uses for reactor waste, up until recently the decommissioned reactor in Chernobyl was actually still in use for some stuff like this. How many steps there are in this cycle and if actually is a net positive in energy production has not been born out by any research I am aware of. So your skepticism is warranted.

Schroedingersat 4y ago
One other note is that reprocessing is distinct from breeding. Reprocessing doesn't create new fissile material. You're stuck with the small fraction of Pu239 in the waste (which is about a 7th of the original U235). It buys you very little extra energy at huge financial cost and in the current form releases more radiation than the rest of the nuclear industry combined if you exclude weapons tests and chernobyl -- it even rivals coal in terms of radiation released per joule. Plus there is a hidden amount of CFCs and other extremely potent greenhouse gases involved in the process. Breeding to close the fuel cycle would be great (if it could be done economically and safely), but there is a laundry list of reasons why it may never happen, and every tonne of fissile material used before it happens is 200GW that can't be produced until a decade is spent breeding it back.
- sidewndr46 4y ago
  There might actually be an interesting opportunity to use excess solar & wind power during some times to do the reprocessing.