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Very true, though fuels that start as water-soluble halide salts should theoretically produce somewhat less complicated flowsheets. You have elegantly summarize

Very true, though fuels that start as water-soluble halide salts should theoretically produce somewhat less complicated flowsheets. You have elegantly summarized why adding a fuel reprocessing step to commercial BWR/PWR fleets makes the systemic costs of nuclear power higher and the waste problems worse. EDIT: oh, uranium and thorium halides hydrolyze except at very low pH. And so will a number of fission-product-halides. So maybe not simpler to start with halide salts instead of oxide fuels.

mjevans 9y ago
Am I correct in understanding that "waste reduction" (breeder) reactors essentially burn more (most?) the fuel in the core, without that external re-processing?
- philipkglass 9y ago
  Breeder reactors still require a chemical re-processing step to separate fission products (the lighter atoms produced when heavy actinides like uranium split and release energy) from the fuel. There are two main theoretical advantages for breeder reactors. One advantage is that the total energy extractable from terrestrial mineral resources is much greater with dedicated breeder reactors than with reliance on naturally fissile U-235 in simpler non-breeding reactors. In practice, nuclear power production has not grown fast enough to cause uranium shortages. Until there is a significant uranium shortage, reflected in much higher prices for freshly mined uranium, the higher complexity/cost of a breeder reactor cannot be offset by cost savings on fresh uranium fuel. The other theoretical advantage is a reduction in actinide waste production (plutonium, americium, curium). These heavy waste atoms dominate the radioactivity of spent nuclear fuel in the medium term, thousands to tens of thousands of years from now. But in the short term (years, decades, and centuries), the radioactivity of spent nuclear fuel is dominated by fission products rather than actinides. Breeder reactors do not notable reduce production of fission products compared to conventional reactors. Further, the reprocessing of nuclear fuel to separate the fission products has a tendency to turn potent but small, easily-handled waste problems into less potent but much larger and more unwieldy waste problems. Even though there are some theoretical waste advantages to reprocessing fuel instead of using it once and sealing it up forever, in practice waste reprocessing has always led to higher expenses and more radionuclides actually released into the wider environment.

mjevans 9y ago

Am I correct in understanding that "waste reduction" (breeder) reactors essentially burn more (most?) the fuel in the core, without that external re-processing?

philipkglass 9y ago
Breeder reactors still require a chemical re-processing step to separate fission products (the lighter atoms produced when heavy actinides like uranium split and release energy) from the fuel. There are two main theoretical advantages for breeder reactors. One advantage is that the total energy extractable from terrestrial mineral resources is much greater with dedicated breeder reactors than with reliance on naturally fissile U-235 in simpler non-breeding reactors. In practice, nuclear power production has not grown fast enough to cause uranium shortages. Until there is a significant uranium shortage, reflected in much higher prices for freshly mined uranium, the higher complexity/cost of a breeder reactor cannot be offset by cost savings on fresh uranium fuel. The other theoretical advantage is a reduction in actinide waste production (plutonium, americium, curium). These heavy waste atoms dominate the radioactivity of spent nuclear fuel in the medium term, thousands to tens of thousands of years from now. But in the short term (years, decades, and centuries), the radioactivity of spent nuclear fuel is dominated by fission products rather than actinides. Breeder reactors do not notable reduce production of fission products compared to conventional reactors. Further, the reprocessing of nuclear fuel to separate the fission products has a tendency to turn potent but small, easily-handled waste problems into less potent but much larger and more unwieldy waste problems. Even though there are some theoretical waste advantages to reprocessing fuel instead of using it once and sealing it up forever, in practice waste reprocessing has always led to higher expenses and more radionuclides actually released into the wider environment.