They are most readily applied to metal rather than oxide fuels.
We shall provide them here, a completely different reprocessing plant to deal with the more radioactive oxide fuel.
Reprocessing can potentially recover up to 95% of the remaining uranium and plutonium in spent nuclear fuel, putting it into new mixed oxide fuel.
In the oxide fuel, intense temperature gradients exist which cause fission products to migrate.
A paper describing a method of making a non-radioactive "uranium active" simulation of spent oxide fuel exists.
We are currently spending money on finding the basic properties of advanced mixed oxide nuclear fuels and how the fuel oxidises during the manufacturing process.
Metal fuels have the advantage of a much higher heat conductivity than oxide fuels but cannot survive equally high temperatures.
German rocket scientists were experimenting with nitrous oxide fuel blends as early as 1937.
Nitrous oxide fuel blends testing continued throughout World War II.
This means that they are strongly opposed to the use of mixed oxide fuel.