|Components of irradiated fuel|
A tonne of fuel generally remains in a reactor for three years, during which time a very significant quantity of energy is released by irradiation. Whereas uranium 238 emerges from the reactor largely intact, 25 kg of the initial 35 kg of uranium-235 will have undergone fission. The fuel waste exiting the reactor will also include 34 kg of fission products, 10 kg of plutonium and 800g of actinides. All of the newly formed products are highly radioactive.