Detailed composition
Distribution of the principal radioactive elements present in fuel unloaded from an irradiated pressurised water reactor core in standard operating conditions (burn-up of 33 GWd/t), restated for one tonne of fuel (left column) and for the 23 tonnes used annually in the reactor (right column). The majority of the 31.1 kg of short-lived and intermediate-lived fission products stabilise within around ten years, essentially leaving only approximately 0.1 kg of strontium-90 and 0.1 kg of caesium-137, two radioelements with 30-year radioactive half-lives.
IN2P3 (Source CEA)