 The burnt fuels are Thorium with Reactor-Grade Plutonium (RGPu), Thorium with Weapons-Grade Plutonium (WGPu) and Mixed Oxide fuel (MOX, no thorium).For RGPu and WGPu, the initial amount of U-233 and its decay around a million years can be seen.This has an effect in the total activity curve of the three fuel types.