Fission products

Fission products are nuclei produced by fragmentation of a heavy fissile nucleus such as uranium or plutonium. Immediately after the fission, the fragments are much too rich in neutrons to be stable. Highly radioactive, they seek to regain stability through a series of disintegrations. The return to stability is a very variable and can be very slow. With the actinides, the fission products are the main radioactive waste that are found in the spent fuel of nuclear reactors. Dominant in activity at the time of the discharge, they disappear faster than actinides.