ABSTRACT
Plutonium is created when neutrons emitted from the fission of U-235 atoms are absorbed by some of the left-over U-238 atoms. However much you try to increase the proportion of U-235 in natural uranium (a process know as ‘enrichment’) there is always some U-238 left – and it is this that gets converted into plutonium, a new, heavier element (its designation is Pu-239).
