The energy released by the fission of uranium nuclei would be higher if the uranium nucleus split into three parts rather than into two. Despite this, the fission of uranium only produces two nuclei. Why is this?


It is not correct in quantum mechanics to describe processes in terms of their various parts occurring in a particular order, nor to describe classically conserved quantities as being ‘borrowed’. However, the ‘classical’ description of a quantum effect usually gives a qualitatively correct picture if the ‘borrowing’ of a quantity is interpreted as meaning that the more of it that is borrowed, the less likely the process is to occur.
The volume of the uranium nucleus is equal to the sum of the volumes of its fission products, but the total surface area of the fission products is greater
than that of the original uranium nucleus. This means there is a temporary loss of (binding) energy when the process starts (this is the energy that has
to be ‘credited’ to initiate the fission process), which is later refunded by the decrease in Coulomb energy of the system when the daughter nuclei move
away from each other. If the uranium nucleus were to split into three fission products, the energy required at the start of the process would be so much higher than for two, that, both in theory and in practice, the corresponding probability would be negligible.




Hire Our


Writing & Translation

View All