Question

On neutron-capture induced fission, 235 92U typically splits into two new “fission product” 92 nuclei with masses in the ratio 1:1.4. These are born with the same proton to neutron ratio as the original uranium, so they have too many neutrons to be stable at their mass number and are highly radioactive. Energy is released in two stages: first an intermediate or prompt release leading to radioactive fission products in their ground state; and then a much slower release via the beta and gamma decays of the fission product nuclei, which continue until they become stable. Use the semi-empirical mass equation to estimate the magnitudes of the energy released per fission in each of the two stages. You may take the final Z/A ratios from appropriate known stable nuclei. Furthermore, as this is an estimate, you may ignore the incoming and outgoing neutrons, and drop the pairing term from the SEMF formula.

Please note that the problem as stated here is a simplification: In reality, the 235 92 U nucleus splits into a variety of daughter pairs, most commonly with approximately the above mass ratio, and in some rare instances even into three daughters.

Answer 1