I can't wait to start teaching Nuclear Physics at any level! I just think it is wonderful to begin to explain where the vast amounts of energy released in nuclear reactions come from.
There are nuclear equations to contend with which are perhaps some of the simplest elements of the A Level course, but then there are conceptually challenging graphs which explain nuclear stability, nuclear binding energy, alpha, beta and gamma decay, fission and fusion.
We can use Einstein's famous E=mc2 equation to calculate just how much energy is released from a small change in mass!
And all of this will be synoptic in explaining how stars are formed and a central tenet of special relativity; mass-energy equivalence.