I am most grateful for a comment by "APL" on the heroic "Burning Our Money" blog, which directs us to an article on the potential of radiation-free fusion energy.
There is an international project (ITER) in the south of France to develop this, and if it works...
UPDATE
Thanks to GMG for a link to this discussion of fusion power, which tends to the conclusion that a successful and economically viable fusion system is a very long way off, if feasible at all, and we'd do better to concentrate on fission, i.e. the present type of nuclear power station.