radioactive

Critics have also expressed concern about radioactive waste nuclear reactors leave behind for future generations.

Others fear another Fukushima-scale disaster, where a tsunami disabled three reactors, causing the release of highly radioactive materials and forcing mass evacuations.

That is the stark warning from experts who have said the lack of medical radioactive isotopes available in the UK means delays in tests to diagnose cancer.

The scheme dubbed Project Arthur would see a small-scale nuclear reactor placed at Trawsfynydd in Gwynedd, to produce the radioactive materials.

All of this has cast a shadow over an operation that, as well as taking in newly created nuclear waste, also houses several decades worth of much older radioactive material.