Dounreay PFR (Prototype Fast Reactor)

The advantage is mainly that more active fuel can be created than is used, so getting 'something for nothing'. However experimental reactors such as the sodium cooled fast reactor at Dounreay in Scotland have proved very difficult in practice, with material problems, and as far as I know such experiments are in abeyance at the moment.

The UK has nine nuclear power stations which can be found at Torness, Hunterston (two reactors), Hartlepool, Heysham (two reactors), Wylfa, Sizewell (two reactors), Berkeley, Hinkley Point and Dungeness (two reactors).

Stations at Dounreay, Chapelcross, Trawsfynnedd, Bradwell, Oldbury and Winfrith have either been closed.

Windscale/Sellafield/THORP is a nuclear reprocessing plant rather than a power station, and Dounreay was involved in reprocessing as well as generation.

They may become important in the future but are not at the moment. This type of reactor has been built as prototypes, but is not in commercial use. The importance is that the present type of reactors in service (mostly PWR and BWR, but also PHWR and AGR) all use Uranium 235 as the fissile material, and this may become scarce in future years, though supplies are probably secure for another 50 years or so. When natural uranium is enriched in U235 there is depleted uranium left behind, this has little 235 but is mostly 238. If this is irradiated in a fast reactor it will produce Plutonium, which can then be used as the feed fuel for that reactor and others, so securing a further supply of nuclear fuel. Water cannot be used in a fast reactor as it moderates or slows the neutrons, and liquid metals (sodium or sodium/potassium) have been experimented with. The concept does work but so far is not commercially attractive. This type of prototype experiment can only be done with government funds and at the moment there is not much activity except design studies. Quite a large prototype was built at Dounreay in Scotland but financial support was rmoved and it is now being de-commissioned. See Wikipedia 'Fast Breeder Reactor'