Thorium - letter published in The Daily Telegraph (19-6-06).

Further to my posting "French - British Nuclear Deal Struck", 16-6-06, The Daily Telegraph have published (19-6-06) an edited version of my letter, which focuses on the potential use of thorium as a future nuclear fuel (they have cut out my criticism of another letter claiming that 50 kilograms of uranium could fuel a fast breeder reactor for 40 years - I pointed out that the true figure is nearer 50 tonnes). I have copied the edited letter below:

Sir - Despite the reassuringly good record of Dounreay over 20 years, there remain grave fears about the overall safety features of fast breeder reactors.

The liquid sodium coolant is a perceived potential fire hazard and the containment of plutonium is a real public relations bugbear, for fear of radioactive contamination and that it might get into the hands of terrorists.

One alternative is to use thorium as the principal nuclear fuel, which can be bred into uranium-233 as the nuclear fuel using slow neutrons, thus avoiding the liquid sodium coolant, and has the following advantages.

First, plutonium and uranium could still be consumed in such a reactor, but without the need to manufacture yet more plutonium.

Second, while uranium-235 and plutonium-239 can be shielded to avoid detection "in a suitcase", to use that cliche', uranium-233 could not, because it is always contaminated with uranium-232, a strong gamma-ray emitter, which is far less easily concealed.

Prof Chris Rhodes, Reading, Berks

I shall see if there are any follow-ups to this. Interestingly, after posting my recent article about "Thorium", I was approached by a journalist wanting to write something on the subject (his boss had given him a 24 hour deadline!), so I gave him a few facts. He was lucky as I didn't get the message until about 7.00 P.M. on the Friday, having picked up my e.mail on my way "out" for the evening! He didn't get back to me so I hope he managed to write his piece O.K., and that I was of some help to him.