[This article was originally published in New Scientist on 17 October 1957]

NO ONE will know precisely what happened at the Windscale works of the Atomic Energy Authority last Thursday afternoon until the AEA’s own inquiry is completed, but it is certain to be considerably more complicated than first reports and the AEA’s own spokesmen have been inclined to suggest.

One of the two seven-year-old reactors had been shut down, and whatever work was being carried out on it – apparently it was being used for experiments of some kind – started a fire in at least two fuel channels in the centre of the reactor which was fierce enough to carry vaporised fission products the whole distance up the 400-foot chimney and through the filters at its top. The fire started at 4.30 in the afternoon; it proved so difficult to control that the following day hoses began to play water down the fuel channels in a desperate attempt to bring the temperature under control.

This is neither a routine plant breakdown nor a minor mishap. It is a major accident, and the most serious that the AEA has yet had to face. For the first time the filters in the Windscale chimneys have proved inadequate to stop the escape of fission products into the countryside, and if the wind had not been blowing out to sea, the extent of contamination might have been more serious than the comparatively light traces which have been found.

Drenching the reactor with ordinary mains water has added immeasurably to the difficulties of bringing it back into working order. So long as it stays out of action, the country’s plutonium production remains cut by one-quarter to one-third and the defence programme is set back accordingly. The engineers have not only to clear the burnt-out channels of radioactive debris, but to dry out the pile in a way that will remove all the waterborne chemicals, such as calcium, which would interfere with the fission process. Unless these products are removed, the future efficiency of the reactor will be impaired; but it has to be seen whether this can be done without going to the lengths of stripping down the entire reactor and rebuilding it.

The reactor at Windscale is one of the oldest in the world, first put on paper nine or ten years ago when scientists knew a great deal less about fission than they do now. Thorough investigation will ensure that any shortcomings in its design will never be repeated. But is it so certain that the AEA will not repeat the mistakes it made after the fire broke out?

Public confidence has been severely shaken by what appeared to be attempts to minimise the gravity of what had taken place at Windscale, and even more by the extremely late hour at which any precautions to safeguard public health were put into effect. The escape of fission products may have been small, but night calls by police two days after the first leaks occurred suggest an unfortunately belated awakening to the degree of contamination that might in fact be involved.

From issue 2578 of New Scientist magazine, 18 November 2006, page s9