shut sellafield

[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. (more…)

World’s worst nuclear accident
Today marks the twentieth anniversary of the Chernobyl catastrophe, the world’s worst nuclear accident. The explosion at the power plant, situated about 100 miles north of Kiev in the Ukraine, then part of the Soviet Union, sent a cloud of radioactive gas around the world. The cloud contained twenty times the amount of radiation released at Hiroshima.

Estimates made at the time in the New Scientist magazine, that 100,000 would eventually die as a direct and indirect result of the radiation release, may have been too high. But if the wind had been blowing in the opposite direction on the day, towards the densely populated city of Kiev instead of over relatively sparsely inhabited areas, the outcome would have been worse than even the New Scientist estimate.

The reactor at Chernobyl was a boiling water, graphite moderated type called a RBMK, many of which are still in operation in the states of the former Soviet Union (the final reactor at the Chernobyl power station was only shut down 15 years after the incident). It is inherently unsafe in a nuclear reactor to have high temperature graphite close to steam under pressure, but this is what happens in the RBMK. (more…)

One year ago this week, 19/04/2005 it was reported that there was a level 3 accident at Thorpe nuclear reprocessing plant Sellafield. Thorpe is closed but the shipments still arrive.

the BBC reported after the event the following.

A leak at the Sellafield nuclear reprocessing plant in Cumbria was not spotted for three months, an investigation has revealed.

More than 20 tonnes of uranium and 160kg of plutonium spewed onto a floor when a pipe fractured at the Thorp reprocessing complex in January.

The British Nuclear Group, which carried out the inquiry, stressed that the material leaked into a sealed cell.

The discovery was made after a camera inspection of the cell in April.

It was classified as a level 3 accident by the International Nuclear Event Scale (INES) because of the acid released in the incident.

INES measurements listed the 1986 Chernobyl disaster as a level 7 incident and Three Mile Island in the United States in 1979 as level 5.