Original URL: http://www.theregister.co.uk/2007/10/08/windscale_mess/

Nuclear accident messier than we thought

Checking Windscale's sums after 50 years

By Lucy Sherriff

Posted in Science, 8th October 2007 10:51 GMT

The amount of radioactive fallout from the Windscale nuclear accident half a century ago was grossly underestimated, according to new research.

In 1957, a fire broke out at one of two nuclear reactors on the Windscale site when its graphite control rods overheated. The fire was extinguished with water, deemed necessary to limit the amount of radioactive material that escaped, despite the fact it could have caused an explosion.

John Garland, formerly of the UK Atomic Energy Authority, and Richard Wakeford, a visiting professor at the University of Manchester, suggest the accident may have generated twice as much radioactive material and caused an additional 40 cases of cancer. Their work is published in the journal Atmospheric Environment.

Garland and Wakeford have combined modern computer modelling techniques with a re-analysis of the environmental data collected at the time of the near-disaster, and since. The pair then calculated the likely spread of the radioactive cloud, based on records of the local historical weather conditions.

According to the BBC, the team confirmed that the contaminants released by the fire included radioactive iodine and caesium, as well as polonium and a small amount of plutonium. But, John Garland told the Beeb: "The reassessments showed that there was roughly twice the amount than was initially assessed."

More contaminants mean more cancers. The volume of material originally thought to have been released would have caused roughly 200 cases of cancer. The level of radioactive material the team now thinks was released probably caused more than 240 cases, the researchers said.

Most of the material has now decayed to safe levels, but some plutonium and caesium still remain. The team says the levels are not high enough anymore to pose a risk to human health.

It is unlikely that the findings will have any impact on the government's plans to build more nuclear power stations. To paraphrase Paul Howarth, director of research at the Dalton Nuclear Institute at Manchester University, they don't build 'em like that anymore. ®