The radioactive cloud from Britain's worst nuclear accident exactly 50 years ago spread contamination over large parts of Europe, much further than previously admitted.
New Scientist reports that studies by British and Norwegian scientists show that radioactivity from the fire at Windscale in Cumbria on 10-11 October 1957 was blown east over Belgium, Holland and Germany, and north over Scandinavia.
The fire, which consumed one of the UK's first bomb-making reactors for 17 hours, also dumped contamination over a huge swathe of England including Blackburn, Bradford, Lancaster, Preston, Manchester and London. Across 200 square miles of northwest England, milk was poured away to prevent it from poisoning children.
"The plume extended further east than accepted in previous assessments," concludes a study funded by the British nuclear industry. Another analysis of declassified monitoring results from the Norwegian Defence Research Establishment says that fallout "extended farther north over Norway than originally considered".
Because Windscale was a military plant, much about the accident was kept secret at the time. The full truth about the large amounts of polonium-210 that were released didn't emerge until 1983, after it was highlighted in an article in New Scientist (vol 97, p 873).
The failure to properly account for the polonium-210 was "perplexing", according to Richard Wakeford, a former British Nuclear Fuels scientist now at the University of Manchester. The isotope is blamed for 70 of the 100 fatal cancers that the accident is officially reckoned to have caused.
The operation of the Windscale reactors up to 1957 was plagued with unforeseen problems, and was described in the 1995 official history as "an accident waiting to happen". When the accident came, Wakeford says, "it could have been a lot worse".
Fifty years on, cleaning up the fire-damaged reactor is still proving a tricky business, with the UK Atomic Energy Authority now designing robots to help dismantle the radioactive core. "I am confident that we can develop the existing prototype machine to complete this task safely and successfully," the authority's programme manager, Richard Roper, told New Scientist. The aim is to complete decommissioning by 2060.