A radiation leak halted a waste treatment operation at Sellafield last week. The accident appears to have occurred when pressure built up inside one of two flasks containing the cladding from spent Magnox fuel, and automatic vents opened to prevent an explosion.
British Nuclear Fuels said that none of the 13 workers who were in the building at the time had suffered any ill effect, but the building itself could be significantly contaminated.
BNFL halted operations at the Magnox Encapsulation Plant at which the radioactive swarf is grouted into stainless steel drums while a ‘recovery’ procedure to retrieve and clean the flasks and decontaminate the building takes place. This is likely to take several weeks.
But the company said this should not interrupt the reprocessing of Magnox fuel, because the reprocessing plant is in the middle of an annual shutdown and was not due back on stream for about seven weeks.
A BNFL spokesman said: ‘We’re confident that it will be back by mid-September.’
The Nuclear Installations Inspectorate is investigating the incident.