Safety limits on the storage of some of the world’s most dangerous nuclear wastes at Sellafield in Cumbria have been relaxed after an accident knocked out a treatment plant and caused “gross contamination”.
The government’s safety watchdog, the Office for Nuclear Regulation (ONR), has permitted the private company that runs Sellafield to breach legal restrictions on the amount of hot, high-level radioactive waste that can be kept in tanks. The limits are likely to be exceeded by up to 350 tonnes between April 2014 and July 2016.
Critics accused ONR of breaking their promises and putting Sellafield’s profits before safety. But ONR insisted there was “minimal hazard increase”, while Sellafield said it put safety first.
The waste storage limits, imposed in 2001, were meant to reduce stocks to below 5,500 tonnes of uranium equivalent by July 2015. The aim was to minimise the risk of a disaster spreading a plume of potentially lethal radioactive contamination over the UK and Ireland – officially regarded as Sellafield’s “worst credible accident”.
The liquid waste comes from Britain’s nuclear power stations and generates significant amounts of heat. It has to be constantly cooled and stirred to prevent it from overheating.
Sellafield asked for permission to breach the storage limits to help cope with a backlog caused by an accident in November 2013. A plant meant to solidify the waste to make it safer lost power, suffered "gross contamination” and had to be closed for 11 months.