A nuclear reprocessing site which has been in operation for 20 years is to close in 2018 after current contracts are completed, it was confirmed today.
The Thermal Oxide Reprocessing Plant (Thorp) at Sellafield in Cumbria, which employs up to 800 workers, was commissioned in the early 1990s.
The Prospect union said the news had come as a "great disappointment", adding that only a fraction of the existing workforce will remain during the clean-out phase prior to decommissioning.
National officer Mike Graham said: "Today's announcement comes as a great disappointment to our members at Thorp who believe firmly that the plant has a future and have been actively campaigning for new reprocessing contracts.
"The announcement, though not surprising, is sudden and it is fair to say that the way this was communicated to the workforce could have been better.
"The closure will see a reduction in the numbers employed on the plant once operations cease, with only a fraction of the existing staff remaining during the clean-out phase prior to decommissioning."
Prospect said it will press the Nuclear Decommissioning Authority (NDA) on the potential redeployment of staff affected by the decision.
The NDA said in a statement that the closure decision was confirmed after it completed a strategic review of the options for the management of oxide fuels.
It added: "Oxide fuels include the remaining overseas-derived spent fuels that are being stored at Sellafield pending reprocessing in Thorp and also the spent fuels coming from the UK's fleet of AGR (advanced gas-cooled reactors) power stations owned and operated by EDF Energy.
"The strategic review confirms the NDA's position that completing the reprocessing contracts at Thorp remains a viable and cost-effective strategy.
"Any remaining AGR fuel, including any future arisings, will be placed into interim storage pending a decision to dispose of it in a geological disposal facility.
"This will result in the reprocessing contracts being complete by 2018, at which time Thorp would cease reprocessing activities and enter a post-closure and clean-out phase prior to decommissioning."
Other decommissioning and reprocessing facilities and waste treatment plants on the Sellafield site remain in operation.