Shift workers at Britain's only nuclear reprocessing plant, Sellafield, resolved today to walk off the job within the next two weeks in a pay dispute that threatens to disrupt production at the plant.
The GMB union said it and another union, Amicus, planned a day of strike action within the fortnight.
A BNFL spokesman said there was no question of the plant closing down as a result of a strike, but could not predict the likely effect on individual operations.
"With regard to specific plants, will they temporarily shut down, will those operations temporarily cease? We need to see the precise details of the industrial action before we know the answer to that," the BNFL spokesman told reporters.
"It's not inconceivable, but we're not in a position to say either way at the moment."
Ireland has been calling for the closure of Sellafield, concerned about radioactive discharges into the Irish Sea, and environmental groups have mounted protests against waste shipments to the plant.
The GMB said it remained committed to providing emergency staffing if the operation was shut down during the dispute and had invited the company to discuss safety cover.
The BNFL spokesman stressed that safety at the plant, which manages the safe nuclear waste as well as reprocessing spent fuel rods for customers in the UK, Japan and Europe, would not be compromised in the event of a strike.