Managers of the Sellafield nuclear site in Cumbria will be fined today for exposing staff to radioactive contamination.
The representatives are expected to be imposed with a substantial penalty at Carlisle Crown Court after pleading guilty to failings under the Health and Safety at Work Act.
Following an investigation by the Health and Safety Executive, it found two contractor employees had been exposed to airborne radioactive contamination on 11 July 2007 at the nuclear reprocessing complex.
The men were drilling through a concrete floor contaminated with plutonium when they inhaled radioactive dust.
The Health and Safety Executive said the dose of radiation they were exposed to, however, was below the annual dose limit and there was no immediate impact on their health.
Sellafield, now owned by Amec, Areva of France and URS Washington of America, was fined £500,000 plus costs of more than £50,000 three years ago following the discovery of a large leak of highly radioactive materials at its Thermal Oxide Reprocessing Plant.
Although no one was injured at the time, there was concern that the leak had continued for eight months before it was detected.