British Nuclear Fuels said a single manager was responsible for a safety breach that led to the company being fined £20,000 last week.
Whitehaven Magistrates imposed the maximum fine after hearing that BNFL had failed to take action on several reports between 1990 and 1995 that indicated the need to repair the 100m-long bridge carrying the Sellafield discharge pipeline over a railway to the Irish Sea.
The company, which pleaded guilty to a breach of the Radioactive Substances Act, said that under its policy of devolving responsibility, the manager alone was to blame for the inaction and had been dismissed.
One of the reports had warned of an eventual `partial or total collapse’ of the 50-year-old structure.
BNFL said the pipeline would have remained intact even if the bridge collapsed, but this argument did not convince the Environment Agency, which brought the prosecution.