Bradwell nuclear power station in Essex is at the centre of the claims
Operators of a nuclear power station in Essex have been accused of allowing radioactive waste to seep into the ground for 14 years.
The Environment Agency claims waste leaked from a unit at Bradwell power station, now decommissioned, between 1990 and 2004.
Mark Harris, prosecuting, said leaks were caused by poor design, too few checks and a lack of maintenance.
Magnox Electric Ltd denies 11 breaches of radioactive waste disposal laws.
Mr Harris told Chelmsford Crown Court the power station was no longer running.
"The case concerns the disposal of liquid radioactive waste which leaked to the ground from a sump at the site of what is now the former Bradwell nuclear power station," he said.
"These leaks occurred on a number of occasions between as long ago as 1990 until discovery of these leaks in February 2004.
"The leaks were caused by a combination of poor original design of the sump ... and, in the period when this company was running it... there was no routine inspection or maintenance of the sump until after the leak was discovered."
Mr Harris said Bradwell had been run by the Central Electricity Generating Board (CEGB), then, after privatisation, Nuclear Electric plc then Magnox Electric plc then Magnox Electric Limited.
Judge Peter Fenn warned jurors not to carry out private research.
"Resist the temptation to go down to your local library or on to the internet to conduct research into nuclear physics or nuclear power stations," he said.
The case continues and may last 10 days.