Nuclear power flounders

The discovery of radioactive fish in the Severn estuary might yet break Britain's nuclear industry

The nuclear industry is facing a multi-million pound increase in its clean-up costs after it emerged that some of its radioactive waste was more dangerous than thought.

The Environment Agency (EA), the government regulator, is to impose tougher discharge limits on firms such as British Nuclear Fuels (BNFL), nuclear engineering company Devonport Management and British Energy, cutting their releases of radioactive tritium.

The clampdown began after safety studies around the Severn estuary close to medical-equipment company Amersham's radio-isotope plant near Cardiff discovered tritium in flounder and shellfish several hundred times higher than expected.

Tritium, a mildly radioactive by-product of industry production lines, is the most heavily discharged waste across the nuclear industry. BNFL's Sellafield reprocessing plant in Cumbria and Chapelcross nuclear power station in south-west Scotland discharge millions of litres of tritiated water and air every year. The agency's crackdown began after a report by specialists from the National Radiological Protection Board and St Bart's Hospital in London disclosed that tritium was at least twice as dangerous to humans as previously thought.

Organically bound tritium – the more dangerous form of tritium which was found in large quantities in the Severn estuary fish samples – can be up to 12.5 times more dangerous for infants. The International Commission on Radiological Protection is now expected to raise health limits for tritium two-fold for adults and four-fold for children.

Amersham was the first firm hit by the revised figures. Ordered by the EA to make an 85 per cent cut in tritium discharges, it has halted all releases of organically bound tritium as part of a £20m programme to cut discharges.

Devonport Management, which refits Royal Navy nuclear submarines in Plymouth, is planning to spend up to £5m building a new undersea pipeline to carry its tritiated water further out into the Tamar estuary. The pipeline was ordered by the EA after it granted Devonport a five-fold increase in its tritium discharge authorisations in February.

But the heaviest bills are likely to be born by BNFL, which has already spent £2bn on cutting its radioactive discharges over the last 20 years. The EA is expected to ask for a deep cut in its tritium releases this summer, when it gives Michael Meacher, the environment minister, a revised discharge authorisation for Sellafield.

BNFL was unable to predict how much a cut would cost, but its finances are already fragile. The company said it expected to reduce radioactive discharges as part of an international convention.

But Stephen Tindale, executive director of Greenpeace, claimed: "These new estimates will be a major headache for the industry. It will make their dreams of building new nuclear power stations even more unrealistic and hasten the end to reprocessing at Sellafield."