The storage of high level radioactive waste at the Sellafield nuclear reprocessing plant is "one of the world's most dangerous concentrations" and should be immediately suspended, a report published by the Institute for Resource and Security Studies (IRSS) recommended yesterday.
The "catastrophic consequences" of a leak of the nuclear material stored at the plant, material such as caesium-137, could be a nuclear disaster 10 to 100 times greater than that caused by the fire at the Chernobyl plant in 1986, the report claims.
Presenting his report at a press conference in London, Dr Gordon Thompson, the director of the Massachusetts-based IRSS research group, accused the UK nuclear industry and the Nuclear Installations Inspectorate (NII) of failing to understand the risks of radioactive waste storage and he warned that "the Chernobyl accident is a precedent".
The Irish General Council of County Councils and the W. Alton Jones Foundation, a US pro-environment group, funded the IRSS report. The chairman of the UK Nuclear-Free Local Authorities, Mr Martin Hemingway, said his organisation would investigate mounting a legal challenge against the Health and Safety Executive over whether it had minimised the risk to public safety at the plant. Asked if he believed the Sellafield plant was operating at an acceptable public safety level, Dr Thompson told The Irish Times: "No. We have focused on the particular problem of the waste storage tanks and the judgment of what is an acceptable level of safety is a systematic and democratic process which has not been proven by BNFL."
Dr Thompson said he recognised the particular fears in Ireland about the safety of the Sellafield plant. "The Irish people should insist that the Irish Government acts on their behalf to demand that the UK government is much more open and assess the risks and alternatives. Until the tanks are proven safe, reprocessing should be suspended. The Irish Government has this responsibility," Dr Thompson insisted.
The NII is severely criticised in the IRSS report, which says the inspectorate has a small staff and operates on a low budget. In comparison with US decision-making on nuclear projects, the report says, the NII operates within a "culture of secrecy".
The fears over safety at Sellafield centre on acidic radioactive waste, which is stored in liquid form in 21 stainless steel tanks. The tanks must be cooled and ventilated while the waste is contained in them. The material is then converted to a glass form for long-term storage during a process called vitrification. The potential risk of leakage of radioactive material from the tanks in the form of liquid draining into the Irish Sea or an atmospheric plume travelling downwind is related to the amount of caesium-137 stored at the plant.
This radioactive isotope material was responsible for most of the off-site radiation exposure from the Chernobyl accident and its reactor core contained about 70 kgs of caesium-137, whereas Sellafield's tanks contain 2,100 kgs.
Dr Thompson suggested that if it were possible to uniformly distribute 140 kilograms of caesium137 (the amount contained in a typical storage tank) over Ireland, during the next 30 years Irish people would receive an annual radiation dose of about 15-20 times the natural background level. This exposure could result in an increase of 50 per cent in cancer fatalities.
Listing the possible scenarios that could lead to a leak of nuclear material, the IRSS report says Sellafield's waste storage tanks are vulnerable to severe and low-level earthquakes. It also challenges the assertion that fire and explosion do not pose a threat to the tanks.