from Sunday Herald, 30 August 2009
A huge and virtually unknown crane poses the biggest risk of a nuclear disaster at the Faslane naval base on the Clyde, according to newly released safety assessments by the Ministry of Defence (MoD).
Plutonium from up to 48 nuclear warheads could escape and cause widespread contamination and cancers if there was an accident while a Trident submarine was in the shiplift, the reports say.
But the MoD has been accused by experts and anti-nuclear campaigners of playing down the real dangers. The amounts and risks of the radioactivity that could be released have been underestimated, they say.
The shiplift at Faslane is a unique facility with a chequered history. Opened in 1993, it uses nearly 100 winches to hoist 16,000-tonne Vanguard-class submarines into the air for maintenance while they remain loaded with up to 48 Trident nuclear warheads.
The shiplift had to be modified in 1997, and in 2003 a report by consultants suggested that accident risks had been underestimated. Regarded by some as Faslane’s most hazardous operation, there have been hints that it may end up being replaced by the kind of dry dock used elsewhere.
But for now, it is still in regular use, for example lifting up the damaged HMS Vanguard after its collision with a French nuclear submarine in the Atlantic in February. And its use remains highly controversial.
In July, more than 20 months after they were first requested under freedom of information law, the MoD released two internal assessments of the accident risks posed by the shiplift. They consider the dangers of fires, explosions, plane crashes and the collapse of the shiplift platform or crane.
They assume that, in a worst case scenario, the plutonium from all the warheads on the submarine will be released. In a fire, this could result in tiny particles of plutonium being blown over a large area, increasing the risk of cancer risk for anyone who breathes them in.
The biggest risk is “societal contamination”, according to a report written in 2000 by expert scientists from the Atomic Weapons Establishment (AWE) at Aldermaston in Berkshire. But the numbers indicating how far the contamination would spread, how many cancers it might cause and how probable it might be have all been blacked out.
The risks are “close to the tolerability criterion level” set internally by the MoD, the report said. “There is a strong argument for ensuring that the risks are as low as reasonably practicable. These conclusions do not constitute AWE endorsement of the facility and procedures assessed.”
John Large, an independent expert on nuclear submarine accidents, warned that plutonium from a fire at Faslane could contaminate Glasgow, Edinburgh, Aberdeen or Inverness. It would depend on which way the wind was blowing, he said.
“If the containment of a nuclear weapon was breached, the consequences could be dire indeed, particularly if the plutonium was lofted high into the air by a fire,” he told the Sunday Herald. “No civil contingency plans could cope with it.”
Large disputed the MoD’s safety assessments and standards, pointing out that they were agreed internally without independent oversight. “The risks aren’t minimised to an acceptable level,” he said.
The Scottish Campaign for Nuclear Disarmament (CND), which originally requested the assessments, argued that they were “flawed”. Although they accepted that radioactivity could leak from the submarine reactor as well as its warheads, the accident estimates failed to include this.
“The calculations consider the effect of scattering around 200 kilos of warhead-grade plutonium across the countryside but take no account of the deadly cocktail of radioactive material which would escape from the reactor,” said Scottish CND’s co-ordinator, John Ainslie.
The risks for most people in Scotland were “totally unacceptable”, he maintained. “Gordon Brown should be considering how to remove this risk from the Clyde, not trying to persuade us to live with it for the next 50 years.”
The MoD insisted that the shiplift met all its safety requirements. “The Ministry of Defence works to ensure that all risks are fully identified and adequately managed,” said an MoD spokesperson. “Safety of workers at the base, the safety of the local population and the protection of the environment remain paramount at all times.”
Scans of the shiplift documents released by the Ministry of Defence can be downloaded here (1.1MB pdf), here (2MB pdf) and here (5.3MB pdf annex).
If the ship lift facility is ever to be considered safe, the law needs to be changed to make it and similiar facilities subject to licensing by the Nuclear Installations Inspectorate under the Nuclear Installations Act
Posted by: Fred Dawson | 30 August 2009 at 04:14 PM