from Sunday Herald, 03 April 2011
A massive crane that lifts fully armed nuclear submarines out of the water at the Faslane naval base on the Clyde has 22 safety “shortfalls” and could suffer a nuclear disaster, according to a secret Ministry of Defence (MoD) report.
The submarine shiplift, housed in a huge shed on the shore of Gareloch, is at risk from earthquakes, high tides, overloading, explosions and fails to met the MoD’s own safety targets, the report reveals. It was released last week in response to a freedom of information request from the Sunday Herald.
The 256-page “Shiplift Facility Safety Case”, drawn up in January 2010, says that if the crane collapsed there could be an “inadvertent detonation” of Trident missiles that could lead to a “major strategic weapons system accident” involving nuclear warheads.
Campaigners have warned there’s a danger of an accident scattering dangerous levels of radioactivity over a wide area, as at Fukushima in Japan. They are calling for a full review of nuclear safety at Faslane.
The shiplift is regarded by critics as one of the most dangerous buildings in Britain, and has a chequered history. It had to be modified in 1997, and in 2003 a report by consultants suggested that accident risks had been underestimated.
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 warheads. It also lifts other nuclear-powered submarines, and will be used for the new Astute-class boats.
The newly released report, which was marked “restricted” and parts of which have been blacked out, is a comprehensive and detailed assessment of the shiplift’s safety. “There are some outstanding regulatory issues to be addressed,” it concludes.
Four of the 22 identified shortfalls concern the shiplift’s potential vulnerability to earthquakes. “The seismic analysis and deterministic assessment of the roof structure is not adequate,” the report says.
Similarly, seismic analysis “does not provide sufficient confidence in the withstand capabilities of the cranes” and shows that loads on retaining clips could exceed their capacity. Earthquakes could also cause pipework in vital cooling water systems to become “over-stressed”, the report says.
In extreme circumstances, predicted loadings could threaten the stability and strength of the cranes. The report also suggests that the Clyde base had underestimated the heights of future tides.
The shiplift building could be damaged by an explosion, because its tolerances “would be exceeded” by a blast. The risk of “inadvertent ignition/detonation of missile/strategic weapons system ordnance was dominated by the possibility of platform collapse resulting in a significant impact between the submarine and the adjacent civil structures/water,” the report adds.
It concludes, however, that the risks to public safety are “acceptably low”. The shiplift meets the MoD’s basic safety limits, but fails to meet its safety objectives, it says. “It is judged that the continued operation of the facility remains tolerable.”
John Ainslie, the coordinator of the Scottish Campaign for Nuclear Disarmament, pointed out that even after 18 years of use, the safety case for the shiplift was incomplete. “In an earthquake the roof could collapse and the overhead crane fall onto the submarine,” he said.
“Pipes that supply vital coolant for the reactor could also be ruptured. At the very least, there should be a full review of the implications of the Fukushima accident for nuclear safety at Faslane.”
The MoD insisted that it had an excellent nuclear safety record over 50 years of operations. “Safety reviews will usually identify areas for improvement but this does not mean that a facility is unsafe,” said an MoD spokesman.
“The regulator is content with the safety of the shiplift and would not allow it to be used if this were not the case.”
The version of the Shiplift Facility Safety Case released by the Ministry of Defence is available here.
Previous stories about the Faslane shiplift are here and here.