THE UK’s nuclear bomb factory has been struggling to remedy as many as 1000 safety defects uncovered by the government’s official watchdog. It is only allowed to stay open because the Ministry of Defence (MoD) says the work it does is vital for national defence.
The remarkable and, until now, secret story of the serious problems faced by the nuclear weapons complex at Burghfield, Berkshire, is revealed in 12 internal reports released by the UK’s Nuclear Installations Inspectorate to 91av under freedom of information laws. For the past five years the NII has been trying to force Burghfield’s operator, the Atomic Weapons Establishment (AWE), to tackle 1000 “shortfalls” inspectors identified in its safety procedures. Yet an inspection in April 2007 found that more than 300 of them were still outstanding, and they will not now be completed by 27 September as promised.
The NII has criticised AWE’s progress as “poor” and “unacceptably slow”. The only solution, it says, is to start again from scratch. “The current facilities fail to meet modern standards,” an NII assessment found in 2006, adding that “only the design, construction and operation of new facilities” will ensure that standards are met.
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The facilities at Burghfield are used to keep the nuclear warheads on the UK’s Trident missiles in working order. Inside circular cells encased in concrete and buried under nearly 7 metres of gravel, technicians dismantle nuclear warheads, check them and then put them back together.
One of the potential hazards is that the high explosives packed around the weapons’ plutonium core could detonate. Should an explosion occur, the roofs of these cells – known as Gravel Gerties, after a character in 1940s Dick Tracy comics – are designed to collapse, allowing the gravel to pour in and so prevent particles of plutonium from being blasted into the air (see Diagram). In the US, which has similar Gravel Gerties, there have been concerns about the risk of plutonium leaking (see “American Gerties”).
“One of the potential hazards is that the high explosives packed round the weapons’ plutonium core could detonate”
In the UK, the NII asked AWE to improve the safety of its Gravel Gerties in 2002, five years after it gained legal powers to regulate them. A detailed review later uncovered a long list of “shortfalls” that the NII said needed to be rectified.
Few details of the problems appear in the documents released to 91av, but it seems that a substantial proportion of them were classed as category 1, the most serious category. They included potential deficiencies in concrete, bricks, filters, glove boxes and door seals, as well as in the ability of roofs and masonry to withstand earthquakes.
The AWE’s programme to address the shortfalls was initially due to be completed by April 2006, but it was postponed to April 2007, and then again to the end of September. “Very limited remedial work has been undertaken to date,” the NII reported in August 2006.
An inspection by the NII in April this year discovered evidence that some of the “engineering fixes” which AWE claimed to have delivered had not worked. This, the NII said, “does not instil confidence that AWE’s own procedures are being followed”.
In May the NII wrote to AWE listing 46 problems with hoists, fire dampers, gas cylinders, cables, valves and other equipment that were not due to be resolved before the September deadline. Without “robust” arguments justifying the delays, the NII said it would consider imposing “operational restriction” at Burghfield, which it has now done. Despite this, it is still allowing bombs to be dismantled in the Gravel Gerties because the MoD insists that the work is “necessary in support of the UK strategic deterrent”.
According to the NII’s 2006 safety assessment, the number and nature of the shortfalls would normally have caused operations to be suspended. But it added: “The true benefits from such ongoing operations can only be fully assessed by the MoD and can only therefore be fully evaluated by it.”
Campaigners opposed to nuclear weapons claim public safety has been compromised. Di McDonald from the Nuclear Information Service in Southampton, UK, says: “The NII has been effective in warning of the unsuitable state of the buildings and the poor working practices at Burghfield, but it is powerless to override the MoD.”
The work at Burghfield is bound to conflict with normal safety guidelines, McDonald argues. “AWE are tasked with fitting a high explosive into a nuclear device that will work,” she says. “The NII’s job would normally require them to ensure that such components are kept a safe distance apart.”
The NII now says that “appropriate progress” is being made at Burghfield, despite the “limited” resources available to AWE. “If NII believed a particular operation were unsafe, it would not allow it to take place,” a spokesman told 91av this week.
AWE denies that safety has been compromised. “The documents released by the NII demonstrate the comprehensive and robust nature of the regulatory process for AWE Burghfield,” it says.
American Gerties
Safety fears forced the US to temporarily stop dismantling nuclear bombs in Gravel Gerties in September 2003. Government regulators were concerned about faulty welds which could have allowed plutonium to escape in an accident in the installations, which are similar to those in the UK.
Inspections at the BWXT Pantex plant near Amarillo, Texas, revealed that welds around doors had not been repaired six years after a series of 7-centimetre-long gaps had been found. The Defense Nuclear Facilities Safety Board, created by Congress to oversee the nuclear weapons industry, intervened and operations were suspended while the welds were sealed.
According to a report by the board in July 2004 the potential accident “of greatest concern” was the detonation of less than 32 kilograms of high explosive -too little to collapse the roof. No gravel would fall to smother the blast, so aerosols of plutonium could be forced out through any gaps in the Gerties.
Improvements to close potential gaps should be “prioritised”, the board recommended. Nuclear scientists have also been assessing models designed to predict the effect of accidental explosions in Gravel Gerties, which are sited on the Nevada test site near Las Vegas, as well as at the Pantex plant.
