'Disturbing' gaps in nuclear warhead factory emergency plans

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Nuclear emergency planning arrangements at the factories where the UK's nuclear weapons are manufactured do not meet standards adopted at a similar plant in the USA and should be reviewed in the light of the Fukushima emergency, according to an independent expert on nuclear safety.

Emergencies resulting from acts of terrorism at the bomb factories have not been taken into account in risk assessments because they are not considered to be 'reasonably foreseeable' by nuclear regulators, and hazard appraisals are “vague” and fail to identify the nature and severity of potential accident scenarios.

John Large of Large & Associates, a consulting nuclear engineer who examined the emergency arrangements at the Atomic Weapons Establishment (AWE), where warheads for the UK's Trident nuclear weapons system are manufactured, described the results of the study (available to download below) as “very disturbing”.

Large concluded that it was “not at all clear” how AWE had arrived at recommendations on the size of emergency planning zones for its two sites in Berkshire, within which householders would be advised to stay indoors and take precautions in the event of a release of radioactive materials.  

The size of each zone is “remarkably small”, covering a radius of 3km from AWE's Aldermaston site and just 1.5 km from the assembly plant at nearby Burghfield, where fissile warhead components are mated with high explosives to form live warheads.  A corresponding emergency planning zone at the Pantex warhead assembly plant at Amarillo, Texas, which performs similar work to Burghfield, has a much larger double zone radius of 8 km and 16 km, the latter of which has to be further extendable in itself.

Evacuation of the public from areas around the crippled Fukushima Daiichi nuclear power plants in Japan involved about 140,000 individuals out to a distance of 60km from the reactors, and a year after the emergency a total exclusion zone is in force for 20km around the plant.

Large concluded that emergency planning risk assessments submitted by AWE to the government's Office for Nuclear Regulation (ONR) provide no meaningful detail about the types of accident that are relevant or credible at either site and do not specify the types and quantities of radioactive materials that might be released during an emergency, raising questions about the credibility of the plan.    Internal communications between ONR nuclear safety inspectors suggest that full documentation was denied to the ONR, that it never examined the previous three-year AWE safety assessments, and, for the most recent 2008 assessment, that it “does not have the time available to undertake detailed assessments of such submissions”.

Other documents obtained as part of the study under the Freedom of Information Act reveal that an accident during experiments in an unnamed facility at the Aldermaston site could result in an off-site radiation dose exposure to members of the public that could soar to 560 times the annual permissible limit for a member of the public.

Nuclear Information Service, which commissioned the study by Large & Associates, has written to members of the AWE Local Liaison Committee, which represents local authorities with responsibilities for off-site emergency planning in the event of an accident, to call for a review of emergency arrangements at AWE.  Liaison groups at other nuclear sites, such as the Sizewell nuclear power station, have formally requested local authority emergency planners to expand the size of emergency zones on the basis of lessons learnt at Fukushima.

We have also written to ONR calling for an explanation of the apparent shortfalls in scrutiny of justification documents provided by AWE.

John Large said: “Given similar weather conditions, superimposition of the Fukushima radiological conditions on the Aldermaston site shows that an accident would result in a radiation emergency being declared as far as 60km from the point of the radioactive release.  With a prevailing wind from the South-West, the radiation fallout from the overhead plume could reach as far as Reading, Slough and a large part of the western suburbs of London.”

Nuclear Information Service Director Peter Burt said: “Local residents have a right to know about the risks posed by the Atomic Weapons Establishment and to receive the highest standard of protection in the event of an accident.   In the light of the accident at Fukushima the Local Liaison Committee should follow the example of similar groups at other nuclear sites in the UK and insist on an open and transparent review of on- and off-site emergency arrangements”.

You can download copies of the report from Large & Associates and correspondence with the Office for Nuclear Regulation and AWE Local Liaison Committee members here: