Trident nuclear warheads damaged in a vehicle pile-up or a plane crash could partially detonate and deliver a lethal radiation dose, according to a newly declassified report from the UK Ministry of Defence obtained by 快猫短视频. The MoD has also revealed that an attack by terrorists on a nuclear weapons convoy could produce an even more disastrous outcome. 鈥淭he consequences of such an incident are likely to be considerable loss of life,鈥� says a senior MoD official.
Trident warheads are regularly transported to weapons facilities in the US and the UK, where they are inspected to make sure that ageing materials don鈥檛 render them unreliable or unstable. The MoD has always insisted that an accidental nuclear explosion could not happen in transit, because a warhead鈥檚 plutonium core must be compressed symmetrically by conventional explosives. Bombs are designed to be 鈥渟ingle point safe鈥� so a knock at a single point should not trigger all the explosives around the core.
But according to the report extreme accidents could result in a nuclear explosion. A serious vehicle collision or an aircraft crash combined with multiple failures of the MoD鈥檚 secret protective measures could mean that the weapon might not remain single-point safe. The report puts the overall yearly risk of an 鈥渋nadvertent yield鈥� in the UK at 2.4 in a billion, mainly due to the possibility of an aircraft crashing onto a convoy. Inadvertent yield suggests a partial nuclear explosion, also called fizzle yield, smaller than the full yield of up to 100 kilotons.
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The report judges this risk to be 鈥渢olerable鈥�. Nevertheless, the MoD has drawn up contingency plans for responding to such an event, which has 鈥減otentially high off-site consequences鈥�. They say that radiation doses could range from 1 to 10 sieverts. According to the UK Health Protection Agency, people exposed to 4 sieverts have a 50 per cent chance of dying from acute radiation poisoning, while 6 sieverts or more will kill everyone exposed. The report concludes that emergency arrangements are adequate, though it does not spell them out.
US experts agree that the risk of an accidental explosion is real. 鈥淵ou can鈥檛 rule it out,鈥� says Philip Coyle, from the Center for Defense Information think tank in Washington DC. 鈥淚f we are going to have nuclear weapons, we have to live with the risks.鈥�
A less predictable danger of moving nuclear weapons is terrorist attack. When David Mackenzie, a Scottish anti-nuclear activist concerned about bomb convoys driving over weight-restricted bridges, filed a freedom-of-information request, he was told that the MoD could not release information on convoy routes or axle weights because that might help terrorists plan an attack. 鈥淪uch an attack has the potential to lead to damage or destruction of a nuclear weapon,鈥� wrote the MoD鈥檚 director of information, David Wray, in May. 鈥淭he consequences of such an incident are likely to be considerable loss of life and severe disruption both to the British people鈥檚 way of life and to the UK鈥檚 ability to function effectively as a sovereign state.鈥�
Despite this, the MoD stuck to its line this week that neither a terrorist attack nor an accident could trigger a full nuclear explosion, because each warhead is transported with 鈥渧ital parts of its final configuration removed鈥�.
鈥淎 nuclear-bomb-type explosion is therefore impossible,鈥� said an MoD spokesman. Though he accepted that an inadvertent yield was theoretically possible, he said it was incredibly improbable, and would not be greater than a few kilograms of TNT equivalent.
This is disputed by Frank Barnaby, a nuclear physicist who worked on the UK nuclear weapons programme and is now a consultant with the independent Oxford Research Group. 鈥淭he MoD report confirms what many scientists have long suspected 鈥� that nuclear bombs can go off by accident,鈥� he says. 鈥淭hey have also effectively admitted that a terrorist attack could cause a nuclear explosion. A Trident warhead exploded in a densely populated area could kill hundreds of thousands of people. However small the risk, that is too horrifying to contemplate.鈥�
You can download the report, entitled Operational safety case for the transport of nuclear weapons (pdf format, 8MB). Some text has been blacked out by the MoD, which cites reasons of national security in most cases.
