Defence Nuclear Material Transport Operations - Accident and Terrorism Risks

Accident and Terrorism Risks

Transport containers for nuclear weapons, SNM and new and used reactor fuel, provide protection from impact, mechanical stress and fire. They are tested against International Atomic Energy Agency (IAEA) standards for abnormal environments.

In the event of an incident, control passes to Ministry of Defence Nuclear Accident Response Organisation (NARO). Defence Nuclear Material Transport Contingency Arrangements are in place in case of accidents involving DNMs.

In a report from the Nuclear Movements and Nuclear Accident Response Group an extreme accident could result in a nuclear explosion. A serious vehicle collision or an aircraft crash combined with multiple failures of the MoD's secret protective measures could mean that the weapon might not remain single-point safe. The report puts the overall yearly risk of an "inadvertent yield" in the UK at 2.4 in a billion, mainly due to the possibility of an aircraft crashing onto a nuclear weapons road convoy. Inadvertent yield suggests a partial nuclear explosion, also called fizzle yield, smaller than the full yield of up to 100 kilotons. However, the most significant health risk to members of public arises from the potential for a release of plutonium oxide aerosol from the fissile pit of a warhead, a high probability event if the warhead(s) was subject to intense fire sufficient to initiate detonation of the conventional high explosive compression packs that surrounds the nuclear heart of the warhead.

A potential risk of moving nuclear weapons is terrorist attack. In May 2005 the MoD's Director of Information, David Wray, refused a Freedom of Information request about convoy axle weights (it was alleged that the convoy had used a weak bridge) from an anti-nuclear activist on the grounds that it may help terrorists to plan an attack. "Such an attack has the potential to lead to damage or destruction of a nuclear weapon," he wrote. "The consequences of such an incident are likely to be considerable loss of life and severe disruption both to the British people's way of life and to the UK's ability to function effectively as a sovereign state."