A London court last Tuesday learned just how simple it might be to bring a form of nuclear terrorism to a major city. All a terrorist would need, the court was told, is a so-called "dirty bomb" assembled from household smoke detectors.
Most smoke detectors that trigger an alarm contain a small quantity of the radioactive isotope, Americium- 241, a by-product of the plutonium- 241 generated in nuclear reactors.
In almost all circumstances, household smoke detectors present no risk to occupants, according to the Melbourne Uranium Information Centre, a service funded by the uranium industry. But Americium- 241, says the centre's website, can be "a potentially dangerous isotope if it is taken into the body in soluble form".
Dhiren Barot, 34, an al-Qaeda- linked would-be terrorist whom the court sentenced to life imprisonment, had a plan to arrange just that in New York and London. He sought al-Qaeda funds to buy 10,000 smoke detectors containing radioactive material at 5 ($A12.40) each, and either "set them alight" or "place them on top of an explosive device". The immediate death toll might be small or nonexistent, but the ensuing panic might well empty most of a city.
"Dirty bombs" scientists call them radiological dispersion devices are, of course, the least of the world's radioactivity fears. A terrorist nuclear bomb of the kind that devastated Hiroshima and Nagasaki tops the list of 21st century worries.
That fastest measure of what the world is thinking about the Google Search website returns 17.1 million listings for "nuclear terrorism".
Hollywood, of course, caters to the fear. For the past couple of movie decades, wild-eyed gentlemen with nuclear backpacks have been threatening the central business districts of major cities.
Exploded in New York's Times Square on a week day, a 10-kiloton bomb, one even smaller than Hiroshima's, would vaporise everything between Carnegie Hall and the Empire State Building, we're told, destroy the United Nations headquarters and kill an estimated 500,000 people. One such bomb detonated at, say, Parliament House, would effectively obliterate the ACT.
Washington's ever-booming rent- a-threat industry makes the most of the angst generated by such notions.
As The Bulletin of Atomic Scientists recently put it, "Sometimes it seems as if the sources of newly announced dangers must be the basement of the White House or a back room at a Washington think tank, where the thousands of monkeys who have yet to type out exact copies of Shakespeare's works are nonetheless producing dozens of new ideas for attacks on America, to be trotted out on the news at 10."
What really are the odds of an attack by a terrorist's nuke (something way above RDD level)?
Probably quite low, says the most recent authoritative study of the problem.
A paper released by London's International Institute for Strategic Studies takes the view that "the risk of nuclear terrorism, especially true nuclear terrorism, employing bombs powered by nuclear fission, is overstated, and that popular wisdom on the topic is significantly flawed".
The paper Nuclear Terrorism After 9/11 (IISS Adelphi series, 378), by Robin M.Frost, a Canadian government analyst specialising in nuclear proliferation looks at "the considerable, probably insurmountable, technical challenges" in obtaining a nuclear weapon "whether 'home-made' or begged, borrowed or stolen from a state arsenal".
Especially since the Soviet Union's collapse in 1992, the stolen weapon has received much attention. During a series of interviews that I made for Fortune magazine in Siberia in 1998, Russia's former national security adviser, General Aleksandr Lebed, told me that more than 100 suitcase- sized nuclear bombs had gone missing during the Soviet break-up.