Analysis: 'Bin Laden's nuclear threat'

Nuclear material can be used in "dirty bombs"

By BBC News Online's Natalie Malinarich

Osama Bin Laden and his al-Qaeda network may have acquired nuclear materials, according to the Western intelligence sources quoted in the British media.

Although it is widely believed that al-Qaeda does not have the capability to build a conventional atomic bomb, experts fear that the radioactive material could be used in a so-called "dirty bomb" - a device to spread radioactive material. These so-called dirty weapons have never been used before.

Bin Laden does not have the technology to build a bomb

Radiation could be scattered from the top of a building, by detonating explosives wrapped with the radioactive material or by piloting an aircraft into a nuclear reactor.

Thousands could be exposed, causing both short- and long-term deaths and rendering areas uninhabitable for years.

Shopping for uranium

Bin Laden and his associates have long been accused of trying to acquire nuclear material.

Pakistan has an early nuclear programme and its highly enriched uranium would be very precious to it. It would not have enough to spare

John Large, nuclear consultant

A close Bin Laden associate was charged by the US of trying to buy a cylinder of South African uranium in Sudan.

A letter alleged to have been written by Bin Laden and seized in London three years ago, called on Muslim nations to acquire nuclear weapons.

"We call for the Muslim brothers to imitate Pakistan as to the possession of nuclear, chemical and biological weapons," says the letter dated May 1998.

It is not known where Osama Bin Laden may have got his nuclear materials - if he has them - is not known, but fingers are pointing to ex-Soviet republics or Pakistan.

Pakistan says its nuclear materials are "in safe hands"

Pakistan has denied the accusations and insists that its nuclear assets are in safe hands.

John Large, an independent nuclear consultant, also says Pakistan is an unlikely source.

"Pakistan has an early nuclear programme and its highly-enriched uranium would be very precious to it. It would not have enough to spare, even if it wanted to," he says.

No nuclear competence

John Large thinks that Bin Laden probably does have enriched uranium bought in a former Soviet republic, possibly Kazakhstan or Uzbekistan.

"Unfortunately, he is in the right place at the right time. That area of the world is the worst place in terms of possible proliferation," he said.

A nuclear bomb is difficult to manufacture and requires a lot of industrial infrastructure, materials, machines and tools

John Large

"With the break up of the Soviet Union there were many leaks, typically about 30 cases of smuggling of nuclear materials a year. It is like an open sieve. You get a superpower like the Soviet Union break up and of course its materials will come out."

The Washington-based Center for Defense Information (CDI) warns that there is still a long way to go to bring Russian nuclear security up to international standards.

However, experts insist that al-Qaeda does not have the technical competence to build a nuclear weapon.

"It is difficult to think of a sub-national group doing it without the help of a nuclear state," says John Large.

"A nuclear bomb is difficult to manufacture and requires a lot of industrial infrastructure, materials, machines and tools. It also takes a long time to develop the capability."

Israel, for example, took about 15 years to achieve nuclear status.

But not being able to build an atomic bomb does not mean that radioactive materials cannot be used to cause extensive damage, as many specialists have warned.

Dirty weapons

Weapons involving radioactive materials can take many forms.

A "dirty bomb" could leave areas uninhabitable for years

The most accessible for any terrorist is a radiological dispersion bomb, says the CDI.

This "dirty bomb" consists of waste by-products from nuclear reactors, wrapped in conventional explosives.

On detonation the dirty bomb would spew deadly radioactive materials into the environment.

According to some experts, it would be sufficient to explode an old X-ray machine containing cobalt 60 to produce radiation poisoning.

Another feared possibility is the spread of radioactive particles.

Elements such as caesium, cobalt, plutonium or uranium can be oxidised into respirable-sized particles and then dispersed in the environment.

The particles would settle as dust, and be very difficult to detect and clean up, leaving areas uninhabitable.

Thousands of people could suffer short- and long-term effects from the inhalation of radioactive material.

But experts say the ultimate dirty bomb is a nuclear power station which could serve as a target for a terrorist attack.

Crashing an aircraft into the cooling pool that holds the spent fuel, could have a devastating effect on the nearby population and environment.

Recognising the threat, the French military has stationed surface-to-air missiles at key nuclear processing sites in western France as a precaution against airborne suicide attacks and both the UK and US governments have said security measures are being reviewed.