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Article: Technology of 'Dirty Bomb' Simple, but Not the Execution
This appeared in today's Washington Post.
-- John
John Jacobus, MS
Certified Health Physicist
3050 Traymore Lane
Bowie, MD 20715-2024
jenday1@email.msn.com (H)
Technology of 'Dirty Bomb' Simple, but Not the Execution
By Guy Gugliotta
Washington Post Staff Writer
Wednesday, December 5, 2001; Page A12
Finding enough radioactive material to make a "dirty bomb" might be
relatively easy, experts say, but the effects of such a weapon could never
remotely approach those of a nuclear explosion.
"The nuclear device is a weapon of mass destruction," said nuclear scientist
Siegfried Hecker, former director of the Los Alamos National Laboratory.
"Dirty bombs are weapons of mass disruption, in terms of frightening people,
the cleanup and the potential economic consequences."
Interest in dirty bombs has deepened recently among U.S. intelligence
officials because of mounting evidence that Osama bin Laden and his al Qaeda
network may be developing expertise in building them.
But Homeland Security Director Tom Ridge said yesterday that U.S.
authorities had no information that bin Laden had made such a weapon. Ridge
added that the Bush administration's latest anti-terrorist alert had nothing
to do with the threat of a dirty bomb. Sources have told The Washington Post
that concerns about al Qaeda's nuclear capabilities had played a role in the
alert.
The technology to make the bomb is relatively simple: Find some radioactive
material, wrap it around a core of ordinary high explosive and detonate it
so that contamination spreads over the widest possible area.
This is not a nuclear explosion. That occurs when two subcritical masses of
highly processed radioactive material are thrust suddenly together,
triggering a violent chain reaction and release of energy.
Blast effects and heat from a nuclear device can flatten city blocks and
kill thousands of people; the only blast from a dirty bomb is provided by
the explosive.
Still, while fatalities may be light, a dirty bomb can cause a higher
incidence of cancer in local residents even decades after the attack, and
more immediately, provokes the same psychology of fear as a chemical or
bioweapons threat. In that respect, Hecker said, a dirty bomb "would have an
instant terrorist effect."
But the bomb-maker must always contend with a Catch-22, for the more
powerful the radiation source, the more dangerous it is to handle. The
weaker the source, the less damage the weapon will cause.
"The dirtiest spent fuel is from a nuclear reactor," said Lisbeth Gronlund,
senior staff scientist of the Union of Concerned Scientists. "It is very
radioactive, and one reason to consider it proliferation-resistant is that
the dose you get from stealing it would kill you pretty quickly."
Even if the thief is prepared to die, making bombs from "hot" radioactive
material and getting them to the target present dangers. "How do you figure
out how much you need?" asked Tom Cochrane, nuclear program director for the
Natural Resources Defense Council. "And how do you transport it?"
The alternative is to pick a weaker radiation source. That means using
plutonium or enriched uranium, which give off "alpha" particles that cannot
penetrate the human body from outside, unlike the "gamma" particles or
neutron radiation common in spent fuel waste or cobalt-60.
If the terrorist chooses alpha, then the plutonium must be milled fine, like
anthrax spores, because the only way it can hurt humans is through
inhalation, Cochrane said. This adds another requirement for technical
expertise. But as long as the maker can deal with the radioactivity,
detonating the device is as easy as triggering a bomb in a car or arming it
from the air.
Damage could be problematic, experts say. In October, the nonprofit National
Council on Radiation Protection and Measurements estimated that
contamination would spread over "only a small area of a few city blocks."
The International Physicians for the Prevention of Nuclear War argued that a
plutonium dirty bomb would have almost no immediate health consequences, and
even though it could lead to cancer years after the attack, the effects
"would probably not be dramatic."
Still, the terrorist group that used a dirty bomb would garner immense
prestige among its peers, said British political scientist Gavin Cameron in
a paper prepared last month for the International Atomic Energy Association,
and "the mere fact of being nuclear would almost certainly ensure that it
had a considerable impact on the public's imagination and fear."
© 2001 The Washington Post Company
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