[ RadSafe ] Article: Dirty Bombs Not Such a Blast

[John Jacobus]

This was sent by a co-worker, and thought it would be
of interest.  Again, experiments need to verify
computer models.

------------------
At
http://sciencenow.sciencemag.org/cgi/content/full/2007/218/1

Dirty Bombs Not Such a Blast
By Eli Kintisch
ScienceNOW Daily News
18 February 2007

SAN FRANCISCO, CALIFORNIA--Radioactive dispersal
devices--also known as dirty bombs--might be less
harmful to fire fighters or police officers than long
feared. That's the conclusion of a new set of
explosive experiments described here yesterday at the
annual meeting of the American Association of the
Advancement of Science (which publishes ScienceNOW).
Dirty bombs have been on the radar for decades, but
their threat has taken on increased urgency since 11
September 2001. The idea goes that terrorists unable
to secure a nuclear weapon would instead strap an
explosive device to a container filled with
radioactive material, which would likely be stolen
from a medical or industrial facility. Although the
damage caused by a dirty bomb would pale in comparison
to that caused by a true nuke, experts fear that such
bombs could still cause panic and possible injury or
death by spreading radioactive material over
potentially large areas.

To better gauge the threat, physicist Fred Harper and
colleagues at Sandia National Laboratory in
Albuquerque, New Mexico, conducted a series of blasts
to determine how certain materials behave during an
explosion. In one set of tests, Harper and Canadian
defense scientists exploded various devices thought to
be similar to terrorist bombs a few meters off the
ground. Those tests suggested the kinds of fragments
that could lead to acute radiological sickness tend to
travel less far than feared. Other tests, simulating
urban ground environments such as sand, dirt, and
concrete, suggested that dirt or grit from the area
tended to create larger fragments during the blast,
lowering their distance.

That's good news for first responders, such as police
and fire fighters. They shouldn't need to wear full
radioactive suits or air tanks, Harper says, because
the size and type of fragments that would be produced
by likely weapons wouldn't warrant that kind of
protection, ending up mostly on the ground rather than
in the air.

"Until Fred made this data available, people were
using assumptions," says Steve Musolino, a health
physicist at Brookhaven National Laboratory in Upton,
New York.

Still, the new data are agnostic on the long-term
risks for cancer for the general public that such
devices create. But Musolino says the findings could
have implications for the arduous task of cleanup.
Even from a small device, that process could take
months or years in a city as officials struggle to
find radioactive particles that went airborne after
the blast. Harpers findings hint, however, that a
greater fraction of bomb fragments would stay close to
the blast site, making for an easier cleanup effort.



+++++++++++++++++++
“We must face the fact that the United States is neither omnipotent or omniscient — that we are only 6 percent of the world’s population; that we cannot impose our will upon the other 94 percent of mankind; that we cannot right every wrong or reverse each adversity; and therefore there cannot be an American solution to every world problem.”
-- John F. Kennedy 

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com


 
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