Dirty Bombs Not Such a Blast

ScienceNOW Daily News ^ | 18 February 2006 | Eli Kintisch

[neverdem]

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.

[neverdem]

Fact Sheet on Dirty Bombs

Dirty work.
Physicist Frederick Harper used simulated dirty bombs to quantify the threat of real ones.
Credit: Randy Montoya

[MaxMax]

[neverdem]

LOL!

[Herakles]

"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."

Ok, let's see if I got this right; material heavier that lead is going to mysteriously "hang" in the air and spread all over the place, making life barely livable for people who know little about the methodology behind boiling water let alone the physics of kinetic energy and radioactive materials!

Where does God find all these people who have panic attacks every time someone in the MSM says boo?

[Lurker]

Where does God find all these people who have panic attacks every time someone in the MSM says boo?

There's one couple in Minnesota breeding all of them.

L

[CenturionM]

Dirty bombs prey on the fact that for most people, radiation ranks up there with evil spirits as something unseen that is out to get you.

Even without the MSM's help, people get hysterical when the "R" word is mentioned.

[Fresh Wind]

What about the long term effects of the lawsuits that would result from a dirty bomb?

[showme_the_Glory]

Jack Bauer is not skeered.

[fishtank]

You might want tot look at this:

http://www.radiation-scott.org/deposition/particles.htm

Then, you can do a search on the term "aerodynamic diameter".

A (spherical) heavy particle behaves exactly like a spherical water droplet; the relation between the diameters is based on the square root of the material density.

So, yes, you can easily have a particle of lead that has a 10 micron (equivalent) aerodynamic diameter that can float in the air.

[The Great RJ]

The British made for TV movie The Dirty War that has been shown recently on HBO, is pretty accurate. The actual number of radiation deaths might not be all that high, but medical facilities would be overrun and panicked victims might spread the radioactive materials further in their attempts to flee the area. The whole purpose of using such a weapon is to spread fear.

[Herakles]

"Then, you can do a search on the term "aerodynamic diameter". "

Thanks for the info, however much of the research would be oriented to a high energy explosion such as a Nuke where you very well would have a large population of small particles. A dirty bomb however is not a nuke and will not produce this large amount of small particles due to the very nature of the detonation not to mention temperature; low energy in thousands of degrees versus high energy in millions of degrees'

Also, temperature of the explosion would play a significant part in dispersal; low temperature small yields would more or less scatter particles in the immediate area where as high temperature, high yield would result in a chimney effect resulting in a large dispersal radius.

A quick understanding of dispersal could be calculated using standard dispersal formula for distribution from smoke stacks, and as I remember, the higher the stack, the larger the dispersal radius. A low energy ground detonation would result in minimal dispersal of small particles and the majority of the material would be in the immediate area.

Particle size is not everything and when you have done some of these calculations before, you get a feel for what would happen.

[RightWhale]

Lawsuits and FedGov expenditure are the main potential damages. They would be big. Bigger than New Orleans.

[Herakles]

"There's one couple in Minnesota breeding all of them."

LOL. Do you happen to know their names? Let me guess; Mr. and Mrs. John Q Public.

[Lurker]

If you're looking for a nuclear disaster modeling tool I think the industry standard is NACAR.

L

[fishtank]

Thanks for the reply.

I first thought that you weren't up on the technical details, but I was wrong. You are quite correct in what you just said.

[PapaBear3625]

The assumption is that a dirty bomb's radioactive material would be dispersed by explosion, rather than being mixed with some high-burning-temperature material (like thermite) and ignited to produce radioactive vapor and soot that would be dispersed over a wide area

[Herakles]

"The assumption is that a dirty bomb's radioactive material would be dispersed by explosion, rather than being mixed with some high-burning-temperature material (like thermite) and ignited to produce radioactive vapor and soot that would be dispersed over a wide area"

OK, seeing is believing; go do it; you will find I am right.

This dirty bomb stuff is not a problem except when you consider the artificially low levels imposed by the NRC because of people who are ignorant about radiation and will only listen to any member of the MSM who has a degree in communications from Penn State.

If you want to know how much of a REAL problem this is, ask a nuclear engineer - oh, that's right, you already did, you are talking to one. The only problem with a dirty bomb is how much the politicos would have to pay people like me to sweep the dirt up while I'm laughing the whole way to the bank.

Wait a second, what a great idea, you are right, these dirty bombs are REALLY dangerous and if one goes off, I'll be there to protect you from the radiation - better fire up my off shore bank accounts just in case, I see a big white beach in my future!

Hey, if they can give clowns at universities billions for global warming, they can spare a few mill for me to use a broom; at least I will give them something for their money!