[ RadSafe ] Tungsten Alloy Munitions Pose Unforeseen Threat -NIHresearch

[James Salsman]

Don Mercado wrote:

> James Salsman wrote:
> 
> "Right, each round has about 280 grams of metallic uranium, so based on
> the percentage that burn when fired at a hard target"
> 
> Do you mean "fired at a hard target" or "striking a hard target"? Simply
> because a round is fired from a gun doesn't mean it burns. How did you
> figure the percentage that burn?

You are right: my figure is high.  According to
   http://www.globalsecurity.org/military/systems/munitions/du.htm
the average number of 20-30mm rounds fired which hit their target
is about 10%, and of those only about 40% of the metal in the
incendiary rounds burn.  So, assuming that only 4% of the uranium
burns, that makes 12 released grams of elemental uranium per round.
This assumes that only the rounds which strike the target burn at
all, which is probably very conservative.  Roads are hard enough
to ignite the rounds, although sand isn't.

> "Even if you ignore uranium trioxide, which everyone except Salbu et al.
> last year has, then you still get multimiligram resperable quantities of
> U3O8 and UO2 dust at least 1200 meters downwind, even in a fairly strong
> wind:  Mitsakou, et al., "Modeling the Dispersion of Depleted Uranium
> Aerosol," Health Physics, vol. 84, no. 4 (2003), pp. 538-544:
> http://www.bovik.org/du/aerosol.pdf "
> 
> I'm not sure where the "multimilligram respirable quantities" you are
> talking about come from, but if you look at Figure 3 of the report,
> they're talking about <1 X 10E-6 Bq/m^2 for even the closest distances
> from the fire.

Figure 3 shows concentrations at distances 10 km and 100 km; you are
referring to Figure 2.  They both show depositions on the ground from
only a 1 Bq release.  Since the specific activity of DU is 12500 Bq/g,
the 20-round, two-second firing I've been talking about would involve
a release of 3 MBq based on 12 g/round, or, from Figure 3, 0.18 Bq/m^3
at a distance of 10 km after half an hour in an 11 mile/hour wind.

If the air concentrations are proportional to the deposition rates
shown in Figure 2, that's still about a milligram of elemental uranium
every 220 four-liter breaths at a kilometer away in the same wind.

>... The studues they quote on particle sizes indicate fires
> cause particles between 1 and 10 microns. No mention of "nanoparticles".

The tremendous divergence of particle size ranges from various
publications is a clear indication that the science in this area
is tremendously flawed.  Elder and Tinkle (1980), quoted in that
report, claim that the median particle size was ten microns, with
a standard deviation of only 1.7.  About 18% of the particles are
indicated as less than 0.1 micron wide in J. Glissmeyer et al.,
"Prototype Firing Range Air Cleaning System," from the Proceedings
of the 18th D.o.E. Nuclear Airborne Waste Management and Air
Cleaning Conference (August 1984.)

Sincerely,
James Salsman