John W Burgeson wrote:
> I was at a meeting yesterday where the subject was the US sanctions on
> Iraq (the speaker, of course, was against them). Much of what he had to
> say made a lot of sense; some did not.
>
> In a leaflet he distributed and talked about was a description of what
> was called "Depleted Uranium," (DU), which was also identified as the
> isotope U-238. Included were all sorts of claims about it, claims which I
> do not see as credible. But my physics career is too far remote now in
> time for me to fairly judge these claims; perhaps someone here might
> comment on them.
>
> These are the claims, as extracted from somewhat more volitile phrases in
> the leaflet:
>
> 1. The US used DU munitions in Iraq, Kuwait, Kosovo, Serbia, Bosnia,
> Puerto Rico, Okinawa and within the US.
>
> 2. Thousands of individuals have been exposed (to what?) ...
>
> 3. DU is a health hazard if inhaled, ingested, or gets in wounds.
>
> 4. Respiratory and skin protection must be worn by everyone within 80
> feet of DU contaminated equipment.
>
> 5. DU contamination makes water & food unusable.
>
> 6. DU is made from the non-fissionable byproduct of the uranium
> enrichment process.
>
> 7. DU is used in munitions, shielding and commercial concrete.
>
> 8. DU munitions are solid U-238 (several examples given).
>
> 9. Upon impact, radioactive and heavy metal poison U-238 fragments &
> oxides are created.
>
> 10. Reported health effects (official DOD document, not identified)
> include (long list of diseases).
>
> 11. Doing nothing wall leave "thousands of radioactive heavy metal poison
> bullets" around.
>
> The article is written by a Doug Rome, Ph.D., who is identified as a
> former ODS (?) health physicist and a former Army DU Project director.
>
> If U-238 is a stable isotope, as I always thought it was, then whence
> comes the radioactivity? And while I'm fairly sure that ground up U-238
> powder is probably not good to inhale, is it really a poison? That is, is
> it worse than, for instance, an equal amount of West Texas dust?
>
> The anti-sanctions movement seems to me to be a good one to support. But
> these claims, which seem wild to me, don't give me any confidence in the
> rest of their message.
U-238 is not stable but decays by alpha emission with a half-life of
~4.5 x 10^9 years, as compared with a lifetime of ~7 x 10^8 years for U-235.
U-238 is not really "non-fissionable" (item 6 above) but a chain reaction
(either for power or for a bomb) can't be sustained in pure U-238 or natural
uranium (which is only 1/140 U-235 and the rest U-238). It is the removal of
U-235 to obtain a chain-reacting material which leaves "depleted" uranium.
Someone else will have to enlighten us as to why Pu-239 is apparently
much more toxic than U-238 The alpha energies (5.1 MeV for Pu-239 and 4.2
MeV for U-238) aren't that much different.
BTW, the half-lives and present abundances of the two uranium
isotopes can be used to get an
estimate of the age of the earth (or more precisely, of the material from
which the solar syatem formed). If we assume that their abundances were
initially about equal, a back of the envelope calculation shows that around 6
x 10^9 years must have elapsed between then and now. Of course this is a
rough calculation but it's sufficient to show the implausibility of YEC
claims absent apparent age arguments.
Shalom,
George
George L. Murphy
http://web.raex.com/~gmurphy/
"The Science-Theology Interface"
This archive was generated by hypermail 2b29 : Fri Feb 23 2001 - 17:30:00 EST