[ RadSafe ] Re: uranium smoke is a teratogen
BenjB4 at gmail.com
Tue May 6 21:48:28 CDT 2008
Thank you for your good questions:
Mike Brennan wrote: "So does this mean that a coal fired power plant,
especially one with inadequate exhaust scrubbing (as I believe
describe most of those in China), which burns coal that has uranium in
it (as most coal does, to one extent or another) is releasing uranium
smoke with the uranium in the +6 oxidation state? Considering that
there are a huge number of coal fired power plants, and their fires
and uranium smoke production is ongoing, and the exposed population is
truly huge, isn't this a far more important exposure concern than DU
projectiles? And if you say it isn't, where is your proof that it
isn't? (No reasoned arguments here: it has to be proof that Chinese
uranium smoke isn't as bad as American uranium smoke)."
Coal fired plants do release uranium in the +6 oxidation state, but
not much. I can't give you exact numbers for China, but I do have
numbers for the U.S. Coal has uranium oxides (in the +4 oxidation
state) distributed uniformly, and it burns at under 1300 Kelvin,
producing very little U(VI). The vapor pressure of UO3 at 1250 K is
only 1e-5 mbar, so not much makes it airborne. Only about 8 tons of
uranium per year in the U.S. is released in airborne coal ash ("This
uranium is released to the atmosphere with the escaping fly ash, at
about 1.0% of the original amount [800 tons/year U.S.], according to
NCRP data." -- http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html
) A tiny fraction of that is uranyl; I would guess far less than 10%.
And most of that, if it isn't scrubbed, weathers before being
inhaled. So how many coal plants are there in the U.S. pumping out
that < 0.8 tons of uranyl per year?
The difference between the airborne soluble uranyl concentration in
coal plant smoke spread out over the country and uranium smoke in the
region around a DU-against-metal firefight is a huge difference. When
metalic uranium particles burn in air, the temperature exceeds 2800 K
(Mouradian and Baker (1963). "Burning Temperatures of Uranium and
Zirconium in Air". Nuclear Science and Engineering 15: 388-394) which
pushes the partial pressure of the uranyl production into the majority
of the combustion product. At 2800 K, the vapor pressure of UO3 is a
full atmosphere, 1000 mbar, or a hundred million times more volatile
than at the burning temperature of coal.
However, coal plant smoke is responsible for most of the uranyl in the
atmosphere right now, and most of the uranyl that has been breathed;
but not any of the largest acute or chronic human exposures.
Mike Brennan also wrote: "Also, Iran is enriching uranium for its
civilian power plant. This means that soon Iran will have a
substantial amount of deplete uranium. Iran boarders two countries
occupied by a hostile power with an army that has great superiority in
armored vehicles. It is only reasonable to believe that Iran will
soon start manufacturing DU weapons for its own defense (indeed, it is
not at all impossible they have already started). Wouldn't NOW be an
excellent time for the anti-DU forces to start bringing pressure to
bear against Iran, to get them to promise to never make or use DU
weapons? That way, if there is a war between the US and Iran, only
one side will be using them, and thus limit the damage they will do."
If you do a Google News search on [depleted.uranium birth.defects] you
will see that the Iranian press is more interested in the issue than
the U.S. press. What more can one person do? I am not affiliated
with any "anti-DU forces."
James Salsman, as Ben Fore
> -----Original Message-----
> From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf Of Ben Fore
> Sent: Tuesday, May 06, 2008 10:26 AM
> To: radsafelist
> Subject: [ RadSafe ] Re: uranium smoke is a teratogen
> Thank you for your helpful question:
> > Since everyone on the planet has been exposed to natural
> > concentrations of uranyl ions, constantly, day after day after day for
> > their entire lives, how exactly is this so different from a brief, downwind exposure to smoke?
> U(VI) weathers to U(IV), and the proportion of natural uranium in world-wide average soil in soluble compounds in the +6 oxidation state is less than 0.01%, is it not?
> Whereas in uranium smoke, most of the uranium is soluble, and most of it is in the +6 oxidation state; at least 1/3 dissolves into the uranyl ion
> > And at what distance? Since the smoke should follow the behavior of a
> > Gauss "puff", as opposed to a "plume", after a kilometer or so of
> > diffusion the concentration is very low.
> I have studied the aerosol dispersion papers in Health Physics and the recent papers by R. Guilmette and M. Parkhurst. There is no doubt that someone in a typical 500 m downwind or 150 m vicinity of a 1 kg uranium fire will be exposed to thousands of times as much uranyl as they usually get in a month.
> But what good would it be if we knew the exact dose? We still have no idea what the effect is on any mammal with a nine-month gestation period ten years after such an exposure.
> That's why I keep asking everyone to try and get people to find out, please.
> > Once the dust settles, infiltration of rainwater will move it deeper
> > into the soil column along with all the other nicely-behaving, natural uranyl complexes.
> Which soluble U(VI) complexes remain after weathering? None.
> Mattias Olsson wrote:
> > The interesting post below reminded me about an old incident I've been
> > told about with radiation alarms being set off by the smoke from a
> > Danish coal fired power plant. The detector was placed at the
> > Barsebäck NPP site in Sweden, apparently in the plume. Burning stuff
> > that has been dug up from the ground seems like a nice way to spread
> > uranium. Or did, before modern filter technology anyway.
> Do you mean radiation alarms or uranyl alarms? While coal-fired plants make a huge contribution to the amount of uranyl in the atmosphere (though not approaching being in the vicinity of 30 mm DU autocannon fire), they have not increased soil concentration of uranium much above 1600 levels, because U(VI) weathers to U(IV).
> James Salsman
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