From: stead@skadi.CSS.GOV (Richard Stead)
Newsgroups: sci.energy
Subject: Re: Notch another one up for the Greennazis
Date: 15 Dec 92 01:38:41 GMT

In article <1992Dec14.154501.25009@inel.gov>, dpe@inel.gov (Don Palmrose) writes:
> Again, we have a difference of perspective.  What you say above for the most
> part, I do not doubt.  But to say that something 1.6 mm square or a powder 
> that is twice as big is large enough to be noticable by someone exposed to 
> that amount is not correct.  From my experience, such quantities can be easily
> digested or inhaled in a day by an unranium worker without their knowledge if 
> the proper precautions are not taken.  Accidents could cause that amount to be
> easily exceeded also.
> Thus, when handling uranium, I would be careful with it (especially if it
> is in a powdered form) because it is dangerous and I would want to minimize
> my exposure to as low as practable.
> I found it extremely interesting that the workers who built the first fission
> reactor fifty years ago would handle the natural uranium with their bare 
> hands and without face filters or resperators.  They even made some uranium
> dice and rolled them down the concrete hallway watching the sparks flying
> everywhere.
> Again, they are both dangerous, whether their path is through chemical
> interactions or through damage by radiation and both need to be treated with
> a healthy dose of respect.

I agree on most things here, and I agree that Uranium needs some
respect.  But I don't think people should be afraid of Uranium.  It
really is _everywhere_.  It is often at least ppm quanities in most all
rocks, and it is found in small traces in many plants as well.  It is a
relatively common element, moreso than other heavy metals like the
platinum group, rare earths, etc.  So it is all around us all the
time.  Now, anything we might do that concentrates it in our bodies is
truly dangerous, but you would have to try, or be exposed to it in
concentrated non-natural forms (such as metal U, UF6 gas, soluble U
compounds, or U-rich powders).  As I said, I have handled pounds of U
in the form of natural minerals, and my kidneys are fine.  I handled
them with my "bare hands" and without masks.  (I did make sure that the
specimens in the mineral collection where I was an undergrad were
wrapped in lead foil - I had a job were part of my responsibilities
included the collection.  It made sense to be a bit cautious.  It
didn't scare me nearly as much as the crocidolite.) I have been in
abandoned quarreys and adits oozing U.  It really is safe so long as
you are reasonably cautious.  (Of course, one should be reasonably
cautious with most ore materials - the vast majority are toxic to some
degree).  Pu is something one never comes across naturally.  Naturally
occurring Pu has been found - at barely detectable trace amounts less
than 1 ppb - in the ore from the natural nuclear reactors.

Another source of U contact - modern warfare.  Our modern ammunition
can be depleted U tipped.  This is just for the density of it - it is
only a little less dense the the densest materials - Ir and Os, but
megabucks cheaper.  The stuff rips through inches of steel plate as if
it were just a nuisance.  After the Gulf war, U was all over the
battlefield.  But it was chemical and biological agents they were
worried about, and an insect bite that caused the worst problems,
the U was no big deal.

Use caution, but don't fear U.  Think of it more along the lines of Pb, not Pu.


--
Richard Stead
Center for Seismic Studies
Arlington, VA
stead@seismo.css.gov