DU issues

[Phillip Hypes <phypes@nis5.lanl.gov>]

As I'm sure everyone knows, the military isn't the only place you can come
into
contact with DU.  A year or two ago a Nurse at the hospital where I worked put
me in touch with a friend who was having some health problems. The individual
was a photographer who for reasons that escape me had a solid mass of DU in
his photo lab for a few weeks.  Having heard about DU exposure and it's
possible
health effects on the news, he was concerned that this may have caused or
contributed to his problems.  When he called, I gave him a brief
explanation of
the differences between external exposure and internal uptake, and we
determined
that his chances of having had any significant uptake were very low.  I
believe he
told me the DU was from an aircraft, in which it had been used for load
balancing.

Test question;  How long would a 5kg mass of DU have to remain at 15 cm from
a sheet of photographic film before fogging will occur?  Besides needing
additional
information about the film in question, what additional information do you
need
about the DU?

The exact isotopic content of DU has a large impact on it's gamma constant.
Removing the U235 (Gammay Ray constant of 9.159e^-5, compared to 1.763e^-5
for U238) greatly reduces the exposure rates.  The exact amount of U235 needs
to be known to get the most accurate exposure rate results.  At the
beginning of
the Army's work on DU dose assessments, DU isotopic composition data was
a major concern.  I remember the lab manager grousing about people wanting
samples analyzed for DU content without being able to provide any better
isotopic
data than "less than 0.7% U235."  If anyone knows of references that
address this
issue, I'd like to hear about it.  I would expect that the composition
would vary
from source to source, so generalizations may be difficult (or classified,
in which
case I can't really claim "need to know").

P. Hypes


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