Sequel to Radioactive Rocks

[Sue Dupre <DUPRE%PUCC.bitnet@vmd.cso.uiuc.edu>]

A week or two ago I sent out an inquiry which was spurred by our need to ship a
collection of rocks, some of which were significantly radioactive.  In case you
may be interested and in reply to my respondents, let me provide you with more
detail and a description of subsequent events.

Years ago we worked with the Geology Dept to identify and isolate its most
noticeably hot rocks.  These rocks (several hundred rocks) were not in much
demand and were placed in two open-sided cabinets in a rarely used penthouse
on the building roof.  The room was kept secured and monitor film badges have
been kept in the area since then.  We didn't espcially worry about radon be-
cause the room was drafty and people rarely went there.

Now a geologist at a major museum has agreed to accept the whole collection
including the hot rocks so we've been busy working to make sure all parties
are informed about the problems the rocks can pose.  We've done ion chamber
surveys of the rocks, put film badges on them, done smear surveys in the cab-
inets and done radon monitoring in the room.  The hottest rock gives us an on
contact deep dose film badge reading of 100+ mrem/hr.

We got Rn levels of 39 pCi/l in the open-sided cabinet and find a fair amount
of contamination, which decays rapidly, wherever the rocks have been sitting.

We've provided a report; our legal people have worked out an agreement and the
museum will come here to package the rocks and will act as shipper.  I did talk
to DOT and was told, as I had figured anyway, that it doesn't matter whether
the rocks are regulated as NORM; if they meet the DOT definition of radioactive
then they get shipped accordingly.  They would probably most easily be shipped
as LSA materials, by defining them as ores.  The rocks are still here, waiting
for the final details to be finished, but we expect them to leave soon and hope
that the museum will treat the hottest rocks with some reasonable degree of
respect.

Sue Dupre/Health Physicist/Princeton University