Re: Characterising unknown waste drums

[dryeamans@lanl.gov (David Yeamans, CST-7, 5-8832, dryeamans@lanl.gov)]

How well you have to characterize your waste depends on what you intend to
do with it.  There is an excellent technology developed by Los Alamos that
has worked well in demonstration and production runs at Rocky Flats.  The
segmented tomographic gamma scanner (S/TGS) digitizes the image of a drum as
it is rotated past a source.  In about 20 minutes, you can get a 'high'
resolution 3-D image of your waste.  We hope to utilize the technology to
downgrade some of our TRU waste to LLW by identifying individual components
that can be removed from a drum.

As I am a 'manager' and not an imaging expert, I refer you to Steven Betts,
505-667-7266,           stephen.betts@lanl.gov             for better
information.  He can also lead you to the experts in PAN and RTR.

In a related matter, how do you meet CERCLA regs for reportable quantities,
and DOT regs for forbidden materials without fairly complete
characterization?  Do you rely strictly on knowledge of process?

> 
>Does anybody out there have any good ideas for characterising lab waste in
>a drum, assuming there are only gamma emitters present?  This is also
>assuming that it is a non homogenous mixture, and it is difficult to get a
>representative sample to count.
>
>Do you still try to get as good  a sample as possible? or?
>
>One method is to  count the drum on a Ge-li detector, while the drum
>is being rotated.
>Then dose rates have to be taken at eight different points outside the drum.
>Then one has to apply all kinds of efficiency, geometry, tau,  and density
>factors and come up with activities for different isotopes.  This is a very
>time-consuming process. After all, we are talking about "waste".
>How close do the estimates have to be? Within a microcurie? Within
>hundreds of microcuries? Remember, the final results are expressed as
>curies on the shipping paper.
>
> Any ideas are welcome.
>
>Ninni Jacob
>Radiation Safety Officer
>University of Rhode Island
>
>
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Keeping Our Eye on the Target -- CST-7 Waste Management
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David Yeamans
CST-7, MS E516, (505) 665-8832
Los Alamos National Laboratory
Los Alamos, New Mexico 87544

dryeamans@lanl.gov