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Re: Decommissioning problem



Greg:

If you saved all of your LSC samples, try recounting them, do you get the same
results or has the count rate dropped.  If the contamination is radon daughters
they will decay away rather quickly and your bag of paper towels shouldn't be
a disposal problem.


Greg Krause wrote:

> I inherited the clean up of an old subcritical reactor.  The fuel and PuBe sources are gone (thank you Sherry Jones and the Y-12 people), but:
>
> the fuel and other U itmes were stored with Aluminum reactor components in a small sealed room for many years.  All of the Aluminum items now appear to be contaminated when I perform  wipe tests on them using liquid scintillation.   Other items in the room: cardboard, wood, steel don't appear to be contaminated.  Is this consistent with deposition of radon daughter products? (leaded glass is also contaminated while the metal frame is not.)  Contamination levels appear to be around 300 - 1000 dpm/100 cm2.
>
> The contamination appears to wipe off easily with detergent, so I have a choice of contaminated aluminum or contaminated paper towels.  Assuming that the contamination is radon daughters, how to dispose of the bags of towels?
>
> Final question:  although I got rid of the PuBe sources, I still have the storage container.  Its a large aluminum can filled with parafin, but would anyone know what the thin sheet of soft, gray metal is that's apparently used as the thermal neutron absorber?  I need to know, because unless someone out there wants it, I intend to send it to the landfill.  The only info I have on the container is that a tag on the outside reads: Universal Nuclear, New York, NY
>
> Greg Krause, P.E.
> Director, Radiation  & Chemical Safety
> University of North Dakota
> 701-777-3341
> greg_krause@operations.und.nodak.edu
>
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