RE: Adsorption and wet well irradiator sampling

["Frame, Paul" <FRAMEP@ORAU.GOV>]

> I'm trying to find information on the adsorption of >cobalt-60 (or metals
in general) in sample container >walls. I'm specifically interested in
original work 
>done that may shed some light on the question "How much >activity is lost
if we are looking for subpicocurie/ml >levels and analyzing the sample
within hours rather >than days or weeks and don't acidify the sample?" 

Rick:

I believe the answer is "It depends" - on the water chemistry and container
material. The conventional wisdom is that we can reduce losses by using
plastic containers and acidifying immediately after collection. Some
facilities even require that acidification be done within 30 minutes of
collection (Of course, acidification is understood to be inappropriate for
some elements). 

That the conventional wisdom doesn't necessarily match up with reality is
indicated in  "Fractionation of Radionuclides in Liquid Samples from Nuclear
Power Facilities" by Bernabee et al in Health Physics 39:57-67:1980. That
would be the only good reference I know of, but the vast bulk of the
literature on this topic won't be in the nuclear/rad literature. I'd talk to
an analytical chemist.

TGIF

Paul Frame
Professional Training Programs
ORAU
framep@orau.gov
http://www.orau.gov/ptp/ptp.htm
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