[ RadSafe ] Field determination of radon progeny

[Eric.Goldin at sce.com]

I didn't ever see too much on the actual answer to Rick Hansen's question 
on field determination of radon progeny:

I have a question for radsafe:

What are some methods to use in the field to determine if low levels of
radiation detected on a person or clothing is due to radon daughters
rather than radioactive contamination from other sources?

Nuclear plants have a duty to not release people who are contaminated with 
licensed radioactive material (plant-related).  So to distinguish between 
naturally occurring rad material (i.e. radon progeny) and plant-related 
noble gases (typically Xe-133), the worker is typically asked to simply 
wait for decay.  With most radon progeny having short half-lives (less 
than 20 minutes), a short decay period will usually drop the 
electrostatically bound radon daughters to a sufficiently low level such 
that they will pass the whole body contamination monitors.  Anything 
longer-lived is likely plant-related and therefore requires documentation, 
decontamination, investigation, . . . .     Of course an option is to take 
the clothes and place them on a HpGe detector for a qualitative evaluation 
- if the count room has the time.


Eric M. Goldin, CHP
<Eric.Goldin at sce.com>