Re: Activated rocks

[AndrewsJP@AOL.COM]

In a message dated 12/7/2001 2:02:45 PM Eastern Standard Time, Cehn@AOL.COM writes:



> I am D&Ding activated concrete sheild walls. Part of the floor is above the DCGL and will have to come out.  Under the floor is a gravel subfloor.  I haven't been able to sample the gravel yet (floor is still in place).  Has anyone run into this situation?  What nuclides show up in the gravel?  Co-60?
>
>
> Joel I. Cehn, CHP
>
> cehn@aol.com


If it is just activation, there should be no Co-60 in plain gravel.  Co-60, if any should be in the rebar or screening withing the concrete. You might find some longer lived rare earths, though.  It depends a lot on the specific elements in the gravel matrix.  You will find uranium and thorium in normal gravels, so there may be some fission products, but these should be very low and not detectable.  The U and Th daughters will be there in varying concentrations depending on the source of the gravel.  This is gravel placed under the concrete floor, right?


Let us know what you find when you are done or when you discover an unusual problem.


John Andrews

Knoxville, Tennessee