Re: Clean up criteria

[ERGKBAKER@aol.com]

We at Environmental Restoration Group, Inc. have worked at several uranium
and throium contaminated sites, working to cleanup criteria approved by the
NRC.  For the uranium mill tailings sites, we have obtained approval for
using high density gamma data obtained via GPS-based detectors as a primary
verification method.  Gamma action levels are established through correlation
studies.  A limited soil sampling program provides the backup confirmation
that the site is clean.  More detail can be provided if interested.  

For the thorium sites, we prepare a composite sample for each 100 sq m area
and analyze for the contaminants.  The NRC also requires that no hot spots
will be greater than 3x cleanup limit.  This presents a problem in that as
you extrapolate to zero volume, naturally you can't meet the criterion.  In
practice, the NRC walks the area and if they find any hot spot that is likely
to exceed the 3x criterion, we remove it.  Most of this is some how related
to NUREG/CR-5849 guidance.

For more information you may contact me at ergkbaker@aol.com

Ken Baker