Re: Sewer Reconcentration & Solubility

[<cgj@nrc.gov> (Cynthia G. Jones )]

Dale-

If the material is "readily dispersible biological 
material," then it still can be disposed of without 
regard to its solubility, because, by definition it 
meets the criteria in 20.2003 (see also 56 FR 23381, 
column 2, Statements of Consideration).  The 
prohibition on disposal of insoluble materials via 
the sanitary sewer was intended to prevent disposal 
of material in which the radioactive material is 
primarily in an insoluble form such as flakes of 
metallic form containing Am-241 (which the type of 
radioactive material that started this reconcentration 
issue in late 1983--reconcentration of Am-241 from 
smoke detector manufacturer operations in New York).

As for non-biological material, it gets difficult to 
determine how to should that a particular material 
is indeed soluble.   Although NRC Information Notice 
94-7 provides two methods for determining solubility, 
licensees have used other methods, and in some cases, 
actually sample the local sewer treatment plants' 
(1x/month) influent (usually in fairly remote areas) 
to make sure that what they have discharged is insoluble.

Cynthia Jones.....CGJ@NRC.GOV
Division of Industrial and Medical Nuclear Safety
******The opinions expressed above are my own 
and do not necessarily reflect the policy of 
the U.S. Nuclear Regulatory Commission.******