Re: Gypsum

["Franz Schoenhofer" <franz.schoenhofer@CHELLO.AT>]

-----Ursprüngliche Nachricht-----

Von: Richard F. Orthen <rorthen@EARTHSCIENCES.NET>

An: Radsafe BBS <radsafe@list.vanderbilt.edu>

Datum: Freitag, 10. Mai 2002 17:42

Betreff: Gypsum





>Where are published credible values found for the typical isotopic assay

>(U-Ra-Th et. al.) of the following gypsum materials: (1) phosphogypsum

>"stacks", (2) mine, (3) synthetic (FGD), and (4) underlayment (flooring)?





The concentration of the radionuclides mentioned depend extremely on the

source of gypsum and in the case of phosphogypsum on the raw phosphates they

derive from. Therefore no "typical isotopic assay" can be given - you have

to measure it! Gypsum from natural sources (mines) are usually extremely low

in radium and other NORM. How do you know, where some gypsum originates

from? Again - you have to measure it. Uranium and thorium normally do not

matter, but radium sure does. At least one US-state has strict legislation

about the use of phosphogypsum - in case it is of importance for you I could

check my files.





>Trying to objectively demonstrate whether the demolition waste profile

>signature I have is classifiable as NORM or TENORM.  The major gypsum

>suppliers (like USG) don't have a clue about this aspect of their products,





I would be very surprised, if they had not. My experience is. that companies

usually know very well all the details of their products, but they do not

tell you the data they have, unless they are legally forced to.





>although some are smart enough not to source phosphogypsum.





I take this as a clear hint, that they know very well about the problems

associated with gypsum.





Best regards,



Franz







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