Re: NORM by definition

["Gerald Falo"<gerald_falo_at_chppm7__apgea@chppm-ccmail.apgea.army.mil>]

     Gert,
     
     For samples in the natural environment that are exposed to any type of 
     weathering or other alteration secular equlibrium may not exist.  Just 
     about any paper covering measurements of U, Th, and associated members 
     of the series will show that.
     
     Also, there is a book called "Uranium Series Disequilibrium", which 
     cover the topic in some detail.  I forgot the authors' names, but the 
     book was available from Oxford University Press several years ago.  I 
     have the book at home.  If you email me at the address below, I'll 
     send you more information by return email.
     
     Jerry Falo
     jer3ry@aol.com


______________________________ Reply Separator _________________________________
Subject: NORM by definition 
Author:  <radsafe@romulus.ehs.uiuc.edu > at internet-mail
Date:    12/11/98 5:41 AM


Group,
     
For one of my clients I strongly need analysis results for 'natural 
materials', which do indicate that for these materials no secular 
equilibrium exists within the U-238 and Th-232 series. Who can provide me 
with data or point me to reports, books etc. which do contain these data. 
Many thanks in advance.
     
BACKGROUND:
the current Dutch legislations states an exempt limit for 'natural' 
materials of 500 Bq(total) per gramme material, and 100 Bq(total) per gramme 
for 'non-natural' or 'artificial' materials. With respect to maintaining 
these limits, a so-called practical definition is used: if an (naturally 
occurring radionuclide) analysis of a material shows there is no secular 
equilibrium within the U-238 or Th-232 series this material is by definition 
declared to be 'non-natural' (as I do have a clear opinion on the use of 
this definition as well - please only react by providing me with data 
requested or by pointing me to easy accessible literature sources) 
     
     
Kind Regards, Gert Jonkers 
CTAN - Analytical - Nuclear Measurement Techniques 
http://sww.ksla.shell.nl/analytical/skills/nuclearmea/1.html
   Radiotracer applications, 
   Gamma-transmission and Neutron BackScatter (NBS) measurements 
   Naturally Occurring Radioactive Materials (NORM)
   Radiological Protection Advice
Shell Research and Technology Centre, Amsterdam (SRTCA), 
http://www.srtca.shell.nl/welcome.html
PO Box 38000, NL-1030 BN Amsterdam, the Netherlands 
tel.        +31 - 20 - 630 3424
fax        +31 - 20 - 630 2911
e-mail   Gert.G.Jonkers@OPC.Shell.COM 
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