NORM by definition

["Jonkers, Gert SIC-CTAN/2" <Gert.G.Jonkers@opc.shell.com>]

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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