[ RadSafe ] Tritium Surface Contamination

[Michael McNaughton]

Dear RadSafers

I have two questions about measurements of tritium surface 
contamination. At US DOE sites, it is common to take 100 cm2 smears 
of a surface suspected of tritium contamination, count the smears 
(with liquid scintillator), and report the results as dpm/100 cm2. 
The data are then compared with the DOE criterion of 10,000 dpm/100 
cm2 for tritium. However, even if you clean the surface thoroughly, 
tritium diffuses from beneath the surface and re-contaminates the 
surface, so what you count on the smear is not all there is.

1. Are such measurements used at non-DOE sites (e.g., in Canada)?

2. Is there any way to relate these measurements to volume 
contamination (e.g., units of dpm/g) or to the total amount of 
tritium in the object?

Thank you.

mike

Mike McNaughton
Los Alamos National Lab.
email: mcnaught at LANL.gov or mcnaughton at LANL.gov
phone: 505-667-6130; page: 505-664-7733