Re: tritium -Reply

[FRAMEP@ORAU.GOV]

>Wasn't there a recent (past two years) article in the HP Journal 
>comparing counting efficiencies with different substrates, dry vs.
>wet, 
>water wipe vs. alcohol wipe, etc ??

A couple that might fit the bill are Campbell et al Health Physics
May 1993 V64(5) p 540 and Klein et al Health Physics Feb. 1992 V62(2)
p186. other references can be found in these.

The issue of collection efficiency is interesting. When limits for
removable contamination were established, the ballpark assumption was
that the smear collection efficiency for removable activity was 10 %.
The NRC in 10 CFR 71.87 says as much. The limits were to apply only
to what the smear picked up. I have heard that in some cases DOE is
asking for the activity on the smear to be divided by a collection
efficiency. This calculates the total removable contamination which
is then compared with the limit. This requires the removal efficiency
to be calculated. Presumably this is done by a series of repetitive
smears over the same 100 sq cm. The DOE Decommissioning Handbook
justifies this approach by citing 10 CFR 71.87. It is a complete
misinterpretation of what the NRC says in the cited regulation.

Good luck

Paul Frame