Re: Tritium and plastic

["John C. Elliott" <jce@primenet.com>]

Repost - return note as undelivered.

At 01:10 PM 1/24/97 -0600, you wrote:

>Can tritium permeate through plastic
>sample containers?  And if you were going to
>sample for tritium would you use glass or plastic
>sample jars?
>
>Mark P. Winslow
>US EPA - Region II
>
>ps.  This is concerning the "leak" at BNL.
>
>
When I started work at a university they had a neutron generator which
employed 8 Ci tritium hydrided on metal foil.  The foils arrived from the
manufacturer in a plastic bag, inside a screw cap glass jar, inside a sealed
tin can (can opener required).  There was 3H removable contamination on the
shelf where they stored the targets, even though the cans had allegedly wipe
tested clean on arrival.  To "eliminate" the contamination problem, they
installed a fiberglass "always on" 200 lfm fume hood, coated it with
stripable paint, placed a gasketed military ammo box in the hood, and stored
the unopened tritium foil containers (no detectable 3H on arrival) in the
ammo box.  Within a year 3 H was detectable on the outside of the ammo box
and on the inside of the hood.  10 years later they closed the facility and
removable 3H was found on the outside of the hood and on the wall behind the
hood, as well as in the hood ducting, all the way to the roof 6 stories
above.  The level of activity (from highest to lowest) was: Inside glass
bottle-->outside glass bottle-->inside can-->outside can-->inside ammo
box-->outside ammo box -->inside hood -->outside hood-->ceiling over
hood-->surface of wall behind hood. 
I also recall a handbook (ICRP?NCRP?) on tritium which said that 3H would
migrate through plastic gloves in 10 minutes or so.
Finally, old, unopened flame sealed ampules containing tritium seemed to be
the source of contamination in freezer ice in non-sel defrosting freezers.
The ampules were the only source of 3H which were stored in the freezers,
which were not contaminated before the vials were stored in them for 2 years
(I know, why would a researcher order something that they weren't going to
use for 2 years!) 

Hope this helps

John Elliott
jce@primenet.com