Re: Tritium and plastic

[Schoenhofer <schoenho@via.at>]

At 13:11 24.01.1997 -0600, you wrote:
>I remember a while back I asked a question
>regarding tritium permeating through protective
>clothing.  I have another question regarding
>tritium.  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.
>
>....................................................

Mark,

Tritium is one of the nastiest radionuclides. We should be grateful that its
radiotoxicity is extremely low.

I suppose that you refer to HTO. HT would be even worse. It diffuses through
practically everything - through plastic of any kind, through metals,
through joints in screw locks, through joints of glass bottles and stopcock.
One can only think of barriers to keep diffusion as low as reasonably
achievable...

On radsafe I have mentioned already a few times that we have conducted a
series of experiments concerning the emission of tritium from watches with
luminous dials containing tritiated polystyrene. We found, that tritium
diffuses from all kind of watches rapidly into the water in which we
submersed the watch and also into the human body, the amount depending on
the material of the watchs' encasing. Regarding stainless steel encasings
this is obviously effected through the joints and is lowest. A titanium
encasing allows more rapidly diffusion, since tritium gas is soluble in
tritium and diffuses even through the metal. Diffusion is highest in the
case of plastic encasing, rendering a concentration of about 3000 Bq/l of
tritium in urine in equilibrium.

Cases of severe contamination of samples with tritium are well known.
Samples should be handled very carefully, have to be stored in glass bottles
for a minimum of time and be analyzed as soon as possible. Even glass
bottles with very different concentrations of tritium should not be stored
in close contact. In most low-level tritium laboratories it is strictly
forbidden to enter with a watch with tritium luminous dials. 


Sorry, I do not know what BNL is and not the story about the "leak".

Franz
Schoenhofer
Habichergasse 31/7
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AUSTRIA/EUROPE
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