Re: Is Tritium Really That "Nasty"?

[Schoenhofer <schoenho@via.at>]

At 12:48 28.01.1997 -0600, you wrote:
>     
>     The thread identifying tritium as "nasty and HTO and particularly 
>     nasty" disturbs me a bit. 
>     
>     In term of the risk posed per unit intake (i.e., Sv/Bq), tritium and 
>     tritium oxide are among the least hazardous of radionuclides.  What 
>     with all the expressed concerns of LD 50/30 and the various numbers of 
>     7 and 8 curies calculated (for comparison with 25 curie sources), one 
>     must remember that there is a very big difference between HT (or T2) 
>     and HTO.  The exit signs that prompted the discussion may consist of 
>     2-100 (ok, nominally 25) curies of tritium, however it is some 90+ 
>     percent in the elemental gas form.  Actual experiences with the signs 
>     has been that there is very little dose associated with routine use or 
>     accidental breakage/leakage of these units.  Other applications of 
>     tritium luminescence (e.g., watches, gun sights) also bear this out.
>     
>     I don't mean to underscore the nuisance that can be caused by 
>     background tritium levels from these sources, nor the need for 
>     vigilance in radiation protection programs associated with them.  
>     However, it is recognized among those who routinely work with tritium 
>     that absolute control of it is a myth because of its ease of 
>     permeation and diffusion through barriers that would seem impenetrable 
>     to most materials.  This nuisance factor becomes particularly apparent 
>     when a zero-tolerance of contamination levels for workplaces is 
>     applied by a well-meaning but naive authoritative or regulatory body.
>     
>     Referring to tritium as "nasty" and "particularly nasty" promulgates 
>     unwarranted fears about the nuclide.  It raises a flaming torch to a 
>     straw man and shouts "watch out for this extremely dangerous 
>     situation."  
>     
>     Eugene H. Carbaugh
>     Internal Dosimetry
>     Pacific Northwest National Laboratory
>     eh_carbaugh@pnl.gov
>
>----------------------------------------------------------------------

Eugene,

As far as it concerns me, my referring to tritium as "nasty" was in no way
connected to any radiation protection questions and it was directed to the
radsafe collegues, who hopefully have enough knowledge to know about the
risks which tritium poses and not to the public. The nastiness I refer to is
toward the behaviour of tritium in the environment and that tritium
practically cannot be contained anywhere, without it would diffuse out and
contaminate the environment. Since I am concerned with low-level counting of
tritium I know what kind of problems this behaviour causes. 

Legislation usually considers the extremely low toxicity of tritium. In
Austria we have a maximum permissible concentration level of 37 kBq/l for
drinking water. For my own laboratory and my four Quantulus liquid
scintillation spectrometers I actually prefer a zero contamination! 

Tritium might be interesting when using the concept of manSieverts, due to
its wide spread occurrance and on a long term basis. 

I dislike furthermore the idea of living in a tritium world, where the
"clean" fusion energy has replaced the "dirty" nuclear energy - don't you?

Franz
Schoenhofer
Habichergasse 31/7
A-1160 WIEN
AUSTRIA/EUROPE
Tel./Fax:	+43-1-4955308
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e-mail:		schoenho@via.at