Beta source exposures

["Wesley M. Dunn" <WDUNN@brc1.tdh.state.tx.us>]

It depends on what you call "limiting" access.  The short range 
of beta emitters can easily allow access for non-radiation 
workers just across the room from a very large beta source.  

"Once upon a time", academic research labs routinely used 20-50 mCi 
batches of P-32 (as one example).  The potential dose to the worker's 
eyes and fingers was high.  But the person two benches over could 
easily be in a clean and low-radiation area.  So while the other lab 
members knew radiation was being used (and were "commensurately" 
trained), they were not radiation workers.

Of course, this scenario is pretty rare these days -- by the mid-
80's, it was cheaper (and much easier) to buy pre-labeled (250 
uCi) from the manufacturers than to do your own labeling.  It was 
also possible to get bulk P-32 in smaller batches, so with good 
techniques (and counting good equipment!), one could get by with 1 or 
5 mCi.

So even if rad and non-rad work is being mixed, the potential 
radiation dose to the P-32 worker has become pretty low.

Wes

> Date sent:      Thu, 14 Nov 96 16:59:30 -0600
> Send reply to:  radsafe@romulus.ehs.uiuc.edu
> From:           "Sandy Perle" <sandyfl@ix.netcom.com>
> To:             Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
> Subject:        re: ionization chambers, micro rem meters, etc.

> > What kind of operations involving radionuclides could result in a
>  need to monitor beta dose rates and would not already limit access to
>  the area by non-radiation workers due to contamination concerns?
>  Maybe I spent too much time in the nuclear power community, but I
>  couldn't think of anything. If there is, I would appreciate a reply<
> 
> Your assumption is correct, as I see it. Considering the SDE 
> regulatory limit of 50 rem/yr, there really exists no occasion for 
> this scenario to be true. Even considering 100% inhalation of all 
> contaminants .. it just isn't possible.. If this isn't the case, I 
> too would be interested in probable scenarios where this concern is 
> valid.

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Wesley M. Dunn, CHP                        512-834-6688
Deputy Director, Licensing                 512-834-6690 (fax)
(Texas) Bureau of Radiation Control        wdunn@brc1.tdh.state.tx.us
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