Re: Kr-85

[Bob Hearn <rah@america.net>]

Dr. Franz-

A look at your books (I appreciate your caveate of being at home) will show
you that Kr-85 is not a pure beta emitter, albeit an infrequent gamma
emitter, its signature can be observed in nuclear power reactor spectra at
514 keV with a low abundance of 0.43%, with an averge beta energy of 250
keV, thus resulting in a significant external skin dose factor from cloud
submersion. (The average energy for C-14 is about 49 keV.)

I have the good fortune of working at home and thus have the convenience of
many of my references at hand to confirm my recollections.

Bob Hearn
Unafilliated
rah@america.net

At 03:59 PM 12/4/96 -0600, you wrote:
>At 09:39 04.12.1996 -0600, you wrote:
>>Radsafers:
>>Reading a report from a company that produces specialty gases (e.g., Kr from
>>the atmosphere via a cryogenic method), they are convinced that they have a
>>rad problem with Kr-85.  I do not know the basis for their concern. Has
>>anyone ever heard of a similar situation.
>>---------------------------------------------------------
>
>Joe,
>
>Kr-85 is present in the air at a concentration which is - at least it was
>some years ago - about 1 Bq/m3. It originates from spent fuel and is
>released during reprocessing. Various methods to remove it from the gaseous
>effluents are known, but as far as I know, no removal is done in the
>existing reprocessing plants. It is a pure beta emitter, the energy is
>similar to C-14 (sorry I am at home and do not have any tables at hand). 
>
>Since Kr-85 is a low energy beta emitter I cannot imagine any radiation
>protection concern, because the pipes and steel tanks will act as a perfect
>shielding. Nevertheless the specific activity is rather low.
>
>Franz
>Schoenhofer
>Habichergasse 31/7
>A-1160 WIEN
>AUSTRIA/EUROPE
>Tel./Fax:	+43-1-4955308
>Tel.:		+43-664-3380333
>e-mail:		schoenho@via.at
>
>
>