Re: Kr-85

[Les Fraley <les@lamar.ColoState.EDU>]

Something seems out of place here.  According to my info, 85m-Kr has a 
half-life of 4.4 h.  It decays to 85-Kr which has a half-life of 10.8 y.  
85-Kr decays by negatron emission to (stable) 85-Rb.  85-Kr emits a 514 
keV gamma, but only 0.0041 of the time so it should not be much of a 
problem - as long as the 85-Kr is contained in a suitable gas cylinder 
(suitable by design and markings)!  A couple of decades ago, a nitrogen 
cylinder that contained 5 Ci of 85-Kr was picked up as empty, taken to 
Denver, all of the activity purged to the atmosphere near downtown 
Denver, then the cylinder was filled with N2 and delivered to the next 
customer.  Post event analysis indicated that only the driver receiver 
any dose and his was small.  Needless to say, the type of tanks used and 
the way they were marked changed drastically during the next few weeks.
Les Fraley

On Wed, 4 Dec 1996 Peter.Darnell%EM@em.doe.gov wrote:

> Message authorized by:
>     : umtrahp@concentric.net_at_INTERNET at X400PO
>      Kr-85 only has a half-life of about 4.5 hours - unless they're using 
>      nuclear methods to generate the Kr, there shouldn't be a rad problem.
>      
>      Pete Darnell
>      peter.darnell%em@em.doe.gov
> 
> 
> ______________________________ Reply Separator 
> _________________________________
> Subject: Kr-85
> Author:  radsafe@romulus.ehs.uiuc.edu_at_INTERNET at X400PO
> Date:    12/4/96 10:42 AM
> 
> 
> Errors-To: melissa@romulus.ehs.uiuc.edu 
> Originator: radsafe@romulus.ehs.uiuc.edu 
> Precedence: bulk
> X-Listserver-Version: 6.0 -- UNIX ListServer by Anastasios Kotsikonas 
> X-Comment:  Radiation Safety Distribution List
>      
> 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.
> I would appreciate any information you have.
>                 Joe Bianconi
>          Rust Federal Services, Inc.
> Uranium Mill Tailings Remedial Action Project
>      2309 Renard Place SE, Suite 300
>           Albuquerque, NM 87106
>  505/246-2537 voice        505/766-1813 fax
>