[ RadSafe ] Salsman RE: Gardner Sellafield cluster

[John Andrews]

James Salsman wrote:

> John Andrews wrote:
>
>> ... I wonder how long this UO3 will stay in the vicinity of the 
>> vehicles that were damaged and continue to be an exposure hazard.  If 
>> it has a very slow setteling rate (is this true?) then it will 
>> disperse with the normal air movement and not be a significant 
>> problem because of dilution and dispersion.  
>
>
> The terminal gravitational settling velocity is given by Stokes law, as:
>
>       W = r*G*d^2/18*n
>
> where r is the particle density (about 8 g/cm^3 for UO3),
>       G is the gravitational acceleration constant,
>       d is the particle diameter (about 7 Angstroms for UO3),
>       n is the dynamic viscosity of the media,
>
> Using the viscosity of air at 25 deg. Celsius, UO3 gas particles settle
> out at about 60 cm/year.  However, that understates the rate to the
> extent that atmospheric mixing and diffusion results in deposition on
> the ground, plants, animals, exposed food, etc.
>
> As for diffusion, that is determined by the diameter of the particle,
> so in this case it is a little more volatile than benzene C6H6.
>
> In order to get all this exactly right I am supposed to read
> D.L. Ermak in Atmospheric Environment, vol. 11 (1977) pp. 231, which
> I have not done yet.
>
> Sincerely,
> James Salsman
>
>
> _______________________________________________
> You are currently subscribed to the radsafe mailing list
> radsafe at radlab.nl
>
> Before posting a message to RadSafe be sure to have read and 
> understood the RadSafe rules. These can be found at: 
> http://radlab.nl/radsafe/radsaferules.html
>
> For information on how to subscribe/unsubscribe and other settings 
> visit: http://radlab.nl/radsafe/
>
James, did you miss my point.  The stuff blows away.  It does not stay 
where it is generated and deposit at the rate of 60 cm/year.  It blows 
away.  Far away.  It dilutes.  It mixes.  It disperses.  It does not 
stay around.  Soon it is gone.  That is my point.

John Andrews, Knoxville, Tennessee