Re: Alpha shielding in "Masslin"

[DTu7266800@aol.com]

in the early 1980's at Oyster Creek we performed smear removal efficiency 
tests to measure the actual removal efficiency using coin smears on fuel 
shipping casks.  The removal efficiency averaged 10% as I recall and varied 
widely.  Technicians had to be trained to apply the correct amount of 
pressure, use 3 fingers, use a 100 cm-2 cardboard template etc.  The surface 
being smeared can result in removal efficiency as low as 1% on rough porous 
surfaces to as high as 30% on mirror like surfaces.

I did some tests using masslin brooms in the 1960"s on waxed linoleum floor 
surfaces between hot cells.  The maximum activity is NOT collected on a 
Masslin broom.  The masslin broom tends to smear and pick up an average 
removable activity.  That is why the shipping regulations require 100cm-2 
smears averaged over no more than 1m-2.  Masslin mops contain an oily film 
which can easily shield alpha particles.

Doug Turner,DTu7266800@aol.com>
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