RE: Alpha shielding in "Masslin"

[Glen.Vickers@ucm.com]

Mike,

I believe there may be some self absorption if some of the alpha gets worked
into the fabric of the masslin; however, the masslin permits you to assess
much larger surface areas than you could with a traditional 15.5 cm^2 size
smear.  For shipping purposes we use traditional smears for reporting
dpm/100 cm^2, but we still conservatively do large area masslins to ensure
we're not missing anything.  

We report no activity found on a large area masslin as "NCF"(No Contam
Found), we do not attempt to take credit for an efficiency or area size.  If
activity was found, we would attempt to document with a 100 cm^2 smear, but
realistically the low level contaminant was just deconned with the large
area masslin.  

Regardless of the technical hurdles, the large-area masslin survey is the
best way of detecting low-level contaminants before they become visible with
a smear.  If you wait until your problem is identifiable with a traditional
100 cm^2 smear area, then things have been out of line for a little too
long.

I would be interested to know if anyone has any smear efficiency data in
addition to the self-absorption question.

Sincerely,
Glen Vickers
Braidwood Nuclear Station

> -----Original Message-----
> From:	Winters, Mike [SMTP:wintersMS@pgdp.usec.com]
> Sent:	Wednesday, April 12, 2000 12:02 PM
> To:	Multiple recipients of list
> Subject:	Alpha shielding in "Masslin"
> 
> Hello Radsafers,
> 
> Has anyone evaluated the use of masslin in areas of alpha removable
> contamination?
> 
> I'm looking for data to prove that the oil and fibers on the masslin cloth
> will not shield the alphas from a portable survey instrument.  I'll
> collect
> it myself if I have to, but I'm hoping one of you can save me the legwork.
> 
> 
> If you're at a facility where alpha contamination is a concern, do you use
> masslin? Why? Why not?
> 
> Michael  S. Winters
> USEC Health Physics
> Paducah Gaseous Diffusion Plant
> Mailstop 7115
> 5600 Hobbs Road, Paducah, KY, 42001
> ph  270-441-6943
> fax 270-441-6113
> email: wintersms@pgdp.usec.com
> 
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html


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