Re[2]: Technical Basis Documents

["PAUL E RUHTER" <RUH@inel.gov>]

Supervisor, Radiation Dosimetry & Records
User ID-RUH; Mail Stop-4147;  Ext. 6-1973
I'll jump out on this one, although my memory doesn't distinguish
between what I've been told versus what I have made up!!!

We have "always taken smears" in an attempt to quantify surface
contamination. Long before the large area Maslin smear, these smears
were taken with filter paper disks, largely because they worked. We
(understand the HP/RC profession collectively) recognised that the size
of the area smeared was important in comparing results with this
technique. Since a handy (pardon the pun) length for the smearing motion
was 7-8 inches, which was reasonably close to 100 square centimeters,
the "standard area" for this survey technique was adopted as 100 cm|2.
It remained to quantify the activity on the smear in a "smear counter"
in units of "dpm", and, Eureka, we have "dpm/100 cm|2".

Obviously, the "smearing" process is aptly named with respect to its
precision; it is a practical blending of qualitative and quantitative
processes. It is a practical process that works. Attempts to make it
more precise or create a rigorous scientific/technical basis are doomed,
despite the pressures from the auditors, regulators, and those
requesting Technical Basis Documents.

Remember back to the recent discussion about the basis for surface
contamination limits; there is no scientific, first principles basis;
the limits are predicated on practical detection capabilities. Let's not
lose sight of the fact that although our profession relies on an
unprecedented span of the sciences (due respect to the medical
profession), and parts of the profession are very scientific, the
profession is more practical in it's overall application than
scientific.

Paul E. Ruhter    LMITCO, INEL, ruh@inel.gov

*** Reply to note of 09/16/96 08:34
To: RADSAFE --INELMAIL RADSAFE

Subject: Re[2]: Technical Basis Documents
     Here's one.  Someone explain where the unit "dpm/100cm^2" came from.
     I've heard a couple of different explanations but I'm still not
     completely satisfied that I have the correct answer.  There may be
     some good technical reason or it may have been created out of
     convenience and nothing more.

     Glen vickers


______________________________ Reply Separator ________________________________
_
Subject: Re: Technical Basis Documents
Author:  radsafe@romulus.ehs.uiuc.edu at INTERNET
Date:    9/13/96 2:26 PM


Melissa

Is this a joke?