Re[4]: Technical Basis Documents

[BRZGV@ccmail.ceco.com]

     The units that contamination is represented in is not of much concern; 
     however, the actual area that is smeared is of great concern.  If you 
     suddenly go from smearing 100 cm^2 to 10 cm^2 your release criteria 
     instantly goes out the window.  In this new age of NaI tool monitors, 
     the efficiency/LLD of the GM frisker is terrible.  
     
     The 100 cm^2 smear has become the defacto standard when quantifying 
     smearable contamination and I don't see the actual smear area going 
     down.  In fact somebody better tell us "when to say when" or we're not 
     going to be able to release anything someday.  Does anyone remember 
     the term "BRC"?
     
     Glen


______________________________ Reply Separator _________________________________
Subject: Re: Re[2]: Technical Basis Documents
Author:  radsafe@romulus.ehs.uiuc.edu at INTERNET
Date:    9/25/96 5:03 PM


At 06:44 PM 9/22/96 -0500, you wrote:
     
>Units are important.
>
>There is a principle in math and science that the denominator is "unitized" 
>as you make reference.  The 100 cm^2 is not a unit area, cm^2 is.....
>
>
>Pardon my ignorance, but didn't the 100cm^2 area eventuate due to the fact that
>contamination probes typically had an acvtive area of about 100cm^2 when 
>monitoring for contamination directly?
     
     
OK, Ok, Units are important.  "that may have been what I said, but what I 
meant was..."  There is no difference between 10 dpm/cm2 and 1000 
dpm/100cm2.  Yes, when we sit down to do calculations it makes it convenient 
to have everything in compatible units, but how often are we handed a real 
life situation where we don't have to make conversions during the process of 
calculation??  We're talking grade school math here.  I just think we're 
puting too much emphasis on the color of the measuring stick rather than the 
size of what we're measuring.  Yes, I suppose we are making all good 
mathematitions cringe by not reducing our fraction, but the purpose of using 
100 cm2 in the reporting is to represent the fact that we measured the 
contamination over an area of 100 cm2 NOT over an area of one cm2.  In other 
words, the reported value also says something about the process or method of 
the assessment.  Why we don't say decimeter .... Idunno. 
     
It was suggested that among other reasons, "political friendliness" would be 
a good reason for using dpm/cm2, because it has a smaller number attached.
I do not agree with this premise.  We have enough credibility problems 
without being accused of trying to make things sound "better" than they are. 
(If we use Bq. we're sunk if we are concerned with this - wow! a 
Giga-becquerel)  I do think that we should use units that allow for the 
representation of the data using ordinary numbers.  For instance, use Ci, 
uCi, pCi, (or Bq, MBq..) to keep from having to use huge powers of ten. (i.e. 
Don't call a 10 Ci source a 10,000 millicurie source)
     
Alex,  I don't think the original (and still standard) common probes for 
contamination monitoring really see a 100cm2 area, but I may be wrong.  Has 
anybody done or heard of an assessment of this??  If you hold a pancake 
probe over a surface, how much active surface area is really measured?
     
Keith Welch
Thomas Jefferson National Accelerator Facility 
Newport News VA
welch@cebaf.gov