Re: 49 CFR Contamination Surveys

[LIPTONW@detroitedison.com]

When interpreting the 300 cm2 specification of 49 CFR 173.443, it is
important 
to read to the end of the section, especially the statement:  "The amount of 
radioactivity measured on any single wiping material, WHEN AVERAGED OVER THE 
SURFACE WIPED, may not exceed the limits ..." (emphasis mine).  Thus, the 
important aspect of this specification is NOT the area wiped by a single 
smear, but the maximum area over which you can average the activity.  This
is 
important if hot spots are present, since it allows you average the hot spot 
over a fairly large area.  (It is important to keep in mind the "as low as 
reasonably achievable" provision, however.)  The question of how many smears 
to take and what area to cover is answered in the intervening statement:  
"Sufficient measurements must be taken in the most appropriate locations to 
yield a representative assessment ..." 
 
The opinions expressed are strictly mine. 
It's not about dose, it's about trust. 
 
Bill Lipton 
liptonw@detroitedison.com