? -Reply

[Roger Pedersen <RLP1@nrc.gov>]

Depending on the precision needed, 12 inches and 30 cm are the same.  However,
I don't think you will find that the NRC has ever stated that they are exactly equal. 
I presume that the "nuance" that you refer to is whether  an area has a dose rate of
 > 100 mrem/hr at 30 cm but < 100 mrem/hr at 12 inches is a High Radiation Area. 
Unless you have a license condition that says otherwise, you need to comply with
10 CFR 20.1601 (a)(1) which specifies 30 cm.  In my opinion, if you need to split
hairs this closely, something else is wrong.


Roger Pedersen
Senior HP
NRC

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  "Our loftiest plans have fallen through,
      our airiest castles tumbled over,
    because of lines we neatly drew,
       and later neatly stumbled over."  - Piet Hein

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The above is my own call and not necessarily an "Official NRC Position"

>>> "Donald T. Flahardy" <FLAHADT@naesco.com> 05/14/98 10:46am >>>




Hello fellow radsafers:

Can anyone provide a reference where the NRC clearly stated that 12 inches
is equivalent to 30 cm?  This is in regard to 10CFR20 definitions for
Radiation and High Radiation Area measurements.  I did see in Q&A #52 where
30 cm was given with 12 inches in parenthesis,  but I was looking for
something more clear and concrete. I realize I am concerning myself with
two tenths of a cm, but you know how important these nuances can be.


Don Flahardy
Seabrook Station
Flahadt@Naesco.com
603 773-7312