Re: 5 rem (50 mSv)/y as BRC Level

["Dale E. Boyce" <dale@radpro.uchicago.edu>]

I agree with Ron K.  I personally wouldn't want to take a 5 Rem 
every year, simply because after not all that many years you
are getting up into the range where stochastic effects have been
observed, although one would need tens of years including latency
to have a few percent increase in risk.  I believe the 5 Rem limit
is appropriate from the regulatory standpoint, though.  As an
informed individual, I don't mind making the decision to accept
an exposure to complete a necessary task.  I just wouldn't want
to be forced to take that exposure every year.  I occasionally
speed, but I wouldn't want a career as a race car driver.
I occasionally fly, but wouldn't want to be a fighter pilot.
ALARA builds into the system a cushion that allows workers
a comfort margin.  I think that most radiation workers should
be willing to accept 500 mrem/year or they might be in the wrong
line of work.  Since background exposures vary by more than 100
mrem/year depending on your location, and very few if any people
take background into consideration in choosing where they live
and work, that 100 mrem would be a good choice for BRC.  That
would possibly need to be modified in a reasonable way to
reflect the number of potential sources.  Ten mrem should
without any question be BRC, since for example I get between
20 and 40 mrem/year more from the building that my office is in
than people located in buildings made of different material
on campus.  If we can't control our exposure from where we work
or live, why try to control "artificial" exposure below that
natural fluctuation?

Dale E. Boyce
dale@radpro.uchicago.edu