Re: HPS Objective

["David W. Lee" <lee_david_w@lanl.gov>]

At 09:42 AM 08-08-97 -0500, you wrote:
>I have a question for those who have suggested that there should be no
>control over exposures below those where acute harm has been directly
>observed:  Why not?  Put another way, what are the reasons for releasing
>control?  Ron has given his reason for ALARA: prudence.  What are yours?
>
>Dave Scherer
>scherer@uiuc.edu
>
>

	Ron Kathern responded in part: "...given the fact that our knowledge of
potential low level radiation effects is at best incomplete, prudence would
dictate that we eliminate such unnecessary exposures, even if we cannot say
with absolute certainty that there will be a discernable detrimental effect
attributable to them.  This is the essence of ALARA...."

	As exemplified by the historical shoe-fitting fluoroscope issue, and one
can certainly think of other "unnecessary" exposures that did not involve
nearly as much exposure/dose, some may consider it "prudent" to eliminate
such an "unnecessary" exposure under the ALARA philosophy purely because it
is "unnecessary."  Those who adopt such a school of thought, however, must
then be willing to specify a lower dose/exposure level below which they
will no longer be such an ALARA zealot.

	Thus a question back to David Scherer:  How low-level must the exposure
rate or dose be before you declare an "unnecessary" exposure to be so
trivial as to not concern yourself with it anymore?  The point being that
if you are going to go after an "unnecessary" exposure, there ought to be
some point at which one quits playing Don Quixote chasing after and
jousting with a few hundred millrem sustained either episodically or
non-acutely.

	I think those who wish to zealously stamp out or reduce "unnecessary"
exposure should be accommodated, but I would suggest that the level at
which even they should call things "good enough" ought to be a reasonable
multiple of the mean, chronic natural radiation background dose which each
of us unavoidably sustains and to which we do not apply the ALARA
philosophy.  The NCRP would have us believe that the total mean background
dose is approximately 300 mrem, effective dose from radon included, from
which no "harmful" effects have been observed.  Since the terrestrial
portion of the background dose can be as high as 10 times the mean
terrestrial level in certain regions of the world and the effective dose
from radon is even more variable geographically, two to three times the
mean background dose puts you in the neighborhood of 600--900 mrem/year.

	I would suggest that it is no longer "prudent" to expend significant
radiation safety effort on radiation producing device or radioactive
material use operations that impart less than 600--900 rem/yr.  What is the
benefit to society by expending such effort below this level?  Example:
What is really gained by providing individual dosimetry to radiation
workers who routinely sustain on an annual basis less than the dose that
they will unavoidably sustain from the natural background?

	The ALARA Radsafers are now invited to have fun declaring me to be a heretic.
David W. Lee
Los Alamos National Laboratory
Radiation Protection Services Group (ESH-12)
PO Box 1663, MS K483
Los Alamos, NM  87545
PH:   (505) 667-8085
FAX:  (505) 667-9726
lee_david_w@lanl.gov