Re: High Altitude Exposures

["ALDEN N TSCHAECHE" <XAT@inel.gov>]

Clearly annual doses below 100 mrem should not be included in
calculation of collective dose for ALARA purposes. I suspect that most
ALARA programs count ALL doses measured in such calculations, even if
some of those doses are below 100mrem per year. That practice is, to me,
inconsistent.If you don't have to measure it, why should you have to
count it if you do measure it?

Therefore, I would agree with you if you are saying 100 mrem is the de
minimis dose below which I don't need to take action or spend resources
to reduce it further. Al. xat@inel.gov Now I need to make a disclaimer -
nothing I say or have said or will say on RADSAFE has been approved by
either my employer or its customer.

*** Reply to note of 12/12/95 09:53

From: Bob Flood
To: RADSAFE --INELMAIL RADSAFE

Subject: Re: High Altitude Exposures
Sidenote on military high altitude data - there are dosimeters made
exclusively for the very high altitude missions (U-2, SR-71, Aurora) but the
dosimeters and dose data are classified. Knowledge of such doses and high
altitude dose rate distributions about the planet (altitude, pole vs
equator, etc.) and over time (solar activity and such) could allow a
potential enemy to estimate flight levels, flight paths, and past flight
schedules. This would endanger the flights, and the military will not
release the data for this reason.

Question for discussion: both regulatory systems (DOE, NRC) have monitoring
thresholds. The NRC's is 500 mrem/y, the DOE's 100 mrem/y. Doses below these
levels have no regulatory standing, i.e., they do not have to be measured or
recorded. Are these values not operational de minimus levels? As a
dosimetrist in a DOE program, I am not compelled by law to pay any attention
to doses under 100 mrem/y other than to be confident that the doses are
below the threshold. Doesn't this mean that any dose total below 100 mrem/y
is "reasonable," i.e., so small that it doesn't even have to be measured? Is
such a dose ALARA?

Should help keep the conversation lively.
Bob Flood
Unless otherwise noted, all opinions are mine alone.
(415) 926-3793
bflood@slac.stanford.edu