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Re: Radiation Exp. on Aircraft
When I was a HP grad student, I participated in a research project, where we
measured radiation levels in the cabins of passenger planes that had been
loaded with radioactive packages, mainly Tc-99m generators. At that time, a
plane could be loaded with a total "Transport Index" (TI) of 50. (The TI for
a non-fissile package is the dose rate, in mrem/hr, at 1 m from the surface of
the package.) We found some situations where there were high dose rates (up
to several mrem/hr), primarily due to radioactive packages being stacked
rather than being distributed throughout the cargo hold. In some cases, this
may have been unavoidable, since the packages should be kept away from
passenger baggage or other packages which may have undeveloped photogaphic
film. At that time (ca 1973), there was also a horror story about a
radiographic camera being carried on a passenger plane with the source in the
unshielded position. Shortly after the study, and I assume partly due to the
results, the US implemented stricter regulations. There is now a 10 TI limit
for a passenger plane and, for nonexcepted packages, only medical and research
material can be carried on passenger planes. This is a special exception the
US takes to the IATA regulations.
In the nonradioactive, hazmat area, there was the Value Jet crash, blamed on
oxygen generators. I suspect that the regulations will now become even
stricter.
The moral of the story, if there is one, is that if we don't restrain
ourselves to good practices, the regulators will do it for us.
The opinions expressed are strictly mine.
Here's to a risk free world, and other fantasies.
Bill Lipton
liptonw@detroitedison.com
There is an interesting story on the CNN Home Page (cnn.com)
today (Sunday, 6/22).
Apparently, passengers aboard a KLM flight were exposed to "excessive
amounts of nuclear radiation". The KLM plane was transporting technetium
generators. Upon landing in London, an inspector from the National
Radiological Protection Board found that one of the packaged generators
read beyond the maximum of 10 mSv/hr.
"Government investigators" said that individuals seated in rows 6 and 7
of the aircraft may have received a dose of 1 mSv -- "an acceptable
annual dose".
A KLM spokesman indicated that the passengers "...were exposed to no
higher than the radiation from a routine x-ray in the hospital". The
spokesman was speaking with the "customary anonymity".
Rick Mannix
Univ. of Cal., Irvine
rcmannix@uci.edu