AW: [ RadSafe ] Fallout patterns and distribution

[Franz Schönhofer]

Richard,

You asked about the distribution of fallout, but unfortunately you did
not mention which kind of fallout you were thinking of - the atmospheric
nuclear bomb test fallout or the fallout from a nuclear accident in a
nuclear power plant. 

The geographic distribution from nuclear tests fallout has been governed
by prevailing winds. See the infamous Bikini-test, where the wind
changed and a lot of indigenous people were heavily contaminated. The
same is true for such test sites like in Kazakhstan. Furthermore the
mushroom clouds took fission products to very high elevations and they
were distributed over vast ranges. Since there is hardly any exchange of
air masses between the Southern and the Northern Hemisphere the Northern
Hemisphere is much more contaminated than the Southern one. The world
wide contamination caused by the nuclear bomb tests is distributed very
unevenly as to the geographical latitude. The fission products injected
into the stratosphere are still circling the earth. Each spring there
opens a so-called "spring window", a meteorological phenomenon, which
brings down air masses from the stratosphere to the earth surface and
therefore also radionuclides originating from the nuclear atmospheric
explosions from long ago. This creates a very characteristic pattern of
concentration of radionuclides like Cs-137 or especially tritium and
C-14 in aerosols and precipitation. The contamination by fission
products from nuclear atmospheric tests is declining, partly because of
the half-life of the radionuclide, partly because they are removed
slowly from both the stratosphere and from the atmosphere, from the soil
and from the aquatic environment because of radioecological processes. 

Regarding fallout from a nuclear power plant accident, the distribution
by wind is much more of importance. It has been shown, that the
contamination of European countries by the releases from the Chernobyl
accident was partly heavily dependent on prevailing winds. Trajectories
were analysed and to some extent forecasts could be done. Much more the
contamination was dependend on weather conditions like rain or snow. I
was heavily involved in the mitigation and research on the Chernobyl
impact on Austria and so I can tell you that the contamination map of
Austria is almost identical to the map of rainfall during the passing of
the radioactive clouds. 

After the Chernobyl accident there have been developed much better
meteorological methods to predict trajectories from potential release
points and to connect them to other meteorological date like
precipitation. While aerosols contribute for a rather short time and to
a low extent to contamination of persons, food and feed, wash out will
contaminate soil, food and feed to a much higher and long lasting
extent. 


Simple models cannot be applied in either case. This questions include
several sciences, among others radioecology and meteorology. It is not
so easy like with the TFP, where obviously the Tooth Fairy takes the
Sr-90 out from the fuel elements and implants it directly into the teeth
of babies and children, in order to give the TFP celebrities a good
press and a steady income. 

Do not hesitate to contact me for further information, which I promise
to supply if I can.

Best regards,

Franz




Franz Schoenhofer
PhD, MR iR
Habicherg. 31/7
A-1160 Vienna
AUSTRIA
phone -43-0699-1168-1319


> -----Ursprüngliche Nachricht-----
> Von: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] Im
> Auftrag von Richard L. Hess
> Gesendet: Freitag, 25. Februar 2005 01:54
> An: goldinem at songs.sce.com; radsafe at radlab.nl
> Betreff: Re: [ RadSafe ] Nuclear Power Plant Effluents / EMP
> 
> I do have a question: does nuclear fallout (or radiation release to
the
> atmosphere) follow an inverse square law distribution, or does the
nature
> of it and the distribution by wind make it more variable and
potentially
> more concentrated?
> 
> Cheers,
> 
> Richard