RE: estimates of human-human irradiations

["Heinmiller, Bruce" <heinmillerb@aecl.ca>]

Yes, most of the numbers you see for spousal irradiation are grossly in
error, as can be shown by a back-of-the-envelope calculation.  Some time
back I employed someone-else's idle student (he was between projects) to
corroborate my calculations with some Monte Carlo runs using simple
cylindrical phantoms on a water-bed.  As I recall, the agreement was good,
so I gave a branch talk entitled, "Spousal Irradiation - Debunking the
Folklore".

It's difficult to trace the origin of the incorrect data, but I think what
may have happened (in at least one misinformation lineage) is that someone a
few decades ago screwed up a calculation because they didn't bother to check
the decay scheme of K-40, and the resulting number for spousal irradiation
clearly exceeded the nuclear-power contribution to population dose (which
may still be true for the correct number), and this comparison was too cute
not to propagate (and further distort) geometrically. There are several
other sources of significant error as well.  Assuming, for example, that
Reference Man represents an average person, can introduce considerable error
in the case of K-40.

Bruce Heinmiller CHP
heinmillerb@aecl.ca

> ----------
> From: 	Lieskovsky, Miro[SMTP:MLieskovsky@nbpower.com]
> Reply To: 	radsafe@romulus.ehs.uiuc.edu
> Sent: 	Wednesday, December 08, 1999 8:07 AM
> To: 	Multiple recipients of list
> Subject: 	RE: estimates of human-human irradiations
> 
> Kim,
> A quickie using MicroShield:
> 
> Source: 7kBq of K-40 in a sphere (water) with a 30cm DIA.
> 
> The exposure rate at 100cm from the sphere centre is ~1.2E-5mR/h, that's
> 0.012microR/h or ~1000times less than environmental exposure rates. At
> 30cm
> from the sphere centre it is ~1.4E-4mR/h. 
> 
>   :-)  However, I think, that a person standing in my
> 'too-close-for-comfort' zone shields off more radiation than s/he
> contributes.  Next time I hug my wife, I'll have a gamma meter on me....
> 
> 
> Regards,
> 
> Miro
> 
>  
> 
> -----Original Message-----
> From: Kimberlee Kearfott [mailto:kearfott@umich.edu]
> Sent: December 8, 1999 12:40 AM
> To: Multiple recipients of list
> Subject: estimates of human-human irradiations
> 
> 
> Hi
> 
> I don't want to start an instoppable thread-- but has anybody 
> computed how much irradiation we get from standing by others, due to 
> our natural concentrations of radionuclides?  Any other similar 
> comparisons?
> 
> Kim Kearfott
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