RE: How much plutonium?????

["Bradshaw, Keith" <Keith.Bradshaw@nnc.co.uk>]

> The way I put plutonium hazard into perspective is by comparing it to
> Th-232.  This is a radionuclide present in the environment from natural
> sources that many of us have a body burden of just from eating food grown
> in
> the soil and drinking water.  Yet, the ALI (ICRP-61) for ingestion of
> Th-232
> is less than that for Pu-238 and Pu-239.  This tells me that the CEDE does
> not accurately predict the true hazard of these actinides, i.e., it
> overestimates the hazard greatly.  Certainly, if a small amount of Pu
> could
> kill everyone on the planet, we'd all be dead from exposure to Th.
> 
	Well...

	You'd have to inhale about 10 GRAM thorium to get 1Sv - very
unlikely.  To get the same dose from Pu-239 you need 28 MICROGRAM.  Given
that most Pu contains Pu-240 and 238, the true figure will be even less than
that.

	Dose coeffs from IAEA safety series 115 (1996) Table ll-Vll (note
for inhalation rather than ingestion).

	Personal views only

	Regards

	keith.bradshaw@nnc.co.uk

	END







	END


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