Re: Pu isotopic ratios

[mcnaught@Lanl.GOV (Mike McNaughton)]

>Consider a lake with purportedly high levels of plutonium in
>sediment, several miles downstream from a putative point
>source. Managers of the point source attribute the lake's plutonium to
>global fall-out from Chinese weapons tests in the 1970's.

Plutonium from weapons is typically more than 90% Pu-239,
e.g. usually 94% Pu-239, 6% Pu-240, <1% Pu-241 in the USA.
Plutonium from a reactor has been irradiated for a longer time and is
typically about 60% Pu-239, 20% Pu-240, 10% Pu-241.
Pu-241 decays to Am-241 which gives a characteristic 60 keV gamma.
So in principle it should not be difficult to distinguish plutonium from
different sources. If you need more detail I can suggest some names, phone
numbers, and e-mail addresses to contact.

mcnaught@lanl.gov
(505)665-5207