Re: Alternative isotopes in RTGs?

[Bernard L Cohen <blc+@pitt.edu>]

On Mon, 13 Oct 1997, Donivan Porterfield, LANL CST-3 wrote:

> 
> Given all the attention to the Pu-238 in the Cassini RTGs
> I was wondering what other isotopes might have been suitable
> for this application.  Below are those alpha emitters with
> half-lifes of 10 to 150 years.  Presumably beta emitters,
> despite possibly having a higher energy density (MeV/Z),
> would not be desirable due to bremsstrahlung.
> 
>    Po- 209   103   a
>    Ac- 227    21.8 a
>    U - 232    72.0 a
>    Pu- 238    87.7 a
>    Cm- 243    28.5 a
>    Cm- 244    18.1 a
>    Cf- 250    13.1 a
> 
> For example, in retrospect would U-232 have been a less
> controversial isotope to use in RTGs?  This given that this
> or the others are feasible, e.g. cost of of production and
> other technical issues such as gamma emmissions or physical
> properties.

	--There is no reason to believe that these would be less dangerous
than Pu-238