Re: Cassini Mission and Plutonium RTG's

["Otto G. Raabe" <ograabe@ucdavis.edu>]

August 27, 1997

On August 27,1997 Bernard Cohen wrote:

> --I noticed these numbers in UNSCEAR 1982, but they do not agree
>with the numbers I gave in my message -- about 3.6 million Curies of
>Pu239 evaporated in bomb tests. This is seven times the amount in the 
>Cassini probe, rather than 1/2 the amount as Otto states.I don't see how
>my calculation can be substantially in error, unless I am going "off
>the deep end". Can someone help me with this, by confirming my calculation
>or by showing where I went wrong? [My calculation is 150,000 Ktons of
>fission with 1.7 Ktons/lb = 90,000 lb of Pu used. 80% of this not consumed
>but evaporated = 72,000 lb. Bomb Pu is .11 Curie/gram x 454 gram/lb x
>72,000 lb = 3,600,000 Curies.]

Dear Bernie:

Perkins and Thomas ("Worldwide Fallout", pp 53-82, TRANSURANIUM ELEMENTS IN
THE ENVIRONMENT, W.C. Hanson, Ed. DOE/TIC-22800, 1980) have compiled a list
of all U.S., French, U.K. USSR, and Chinese nuclear tests and releases up
to 1980, and conclude: "Since the first nuclear weapons test at Alamogordo,
N. Mex., on July 16, 1945, approximately 360,000 Ci of 239,240Pu has been
injected into the atmosphere. In addition, 17,000 Ci of 238Pu entered the
atmosphere in April 1964 as a result of the high-altitude burnup of a
SNAP-9 satellite power source."

Maybe you can answer your question by comparing your calculation with the
data provided by Perkins and Thomas (1980).

Otto
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		Prof. Otto G. Raabe, Ph.D., CHP
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