[FPSPACE] Plutonium scarcity

[Jens Kieffer-Olsen]

 From the article below
 http://www.npr.org/templates/story/story.php?storyId=113223613
 I quote:
 
 NASA is running out of the special kind of plutonium needed to
 power deep space probes, worrying planetary scientists who say
 the U. S. urgently needs to restart production of plutonium-238.
 
 [...] stores of plutonium-238 are running low, because the
 production of this man-made material was a byproduct of Cold War
 activities, and the U.S. has not made any new supplies since the
 1980s. 

 [...] For a while, the U.S. purchased plutonium-238 from Russia.
 But Russia's production facilities were also shut down long ago,
 and now Russia has run out, too.

 [...] The White House issued a "statement of administration policy"
 in July urging Congress to give the requested funds for restarting
 domestic production, saying it's "essential" for planned NASA
 missions as well as national security applications.

 End quote.

 There seems to exist a loose end or two here. Why is it not an
 option instead to have Russia start producing the Pu-238, allowing
 NASA to buy some of it? Is the alternative that Russia will end
 up buying US Pu? 

 The article below on Russian Plutonium Disposition 
 http://www.nti.org/e_research/cnwm/reducing/rpdispose.asp
 has the following to say:

 Russia refuses to consider the immobilization option, considering
 the plutonium as a valuable national asset produced with thousands
 of man-years of labor, not something to be thrown away as waste.

 [...] The first step would be converting plutonium metal weapon
 components (known as "pits") to oxide in preparation for fuel
 fabrication, and blending this oxide with a limited amount of
 reactor-grade plutonium to obscure the specific mix of isotopes
 used in weapon plutonium (which is still secret in Russia).

 End quote.

 Maybe isotope separation of Russian weapons plutonium could yield
 an amount of Pu-238 for NASA use? Or am I missing something? Is
 Pu-238 not part of the 'secret' isotopic plutonium mix mentioned? 

--
Jens Kieffer-Olsen
Slagelse, Denmark