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National Security Cuts Into NASA's Plutonium

Posted by michael on from the get-out-the-oars dept.

cleveland61 writes "Space.com is reporting that an "undisclosed national security agency" is being assigned 7 Kg of NASA's 16 Kg supply of Pu 238. With a half life of 90 years Pu 238 is used mainly used in cases where batteries won't do here on earth. (Pacemakers, deep sea diving suits,etc.) It also provided the fuel for the Cassini Probe. My question is; Who is getting it and what are they using it for? Please tell me its Doc Brown looking for his 1.21 jigawatts!"

6 of 76 comments (clear)

  1. Re:Perhaps by TamMan2000 · · Score: 3, Informative

    Pu 238 is a large molecule, fusion requires small molecues combining into larger ones. The only use for Plutonium in a fusion devise is as a "fuse" used to set of a big hot fusion reaction (H-Bomb).

    Along the bomb line...
    we already have a lot of nuclear material stockpiled in bomb form...

    --
    "I'll have a Guinness, no wait, make that a Coors Light" -Grad student I work with, who shall remain anonymous...
  2. Re:Just a guess by David+Frankenstein · · Score: 3, Informative

    More likely the NRO. They are the ones in charge of the sats.

  3. Re:two answers by dramaley · · Score: 2, Informative

    Nukes use Pu-239, not Pu-238 as this article was about.

    --
    ----- "I'm still sane on three planets and two moons."
  4. Re:Think small by RNLockwood · · Score: 3, Informative

    Pu 238 not likely to be used for a bomb since it won't fission, Pu 239 and U 235 are used for that.
    Might be usefull for tamping though but U 238 is lots cheaper.

    The half life of Pu 239 is 25,000 years and I have heard that it is warm to the touch. Pu 238 would be still warmer yet.

    The half life of U 235 is 730 million years.

    If fissile isotopes had short half lives we wouldn't have bombs or reactors. The fissile material would decay away too fast.

    --
    Nate
  5. Correction.... by jsimon12 · · Score: 4, Informative

    Please tell me its Doc Brown looking for his 1.21 jigawatts

    Just so you know the accepted pronunciation of giga was actually " JIGA ", hence the usage in Back to the Future, people just stopped using that pronunciation when gigabyte drives became more prevalent in consumer goods cause people saw the G and figured it was said like Go instead of like Giant . So the time machine in the movie was powered by 1,210 megawatts, or 1.21 gigawatts.

  6. Re:two answers by Muad'Dave · · Score: 3, Informative
    My chart shows that Pu238 is an alpha emitter, and is subject to spontaneous fission. A I recall, the thermoelectric generators use the heat given off by the Pu238 to generate power with what are essentially thermocouples.

    --
    Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.