weapons-grade plutonium

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spohreis

Senior Member
Portuguese-Brazil
Hello,

I have a question about the term "weapons-grade plutonium" in the definition below. The sentence "of a quality adequate for use in weapons" means that the plutoniom had suffered some kind of process in order to be used in weapons? I mean, had the plutoniom been enriched or not?


weapons-grade: of a quality adequate for use in weapons (especially in weapons of mass destruction); "weapons-grade plutonium"; "weapons-grade anthrax" .


Thanks
 
  • cuchuflete

    Senior Member
    EEUU-inglés
    Here is a comment from the Wikipedia article on Plutonium:

    Plutonium-240 has a high rate of spontaneous fission, raising the background neutron radiation of plutonium containing it. Plutonium is graded by proportion of Pu-240: weapons grade (< 7%), fuel grade (7–19%) and reactor grade (> 19%). Lower grades are less suited for nuclear weapons and thermal reactors but can fuel fast reactors. Pu-240 is not fissile, but is fertile material like U-238.
    source: http://en.wikipedia.org/wiki/Plutonium
     

    spohreis

    Senior Member
    Portuguese-Brazil

    cuchuflete

    Senior Member
    EEUU-inglés
    You are right. And you are now mixing up the grading schemes for Plutonium and Uranium. That will lead to an interesting discussion for a physics and chemistry forum, but will put some considerable stress on most members of this language establishment.
     

    spohreis

    Senior Member
    Portuguese-Brazil
    You are right. And you are now mixing up the grading schemes for Plutonium and Uranium. That will lead to an interesting discussion for a physics and chemistry forum, but will put some considerable stress on most members of this language establishment.
    I see, but I was trying to find something that would support my answer. Sorry, it is a tough task to write a sentence with more than two words.:)

    Thanks
     
    Last edited:

    Cypherpunk

    Senior Member
    US, English
    Well, enriched plutonium still may not be weapons-grade. Weapons-grade denotes the most highly enriched form available. Here is a link to a science article on the topic (yes, I realize it is a facebook page, but it is the magazine's page, where they reprint certain articles) that explains the concept in simple language (and nice diagrams!).
     

    JulianStuart

    Senior Member
    English (UK then US)
    cuchu's link had me confused, just for a second :D

    The Pu 240 referenced in that section is the undesirable isotope (at least for making use of the radioactivity - for good or bad). The Pu 239 is the isotope that must be enriched and the 240 must be depleted (or you, indeed we all, risk premature detonation - in the nuclear sense :D ).

    "Enriched" is not a quantitative term. Essentially all (all significant amounts of) plutonium is man made, so the term "enrichment" is used in a different way than for uranium (for which the U235 must be enriched from its natural 0.5 - 0.7% up to a high number for use in weapons). The Pu239 must be purified to remove the Pu240 as well as other undesirable compponents to become usable in weapons or power sources.
     
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