Why Only U-235 and Pu-239? Classroom-Level Graphs for Understanding Heavy-Element Weaponizability Factors
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B. Cameron Reed [1]
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[1] Alma College
Alma College
City of Alma, Estados Unidos
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- Localización: The Physics Teacher, ISSN 0031-921X, Vol. 58, Nº. 8, 2020, págs. 556-559
- Idioma: inglés
- Texto completo no disponible (Saber más ...)
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Resumen
For several years, I taught a general education course on the Manhattan Project for students majoring in the arts and humanities who needed a physical science credit as a condition of their graduation requirements. As might be imagined, the challenge in teaching this course was to find a balance between quantitative and qualitative content. A technical point of particular importance was to find a way to describe how fundamental-physics considerations restrict the number of possible candidate “weaponizability” isotopes to just a handful, of which only uranium-235 (U-235) and plutonium-239 (Pu-239) were practical for developing a first-generation nuclear weapon. After doing so, I could go on to describe how Manhattan Project engineers developed two weapons: a U-235 bomb based on isolating that isotope from its much more populous U-238 sister isotope, and a plutonium bomb based on synthesizing that element by neutron bombardment of natural uranium in a nuclear reactor.
