plutonium 239

Từ điển WordNet v3.1 - WordNet Dictionary

noun

a highly fissionable isotope of plutonium that is used in atomic weapons and as a reactor fuel;
produced by irradiating uranium 238 with slow electrons
• Hypernyms:
plutonium, Pu, atomic number 94
• Hyponyms:
weapons plutonium, weapon-grade plutonium