The uranium or plutonium isotopes are referred to as "fissile," which means we can use them to induce fission by bombarding them with free neutrons.
铀或钚的同位素被称为裂变材料，即我们可以利用自由中子去轰击它们来产生裂变反应。
2
Unlike them, it has refused to sign the test-ban treaty. Unlike them, it declines to end the production of fissile material-uranium and plutonium-for bombs.
与五个核大国不同，它拒绝签署禁止核试条约，它拒绝中止核燃料(铀和钚)生产。
3
"The uranium or plutonium isotopes are referred to as" fissile, "which means we can use them to induce fission by bombarding them with free neutrons."