锕铀铀的同位素，原子质量数为235，与慢。
The isotope of uranium with mass number235, fissionable with slow 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。
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.
根据新协议，一年内，伊朗将向土耳其输送1200千克储备低纯度浓缩铀以交换其120千克浓缩铀（纯度约20%）用以生产药用（特别用于癌症的治疗）同位素的研究用反应堆。
Under the new deal, Iran says it would send 1,200 kg of its stockpile of low-enriched uranium to Turkey.
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