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最初由 oldgoat 发布
不对吧？纯粹采用天然铀的话，纯度偏高反而不利于合金硬度提高。就好象炼钢一样，碳含量高低会影响合金的性能，不是直接用天然铀就行的，不然怎么叫“贫铀”？如果在核反应堆中使用过，铀的浓度就降下来了。
从我给的那个连接复制的，“贫铀”是说U235比较少，而且只是在炮弹尖端，和合金毫无关系。
Since Uranium is a very heavy element, heavier than lead, it is also used in artillery shells. The army would put U238 in the front of a shell and shoot the shell out of a tank or airplane, at the enemy tank. The uranium in this case has been processed so as to not have very much at all of U235 left in it, hopefully pure U238. So then the shell would not be radioactive. There is some controversy as to whether they do a good job of this, and there are concerns that these shells spread radioactive uranium (U235) around.
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PS：是你的理解有问题还是我的表述有问题？铀元素有铀235与铀238两种常见同位素，铀238是天然存在的同位素。纯度在90%以上的铀235用作核武器，3%~4%的则是用作燃料。铀238无法在中子击打下裂变产生链式反应，不过可以吸收快中子成为钚239。铀235必须通过铀238生产出来，天然铀中的一部分铀238转化为铀235并用掉之后，剩下的没有商业价值的则掺在装甲用合金或弹头中，成为贫铀装甲或贫铀弹。有什么问题么？我虽然不是专门学这个，不过还是比较自信能够正确。:)
天然铀矿大部分都是U238,还用您费劲到反应堆中转化？U235也是天然存在的同位素，您的“铀235必须通过铀238生产出来，天然铀中的一部分铀238转化为铀235并用掉之后”真是搞笑得很。注意这个“enriched uranium，翻意过来就是“富铀”。
U238, since it IS stable is the most commonly occuring isotope of uranium when it is dug out of the ground.So usually to use the uranium in a power plant, the amount of U235 must be increased, run the ore thru a plant and pull out slightly more U238 than U235, leaving an enriched uranium, enough U235 to run the reactor. We would not want pure U235 in a power plant, this would make it too much like a bomb. So in this case U238 is "used" to sort of dillute the U235, to make U235 a safe fuel.
