Natural uranium has only seven atoms per thousand of the former.

每上千个自然界的铀才只有7个原子。

youdao

Indeed, ninety-five percent of a spent nuclear fuel rod is natural uranium, and so it can be put right back in the ground, just as it was found.

实际上，一个用尽的核燃料棒中95%的是天然铀，因此我们可以把它重新埋入地下，就像刚发现那样。

youdao

Based on the experiments, a chemical procedure used for rapidly separating thorium from the natural uranium irradiated by 18o ions was developed.

在条件实验的基础上提出了一个从中能18o离子照过的天然铀样品中简便、快速地分离钍的化学流程。

youdao

Natural uranium is only 0.7% U-235, which is what you need for your reactor.

FORBES: Stuxnet and the Iranian Nuclear Program

At Isfahan, natural uranium (yellowcake) is turned into a gas that can then be spun in centrifuge machines to produce more usable uranium.

ECONOMIST: No appetite for carrots, no fear of sticks | The

Some other Nato countries also use munitions with DU, which has 40% less radiation than natural uranium, itself not considered a health hazard.

BBC: No DU weapons risk, say experts