It burned for 10 days and released a cloud of radioactive matter that spread over a wide area of the USSR.

它整整燃烧了10天，产生的放射性物质云笼罩了前苏联的大片地区。

youdao

The positrons, produced by the decay of radioactive sodium, are cooled into a similarly sized cloud of around 1m particles and held in a neighbouring trap.

由放射性钠衰变产生正电子，冷却后形成一个由大约100万个正电子组成的体积同样大小的粒子云团，这团正电子被存放在相邻的一个容器中。

youdao

The fireball and mushroom cloud carry radioactive particles upward, and the wind sends them near and far.

火球和蘑菇云将放射性粒子推到上空，然后风将它们吹送到附近及远处。

youdao

That is why they drove straight into the radioactive cloud.

ECONOMIST: Banyan

In 1986, the fourth reactor at the Chernobyl nuclear complex in the Ukraine exploded and caught fire, spreading a radioactive cloud across Europe in the world's worst nuclear disaster.

CNN: Saturday,

The positrons, produced by the decay of radioactive sodium, are cooled into a similarly sized cloud of around 1m particles and held in a neighbouring trap.

ECONOMIST: Antihydrogen atoms are captured for the first time