放ほう射しゃ能のう雲ぐも

noun

radioactive cloud

Refers to a cloud containing radioactive material, often from a nuclear explosion or accident.

• 核かく実じっ験けんの後あと、放ほう射しゃ能のう雲ぐもが広ひろがった。

  After the nuclear test, a radioactive cloud spread.