They were exposed to radioactive fallout during nuclear weapons tests.

他们在核武器试验过程中暴露于放射性核辐射。

《柯林斯英汉双解大词典》

The phenomenon is called radioactive fallout.

这一现象即称之为放射性尘降。

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Decay rates of the radioactive fallout are the same for any size nuclear device.

核辐射尘降物的衰减率不应核装置的大小而改变。

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The biggest hazard of atmospheric tests was that radioactive fallout would get into the human food chain.

CNN: ASIANOW - Asiaweek

The UK charity Chernobyl Children's Life Line helps families in Ukraine and neighbouring Belarus affected by harmful radioactive fallout.

BBC: Inverness and Nairn charities host Chernobyl events

Meanwhile, fears over radioactive fallout here in the United States, which led to panic buying of an anti-radiation medicine and survival gear in the West, have been allayed for the time being by EPA findings that almost no radiation has survived the 5, 000 mile journey across the Pacific Ocean.

FORBES: Radiation Found in Food and Water in Japan [Updated]