In the worst-case scenario, the fuel can spill out of the containment unit and spread toxic radioactivity through the air and water.

最糟的情况是，燃料会从容器单位中洒出，有毒的辐射会进入空气和水中。

youdao

In fact, unlike Fukushima, Chernobyl had no containment structure whatsoever to limit the spread of radioactivity.

FORBES: An Immodest Proposal to Spur Nuclear Energy Industry Growth -- and Global Safety

But they call for special attention due to the implications of spread of radioactivity with long term consequences including genetic effects on the population and the long time span required to bring back normalcy to the environment.

FORBES: [See update below]