所以，还是每个的设计基础事故都会，有一个组件的单失效，那基本上，就是单失效的标准。

So, again each design basis accident has one single failure of a component which basically is the single failure criteria.

youdao

在增加额外的冗余层后，理论上，这种灾难性的系统失效的事故发生的可能性就非常非常小了。

By adding extra layers of redundancy, the probability of such a catastrophic failure can — in theory at least — be made too small to worry about.

youdao

只有在所有这些系统同时失效时才可能发生事故。

A major accident can only occur if all these systems fail simultaneously.

youdao