Nuclear reactors are protected by what plant designers call "defenceindepth".
设计者声称核反应堆在“纵深防御”[2]下会得到保护。
2
In order to add an additional protection from the view point of nuclear safety defenceindepth, the secondary containment is adopted.
从核安全纵深防御的角度，为了再多增加一道安全屏障，设置了二次安全壳。
3
Although certain coastal areas are heavily defended, these defences do not seem to be in any great depth, and it would appear that the Germans have concentrated their defence on the beaches.