Earlier quoted context omitted.
No you don't understand, the plant didn't trip. The nuclear plant's turbines were literally on the "roof" of the reactor complex completely in the open. Nuclear regulations only require the reactor itself to be enclosed and protected. No shit the turbines froze over. They ignored reports advising them to fully enclose the plant for years.
The turbines have superheated steam flowing into them directly from a source of practically unlimited heat. The only way for them to freeze over would be for the plant to have already shut down.
The feed water system for cooling water froze, and the plant had to be shutdown.
This is what happens when you don't plan your essential services to react to predictable extreme events.
That a nuclear plant can theoretically handle this sort of thing quite easily means nothing if you don't actually implement the systems to do so.