Still don't quite understand the 'waiver' bit - 'waiver' from what?

Framatome had reached out to the US in order to obtain a waiver that would allow them to share American technical assistance in order to resolve the issue at the Chinese plant. There are only two reasons why this waiver would be granted, and one is an "imminent radiological threat," the same verbiage used in the June 8 memo.

I'm guessing they're requesting some sort of advanced, protected technical procedures for fixing a major fuck up in a nuclear plant. The French actions are what makes me think this in on the brink of being something major, but something they're trying to reel in fast. Not only did they request this waiver (an extraordinary action in itself), they then sent a request for their initial request to be expedited. They're in a hurry.