There is no scenario where Saudi Arabia doesn't get whatever nuclear power infrastructure they're after. Nothing will prevent that. China isn't going to have any problems building Saudi Arabia's nuclear power infrastructure, they'll be thrilled to do it. The same is true of Russia. There is nothing the US can reasonably do to stop China or Russia from building nuclear power plants in Saudi Arabia.
Ok, there's one exceptionally dumb broad option: war with the non-US supplier (eg China or Russia), or fundamentally destroy Saudi Arabia as we know it today and kill millions of people to shut down all industrial progress there to prevent any nation from ever attempting to build nuclear power there.
Here's the reality of the near future: you are going to have to accept a bunch of bad actors are going to have access to various nuclear technology. It's only going to spread faster and faster.
Just so you know, that's the definition of an open secret
So, this is basically India and Pakistan all over again, only with countries that are a lot more likely to back terrorists.
"The Trump administration, eager to revive the torpid American nuclear industry, is pushing Saudi Arabia to consider U.S. companies -- such as Westinghouse Electric Co. and Exelon Corp. -- for its nuclear contracts instead of competitors from Russia, China and other countries. "
Perhaps this is about money, or perhaps its about stirring the middle eastern pot. Threaten to give the Saudi's all the nuclear tech they want while deliberately ignoring what they do with it and you might just get Iran to end its own nuclear program if only the U.S. will put a stop to this. Or you might get a nuclear conflict.
This is probably going to go down in history as amazingly dumb. Canada is still a little embarrassed about India, but this will be much worse.