After a quick google search, I think this is a deal that they did with China back in 2012, aiming to get 16 new reactors online by 2030.
In a way, it's a good thing, more oil for the west (at a price), but since the Saudis are chief backers of Pakistans program, the Indians are going to be annoyed.
Furthermore, with Irans NPP plans, it's probably just the beginning of a nuclear reactor race around the Persian Gulf, which can only end well.
