Wow they really bury the lede on what fuel they run on. They say "dual fuel" but don't say which those fuel are, but external searching suggests natural gas or low-sulfur heavy fuel oil. Not sulfur-free, so I'm sure these are great for emissions.

You might think that, but OPS went through an astounding amount of regulatory review. They got an actual license from the NRC to build the first 8.

This article goes into detail of you have access: https://www.newyorker.com/magazine/1975/05/12/the-atlantic-g...