It's unclear what you mean by progress. Due to improved security nuclear plants have gotten more expensive, and as a results almost no new ones are being built

It's unclear what you mean by progress. Due to improved security nuclear plants have gotten more expensive, and as a results almost no new ones are being built in the Western world to replace those that are shutting down. The industry is slowly whittling down. Now you can start inventing excuses why this is happening (popular ones are the greens, and the governments, and scared people, and also people who don't want to pay for the transition off fossil fuels). But it IS happening. There's a fair amount of hype surrounding nuclear tech, e.g. in the form of small plants, but so far that's all vapourware. They are not competing on commercial terms, or even close to.