Kinda sounds like a TTC transit project.
The subsea cable between NL and NS cost $1.7Bn for 170km.
Which would be fine if you had sufficient load every 3-400 km. You can't daisy-chain generation.
Given the history of nuclear plant development worldwide, I await the actual figure to build one to commissioning.
People get a little too excited about the term 'small modular'. Many envision something in a seacan you can drop into a remote FN or arctic community. Again, great if you had 240,000 households of load but I think the remote communities are a tad smaller. Also, many place struggle to develop and maintain the expertise to keep a water system running.