Cars are also not safe, especially at 200+ km/h but somehow it’s OK to drive them this fast in Germany.

Edit: What I want to say is that there is no absolute safety.

Unfortunately use of fossil fuels also continues to hit record numbers year after year.

You basically need a few conditions to be met to make this useable: tide needs to be high enough, there needs to be suitable geological formation that enables building of such power plants, it has to be publicly acceptable to build there, and you need to connect it to the grid. The last two can especially cancel eachother out.

However, this assumes you use potential energy. What you are envisioning might be more like current power (so kinetic energy) where I’m not sure what the limitations are. Perhaps it’s not too practical to build huge plants underwater in locations with relatively constant current and connect them to the grid

Why are you comparing fossil fuels and nuclear “per tonne” that makes no sense. You replace tens of tones of nuclear fuel per year any you burn millions of tones in a comparable fosil fuel plant.

And regarding the carbon emissions from enrichment… Just use nuclear to power your enrichment plants. This way your emissions are extremely low because you don’t need much fuel and you use nuclear energy to produce nuclear fuel. French example: https://en.m.wikipedia.org/wiki/Tricastin_Nuclear_Power_Plant