A large issue is the reluctance, especially in the US, of approving new designs in nuclear. We tested a molten salt reactor in Idaho once in the 80s and it work

A large issue is the reluctance, especially in the US, of approving new designs in nuclear. We tested a molten salt reactor in Idaho once in the 80s and it worked as expected. It can not melt down even in power loss because of the heat transference properties of using molten salt as a coolant and can not build pressure like a more conventional water cooled reactor. But rolling it out into production was killed in the water due to chernobyl and the public response to anything with the word 'nuclear' in it afterwards. We can mitigate a lot of risk now, but it takes lawmakers who don't understand physics or engineering to "bless" it for production. There are some reactor designs that can also reuse already spent nuclear fuel (TERRAPOWER's lightwave reactor). We probably shouldn't also build reactors in areas were earthquakes will occur fairly often and can create tsunamis. Renewables are great, but that is a long term solution that still needs a lot more iteration. If we are looking to reduce our carbon footprint massively with respect to the electrical grid in 30 years, nuclear is the only viable option to garuntee this.