A large portion of the cost to build nuclear power plants is a function of regulation driven by those accidents. Build time (driven by regulatory and political hurdles, increasing from a few years in the 1960s to well over a decade in the 70s and 80s) increases the cost of financing the project and the complexity of the project tremendously. Also, there are the second order effects here a reduction in building nuclear plants drives reduced investment in funding and scaling improved designs, fewer people becoming nuclear engineers, and so on. There are a lot of designs out there with a lot of potential to be both cheaper and safer, but no one can build them.
A large portion of the cost to build nuclear power plants is a function of regulation driven by those accidents. Build time (driven by regulatory and political hurdles, increasing from a few years in the 1960s to well over a decade in the 70s and 80s) increases the cost of financing the project and the complexity of the project tremendously. Also, there are the second order effects here a reduction in building nuclear plants drives reduced investment in funding and scaling improved designs, fewer people becoming nuclear engineers, and so on. There are a lot of designs out there with a lot of potential to be both cheaper and safer, but no one can build them.
See https://www.sciencedirect.com/science/article/pii/S0301421516300106 for an analysis of nuclear plant cost trends globally from the 1950s to the early 2000s.