Update 2025: I no longer believe nuclear is cost-effective in most cases, with the exception perhaps being remote places unsuitable for solar that currently run on diesel. As evidence of this, China is building O(100) times more solar than nuclear, even though they are also very willing to look past traditional environmental concerns in order to build nuclear plants.
Some people think that nuclear is not a necessary part of a low-carbon energy mix
Newer plant models, especially small modular reactors, are likely to be cheaper and safer than prior models, eg zero-human safety
Bold New Nuclear Reactor Designs Promise Safe, Clean Electricity
Recent large nuclear plants have been expensive largely due to soft factors such as regulation costs and low productivity - could be improved by more adaptive regulation (eg acknowledging smaller exclusion zone footprint around a safer small reactor) and more manufacturing-oriented approach of multiple small reactors rather than one-off mega project construction
Sources of Cost Overrun in Nuclear Power Plant Construction
Nuclear evacuations and shutdowns may cause more harm than alternatives
Nuclear waste management is actually more tractable than managing most other types of industrial waste