The International Energy Agency (IEA) has made an assessment of "levelized costs" (LCOE) of different electricity generation types. The study shows that in Europe the different technologies are similar in cost while in the USA there are some differences. In both places lifetime extensions of nuclear power are the cheapest options.
The United Kingdom has a system to encourage investment in new power generation plants with "Contacts for Difference" which guarantee electricity suppliers with a "Strike Price" for a certain period of production. The strike price contact of the new Hinkley Point reactor is frequently used by opponents of nuclear power as an argument against new nuclear plants. This argument is completely false because the strike price for the nuclear plant, currently at £102/MWh is less than that of a large number of offshore wind farms which have strike prices up to £170/MWh and biomass plants which are around £115/MWh.
The Hinkley Point C case: is nuclear energy expensive? by Joris van Dorp
The ETI Nuclear Cost Drivers: Summary Report