From 2nd to 3rd generation PWRs
Ordinary pressurized water reactors

Bearing in mind public concerns prompted by the accidents at Three Mile Island and Chernobyl, competition from other energies, and anticipating a nuclear revival, politicians, safety authorities in various countries, nuclear operators and manufacturers began in the 1990s to prepare the ground for a third generation of nuclear reactors, mainly water-cooled.

Should we simply seek to improve second-generation reactors, or develop new concepts altogether?

All the major nuclear countries (USA, France, Germany and Japan) have clearly expressed their preference, at least in the short term, for "evolution" rather than "revolution". This is how the PWR projects presented here came about.