Pressurized water nuclear reactor, comprising a reactor core, a nuclear reactor fuel assembly disposed in said reactor core, a fuel rod disposed in said fuel assembly, a nuclear fuel column disposed in said fuel rod being enriched to a variable extent with fissionable nuclei over the length thereof, said reactor core having an inlet for liquid water acting as coolant closest one end of said fuel rod and of said fuel assembly and an outlet for the liquid water closest to the other end of said fuel rod and of the fuel assembly, a steam generator having a primary tube connected to said inlet and said outlet, one half of said nuclear fuel column at said outlet having an average enrichment being less than the average enrichment of the other half of said fuel column, and said nuclear fuel column having a depletion zone with an average enrichment being less than the average enrichment over the entire length of said column, said depletion zone having two limits spaced from the end of said column closest to said outlet by distances of substantially 10% and 25% of the total length of said column.