Patent Number: 046577254
Section: abstract

The invention relates to a core for a nuclear reactor cooled with water under pressure.. The core comprises a first group of zones (1, 2) extending over its entire height and over a fraction of its transverse section where the fuel rods contain mainly enriched uranium oxide, and a second group of zones (3) inserted between the zones (1, 2) of the first group where the rods contain mainly plutonium. The rods of zones (1, 2) of the first group emit neutrons and maintain the neutron reactions. The energy spectrum of the neutrons is in the thermal region in the zones (1, 2). The rods of the zones (3) of the second group are spaced at a distance which is appreciably smaller than the distance separating the rods of the zones (1, 2) so that the neutrons produced therein are in the high energy region.. The invention applies, in particular, to nuclear reactors with spectral shift control.