Pressurized water reactor with solid partitioning

A pressurized water nuclear reactor having:

• a core formed by fuel assemblies of prismatic shape disposed side by side inside a cylindrical casing having a vertical axis;
• a solid partitioning located in a space reserved between the core and the casing, the partitioning being formed as a vertical stack of rings each completely surrounding the core, whose external periphery is received in the casing and separated therefrom by a clearance and whose internal periphery matches the external contour of the core;
• and
• keying means fixed to the casing and projecting into vertical grooves formed in the rings for centering said rings with respect to the core casing,
• wherein said stack is formed with a plurality of vertical channels each consisting of a plurality of vertical mutually aligned passages each formed in a respective one of said rings, each channel containing a plurality of vertically aligned plugs,
• wherein said vertical passages are formed in radially thicker parts only of the rings,
• wherein each of said plugs cooperate with the respective ring to define an annular water flow channel which includes a serial arrangement of a radial clearance formed between the respective passage and a lower portion of one of said plugs,
• wherein a pressure balancing chamber is formed between the upper face of one of the plugs and the lower face of the plug situated above, and
• wherein some at least of the plugs comprise a flange bearing on a shoulder of the respective ring, machined for defining channels slanted with respect to the vertical so as to give a circumferential speed component to water flowing along the annular passages.