Pressurized water nuclear reactor with upper and lower core support and positioning means

Claim 1

In a pressurized water nuclear reactor, walls defining an upright substantially cylindrical pressure vessel with upper and lower end portions and having generally dome-shaped upper and lower end closures, a substantially cylindrical core shield positioned within and radially spaced inwardly of the wall of said vessel and defining an annular passageway therebetween, said core shield being attached to the wall at the upper end portion of said vessel and extending downwardly to a position spaced above said lower dome-shaped end closure, a reactor core positioned totally within said core shield, means including outlet nozzles positioned in the upper portion of and extending through the wall of said pressure vessel to define a water outlet from said nuclear reactor pressure vessel, means including inlet nozzles positioned in the pressure vessel for flow of water downwardly through the annular passageway surrounding the cylindrical core shield into the lower portion of the pressure vessel and upwardly through said core and the upper portion of the pressure vessel through said outlet nozzles, the improvement comprising support means fixedly secured to the dome-shaped lower end closure and positioned substantially symetrically underneath the core for directly supporting and transversely positioning said core on the dome-shaped lower closure, a first perforated plate positioned directly above the core and a second perforated plate positioned adjacent the dome-shaped upper end closure, said second perforated plate fixedly secured to the pressure vessel, a plurality of upright tubular control rod guide members having upper and lower ends, said guide members being fixedly secured at their lower ends to said first perforated plate and fixedly secured at their upper ends to said second perforated plate, said tubular guide members and said first and second perforated plates comprising a rigid assembly, and means extending between the core and the first perforated plate for permitting relative vertical movement between said first perforated plate and the core while maintaining lateral alignment between the core and the tubular guide members secured to said first perforated plate.