Nuclear reactor containment arrangement with permanent cavity seal ring

A nuclear reactor containment arrangement including:

• a reactor pressure vessel which thermally expands and contracts during cyclic operation of the reactor, the vessel having a peripheral wall and a horizontally outwardly extending flange thereon;
• a containment wall having a shelf, said wall spaced from and surrounding the peripheral wall of the reactor pressure vessel defining an annular expansion gap therebetween, and
• an annular ring seal extending across said annular expansion gap to provide a water-tight seal therebetween, which annular ring seal comprises:
• a support ring, having support rods depending downwardly therefrom and neutron shielding material supported by the support rods, the outer periphery of the neutron shielding material abutted against a metal liner on the inner periphery of the containment wall, said support ring disposed in said annular expansion gap having inner an outer upwardly extending cylindrical sections, with said inner cylindrical section disposed beneath, and spaced from, the horizontally extending flange of the reactor pressure vessel, and said outer cylindrical section having a terminus at a location substantially parallel with, and spaced from, the shelf of the containment wall;
• radial support beams secured to said support ring supporting the same in said annular expansion gap, which radial support beams span the gap with one end thereof resting on said horizontally outwardly extending flange and the other end on the shelf in the containment wall;
• a vertically extending flexible inner seal, extending between said inner cylindrical section and said reactor pressure vessel flange sealing the space between said section and the horizontally extending flange of the reactor pressure vessel;
• a horizontally extending flexible outer seal, extending between the terminus of said outer cylindrical section and the shelf of said containment wall sealing the space therebetween;
• at least one manway in said support ring with a hinged, sealable access hatch provided to close the manway;
• at least one access port in said support ring with a hinged, sealable access hatch provided to close the port;
• a removable plug of neutron shielding material beneath said manway and beneath said port;
• and
• thermal insulation in said annular expansion gap, including an upper vertical section extending between the peripheral wall of the reactor pressure vessel and inner cylindrical section of the annular sealing ring, a lower vertical section radially outwardly spaced and disposed below the upper vertical section, and a horizontally extending connecting section which connects said upper and lower sections.