Permanent cavity seal ring for a nuclear reactor containment arrangement

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 radially inwardly and outwardly disposed ends, extending across said annular expansion gap, said support ring having inner and outer downwardly extending cylindrical sections, said inner cylindrical section spaced from said radially inwardly disposed end and resting on the horizontally outwardly extending flange of the reactor pressure vessel, said outer cylindrical section resting on the shelf of the containment wall, and a plurality of radial support beams secured to said support ring and extending between said inner and outer cylindrical sections;
• support rods depending downwardly from said support beams within said annular expansion gap;
• neutron shielding material provided in said annular expansion gap supported by said support rods;
• a vertically extending, L-shaped, flexible inner seal, extending between the radially inwardly disposed end of said support ring, with the leg thereof flush with said horizontally extending flange sealing the space between said radially inwardly disposed end and said horizontally extending flange;
• and
• a vertically extending, L-shaped, flexible outer seal extending between said outer cylindrical section and the shelf of said containment wall, sealing the space between said outer cylindrical section and said shelf.