Abstract: A feed water and steam header equipped to a feed water nozzle or a steam nozzle of a reactor vessel in a steam generator for an integrated nuclear reactor is provided. The feed water and steam header may include a nozzle connection portion connected to a steam nozzle or a feed water nozzle of a reactor vessel, a header flange protruded outward from a lower part of the nozzle connection portion, and a tube connection portion disposed on two pipelines branched from the nozzle connection portion and connected to a tube of the steam generator.

Abstract: A nuclear containment arrangement has a permanent pool cavity seal extending across an annular gap between a reactor pressure vessel and a refueling pool wall to provide a water tight seal therebetween. A seal plate has a support ring with a cylindrical section weldedly connected to an outer seal ring on an embedded ring. A J-shaped flexible ring attached to the seal plate allows axial and radial movement of the reactor vessel during thermal expansion and contraction. The inner portion of the seal plate overhangs the J-shaped flexible ring thereby to protect it from damage resulting from an object dropped thereon. Cooperating access holes and access hole covers in the seal plate provide access to the refueling pool cavity. Support arms underneath the seal plate are provided. Each support arm may have leveling screws to adjust the level of the seal plate.