Reactor buildings and vessel systems are disclosed. A nuclear power system includes: a building structure that comprises at least two exterior side walls and two end walls, at least one of the exterior walls angled non-orthogonally relative to a floor of the building structure, the at least two exterior walls and two end walls defining an interior volume of the building structure; one or more nuclear reactor systems mounted at least partially in the interior volume of the building structure; and one or more heat exchanger systems mounted at least partially to at least one of the exterior walls. A nuclear reactor vessel system includes: a nuclear fission reactor; an inner vessel that defines an inner volume sized to at least partially enclose the nuclear fission reactor; and an outer vessel sized to wholly or substantially enclose the inner vessel, the inner vessel being removable from the outer vessel.

System for confining and cooling melt from the core of a water-moderated nuclear reactor comprising a melt trap. The melt trap is installed in the reactor vessel bottom and provided with a cooled containment, consisting of outer and inner housings between which there is a sealant, and the filler for the melt dilution placed in the melt trap inner body. The melt trap inner body has a damper consisting of a central mantle, bearing ribs connected with the central mantle, titled plates, placed between the bearing ribs, the stops providing fastening of the damper to the melt trap body.

A safety system for a nuclear reactor includes a first containment structure and a second containment structure. The double containment configuration is designed and configured to meet all design basis accidents and beyond design basis events with independent redundancy. The remaining systems that control reactivity, decay heat removal, and fission product retention may be categorized and designed as business systems, structures, and components, and can therefore be designed and licensed according to an appropriate quality grade for business systems.

A safety system for a nuclear reactor includes a first containment structure and a second containment structure. The double containment configuration is designed and configured to meet all design basis accidents and beyond design basis events with independent redundancy. The remaining systems that control reactivity, decay heat removal, and fission product retention may be categorized and designed as business systems, structures, and components, and can therefore be designed and licensed according to an appropriate quality grade for business systems.

Disclosed are a system and method for preventing and monitoring a leakage of water from a tank liner at a storage tank having: a concrete reservoir; the tank liner made up of a wall liner that is formed by coupling a plurality of first panels and is attached to an inner wall of the concrete reservoir, and a floor liner that is formed by coupling a plurality of second panels, is attached to a floor of the concrete reservoir, and is coupled to the wall liner by welding; a leaking water collecting plate formed by welding a plurality of third panels and inserted between the floor liner and the floor of the concrete reservoir; and an edge leaking water collecting channel buried in an edge of the storage tank and configured to collect leaking water discharged between the floor liner and the leaking water collecting plate.

Apparatuses for reducing or eliminating Type 1 LOCAs in a nuclear reactor vessel. A nuclear reactor including a nuclear reactor core comprising a fissile material, a pressure vessel containing the nuclear reactor core immersed in primary coolant disposed in the pressure vessel, and an isolation valve assembly including, an isolation valve vessel having a single open end with a flange, a spool piece having a first flange secured to a wall of the pressure vessel and a second flange secured to the flange of the isolation valve vessel, a fluid flow line passing through the spool piece to conduct fluid flow into or out of the first flange wherein a portion of the fluid flow line is disposed in the isolation valve vessel, and at least one valve disposed in the isolation valve vessel and operatively connected with the fluid flow line.

Apparatuses for reducing or eliminating Type 1 LOCAs in a nuclear reactor vessel. A nuclear reactor including a nuclear reactor core comprising a fissile material, a pressure vessel containing the nuclear reactor core immersed in primary coolant disposed in the pressure vessel, and an isolation valve assembly including, an isolation valve vessel having a single open end with a flange, a spool piece having a first flange secured to a wall of the pressure vessel and a second flange secured to the flange of the isolation valve vessel, a fluid flow line passing through the spool piece to conduct fluid flow into or out of the first flange wherein a portion of the fluid flow line is disposed in the isolation valve vessel, and at least one valve disposed in the isolation valve vessel and operatively connected with the fluid flow line.

A containment vessel has an inner shell covering a reactor pressure vessel and an outer shell forming an outer well which is a gas-tight space covering the horizontal outer periphery of the inner shell. The inner shell has a first cylindrical side wall surrounding the horizontal periphery of the reactor pressure vessel, a containment vessel head which covers the upper part of the reactor pressure vessel, and a first top slab connecting in a gas-tight manner the periphery of the containment vessel head and the upper end of the first cylindrical side wall. The outer shell has a second cylindrical side wall surrounding the outer periphery of the first cylindrical side wall, and also has a second to slab connecting in a gas-tight manner the vicinity of the upper end of the second cylindrical side wall and the first cylindrical side wall.

A containment vessel has an inner shell covering a reactor pressure vessel and an outer shell forming an outer well which is a gas-tight space covering the horizontal outer periphery of the inner shell. The inner shell has a first cylindrical side wall surrounding the horizontal periphery of the reactor pressure vessel, a containment vessel head which covers the upper part of the reactor pressure vessel, and a first top slab connecting in a gas-tight manner the periphery of the containment vessel head and the upper end of the first cylindrical side wall. The outer shell has a second cylindrical side wall surrounding the outer periphery of the first cylindrical side wall, and also has a second to slab connecting in a gas-tight manner the vicinity of the upper end of the second cylindrical side wall and the first cylindrical side wall.

A high-temperature containment-isolation system for transferring heat from a nuclear reactor containment to a high-pressure heat exchanger is presented. The system uses a high-temperature, low-volatility liquid coolant such as a molten salt or a liquid metal, where the coolant flow path provides liquid free surfaces a short distance from the containment penetrations for the reactor hot-leg and the cold-leg, where these liquid free surfaces have a cover gas maintained at a nearly constant pressure and thus prevent high-pressures from being transmitted into the reactor containment, and where the reactor vessel is suspended within a reactor cavity with a plurality of refractory insulator blocks disposed between an actively cooled inner cavity liner and the reactor vessel.