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.

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.

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.

A nuclear power plant having a protective superstructure including a first end region configured to cover a nuclear reactor in a containment structure, a second end region opposite the first end region and configured to cover a cooling water pump house, and a central region between the first and second end regions and configured to cover a turbine hall. The superstructure has an oval-shaped plan profile, the oval having a greater degree of curvature at the first end region than at the second end region.

A nuclear power plant having a protective superstructure including a first end region configured to cover a nuclear reactor in a containment structure, a second end region opposite the first end region and configured to cover a cooling water pump house, and a central region between the first and second end regions and configured to cover a turbine hall. The superstructure has an oval-shaped plan profile, the oval having a greater degree of curvature at the first end region than at the second end region.

A nuclear reactor is positioned on a barge which floats on the water of a water tank. The water tank includes a bottom wall, first and second end walls and first and second side walls. The bottom wall includes a lower layer of concrete, an intermediate layer of water impervious material positioned on the lower layer of concrete, and an upper layer of concrete positioned on the intermediate layer of water impervious material. Each of the first and second end walls and the first and second side walls includes an outer layer of concrete, an intermediate layer of water impervious material positioned at the inner side of the outer layer of concrete, and an inner layer of concrete material positioned at the inner side of the intermediate layer of water impervious material.

A nuclear reactor is positioned on a barge which floats on the water of a water tank. The water tank includes a bottom wall, first and second end walls and first and second side walls. The bottom wall includes a lower layer of concrete, an intermediate layer of water impervious material positioned on the lower layer of concrete, and an upper layer of concrete positioned on the intermediate layer of water impervious material. Each of the first and second end walls and the first and second side walls includes an outer layer of concrete, an intermediate layer of water impervious material positioned at the inner side of the outer layer of concrete, and an inner layer of concrete material positioned at the inner side of the intermediate layer of water impervious material.

Nuclear reactors have very few systems for significantly reduced failure possibilities. Nuclear reactors may be boiling water reactors with natural circulation-enabling heights and smaller, flexible energy outputs in the 0-350 megawatt-electric range. Reactors are fully surrounded by an impermeable, high-pressure containment. No coolant pools, heat sinks, active pumps, or other emergency fluid sources may be present inside containment; emergency cooling, like isolation condenser systems, are outside containment. Isolation valves integral with the reactor pressure vessel provide working and emergency fluid through containment to the reactor. Isolation valves are one-piece, welded, or otherwise integral with reactors and fluid conduits having ASME-compliance to eliminate risk of shear failure. Containment may be completely underground and seismically insulated to minimize footprint and above-ground target area.

An integrated passive cooling containment structure for a nuclear reactor includes a concentric arrangement of an inner steel cylindrical shell and an outer steel cylindrical shell that define both a lateral boundary of a containment environment of the nuclear reactor that is configured to accommodate a nuclear reactor and an annular gap space between the inner and outer steel cylindrical shells, a concrete donut structure at a bottom of the annular gap space, and a plurality of concrete columns spaced apart azimuthally around a circumference of the annular gap and extending in parallel from a top surface of the concrete donut structure to a top of the annular gap space. The outer and inner steel cylindrical shells and the concrete donut structure at least partially define one or more coolant channels extending through the annular gap space.