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.

An insulating concrete form system uses a stacked arrangement of foam panels to receive pourable concrete to construct a concrete wall of a building structure. Webs located in the panels hold the panels in parallel spaced relation. The webs have laterally extending ties. The ties have one or more projecting members having arms extending into grooves adapted to receive rebar. Outwardly extending truss member are used to fasten multiple webs during shipping. Couplings releasably connect the ties to end portions of the web and allow the ties to be moved along the length of the end portions as desired.

Stay-in-place forms and methods and equipment for installing thereof. A concrete form includes a vertical component and a horizontal component, the vertical component located substantially perpendicular to the horizontal component. Also, the form includes an interior surface, at least a portion of the interior surface providing a form for supporting uncured concrete; wherein the uncured concrete forms a concrete structural portion upon curing of the uncured concrete; and wherein the interior surface remains attached to the concrete structural portion after curing. The form may include inserts and compatible form attachments. Also, forms including recesses may be utilized to reduce the weight thereof. Lifting equipment and accessories may be utilized to lift the form from a form holder and set same in place. Forms contain the work area as soon as it is installed to minimize fall hazards and the time, costs, and downtime associated with installation of safety measures.

A nuclear fuel assembly is constructed with fuel assembly components that are wire wrapped and positioned in hexagonal rings within a fuel assembly duct. The fuel assembly components positioned in an outermost ring of the fuel assembly are wire wrapped with a pitch that is shorter than fuel assembly components positioned at an interior ring of the fuel assembly. The shorter pitch at the outer ring of the fuel assembly increases pressure drop of a coolant fluid at the edge and corner subchannels and thereby reduces the temperature gradient across the fuel assembly, which provides a higher output temperature of the nuclear reactor without substantially increasing peak temperature of the fuel cladding.

An elongated building element (14) having a pair of longitudinally extending generally parallel co-extensive side walls (15) joined by transverse webs (16). The walls (15) and webs (16) enclose a longitudinally extending space (30) within which there is located a tube (31). The tube (31) is connected to the walls (15) and webs (16) by flanges (33). The tube (31) provides a space (33) with the spaces (30, 33) being intended to be filled with concrete. The building element (14) is intended to be attached to light elements (14) to form a wall.

An elongated building element (14) having a pair of longitudinally extending generally parallel co-extensive side walls (15) joined by transverse webs (16). The walls (15) and webs (16) enclose a longitudinally extending space (30) within which there is located a tube (31). The tube (31) is connected to the walls (15) and webs (16) by flanges (33). The tube (31) provides a space (33) with the spaces (30, 33) being intended to be filled with concrete. The building element (14) is intended to be attached to light elements (14) to form a wall.

An insulated construction panel having a top end, a bottom end, a first end, a second end, a front side and a rear side, the panel for constructing a single or multi-thickness concrete form, the panel including regularly spaced coplanar passages extending completely through the panel from the top end of the panel toward and through to the bottom end of the panel. For each of the regularly spaced coplanar passages, an angular passage perpendicularly intersecting each coplanar passage at the top end and extending toward and through a portion of a front side surface of the front side and rear side surface of the rear side of the panel, each angular passage extending only partially through the panel from the top end toward the bottom end. For each of the regularly spaced coplanar passages, an angular passage perpendicularly intersecting each coplanar passage at the bottom end and extending toward and through a portion of the front side surface of the front side and the rear side surface of rear side of the panel, each angular passage extending only partially through the panel from the bottom end toward the top end.

A nuclear fuel assembly is constructed with fuel assembly components that are wire wrapped and positioned in hexagonal rings within a fuel assembly duct. The fuel assembly components positioned in an outermost ring of the fuel assembly are wire wrapped with a pitch that is shorter than fuel assembly components positioned at an interior ring of the fuel assembly. The shorter pitch at the outer ring of the fuel assembly increases pressure drop of a coolant fluid at the edge and corner subchannels and thereby reduces the temperature gradient across the fuel assembly, which provides a higher output temperature of the nuclear reactor without substantially increasing peak temperature of the fuel cladding.

A nuclear reactor is constructed in sub-modules and super modules which are manufactured, packaged, and shipped to a construction site. At least some of the modules are packaged in suitable shielding containers or portions of containers, which may be steel. The modules are assembled on-site, and some of the modules remain within their respective shipping containers after assembly. One or more of the shipping containers may be used as concrete forms to support the pouring of concrete in between selected modules. The concrete may be used for structural support, shielding, or both.

Structural dovetail decking panel systems that utilize dovetail decking panels with a proximal edge having a proximal arm extending outwardly away from the dovetail decking panel, and a distal edge having a distal arm extending inwardly towards the dovetail decking panel. When adjacent dovetail decking panels are joined, the proximal edge having the proximal arm of a panel is placed over the distal end having the distal arm of the adjacent panel to create a dovetail sidelap. The proximal arm and/or the distal arm aid in restricting movement of the proximal edge and the distal edge of adjacent panels in order control the dimensions of a sidelap cavity and opening in the dovetail sidelap, which improves the strength of the dovetail decking panel systems, allows for the reduction of the thickness of the panels or number of couplings used, and/or allows for anchors to be utilized within the sidelap cavity.