A compact nuclear reactor system can include a set of nuclear reactor each including: a moderating body; a heat pipe disposed within the moderating body and arranged substantially parallel to the longitudinal axis; nuclear fuel arranged within the moderating body and configured to heat a working fluid passable through the heat pipe; and a neutron moderator arranged within the moderating body and configured to slow a rate of fission within the moderating body. The compact nuclear reactor system can also include a control system including: a rotatable sleeve defining a first portion including a neutron poison material; and a second portion including a neutron transparent material. The compact nuclear reactor system can also include a drive system connected to the sleeve and configured to rotate the sleeve about the sleeve axis to control neutron flux between the set of nuclear reactor cores.

The disclosure relates to a high temperature gas-cooled reactor core including a plurality of elongate fuel elements arranged in the form of a multi-lobed prism. Each prismatic fuel element includes an elongate prismatic body and a plurality of elongate fuel channels located within the prismatic body, wherein the cross-sectional area of each prismatic fuel element in a plane parallel to the bases of the prismatic fuel element is no more than 800 cm.sup.2 and wherein a ratio of the height of the prismatic body to its greatest width is greater than or equal to 3.0.

Configurations of molten fuel salt reactors are described that allow for active cooling of the containment vessel of the reactor by the primary coolant. Furthermore, naturally circulating reactor configurations are described in which the reactor cores are substantially frustum-shaped so that the thermal center of the reactor core is below the outlet of the primary heat exchangers. Heat exchanger configurations are described in which welded components are distanced from the reactor core to reduce the damage caused by neutron flux from the reactor. Radial loop reactor configurations are also described.

Fission reactor has a shell encompassing a reactor space within which are a central longitudinal channel, a plurality of axially extending rings with adjacent rings defining an annular cylindrical space in which a first plurality of primary axial tubes are circumferential located. Circumferentially adjacent primary axial tubes are separated by one of the plurality of secondary channels and a plurality of webbings connects at least a portion of the plurality of primary axial tubes to adjacent structure. A fissionable nuclear fuel composition is located in at least some of the plurality of secondary channels and a primary coolant passes thorough at least some of the primary axial tubes. Additive and/or subtractive manufacturing techniques produce an integral and unitary structure for the fuel loaded reactor space. During manufacturing and as-built, the reactor design can be analyzed using a computational platform that integrates and analyzes data from in-situ monitoring during manufacturing.

Fission reactor has a shell encompassing a reactor space within which are a central longitudinal channel, a plurality of axially extending rings with adjacent rings defining an annular cylindrical space in which a first plurality of primary axial tubes are circumferential located. Circumferentially adjacent primary axial tubes are separated by one of the plurality of secondary channels and a plurality of webbings connects at least a portion of the plurality of primary axial tubes to adjacent structure. A fissionable nuclear fuel composition is located in at least some of the plurality of secondary channels and a primary coolant passes thorough at least some of the primary axial tubes. Additive and/or subtractive manufacturing techniques produce an integral and unitary structure for the fuel loaded reactor space. During manufacturing and as-built, the reactor design can be analyzed using a computational platform that integrates and analyzes data from in-situ monitoring during manufacturing.

Fission reactor has a shell encompassing a reactor space within which are a central longitudinal channel, a plurality of axially extending rings with adjacent rings defining an annular cylindrical space in which a first plurality of primary axial tubes are circumferential located. Circumferentially adjacent primary axial tubes are separated by one of the plurality of secondary channels and a plurality of webbings connects at least a portion of the plurality of primary axial tubes to adjacent structure. A fissionable nuclear fuel composition is located in at least some of the plurality of secondary channels and a primary coolant passes thorough at least some of the primary axial tubes. Additive and/or subtractive manufacturing techniques produce an integral and unitary structure for the fuel loaded reactor space. During manufacturing and as-built, the reactor design can be analyzed using a computational platform that integrates and analyzes data from in-situ monitoring during manufacturing.

Fission reactor has a shell encompassing a reactor space within which are a central longitudinal channel, a plurality of axially extending rings with adjacent rings defining an annular cylindrical space in which a first plurality of primary axial tubes are circumferential located. Circumferentially adjacent primary axial tubes are separated by one of the plurality of secondary channels and a plurality of webbings connects at least a portion of the plurality of primary axial tubes to adjacent structure. A fissionable nuclear fuel composition is located in at least some of the plurality of secondary channels and a primary coolant passes thorough at least some of the primary axial tubes. Additive and/or subtractive manufacturing techniques produce an integral and unitary structure for the fuel loaded reactor space. During manufacturing and as-built, the reactor design can be analyzed using a computational platform that integrates and analyzes data from in-situ monitoring during manufacturing.

A molten fuel reactor includes a reactor core having substantially a right-circular cylinder shape with a longitudinal axis. At least one inlet is configured to channel fuel salt into the reactor core. At least one outlet is configured to channel fuel salt out of the reactor core, and the inlet and outlet at least partially define a flow loop of fuel salt with respect to the reactor core. An orifice ring plate is disposed within the reactor core and proximate the at least one inlet. The orifice ring plate is configured to condition a flow of fuel salt entering the reactor core from the at least one inlet. The orifice ring plate extends circumferentially about the longitudinal axis and has a height defined in a direction along the longitudinal axis. The orifice ring plate includes a plurality of apertures configured to allow the flow of fuel salt therethrough.

An entire nuclear fuel core comprising a plurality of fuel assemblies is preassembled in a nuclear fuel cartridge having a self-supporting unitary support structure. During a refueling operation, the unitary support structure is moved into a nuclear reactor vessel. The unitary support structure may be formed by top and bottom core plates coupled together by vertically-oriented connecting rods which compress the fuel assemblies therebetween. A plurality of reflector wall segments circumscribe the core and are the coupled together between the core plates by the connecting rods which are coupled to the core plates. The connecting rods may extend through the wall segments.

An entire nuclear fuel core comprising a plurality of fuel assemblies is preassembled in a nuclear fuel cartridge having a self-supporting unitary support structure. During a refueling operation, the unitary support structure is moved into a nuclear reactor vessel. The unitary support structure may be formed by top and bottom core plates coupled together by vertically-oriented connecting rods which compress the fuel assemblies therebetween. A plurality of reflector wall segments circumscribe the core and are the coupled together between the core plates by the connecting rods which are coupled to the core plates. The connecting rods may extend through the wall segments.