Abstract: Disclosed embodiments include nuclear fission reactor cores, nuclear fission reactors, methods of operating a nuclear fission reactor, and methods of managing excess reactivity in a nuclear fission reactor.

Abstract: Disclosed embodiments include nuclear fission reactor cores, nuclear fission reactors, methods of operating a nuclear fission reactor, and methods of managing excess reactivity in a nuclear fission reactor.

Abstract: Disclosed embodiments include fuel ducts, fuel assemblies, methods of making fuel ducts, methods of making a fuel assembly, and methods of using a fuel assembly. An inner hollow structure has a first geometry and an outer hollow structure has a second geometry different from the first geometry. The first hollow structure is configured to expand in at least one dimension under stress and cause the first hollow structure to contact the second hollow structure. The second hollow structure distributes at least a portion of the stress of the first hollow structure.

Abstract: A nuclear fission reactor, flow control assembly, methods therefor and a flow control assembly system. The flow control assembly is coupled to a nuclear fission module capable of producing a traveling burn wave at a location relative to the nuclear fission module. The flow control assembly controls flow of a fluid in response to the location relative to the nuclear fission module. The flow control assembly comprises a flow regulator subassembly configured to be operated according to an operating parameter associated with the nuclear fission module. In addition, the flow regulator subassembly is reconfigurable according to a predetermined input to the flow regulator subassembly. Moreover, the flow control assembly comprises a carriage subassembly coupled to the flow regulator subassembly for adjusting the flow regulator subassembly to vary fluid flow into the nuclear fission module.

Abstract: A rod transfer assembly has an outer rotating plug. A pick-up arm assembly extends from the outer rotating plug and includes a pivoting arm. An inner rotating plug is disposed off-center from and within the outer rotating plug and is rotatable independent of a rotation of the outer rotating plug. An access port rotating plug is disposed off-center from and within the inner rotating plug and is rotatable independent of rotation of the outer and inner rotating plugs. A pull arm extends from the access port rotating plug.

Abstract: Disclosed embodiments include fuel ducts, fuel assemblies, methods of making fuel ducts, methods of making a fuel assembly, and methods of using a fuel assembly. In one implementation, the fuel ducts have a first hollow structure having a first cross-sectional geometry and a second hollow structure positioned within the first hollow structure, the second hollow structure having a second cross-sectional geometry different from the first cross-sectional geometry.

Abstract: Disclosed embodiments include fuel ducts, fuel assemblies, methods of making fuel ducts, methods of making a fuel assembly, and methods of using a fuel assembly.

Abstract: A cable management system has an outer rotating plug. An inner rotating plug is disposed off-center from and within the outer rotating plug. The inner rotating plug is rotatable independent of a rotation of the outer rotating plug. A tower extends from the inner rotating plug and has an arm pivotally connected to the tower which defines a cable guide.

Abstract: A rod transfer assembly has an outer rotating plug. A pick-up arm assembly extends from the outer rotating plug and includes a pivoting arm. An inner rotating plug is disposed off-center from and within the outer rotating plug and is rotatable independent of a rotation of the outer rotating plug. An access port rotating plug is disposed off-center from and within the inner rotating plug and is rotatable independent of rotation of the outer and inner rotating plugs. A pull arm extends from the access port rotating plug.

Abstract: A cable management system has an outer rotating plug. An inner rotating plug is disposed off-center from and within the outer rotating plug. The inner rotating plug is rotatable independent of a rotation of the outer rotating plug. A tower extends from the inner rotating plug and has an arm pivotally connected to the tower which defines a cable guide.

Abstract: Disclosed embodiments include nuclear fission reactor cores, nuclear fission reactors, methods of operating a nuclear fission reactor, and methods of managing excess reactivity in a nuclear fission reactor.

Abstract: A nuclear fission reactor, flow control assembly, methods therefor and a flow control assembly system. The flow control assembly is coupled to a nuclear fission module capable of producing a traveling burn wave at a location relative to the nuclear fission module. The flow control assembly controls flow of a fluid in response to the location relative to the nuclear fission module. The flow control assembly comprises a flow regulator subassembly configured to be operated according to an operating parameter associated with the nuclear fission module. In addition, the flow regulator subassembly is reconfigurable according to a predetermined input to the flow regulator subassembly. Moreover, the flow control assembly comprises a carriage subassembly coupled to the flow regulator subassembly for adjusting the flow regulator subassembly to vary fluid flow into the nuclear fission module.

Abstract: Illustrative embodiments provide modular nuclear fission deflagration wave reactors and methods for their operation. Illustrative embodiments and aspects include, without limitation, modular nuclear fission deflagration wave reactors, modular nuclear fission deflagration wave reactor modules, methods of operating a modular nuclear fission deflagration wave reactor, and the like.

Abstract: Illustrative embodiments provide a nuclear fission reactor, that includes a reactor vessel, a nuclear fission fuel element capable of generating a gaseous fission product, a valve body defining a plenum for receiving the gaseous fission product, and a valve in operative communication with the plenum for controllably venting the gaseous fission product from the plenum.

Abstract: Illustrative methods are provided for annealing nuclear fission reactor materials, such as without limitation, a nuclear fission reactor core or fuel assembly or components thereof within the nuclear core. Annealing a metallic component of a nuclear fission reactor within the reactor core may include determining an annealing temperature for at least a portion of at least one metallic component of a nuclear fission fuel assembly of the reactor. The temperature of the core may be adjusted to affect the determined annealing temperature, which in some cases may be greater than the predetermined operating temperature range of the nuclear fission fuel assembly. The portion of the at least one metallic component of the nuclear fission fuel assembly is annealed within the core at the annealing temperature range.

Abstract: Disclosed embodiments include nuclear fission reactor cores, nuclear fission reactors, methods of operating a nuclear fission reactor, and methods of managing excess reactivity in a nuclear fission reactor.

Abstract: Disclosed embodiments include nuclear fission reactor cores, nuclear fission reactors, methods of operating a nuclear fission reactor, and methods of managing excess reactivity in a nuclear fission reactor.

Abstract: Illustrative embodiments provide modular nuclear fission deflagration wave reactors and methods for their operation. Illustrative embodiments and aspects include, without limitation, modular nuclear fission deflagration wave reactors, modular nuclear fission deflagration wave reactor modules, methods of operating a modular nuclear fission deflagration wave reactor, and the like.

Abstract: Disclosed embodiments include a vented nuclear fission fuel module system. Given by way of non-limiting example and not of limitation, an illustrative vented nuclear fission fuel module system includes a nuclear fission fuel element capable of generating a gaseous fission product. A valve body is associated with the nuclear fission fuel element, and the valve body defines a plenum therein for receiving the gaseous fission product. A reclosable valve is in operative communication with the plenum for controllably venting the gaseous fission product from the plenum, and the valve body includes a flexible diaphragm coupled to the valve for moving the valve to a closed position.

Abstract: Disclosed embodiments include nuclear fission reactor cores, nuclear fission reactors, methods of operating a nuclear fission reactor, and methods of managing excess reactivity in a nuclear fission reactor.