Abstract: A transportable nuclear power generator unit is provided. The transportable nuclear power generator unit includes a container configured to be transportable by a vehicle, and nuclear power module disposed inside the container. The nuclear power module includes a sealed pressure vessel and a nuclear core disposed inside the sealed pressure vessel. The transportable nuclear power generator unit also includes a plurality of radiation shields provided at a plurality of interior walls inside the container to surround the sealed pressure vessel. The radiation shields are configured to shield radiation generated by the nuclear power module. The radiation shields include a movable shield configured to be movable between a position inside the container and a position on an exterior wall of the container.

Abstract: A liquid-metal-cooled nuclear reactor includes a main vessel containing a primary fluid and a cylindrical separation structure, separating a hot leg from a cold leg. The cold leg encompasses the hot leg. At least one opening is provided in the cylindrical separation structure to enable the primary fluid to flow from the cold leg to the hot leg. A core is submerged in the hot leg. The reactor also includes at least one heat exchanger having an inlet from the hot leg and an outlet to the cold leg for transferring heat from the primary fluid to a secondary fluid of an externally connecting circuit. A reactor lid covers the main vessel. A gas plenum is disposed beneath the reactor lid and above the hot leg. An inner lid is disposed beneath the reactor lid covering the cold leg. The hot leg is open ended towards the gas plenum.

Abstract: A fuel salt shipping system includes an outer container defining an outer containment volume and an inner container disposed within the outer containment volume, with the inner container defining an inner volume configured to contain a molten fuel salt. The inner container and the outer container cooperate to define an annulus region therebetween. The fuel salt shipping system further includes a fuel salt conduit penetrating the outer container and the inner container and fluidically coupling the inner volume to an external environment of the system. The fuel salt shipping system further includes a heating system including a heater disposed in the annulus space and configured to impart a heat output to the molten fuel salt of the inner volume and change a phase of the molten fuel salt held therein from a solid phase to a liquid phase.

Abstract: Fuel cell lifting systems for nuclear reactors are disclosed. A fuel cell lifting system includes a radiation shield comprising: a first plate defining a first plane and comprising one or more first openings; and a second plate defining a second plane parallel to the first plane and comprising one or more second openings. At least one of the first plate or the second plate is rotatable around an axis perpendicular to the first plane and the second plane. A first opening of the first plate can be aligned with a second opening of the second plate to form a combined opening. A lifting motor is configured to extend and retract a tether through the combined opening of the radiation shield. The tether is attachable to a nuclear fuel cell.

Abstract: A nuclear reaction generator includes a chamber configured to contain a gas and including a target. The nuclear reaction generator also includes a filament provided inside the chamber and a voltage source configured to apply a first positive voltage to the filament relative to the chamber. The first positive voltage is configured to heat the filament to a temperature at which thermionic emission occurs and a plurality of thermions are generated, and the plurality of thermions is configured to ionize the gas to generate positive ions in the chamber. The target is configured such that nuclear reactions occur when the positive ions interact with the target.

Abstract: A nuclear reactor control assembly includes a reactivity control device comprising a control rod cluster and a drive rod. The control rod cluster comprises an attaching head. The drive rod comprises an attaching device for connecting the drive rod to the attaching head. The attaching device is movable between a connection position and a disconnection position. The drive rod and the attaching device define an axial trough recess forming a sleeve. A checking device is used for checking separation between the control rod cluster and the drive rod. The checking device comprises a probe rod which is free to move translationally in the sleeve. A lower end of the probe rod can abut the attaching head. Relative displacement of the probe rod with respect to the drive rod can be used to determine whether the drive rod is separated from the control rod cluster.

Abstract: A nuclear reactor assembly may include a fuel rod and an end plug extending from the fuel rod The end plug may include a first engagement surface and a second engagement surface. The second engagement surface may have a circular groove disposed in an exterior surface of the end plug, the circular groove defining a plane orthogonal to a longitudinal axis of the end plug. The assembly may also include a bottom nozzle forming a recess, in which the recess includes a first retainer extending from the recess and a second retainer extending from the recess. The first retainer may engage the first engagement surface and the second retainer may include a second retainer portion to engage the second engagement surface. The first retainer and the second retainer may axially retain the end plug to the bottom nozzle.

Abstract: Fissile target materials are provided. The fissile target materials can include a target substrate and a capturing layer operably interfacing with at least one surface of the target substrate. Fission fissile target materials are also provided that can include a target substrate comprising at least one fissile atom and a capturing layer operably interfacing with at least one surface of the target substrate. The capturing layer can include at least one fission product.

Abstract: The present application relates to nuclear fuel claddings, and more particularly to zirconium alloy tubes with a ceramic covering. A first coating layer is applied to the ceramic covering. A second coating layer is over the first coating layer. The first coating layer includes Nb. The second coating layer includes Cr.

Abstract: A method for replacing a damaged sleeve lining a tube passing through a nuclear reactor pressure vessel. The damaged sleeve has an end including a radially enlarged end portion for resting on a support section of the tube for retaining the damaged sleeve in the tube. The method includes removing the damaged sleeve from a tube; providing a sleeve assembly including a first sleeve with a radially variable end and a retainer; installing the sleeve assembly in the tube so the radially variable end of the first sleeve is received by the support section, the radially variable end being in a radially contracted configuration during installation and being in a radially expanded configuration after the sleeve assembly is installed in the tube; and deforming the retainer from an installation configuration to a retention configuration to retain the radially variable end of the first sleeve in the radially expanded configuration.

Abstract: A container holds radioactive material. A sub-criticality controller protects the radioactive material from reaching a criticality from contact with the water. The sub-criticality controller includes a metallic composition having at least one metal component and at least one borate component bonded to the at least one metal component. The metallic composition forms a new borate that absorbs neutrons when the metallic composition contacts water in the case of an incident.

Abstract: An automatic leveling type maintenance platform for a high-temperature gas cooled reactor is provided. A floating plate is automatically leveled by using a leveling liquid. During leveling, only a water driving assembly needs to be controlled to drive a housing to be close to an inner bottom surface of a liquid storage container. A sliding block assembly and a lifting guide mechanism are controlled to be locked and fixed after the floating plate is leveled. The floating plate can allow for automatic and rapid leveling and locking operation. Thus, complex and time-consuming fine adjustment control does not need to be performed. Also, when the platform is used in a spherical top cap of a pressure vessel of the reactor for a maintenance operation, then support legs of a support assembly do not need to have telescopic motion.

Abstract: A method of determination of a nuclear core loading pattern defining the disposition of fuel assemblies. The method includes defining at least one potential core loading pattern and calculating predictive bowing of the fuel assemblies at the end of the operation cycle for each potential core loading pattern. The calculation is carried out by an automatic learning algorithm trained on a training data set that includes a plurality of other core loading patterns. The set also includes, for each of the other core loading patterns, measurements of bowing of fuel assemblies at the end of operation cycle. The method also includes evaluating the at least one potential core loading pattern based on the predictive bowing calculations and at least one predetermined criteria. The method further includes selecting one of the potential core loading patterns based at least in part on the evaluating.

Abstract: A nested pebble bed blanket surrounds a fusion reactor's vacuum chamber. The blanket includes stacks of nested pebbles composed of neutron multiplier shells filled with breeding spheroids. The shells have perforations passing through their inner and outer surfaces. The shells include therein perforated coolant distributor elements coupled to or unitary with the inner surfaces. Each perforated element is in line with a respective shell perforation, which allows coolant to flow into the sphere through the perforations and elements. When bombarded by neutrons, the nested pebbles produce fusion fuel to sustain fusion reactions. The coolant sweeps out the fusion fuel, and cools the breeding spheroids. Pebbles in the blanket are replenished with conveyor systems. A separator extracts the fusion fuel from the blanket coolant. Heat from the walls and the nested pebble bed is extracted by inert gases and then conveyed to a thermal storage and/or a power cycle.

Abstract: Carbide-based fuel assembly includes outer structural member of ceramic matrix composite material (e.g., SiC—SiC composite), insulation layer of porous refractory ceramic material (e.g., zirconium carbide with open-cell foam structure or fibrous zirconium carbide), and interior structural member of refractory ceramic-graphite composite material (e.g., zirconium carbide-graphite or niobium carbide-graphite). Spacer structures between various layers provide a defined and controlled spacing relationship. A fuel element bundle positioned between support meshes includes a plurality of distributively arranged fuel elements or a solid, unitary fuel element with coolant channels, each having a fuel composition including high assay, low enriched uranium (HALEU).

Abstract: A pressurized water reactor includes a primary reactor coolant circuit flown through by a primary reactor coolant during operation, and a chemical and volume control system for the primary reactor coolant. The chemical and volume control system includes, along the direction of flow of the primary reactor coolant, a letdown line, a high-pressure charging pump with a given discharge pressure, and a charging line leading to the primary reactor coolant circuit. The chemical and volume control system further includes a hydrogenation system with a hydrogen supply and a hydrogen feeding line. In order to achieve efficient and fast hydrogen injection into the primary reactor coolant, a high-pressure feeding pump is arranged in the feeding line to provide a gas pressure higher than the discharge pressure of the charging pump. The feeding line discharges into the charging line.

Abstract: A nuclear fuel rod includes a cladding comprising an interior region. A pressure transmission apparatus is configured to measure pressure in the interior region. Fuel pellets and a resonant electrical circuit are in the interior region. The resonant electrical circuit is configured to generate a pulse that travels wirelessly from the interior region through the cladding. A frequency of the pulse varies based on pressure measured by the pressure transmission apparatus. The frequency of the pulse is indicative of the pressure within the interior region.

Abstract: System for emergency cooling of a nuclear reactor. The system uses passive convection cooling and endothermic reactant cooling.

Abstract: A method for restraining a sleeve lining a tube passing through a nuclear reactor pressure vessel is provided. The method includes attaching in situ a radial protrusion on an external surface of the sleeve; and attaching a collar to an end of the tube and coupling the radial protrusion with the collar to retain the thermal sleeve in position.

Abstract: An example method includes directing gas, via one or more first valves, from within an inner electrode to an acceleration region between the inner electrode and an outer electrode that substantially surrounds the inner electrode, directing gas, via two or more second valves, from outside the outer electrode to the acceleration region, and applying, via a power supply, a voltage between the inner electrode and the outer electrode, thereby converting at least a portion of the directed gas into a plasma having a substantially annular cross section, the plasma flowing axially within the acceleration region toward a first end of the inner electrode and a first end of the outer electrode and, thereafter, establishing a Z-pinch plasma that flows between the first end of the outer electrode and the first end of the inner electrode. Related plasma confinement systems and methods are also disclosed herein.