Abstract: Disclosed herein is a nuclear power plant main steam system that reduces the atmospheric discharge of radioactive materials generated in an accident. The system includes: a decontamination water tank containing decontamination water; and a connection pipe for connecting the decontamination water tank to a main steam pipe which connects a steam generator and a turbine. A main steam safety valve or a connection valve is provided as a three-way valve configured to discharge the generated steam to the atmosphere when an accident occurs within a design basis and to transfer the generated steam to the decontamination water tank when an accident involving damage to nuclear fuel occurs. The main steam system reduces discharge of radioactive materials to the atmosphere when a containment bypass accident (e.g., a steam generator tube rupture caused by high-temperature steam) occurs.

Abstract: A method of generating power using a Thorium-containing molten salt fuel is disclosed. One example includes the steps of providing a vessel containing a molten salt fuel, generating a proton beam externally to the vessel, where the externally generated proton beam is of an energy level sufficient to interact with material within a fuel rod in the vessel to produce (p, n) reactions resulting in the generation of neutrons at a first energy level. Neutrons generated within the vessel through the (p, n) reactions are utilized to produce a fission reaction which increases the heat content of the molten salt within the vessel. In the example, a heat exchanger is used to extract heat from the molten salt within the vessel and power is generated from the extracted heat.

Abstract: A temperature measurement sensor for use in a nuclear reactor is described. The sensor includes a first neutron detector member and a second neutron detector member. The first neutron detector includes an outer shield material with an effective neutron capture cross section that is temperature dependent. The first neutron detector member outputs a first current signal and the second neutron detector member outputs a second current signal. An electrical connection between the first and second neutron detector members produces a net current that is the difference in current between the first and second signals. The difference is proportional to changes in temperature.

Abstract: A fast-neutron nuclear reactor fuel assembly having fuel rods. Each fuel rod has nuclear fuel disposed in a sealed housing in the form of a tubular steel shell and end parts. A steel spacer element is wound in a coil with a specific pitch on the outside surface of the shell and is fastened on the end parts. The spacer element is in the form of a metallic band twisted around its longitudinal axis. The width of said band is approximately equal to the minimum distance between adjacent fuel rods in the fuel assembly. A transverse cross-sectional area of the band is within a range from 0.10 to 0.50 times the area of a circle described around the width of the band.

Abstract: A closed-vessel molten salt reactor (cvMSR) is described herein. A cvMSR may comprise a suspended container, such as a metallic container, within a trench surrounded by a concrete enclosure and a concrete cover having a number of channels. The suspended container may be hollow and a solution of fissile materials and salt materials may be provided within the suspended container. The solution may be capable of undergoing a chain reaction nuclear fission process once a threshold temperature is reached. Heat generated by the solution may heat a fluid surrounding the suspended container. The heated fluid may be transported, through the number of channels of the concrete cover, to an external location where the heated fluid may be used in distributing heat and/or electricity generation.

Abstract: An improved retention system for retaining fuel rods in a fuel assembly is disclosed. The retention system includes a plurality of first engagement surfaces on the bottom nozzle of a fuel assembly. There is at least one engagement surface for each fuel rod. A second engagement surface is formed on the bottom end plug of each fuel rod. The first and second engagement surfaces are configured for engagement with each other for axially and laterally retaining each fuel rod within the fuel assembly. Debris deflectors may also be provided to deflect debris from coolant channels surrounding the fuel rods.

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: A nuclear fuel includes a net neutron-producing material, a neutron-consuming material, and a neutron-moderating material. Upon exposure of the net-producing material, the neutron-moderating material, and the neutron-consuming material to a neutron source, a ratio of the net neutron-producing material to the neutron-consuming material and a ratio of the net neutron-producing material to the neutron moderating material are operable to convert neutrons into charged particles without producing net neutrons.

Abstract: Systems, devices, and methods for generating an orbital confinement fusion reaction are described. An orbital confinement fusion device can include a cathodic inner electrode defining a longitudinal axis of the device. The inner electrode can include an emitter material. The orbital confinement fusion device can include an anodic outer electrode, concentric with the longitudinal axis and defining a chamber between the inner electrode and the outer electrode. The orbital confinement fusion device can also include a plurality of magnetic field generators disposed in a coaxial arrangement relative to the longitudinal axis. The plurality of magnetic field generators can be configured to form a magnetic field parallel to the longitudinal axis in the chamber.

Abstract: A nanofuel engine including receiving nanofuel (including a molecular mixture, where the molecular mixture includes at least one molecule with dimensions on a nanometer scale) internally in an internal engine that releases nuclear energy, is set forth. A nanofuel chemical composition of fissile fuel, passive agent, and moderator. A method of operating a nanofuel engine loaded with nanofuel in spark or compression ignition mode. A method of cycling a nanofuel engine, including compressing nanofuel; igniting nanofuel; capturing energy released in nanofuel, which is also the working fluid; and using the working fluid to perform mechanical work or generate heat.

Abstract: A target irradiation system for irradiating a radioisotope target in a vessel penetration of a fission reactor, includes a target delivery assembly with a body defining a central bore, a basket that is slidably receivable within the central bore of the body, and a winch that is connected to the basket by a cable. The target delivery assembly is affixed to the vessel penetration of the reactor; and a target passage is in fluid communication with the target delivery assembly. The basket is configured to receive a radioisotope target therein via the target passage and be lowered into the vessel penetration of the reactor when irradiating the radioisotope target. The target delivery system forms a portion of the pressure boundary of the reactor when in fluid communication with the reactor.

Abstract: A method for producing 225A including: a method (X) for purifying a 226Ra-containing solution, including an adsorption step of allowing a 226Ra ion to adsorb onto a carrier having a function of selectively adsorbing a divalent cation by bringing a 226Ra-containing solution into contact with the carrier under an alkaline condition, and an elution step of eluting the 226Ra ion from the carrier under an acidic condition; a method for producing a 226Ra target, including an electrodeposition liquid preparation step of preparing an electrodeposition liquid by using a purified 226Ra-containing solution obtained by the method (X), and an electrodeposition step of electrodepositing a 226Ra-containing substance on a substrate by using the electrodeposition liquid; and a step of irradiating a 226Ra target produced by the method for producing a 226Ra target with at least one selected from a charged particle, a photon, and a neutron by using an accelerator.

Abstract: A method of forming a water resistant boundary on a fissile material for use in a water cooled nuclear reactor is described. The method comprises mixing a powdered fissile material selected from the group consisting of UN and U3Si2 with an additive selected from oxidation resistant materials having a melting or softening point lower than the sintering temperature of the fissile material, pressing the mixed fissile and additive materials into a pellet, sintering the pellet to a temperature greater than the melting point of the additive. Alternatively, if the melting point of the oxidation resistant particles is greater than the sintering temperature of UN or U3Si2, then the oxidation resistant particles can have a particle size distribution less than that of the UN or U3Si2.

Abstract: A composite nuclear reactor component comprises a support and a protective layer (2). The support contains a substrate (1) based on a metal. The substrate is coated with an interposed layer (3) positioned between the substrate (1) and the protective layer (2). The protective layer (2) is composed of a material which comprises amorphous chromium carbide. The nuclear reactor component provides for improved resistance to oxidation, hydriding, and/or migration of undesired material.

Abstract: Power conversion systems for converting thermal energy from a heat source to electricity are disclosed. In one exemplary embodiment, the power conversion system may include a substantially sealed chamber having an inner shroud having an inlet and an outlet and defining an internal passageway between the inlet and the outlet through which a working fluid passes. The sealed chamber may also include an outer shroud substantially surrounding the inner shroud, such that the working fluid exiting the outlet of the inner shroud returns to the inlet of the inner shroud in a closed-loop via a return passageway formed between an external surface of the inner shroud and an internal surface of the outer shroud. The power conversion system may further include a source heat exchanger disposed in the internal passageway of the inner shroud, the source heat exchanger being configured to at least partially receive a heat transmitting element.

Abstract: A travelling wave reactor for a space exploration. A reactor core of the travelling wave reactor is dispersed into several modules in a travelling wave direction; a new reactor is sequentially provided with a starting source module and a plurality of new fuel modules at zero burnup; all the modules are coaxially assembled in the travelling wave direction by means of an assembling parts, and each module further includes a heat pipe; the heat pipe in each module positioned at a front part sequentially passes through all the modules positioned at a rear portion thereof and extends out of the module at a rear end; and after a period of time of burn-up, the reactor core of the travelling wave reactor is provided with the starting source module, a spent fuel module, a critical fuel module and the new fuel module sequentially in the travelling wave direction.

Abstract: A nuclear power system includes a reactor vessel that includes a reactor core mounted within a volume of the reactor vessel. The reactor core includes one or more nuclear fuel assemblies configured to generate a nuclear fission reaction. The nuclear power system further includes a containment vessel sized to enclose the reactor vessel such that an open volume is defined between the containment vessel and the reactor vessel. A boron injection system is positioned in the open volume of the containment vessel and includes an amount of boron sufficient to stop the nuclear fission reaction or maintain the nuclear fission reaction at a sub-critical state. The boron injection system is positioned to deliver the amount of boron into the open volume.

Abstract: A getter element includes a getter material reactive with a fission product contained within a stream of liquid and/or gas exiting a fuel assembly of a nuclear reactor. At least one transmission pathway passes through the getter element that is sufficiently sized to maintain a flow of the input stream through the getter element at above a selected flow level. At least one transmission pathway includes a reaction surface area sufficient to uptake a pre-identified quantity of the fission product.

Abstract: A replacement thermal sleeve with a flange for a reactor vessel closure head penetration adapter housing. By altering a diameter of the flange, a replacement thermal sleeve can be installed through the narrow diameter of the penetration adapter housing opening from under the reactor vessel head. The flange can be compressible or expandable or the tubular wall of the thermal sleeve can be inserted in longitudinal sections, one at a time, into an opening in the underside of the penetration head adapter and reformed within the opening when fully inserted.

Abstract: System for separating and coupling a nuclear fuel assembly from/to a top nozzle which has a flow channel plate with guide holes. The system includes a lock insert and a separation member. The lock insert includes an insertion part provided on a top portion of a hollow body. The separation member is configured to separate the insertion part from a guide hole. The insertion part is variable in size. The insertion part comprises a first latching member and a second latching member, each having a step which contacts the flow channel plate. The first latching member includes a latching groove which is inserted into a member protruding from the top surface of the flow channel plate. The second latching member contacts a bottom surface of the flow channel plate. The separation member provides a space accommodating an outer circumferential surface of the first latching member.