Abstract: A nuclear facility includes a fuel element pool which is filled with a cooling liquid. A fuel element rack, which is disposed in the fuel element pool, includes compartments for receiving fuel elements. The fuel elements received in the compartments are in direct contact with the cooling liquid in the fuel element pool. At least one cooling element is disposed in one of the compartments instead of a fuel element. The cooling element acts as a heat exchanger through which a coolant can flow, the cooling element is connected into a cooling circuit and the cooling element is immersed in the cooling liquid.

Abstract: A heat pipe assembly of a nuclear apparatus includes a number of elongated heat pipes and a detection system having one or more fiber optic cable assemblies that are elongated and are wrapped in a helical fashion along an exterior surface of one or more of the heat pipes. The detection system further includes an optical signal generator that supplies to each, fiber optic assembly an optical signal and additionally includes a sensor that detects a number of reflections of the optical signal and generates an output. The output is usable by an instrumentation and control system to determine a number of temperatures along one or more of the heat tubes by detecting a temperature at each of a plurality of locations along each fiber optic cable assembly.

Abstract: Provided are methods to separate an isotope from a first solution including uranium. The methods may include (a) cleaning the first solution to form a second solution including the uranium and a third solution including the isotope; (b) oxidizing the third solution to form an oxidized isotope; and (c) separating the oxidized isotope.

Abstract: There is provided an inspection device for inspecting an inner surface of a nozzle provided in a reactor vessel. The inspection device includes: a device frame, an inspection unit provided on the device frame, an inspection unit push-out moving mechanism for pushing out and moving the inspection unit to the inner surface of the nozzle, a rotation moving mechanism for rotating and moving the inspection unit, a calibration test unit arranged on the device frame for calibrating the inspection unit; and a calibration test unit forward/backward moving mechanism for moving the calibration test unit forward or backward in the direction along the central axis with regard to a track where the inspection unit makes push-out movement.

Abstract: A nuclear reactor cooling system with passive cooling capabilities operable during a reactor shutdown event without available electric power. In one embodiment, the system includes a reactor vessel with nuclear fuel core and a steam generator fluidly coupled thereto. Primary coolant circulates in a flow loop between the reactor vessel and steam generator to heat secondary coolant in the steam generator producing steam. The steam flows to a heat exchanger containing an inventory of cooling water in which a submerged tube bundle is immersed. The steam is condensed in the heat exchanger and returned to the steam generator forming a closed flow loop in which the secondary coolant flow is driven by natural gravity via changes in density from the heating and cooling cycles. In other embodiments, the cooling system is configured to extract and cool the primary coolant directly using the submerged tube bundle heat exchanger.

Abstract: The invention relates to the nuclear energy field, including pressurized water reactor containment internal passive heat removal systems. The invention increases heat removal efficiency, flow stability in the circuit, and system reliability. The system has at least one cooling water circulation circuit comprising a heat exchanger inside the containment and including an upper and lower header interconnected by heat-exchange tubes, a riser pipeline and a downtake pipeline connected to the heat exchanger, a cooling water supply tank above the heat exchanger outside the containment and connected to the downtake pipeline, a steam relief valve connected to the riser pipeline and located in the water supply tank and hydraulically connected to the latter. The upper and lower header of the heat exchanger are divided into heat exchange tube sections on the assumption that: L/D?20, L being the header section length, D being the header bore.

Abstract: The invention relates to the field of thermonuclear fusion and can be used in devices for electrically connecting internal elements of the reactor chamber to the vacuum vessel of the nuclear fusion reactor. The present device for electrically connecting elements inside the chamber of a reactor to the vacuum vessel of the nuclear fusion reactor comprises lamellar electrically conductive elements with surface portions oriented in different directions, said elements being stacked between flanges. The device is made as an integral unit, where profiled slots are formed with connecting walls therebetween. The connecting walls constitute the electrically conductive elements and have profiled sections of an increased thickness between the differently oriented surface portions at transition areas to the flanges provided at the end parts of the integral unit.

Abstract: The present invention relates to a nuclear reactor (1), in particular a liquid-metal-cooled reactor, provided with a separation structure (5) between hot header (6) and cold header (7), narrower in the upper portion (16) for containment of the headers of the fuel assemblies and wider in the lower element (14) at the active part (4) of the core, with a variously shaped connecting element (15) between the lower element (14) and the upper element (16), and with heat exchangers (11) positioned between the upper portion (16) of said separation structure (5) and the reactor vessel (2), which engage on the connecting element (15) via vertical ducts (20) for being fed with hot primary fluid leaving the core (4).

Abstract: Embodiments of the present invention provide a heat exchange medium comprising solid particles and a fluid. Embodiments of the present invention also provide a heat exchange system comprising the abovementioned heat exchange medium, a first heat exchanger, a mixing device disposed upstream of the first heat exchanger and configured to mix the solid particles and the fluid of the heat exchange medium and convey the mixed heat exchange medium to the first heat exchanger, a separating device disposed downstream of the first heat exchanger and configured to separate the solid particles from the fluid in the mixed heat exchange medium discharged by the first heat exchanger, a second heat exchanger, and a first conveying device configured to convey the solid particles separated by the separating device to the mixing device after having passed the separated solid particles through the second heat exchanger.

Abstract: A method and a system includes controlling and monitoring the gas pressure in a nuclear fuel rod during filling of the fuel rod with a gas, and subsequent sealing of the fuel rod. The system includes a control unit and a length measuring system, which control unit is communicatively connected to the length measuring system. The length measuring system is configured to monitor the length of the fuel rod, and the control unit is configured to receive measurements from the length measuring system and to determine the gas pressure inside the fuel rod on the basis of variations of the length of the fuel rod. The method includes positioning an open first end of the fuel rod inside a pressure chamber, allowing gas to enter the fuel rod; pressurizing the gas in the pressure chamber at a first pressure level; closing the fuel rod; and sealing the fuel rod.

Abstract: Fabricating structural components for a spent nuclear fuel container using the steps of forming cylindrical or rectangular channels to produce a structural component for a spent nuclear fuel container and applying a coating that includes tantalum-based material to the cylindrical or rectangular channels.

Abstract: Fuel spacers include at least one specialized bathtub on an outer perimeter band. Specialized bathtubs include an elastic resistive extension and a corresponding deflection limiter on a same outer face of the perimeter band. The elastic resistive extension provides flexible resistance to the channel, and the deflection limiter provides rigid movement limitation beyond a particular threshold between channel and spacer. The positioning, spring constant, length, number, and other properties of the specialized bathtub can be chosen based on the desired fuel assembly properties and expected transverse loads in fuel shipping and operation against which specialized bathtubs resiliently protect. The specialized bathtubs can be formed from a simplified stamp operation out of the perimeter band. Bathtubs can be placed on any position(s) on the perimeter band of example embodiment spacers used in nuclear fuel assemblies.

Abstract: A tool is receivable into an interior region of a core shroud of a Boiling Water Reactor. The tool includes an elongated frame, an elevator apparatus situated on the frame, and a manipulator apparatus situated on the elevator apparatus. The tool further includes a reciprocation apparatus that is situated on the manipulator apparatus and that has a mount that is structured to carry a device thereon. The reciprocation apparatus includes an elongated rack of an arcuate profile. The elevator apparatus is operable to move the reciprocation apparatus along the longitudinal extent of the frame. The tool further includes a foot apparatus that is situated at an end of the frame and that is receivable on a core plate to enable the frame to be pivoted about an axis of elongation of the frame with respect to the core plate.

Abstract: A nuclear reactor cooling system with passive cooling capabilities operable during a loss-of-coolant accident (LOCA) without available electric power. The system includes a reactor vessel with nuclear fuel core located in a reactor well. An in-containment water storage tank is fluidly coupled to the reactor well and holds an inventory of cooling water. During a LOCA event, the tank floods the reactor well with water. Eventually, the water heated by decay heat from the reactor vaporizes producing steam. The steam flows to an in-containment heat exchanger and condenses. The condensate is returned to the reactor well in a closed flow loop system in which flow may circulate solely via gravity from changes in phase and density of the water. In one embodiment, the heat exchanger may be an array of heat dissipater ducts mounted on the wall of the inner containment vessel surrounded by a heat sink.

Abstract: The invention relates to nuclear reactor protection systems and can be used when building nuclear reactors, in particular, the fast neutron reactors. The Technical result of the invention consists in the expansion of 5 functional capabilities of the negative reactivity passive insertion device by securing its reliable actuation in various emergency conditions. The device has two vessels located in a common enclosure one under another with a ring-shape hollow space between the vessels and the enclosure to let the heat carrier flow. Fuel elements are located in the ring-shape hollow space, as well as the tooling for the heat carrier flow formation to cool the fuel elements and heat the upper vessel. The upper vessel is located above the reactor core and is divided with an internal partition wall to the central cylindrical and ring-shape hollow spaces. The partition wall has low thermal conductivity in the transverse direction.

Abstract: There is described neutron shielding for a nuclear fusion reactor. The neutron shielding includes a cemented carbide or boride comprising a binder and an aggregate, the aggregate comprising particles of a carbide or boride compound.

Abstract: A nuclear power plant containment cooling system and a spray flow control method therefor. The system comprises a cooling system liquid tank (2) for storing cooling liquid, wherein the cooling system liquid tank (2) is provided at the top of a containment (1) and the cooling liquid is used for cooling the containment (1) through the gravity of the cooling liquid itself in the situation of an accident, and the cooling liquid is partially evaporated. The nuclear power plant containment cooling system further comprises an adjustment mechanism; wherein the adjustment mechanism is provided at a liquid outlet of the cooling system liquid tank (2), and the adjustment mechanism is used for controlling the flow at the liquid outlet according to buoyancy generated by a liquid level of the collected cooling liquid which is not evaporated.

Abstract: Provided is a fission product processing method for selectively transmuting only a long-lived radionuclide from fission products. The method for processing radioactive waste includes the step of extracting, from the radioactive waste, the isotopes without isotope separation, the isotope elements including radionuclides of fission products and having a common atomic number, and the step of irradiating the isotopes with high-energy particles generated by an accelerator to produce nuclear transmutation of a long-lived radionuclide of the radionuclides into a short-lived radionuclide with a short half-life or a stable nuclide re-utilizable as a resource.

Abstract: A nuclear reactor in one embodiment includes a cylindrical body having an internal cavity, a nuclear fuel core, and a shroud disposed in the cavity. The shroud comprises an inner shell, an outer shell, and a plurality of intermediate shells disposed between the inner and outer shells. Pluralities of annular cavities are formed between the inner and outer shells which are filled with primary coolant such as demineralized water. The coolant-filled annular cavities may be sealed at the top and bottom and provide an insulating effect to the shroud. In one embodiment, the shroud may comprise a plurality of vertically-stacked self-supported shroud segments which are coupled together.

Abstract: A control rod drive system (CRDS) for use in a nuclear reactor. In one embodiment, the system generally includes a drive rod mechanically coupled to a control rod drive mechanism (CRDM) operable to linearly raise and lower the drive rod along a vertical axis, a rod cluster control assembly (RCCA) comprising a plurality of control rods insertable into a nuclear fuel core, and a drive rod extension (DRE) releasably coupled at opposing ends to the drive rod and RCCA. The CRDM includes an electromagnet which operates to couple the CRDM to DRE. In the event of a power loss or SCRAM, the CRDM may be configured to remotely uncouple the RCCA from the DRE without releasing or dropping the drive rod which remains engaged with the CRDM and in position.