Abstract: A neutron detector system for discriminating fissile material from non-fissile material wherein a digital data acquisition unit collects data at high rate, and in real-time processes large volumes of data directly into information that a first responder can use to discriminate materials. The system comprises counting neutrons from the unknown source and detecting excess grouped neutrons to identify fission in the unknown source.

Abstract: A method of determining the R-factor for a bundle of nuclear fuel rods in a nuclear light water reactor of the boiling water reactor kind. The R-factor is a factor that accounts for the weighted local power influence on a fuel rod. A local R-factor (Ri(z)) is determined for each fuel rod (i) in said bundle and for each of a plurality of levels (z) in an axial direction. The individual axial heat generation profile for a certain fuel rod (i) is taken into account when determining the local R-factors (Ri(z)) for said fuel rod (i). A processor is configured for automatically determining the R-factor. A computer program product, a method of determining the critical power for a bundle of fuel rods, a nuclear energy plant, and a method of operating a nuclear energy plant are also described.

Abstract: A tool to slide a channel on a nuclear reactor fuel bundle assembly, the tool includes: a plate having a slot to receive a handle of the fuel bundle and a lower surface that engages an upper edge of the channel; at least one post extends up from the plate, and an arm is attached to a pivot on the post and includes a first end to receive a downward force and a second end adapted to engage the handle of the fuel bundle to apply an upward force to the handle and push down on the channel.

Abstract: The invention relates to a nuclear power station comprising: at least one high temperature reactor; a storage installation (14) for fuel elements (5); means (32) for transferring the fuel elements (5) between the core (4) and the storage installation (14). According to the invention, the transfer means (32) comprise a tunnel (34) for transferring the fuel elements between the reactor core (4) and the storage installation (14).

Abstract: A fast reactor having a reflector control system is provided which decreases the change in reactivity of the reactor core with time without performing control of a reflector lifting speed and that of a water flow rate. The above fast reactor has a liquid metal coolant, a reactor core immersed therein, and a neutron reflector which is provided outside the reactor core and which is moved in a vertical direction for adjusting leakage of neutrons therefrom for controlling the reactivity of the reactor core. The neutron reflector described above is gradually moved in an upward direction with the change in reactivity caused by fuel burn-up, and at least a part of a lower region of the neutron reflector is a high reflection region having a high neutron reflection ability as compared to that of the other region. The high reflection region is located from the bottom to a place between one fourth and one half of the height of the neutron reflector from the bottom end thereof.

Abstract: An apparatus for inspecting and testing a startup range neutron monitoring system for a nuclear reactor. The apparatus includes: a neutron-flux detector; a preamplifier that amplifies an electric signal output from the neutron-flux detector; a pulse measurement unit that counts times when electric signal output from the preamplifier exceeds a discrimination voltage; a discrimination-voltage setting unit that applies the discrimination voltage to the pulse measurement unit; a voltage-setting unit that applies a voltage to the neutron-flux detector; an arithmetic processing unit that calculates an output power of the reactor based upon an output signal of the pulse measurement unit; an output unit that outputs data representing the output power of the reactor, calculated by the arithmetic processing unit; and an inspecting/testing unit that sets the discrimination voltage and the voltage to be applied by the voltage-setting unit.

Abstract: The invention relates to light water reactor designs in which thorium is used as fuel and in particular to designs of jacketless fuel assemblies, which make up the cores of pressurized water reactors (PWRs) such as the VVER-1000. Nuclear reactor cores containing seed and blanket subassemblies that make up the fuel assemblies are used to burn thorium fuel together with conventional reactor fuel that includes nonproliferative enriched uranium, as well as weapons-grade and reactor-grade plutonium. In the first alternative, the reactor core is fully “nonproliferative,” since neither the reactor fuel nor the wastes generated can be used to produce nuclear weapons. In the second version of the invention, the reactor core is used to burn large amounts of weapons-grade plutonium together with thorium and provides a suitable means to destroy stockpiles of weapons-grade plutonium and convert the energy released to electric power.

Abstract: A method of inspecting, performing maintenance on, or repairing a nuclear reactor may include operatively connecting a fixing device, a first track, an arm including one or more second tracks, and an effector to form an apparatus; inserting the apparatus into the reactor; fixing the apparatus within the reactor; and operating the apparatus. At least one of the one or more second tracks may include at least three track sections. The arm may have a contracted length. The arm may have an expanded length. The expanded length may be greater than two times the contracted length. The first track may include one or more motors configured to move the arm relative to the first track. A method of operating a reactor may include shutting down; inspecting, performing maintenance on, or repairing the reactor; and starting up the reactor.

Abstract: Example embodiment damping devices may include a housing capturing a piston. The housing may be filled and/or able to be filled with a damping fluid compatible with the nuclear reactor coolant, so that a leak from the housing or coolant passing into the housing does not damage the reactor or example embodiment devices. Example embodiments may further include one or more springs that provide an elastic force opposing movement between the piston and housing. A shaft of the piston and an end of the housing may be connected to two nuclear reactor components with relative motion or vibration to be damped. Example methods may use example embodiment damping devices to reduce and/or prevent relative motion and vibration among components of a nuclear reactor.

Abstract: Sealing means comprising a seal carrier and a seal connected thereto, wherein the seal carrier is removably fixable between two areas insulated from each other, and a transfer device between two chambers, which are separated by a wall, wherein said transfer device comprises a transfer mechanism and at least one sealing means according to the invention which is positioned between the wall and the transfer mechanism.

Abstract: Control rod guide tubes for a nuclear reactor having a body with an axial length that defines a lower end portion and an upper end portion and a cavity within a substantial length of the body. Orifices are included at the upper and lower end portions of the body. A control rod chamber is located within the cavity and is configured for receiving a control rod. A plurality of ports is coupled to the cavity and is positioned at a substantial length from the upper end portion of the body. Also included are at least two flow channels within the cavity that extend a substantial portion of the axial length of the body. Each flow channel is fluidly coupled to one or more of the ports for receiving fluid flow from outside the body and an outlet proximate to the upper end portion of the body for providing the received fluid flow.

Abstract: The invention describes a product and a method for generating electrical power directly from nuclear power. More particularly, the invention describes the use of a liquid semiconductor as a means for efficiently converting nuclear energy, either nuclear fission and/or radiation energy, directly into electrical energy. Direct conversion of nuclear energy to electrical energy is achieved by placing nuclear material in close proximity to a liquid semiconductor. Nuclear energy emitted from the nuclear material, in the form of fission fragments or radiation, enters the liquid semiconductor and creates electron-hole pairs. By using an appropriate electrical circuit an electrical load is applied and electrical energy generated as a result of the creation of the electron-hole pairs.

Abstract: A generally spherical sealed reactor vessel defining a volume. A target sphere shaped electrode 11 is centered within a nonconductive reactor vessel 21. The target sphere is insulated from and fixedly centered within the nonconductive reactor vessel by an insulated stalk 22. This vessel is suspended in an insulating and cooling medium 241 composed of transformer oil. Deuterium gas 235 is released into and contained within the volume at a predetermined pressure. A source of high voltage, high frequency potential 130 is connected to the target electrode by an electrical connection 13. The other terminal of the high voltage, high frequency potential source is connected to Earth ground 153. The applied alternating electrical potential creates an alternating electrical field within the reaction chamber. This an oscillating electric field is formed within the enclosed space of nonconductive reactor vessel 21, extending between target electrode 11 and heat absorbent container 238.

Abstract: The invention relates to an assembly for exchanging heat between first and second fluids, the assembly comprising a central manifold communicating with one of the inlet and the outlet for the first fluid; an annular manifold disposed around the central manifold and communicating with the other one of the inlet and the outlet for the first fluid; a plurality of heat exchangers interposed radially interposed between the central manifold and the annular manifold; and a plurality of axial inlet manifolds communicating with the inlet for the second fluid, and a plurality of axial outlet manifolds communicating with the outlet for the second fluid, the axial inlet and outlet manifolds being interposed circumferentially between the heat exchangers. According to the invention, the assembly has an inlet chamber disposed at a first axial end of the heat exchangers and putting the inlet(s) for the second fluid into communication with at least a plurality of axial inlet manifolds.

Abstract: Methods and apparatuses are provided for the removal and transportation of thermal energy from a heat source to a distant complex for use in thermochemical cycles or other processes. In one embodiment, an apparatus includes a hybrid heat pipes/thermosyphon intermediate heat exchanger (HPTIHX) system that is divided into three distinct sections, namely: an evaporation chamber, a condensation chamber, and a working fluid transport section of liquid and vapor counter-current flows.

Abstract: The invention describes a product and a method for generating electrical power directly from nuclear power. More particularly, the invention describes the use of a liquid semiconductor as a means for efficiently converting nuclear energy, either nuclear fission and/or radiation energy, directly into electrical energy. Direct conversion of nuclear energy to electrical energy is achieved by placing nuclear material in close proximity to a liquid semiconductor. Nuclear energy emitted from the nuclear material, in the form of fission fragments or radiation, enters the liquid semiconductor and creates electron-hole pairs. By using an appropriate electrical circuit an electrical load is applied and electrical energy generated as a result of the creation of the electron-hole pairs.

Abstract: A reactor core, comprising: an outermost region; a core region surrounded by said outermost region; a plurality of fuel support members, each of which is disposed at a lower end portion of said outermost region and said core region; and a plurality of fuel assemblies loaded in said outermost region and said core region and supported by said fuel support members, wherein a plurality of fuel assemblies disposed in said core region include a plurality of first fuel assemblies, each of which is inserted into a first coolant passage which is formed in said fuel support member and has a first resistor having an opening, and a plurality of second fuel assemblies, each of which is individually inserted into each of second coolant passage which is formed in said fuel support member and has a second resistor having an opening and a larger pressure loss than that of said first resistor; and, four fuel assemblies, each of which is adjacent to each of four lateral sides of each of a plurality of first fuel assemblies,

Abstract: Disclosed herein is a method comprising heating helium in a core of a nuclear reactor; extracting heat from the helium; superheating water to steam using the heat extracted from the helium, expanding the helium in a turbine; wherein the turbine is in operative communication with an electrical generator; and generating electricity in the electrical generator.

Abstract: A feeding system for an absorber liquid containing a neutron poison, in particular for a quick shut-down of a nuclear reactor, has a storage container for the absorber liquid and is configured for high operational reliability with simple construction. In particular, a chemical decomposition of the absorber liquid or corrosion of the container wall of the storage container is to be excluded. For this purpose, the storage container is connected to a pressure container via an overflow line, wherein the pressure container is filled with a motive fluid.

Abstract: A zirconium alloy tube for forming the whole or the outer portion of a nuclear fuel pencil housing or a nuclear fuel assembly guide tube. The zirconium alloy contains 0.8-1.8 wt. % of niobium, 0.2-0.6 wt. % of tin and 0.02-0.4 wt. % of iron, and has a carbon content of 30-180 ppm, a silicon content of 10-120 ppm and an oxygen content of 600-1800 ppm. The tube may be used when recrystallized or stress relieved.