Abstract: Fuel bundles for a nuclear reactor are disclosed, and in some embodiments include a first fuel element including thorium dioxide; a second fuel element including uranium having a first fissile content; and a third fuel element including uranium having a second fissile content different from the first fissile content. Nuclear reactors using such fuel bundles are also disclosed, including pressurized heavy water nuclear reactors. The uranium having the different fissile contents can include combinations of natural uranium, depleted uranium, recycled uranium, slightly enriched uranium, and low enriched uranium.

Abstract: In a pressurized water reactor operation method, a fuel assembly including first fuel rods that operates for a preset first operation time and second fuel rods that operates for a second operation time longer than the first operation time is prepared. An operation schedule of a pressurized water reactor is created by mixing the first operation time of the first fuel rods and the second operation time of the second fuel rods. The pressurized water reactor operates by repeating the operation schedule.

Abstract: A nuclear facility has a fuel pool containing a liquid and an associated cooling circuit for a circulating cooling agent. The cooling circuit contains a cooling module with a first heat exchanger which immerges into the liquid, a second heat exchanger which is located outside the fuel pool, and connecting lines between the first exchanger and the second heat exchanger. In order to provide for reliable cooling even if a filling level drops, the cooling module contains a lifting body and floats in the liquid such that its altitude varies with the filling level of the liquid in the fuel pool.

Abstract: The method includes installing a system for inspecting the core shroud on the core shroud, driving the system horizontally around the core shroud, and using a sensor of the system to inspect the core shroud, where the system includes a trolley, an arm, a tether, and a remotely operated vehicle (ROV) for inspecting the core shroud. The ROV includes a body configured to be operatively connected to the tether, and the sensor is configured to be operatively connected to the body, and configured to provide inspection information of the core shroud. The arm is configured to be operatively connected to the trolley. The ROV is configured to be operatively connected to the arm via the tether, and the tether is configured to provide vertical position information for the ROV relative to the outer surface of the core shroud.

Abstract: A panel that uses the gamma radiation emitted by fission to produce electrical power. The panel includes layers of a metal with a relatively high atomic number (Z), that form an emitter, a high temperature electrical resistor, and an electrical conductor with a relatively low Z value, that forms a collector. The gamma radiation emitted during the fission process produces Compton and photoelectrical electrons in the layer of the Emitter located between the reactor Baffle and the fuel assemblies. The electrons that have sufficient energy to penetrate the resistor layer between the emitter layer and the collector layer will be stopped in the collector. This creates a substantial voltage difference between the emitter and the collector. This voltage difference may be used to produce significant electric power both during reactor operations and with the reactor shutdown to meaningfully augment the electricity produced by the turbine generators.

Abstract: A spent nuclear fuel storage facility. In one embodiment, the invention is directed to a storage facility including an array of storage containers. Each of the storage containers includes a body portion and a lid. The body portion has a storage cavity configured to hold a canister containing spent nuclear fuel. The lid, which may rest atop the body portion in a detachable manner, includes an inlet vent and an outlet vent. Each of the storage containers may be configured to draw air through the inlet vent and into the storage cavity where the air is warmed and passed through the outlet vent as heated air. The body portion of the storage containers may be positioned below grade and the lid of the storage containers may be positioned above grade.

Abstract: A method and a system for performing real-time, continuous, measurements of the boron concentration in the water entering a nuclear reactor coolant system. The invention utilizes knowledge of the impact that boron contained in liquid water has on the attenuation of acoustic or ultrasonic waves. This information, coupled with radiation damage resistant and high temperature operability capable transmitter and receiver equipment, provides the means to place the measurement system sensors and signal processing electronics on the reactor coolant system charging flow piping or the hot leg or cold leg of the reactor coolant loop. This will allow the reactor operator to directly monitor both the reactor coolant system boron concentration value and detect changes in the reactor coolant system boron concentration relative to a reference value as they occur.

Abstract: A neutron capture therapy system and a target for a particle beam generating device, which may improve the heat dissipation performance of the target, reduce blistering and extend the service life of the target. The neutron capture therapy system includes a neutron generating device and a beam shaping assembly. The neutron generating device includes an accelerator and a target, and a charged particle beam generated by acceleration of the accelerator interacts with the target to generate a neutron beam. The target includes an acting layer, a backing layer and a heat dissipating layer, the acting layer interacts with the charged particle beam to generate the neutron beam, the base layer supports the action layer, and the heat dissipating layer includes a tubular member composed of tubes arranged side by side.

Abstract: An in-core instrumentation system for a reactor module includes a plurality of in-core instruments connected to a containment vessel and a reactor pressure vessel at least partially located within the containment vessel. A reactor core is housed within a lower head that is removably attached to the reactor pressure vessel, and lower ends of the in-core instruments are located within the reactor core. The in-core instruments are configured such that the lower ends are concurrently removed from the reactor core as a result of removing the lower head from the reactor pressure vessel.

Abstract: A method, system, and apparatus for the thermal storage of nuclear reactor generated energy including diverting a selected portion of energy from a portion of a nuclear reactor system to an auxiliary thermal reservoir and, responsive to a shutdown event, supplying a portion of the diverted selected portion of energy to an energy conversion system of the nuclear reactor system.

Abstract: A fuel core for a nuclear reactor in one embodiment includes an upper internals unit and a lower internals unit comprising nuclear fuel assemblies. The assembled fuel core includes an upper core plate, a lower core plate, and a plurality of channel boxes extending therebetween. Each channel box comprises a plurality of outer walls and inner walls collectively defining a longitudinally-extending interior channels or cells having a transverse cross sectional area configured for holding no more than a single nuclear fuel assembly in some embodiments. A cylindrical reflector circumferentially surrounds channel boxes and is engaged at opposing ends by the upper and lower core plates. Adjacent cells within each channel box are formed on opposite sides of inner walls such that the cells are separated from each other by the inner walls alone without any water gaps therebetween which benefits neutronics for some small modular reactor designs.

Abstract: A molten salt nuclear reactor a neutron moderator core that has an inner region that defines channels of a first diameter separated by a first pitch and, an outer region that defines channels of a second diameter separated by a second pitch. The first diameter is larger than the second diameter and the first pitch is larger than the second pitch. This configuration allows for an increased capture of neutrons by fertile elements in the outer region. That is, less neutrons are lost to the outside of the core. The configuration is such that the neutron multiplication factor is larger than one in the inner portion and lower than one in the outer portion.

Abstract: A nuclear power plant having a protective superstructure including a first end region configured to cover a nuclear reactor in a containment structure, a second end region opposite the first end region and configured to cover a cooling water pump house, and a central region between the first and second end regions and configured to cover a turbine hall. The superstructure has an oval-shaped plan profile, the oval having a greater degree of curvature at the first end region than at the second end region.

Abstract: Disclosed is a radiation logging tool, comprising a tool housing; a compact generator that produces radiation; a power supply coupled to the compact generator; and control circuitry. Embodiments of the compact generator comprise a generator vacuum tube comprising a source generating charged particles, and a target onto which the charged particles are directed; and a high voltage supply comprising a high voltage multiplier ladder located laterally adjacent to the generator vacuum tube. The high voltage supply applies a high voltage between the source and the target to accelerate the charged particles to a predetermined energy level. The compact generator also includes an electrical coupling between an output of the high voltage supply and the target of the generator vacuum tube to accommodate the collocated positions of the generator vacuum tube and the high voltage power supply.

Abstract: A high-temperature containment-isolation system for transferring heat from a nuclear reactor containment to a high-pressure heat exchanger is presented. The system uses a high-temperature, low-volatility liquid coolant such as a molten salt or a liquid metal, where the coolant flow path provides liquid free surfaces a short distance from the containment penetrations for the reactor hot-leg and the cold-leg, where these liquid free surfaces have a cover gas maintained at a nearly constant pressure and thus prevent high-pressures from being transmitted into the reactor containment, and where the reactor vessel is suspended within a reactor cavity with a plurality of refractory insulator blocks disposed between an actively cooled inner cavity liner and the reactor vessel.

Abstract: A thermal-neutron reactor core includes: a solid moderator expanding to a lengthwise direction; a fuel in the moderator, parallel to the lengthwise direction of the moderator, the fuel containing a fissile material; a cooling tube parallel to the lengthwise direction of the moderator; and a plurality of kinds of burnable poison included in the fuel. The may contain a metal hydride. Furthermore, the plurality of kinds of burnable poison may include one burnable poison containing a concentration of one particular isotope of that one burnable poison.

Abstract: A target system for irradiation of molybdenum with charged particles from an accelerator to produce technetium and molybdenum radioisotopes. The target system comprises a molybdenum-100 material brazed with a brazing alloy to a backing material. The backing material preferably comprises a dispersion-strengthened copper composite. The brazing alloy comprises copper and phosphorus.

Abstract: A pressure vessel includes a pressure vessel body provided with a flow channel through which a fluid is caused to flow, having a rectangular cross-sectional shape, and formed to extend in a direction of flow of the fluid, a body flange provided at at least one end side of the pressure vessel body in a longitudinal direction and having a circular cross-sectional shape, and a connecting member connecting the pressure vessel body and the body flange to each other, and the connecting member has a body-flange connected portion connected to the body flange, having a circular cross-sectional shape, and formed in a cylindrical shape, a pressure-vessel-body connected portion connected to the pressure vessel body, being larger in outer shape than the body-flange connected portion, and formed in a cylindrical shape, and a connecting portion connecting the body-flange connected portion and the pressure-vessel-body connected portion to each other and formed in a cylindrical shape with a shape changing to be gradually smal

Abstract: A radioisotope production apparatus (RI) comprising an electron source arranged to provide an electron beam (E). The electron source comprises an electron injector (10) and an electron accelerator (20). The radioisotope production apparatus (RI) further comprises a target support structure configured to hold a target (30) and a beam splitter (40) arranged to direct the a first portion of the electron beam along a first path towards a first side of the target (30) and to direct a second portion of the electron beam along a second path towards a second side of the target (30).

Abstract: A molten salt reactor includes a nuclear reactor core for sustaining a nuclear fission reaction fueled by a molten fuel salt. A molten fuel salt control system removes a volume of the molten fuel salt from the nuclear reactor core to maintain a reactivity parameter within a range of nominal reactivity. The molten fuel salt control system includes a molten fuel salt exchange system that fluidically couples to the nuclear reactor core and exchanges a volume of the molten fuel salt with a volume of a feed material containing a mixture of a selected fertile material and a carrier salt. The molten fuel salt control system can include a volumetric displacement control system having one or more volumetric displacement bodies insertable into the nuclear reactor core. Each volumetric displacement body can remove a volume of molten fuel salt from the nuclear reactor core, such as via a spill-over system.