Abstract: A fast reactor 1 includes: a reactor vessel 7 accommodating therein a core 2 and a primary coolant 21; a core support 13 supporting the core 2 from below; and a bulkhead 6 disposed on the core support 13, the bulkhead 6 extending upward and surrounding the core 2 from a lateral side. Between an inner surface of the reactor vessel 7 and the bulkhead 6, there is disposed an intermediate heat exchanger 15 configured to cool the primary coolant 21, and an electromagnetic pump 14 configured to pressurize the cooled primary coolant 21. A neutron shield 8 supported by an upper supporting plate 29 from above is disposed below the electromagnetic pump 14. The upper supporting plate 29 has an opening 29a. Between an outlet 14b of the electromagnetic pump 14 and the upper supporting plate 29, there is disposed a coolant guide mechanism 17 configured to guide the pressurized primary coolant 21 from the electromagnetic pump 14 to the neutron shield through the opening 29a of the upper supporting plate 29.

Abstract: A radioactive substance is effectively suppressed by an oxide-film removal step of removing an oxide film on a metallic material surface with which a coolant containing the radioactive substance comes in contact, and a titanium-oxide deposition step of depositing a titanium oxide on the metallic material surface after the oxide film has been removed.

Abstract: A jet pump including a riser as a coolant supply tube, an inlet mixer forming a turn-around path for the coolant, a diffuser, and a jet pump beam provided with a bolt fixing device is disclosed. The bolt fixing device includes: a head bolt of a jet pump beam for pushing and supporting the inlet mixer from an upper side of the riser, the head bolt being provided with a polygonal head portion; a lock cap provided on the polygonal head portion of the head bolt; a body housing disposed on an upper surface of the jet pump beam and adapted to accommodate the lock pin; a plurality of tapered external teeth formed on an outer peripheral side surface of the lock cap; and a plurality of internal tooth-shaped grooves formed to the body housing to fix the head bolt of the jet pump beam.

Abstract: A servicing platform for a nuclear reactor refueling floor is provided. In various embodiments, the servicing platform includes a base structured to be anchored to a refueling floor of the nuclear reactor. The servicing platform additionally includes a telescoping mast having a mounting collar at a first end that is rotationally attached to the base, and a personnel work basket pivotally coupled to a second end of the mast.

Abstract: A mechanical connection between adjacent components of a system may include a first component of the system, a second component of the system, and a multiple degree-of-freedom connection between the first and second components. The multiple degree-of-freedom connection may have at least four degrees of freedom. A method for establishing a mechanical connection between adjacent components of a system may include disposing a first component of the system adjacent to a second component of the system, and connecting the first component to the second component using a multiple degree-of-freedom connection. The multiple degree-of-freedom connection may have at least four degrees of freedom.

Abstract: A soft pivot dimple nuclear fuel assembly grid that utilizes a “dog bone” shaped window cutout and radius coining of edges perpendicular to coolant flow, to reduce the susceptibility of fuel rod leaking during the reactor operation. Radius coining allows the fuel rod to smoothly transition over the radiused edge to the flat rod contact section of the dimple. The symmetric “dog bone” shape enables the dimple to pivot during rod loading resulting in improved alignment between the dimple and the fuel rod, thereby minimizing scratching. The “dog bone” shape also allows for a large contact area dimple to be softer than a typical dimple which reduces contact stresses and fretting wear during reactor operations.

Abstract: The rod contains substantially cylindrical oxide nuclear fuel pellets based on enriched uranium oxide. The H/D ratio of the height over the diameter of the pellets lies in the range 0.4 to 0.6. The initial diametral clearance between the pellets and the cladding does not exceed 200 ?m.

Abstract: A fuel assembly for a nuclear boiling water reactor is provided. The reactor comprises a plurality of such fuel assemblies and a plurality of control rods. Each control rod is insertable between the fuel assemblies. The fuel assembly has a longitudinal center axis and includes a plurality of elongated fuel rods and an elongated channel box. The channel box has inner sides, facing the fuel rods, and outer sides. Each inner and outer side has a longitudinal center line extending in parallel with the center axis and along the length of the channel box. A number of protrusions are distributed along the center line of at least two of the outer sides. The protrusions are configured to ensure a minimum distance between the outer side and an adjacent control rod and to enable the control rod to easily slide over and on top of the protrusions.

Abstract: Disclosed is a target for isotope production, that comprises a porous, nanostructured material with structure elements having in at least one dimension an average size of 700 run or less, preferably 500 nm or less and most preferably 150 nm or less, said nanostructured material comprising one Of Al2O3, Y2O3 and ZrO2.

Abstract: A system for radioisotope production uses fast-neutron-caused fission of depleted or naturally occurring uranium targets in an irradiation chamber. Fast fission can be enhanced by having neutrons encountering the target undergo scattering or reflection to increase each neutron's probability of causing fission (n, f) reactions in U-238. The U-238 can be deployed as layers sandwiched between layers of neutron-reflecting material, or as rods surrounded by neutron-reflecting material.

Abstract: The invention relates to a method of producing radionuclides. According to the method, a target medium comprising at least a target nuclide material is irradiated in an irradiation zone with neutron irradiation. Radionuclides form in the target nuclide material as a result of the irradiation, and at least some of the formed radionuclides are ejected from the target nuclide material. The ejected radionuclides are then captured and collected in a carbon-based recoil capture material which does not have an empty cage structure at crystallographic level.

Abstract: There is provided a holding device which can hold a molten corium for a predetermined period even when the molten corium is exposed to heat or undergoes any chemical reaction and which is applicable to practical use. There is provided a holding device provided below a nuclear reactor pressure vessel for holding a molten corium, wherein the holding device includes a base material in contact with a cooling medium, and a multilayer stack structure on the base material. The multilayer stack structure has a first layer having heat-resistant property, a second layer formed on the first layer and having heat-resistant property with lower heat conductivity than that of the first layer, and a third layer formed on the second layer and having corrosion-resistant property and impact-absorbing property.

Abstract: A method of fabricating a nuclear fuel comprising a fissile material, one or more hollow microballoons, a phenolic resin, and metal matrix. The fissile material, phenolic resin and the one or more hollow microballoons are combined. The combined fissile material, phenolic resin and the hollow microballoons are heated sufficiently to form at least some fissile material carbides creating a nuclear fuel particle. The resulting nuclear fuel particle comprises one or more fission product collection spaces. In a preferred embodiment, the fissile material, phenolic resin and the one or more hollow microballoons are combined by forming the fissile material into microspheres. The fissile material microspheres are then overcoated with the phenolic resin and microballoon. In another preferred embodiment, the fissile material, phenolic resin and the one or more hollow microballoons are combined by overcoating the microballoon with the fissile material, and phenolic resin.

Abstract: An improved grid for a nuclear reactor fuel assembly that has an egg-crate base grid as the primary support structure with each support cell of the base grid that supports a fuel rod having a lock-support sleeve that is rotatable within the support cell between a first and second orientation. In the first orientation the lock-support sleeve fits loosely within the support cell of the base grid and respectively, loosely receives the fuel rods that are loaded therein. The lock-support sleeves are then rotated to a second orientation that locks the fuel rods axially within the support cells.

Abstract: Disclosed is a coolant with dispersed neutron poison micro-particles, used in a supercritical water-cooled reactor (SCWR) emergency core cooling system. Since the neutron poison micro-particles are uniformly dispersed in the coolant of the emergency core cooling system for a long period time, their fluidity is not lowered even though the polarity of water is changed in a supercritical state. Therefore, the neutron poison micro-particles absorb neutrons produced from nuclear fission in a nuclear reactor core. Accordingly, the neutron poison micro-particles can be appropriately used as a means for controlling neutrons and stopping a nuclear reactor in the SCWR emergency core cooling system.

Abstract: Aspects of the invention relate to several methods to deposit and regenerate target materials in neutron generators and similar nuclear reaction devices. In situ deposition and regeneration of a target material reduces tube degradation of the nuclear reaction device and covers impurities on the surface of the target material at the target location. Further aspects of the invention include a method of designing a target to generate neutrons at a high efficiency rate and at a selected neutron energy from a neutron energy spectrum.

Abstract: A neutron generator includes an ion source disposed in a pressurized environment containing an ionizable gas. The ion source includes a substrate with a bundle of carbon nanotubes extending therefrom. The ends of the nanotubes are spaced from a grid. Ion source voltage supply circuitry supplies a positive voltage potential between the substrate and the grid of the ion source to cause ionization of the ionizable gas and emission of ions through the grid. An ion accelerator section is disposed between the ion source and a target. The ion accelerator section accelerates ions that pass through the grid towards the target such that collisions of the ions with the target cause the target to generate and emit neutrons therefrom. The ion source, accelerator section and target are housed in a sealed tube and preferably the carbon nanotubes of the bundle are highly ordered with at least 106 carbon nanotubes per cm2 that extend in a direction substantially parallel to the central axis of the tube.

Abstract: The present invention provides a system and method for reclaiming energy from the heat emanating from spent nuclear fuel contained within a canister-based dry storage system. The inventive system and method provides continuous passive cooling of the loaded canisters by utilizing the chimney-effect and reclaims the energy from the air that is heated by the canisters. The inventive system and method, in one embodiment, is particularly suited to store the canisters below-grade, thereby utilizing the natural radiation shielding properties of the sub-grade while still facilitating passive air cooling of the canisters. In another embodiment, the invention focuses on a special arrangement of the spent nuclear fuel within the canisters so that spent nuclear fuel that is hotter than that which is typically allowed to be withdrawn from the spent fuel pools can be used in a dry-storage environment, thereby increasing the amount energy that can be reclaimed.

Abstract: An axial power distribution control device includes an axial offset calculation unit 52, a parameter calculation unit 53, and an axial offset determining unit 55. The axial offset determining unit 55 predicts whether a core axial offset of the power distribution is increased or decreased after a current time, based on a major axis of an ellipse drawn by the xenon parameter and the iodine parameter calculated by the parameter calculation unit 53 and the xenon parameter and the iodine parameter at the current time. This makes it possible to predict a change of the axial offset of the power distribution of a reactor for suppressing a xenon oscillation in the reactor.

Abstract: A control rod/fuel support handling apparatus that is used in the case where a control rod and a fuel support are held, removed and lifted in a reactor and then are transported into the reactor in a periodical inspection of a BWR and in the case where the control rod and the fuel support are attached and mounted again into the reactor, the control rod/fuel support handling apparatus including: a fuel support gripper that holds the fuel support with a support gripping member; a control rod gripper that includes a vertically movable and rotatable elevating/rotating unit, holds the control rod with a control rod gripping member, disconnects and connects the control rod and a control rod drive mechanism, and allows removal and attachment of the control rod; and a control panel that controls automatically controls the control rod gripper in response to the instructions from an operation pendant.