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.

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: Among the various aspects of the present disclosure is the provision of systems for producing radioisotopes and improving the specific activity of radioisotopes (e.g., Cu-64 chloride). As described herein, the system includes a target material area or target material shape that matches the proton beam strike area or proton beam strike shape, resulting in optimal thickness with less target material required.

Abstract: Passive safety systems cool reactors using surrounding ground as a heat sink. A coolant flow channel may loop around the reactor and then pass outside, potentially through a containment building, into surrounding ground. No active components need be used in example embodiment safety systems, which may be driven entirely by gravity-based natural circulation. The coolant loop may be air-tight and seismically-hardened and filled with any coolant such as water, air, nitrogen, a noble gas, a refrigerant, etc. The ground may include a soil of grey limestone, soft grey fine sandy clay, grey slightly silty sandy gravel, etc. or any other fill with desired heat-transfer characteristics. Coolant fins and/or jackets with secondary coolants may be used on the coolant loop. The coolant loop may be buried at any constant or variable depth, and the reactor and containment may also be buried in the ground.

Abstract: Provided is an apparatus for generating electricity, mechanical energy, and/or process and district heat using a gas propellant chamber fueled with fissile material and enclosed in a sealed containment vessel which also contains an operating gas. The system allows for the operating gas to be compressed as it enters the nuclear fuel chamber where it is heated. As the operating gas exits the nuclear fuel chamber, the kinetic energy of the gas is converted to rotational energy by a variety of methods. The rotational energy is further converted to electricity, mechanical energy, and/or process and district heat. The operating gas circulates in the containment vessel and is cooled prior to re-entering the gas propellant chamber. The apparatus thereby provides a simpler and safer design that is both scalable and adaptable. The apparatus is easily and safely transportable and can be designed to be highly nuclear-proliferation-resistant.

Abstract: Nuclear reactor fuel assembly comprising fuel elements installed in a frame having guide channels and spacer grids; a bottom nozzle; and a removable head. The head comprising collet tubes, an upper shell, a support element in the form of a tube, and springs. The collet tubes comprise two coaxially arranged tubes that are movable relative to each other and that each have stops on their side surfaces. The stops interact with each other to select the length of the collet tubes. The upper shell has a tube with a rigidly fixed plate interacting with the springs. The plate has plural holes having a shape corresponding to a shape of a respective boss of the support element. The clearance in plan view between a respective hole and a respective boss being at least the mounting clearance between the tube of the support element and the tube of the upper shell.

Abstract: The reactor core includes at least one module, a solid neutron moderator, and a liquid neutron moderators. Each module contains a casing, at least one heat pipe, one fuel element and thermal insulation. The heat pipe comprises a casing, a wick, and a coolant. The fuel element is made of nuclear fuel, arranged along an evaporation area of the heat pipe, around the heat pipe casing, in thermal contact with the heat pipe casing, and enclosed in a can. Liquid metals are used as the coolant of the heat pipe. Thermal insulation is arranged between the can and the module casing. At least one hole is made in the solid neutron moderator. Each module is arranged within a respective hole of the solid neutron moderator. The space between the module casing and the solid neutron moderator is filled with a liquid neutron moderator.

Abstract: A nuclear reactor core includes at least one module, a solid neutron moderator, and liquid neutron moderator. Each module comprises a housing, at least one heat pipe, at least one fuel element, casing, and thermal insulation. The heat pipe comprises a housing, wick, and evaporating coolant. The fuel element includes a shell and nuclear fuel. An evaporation zone of the heat pipe and the fuel elements are enclosed by the casing. The casing is filled with a liquid coolant. Liquid metal, for example, lithium, calcium, lead, and/or silver, is used as the heat pipe coolant and the liquid coolant. The thermal insulation is arranged in a space between the casing and module housing. The solid neutron moderator has at least one hole, wherein at least one module is located. A space between the solid neutron moderator and module is filled with the liquid neutron moderator.

Abstract: A facility for producing radioisotopes. The facility includes at least one target holder. The target holder is configured to receive a target that includes a compound to be irradiated with an accelerated particle beam. The facility includes a cyclotron for producing the accelerated particle beam. The cyclotron includes at least one accelerating cavity within which the beam is subjected to a radiofrequency electric field in order to be accelerated and to a magnetic field enabling it to travel through the cavity several times, describing orbits about an axis of the cyclotron. The magnetic field is produced by at least one coil. The at least one target holder is inside the at least one coil as observed along the axis of the cyclotron. The at least one coil does not have symmetry of revolution about the axis.

Abstract: A device for removing shielding balls from calandria of a heavy water reactor is provided. The device includes a head for moving the shielding balls positioned inside of an end shield of the calandria to an outside of the end shield; and a mover for moving the head to the end shield of the calandria. The head includes a head body, an opening former installed on the head body and configured to form an opening in the end shield, and a gate installed on the head body and configured to control an amount of the shielding balls discharged to the outside through the opening.

Abstract: An analysis device for detecting fission products by measurement of a radioactivity includes a first line for carrying a liquid sample, a first detector connected to the first line and designed for measuring the radioactivity of fission products contained in the liquid sample, a second line for carrying a gas sample and a second detector connected to the second line and designed for measuring the radioactivity of fission products contained in the gas sample. The analysis device includes a separation device for separating gas from the first line carrying the liquid sample, which line has an outlet opening into the second line for gas separated from the liquid sample. The outlet opening fluidly connected to the second lines in such a manner that the gas separated from the liquid sample is suppliable as a gas sample to the second detector for measuring the radioactivity of fission products contained therein.

Abstract: Provided herein is a neutron moderation module and a thermal-neutron nuclear micro-reactor.

Abstract: A target irradiation system including an irradiated target removal system having a body defining a central bore, an elevator received within the central bore, and a docking surface for placing the irradiated target removal system in fluid communication with a vessel penetration of a reactor. A target canister slidably receives the radioisotope target therein, and the elevator is configured to receive the target canister. The elevator is lowered into the reactor when irradiating the radioisotope target, and the irradiated target removal system forms a portion of a pressure boundary of the reactor during target irradiation.

Abstract: Fuel assemblies of nuclear reactors that increase the efficiency of a filter for retention of foreign objects in the coolant while maintaining the hydraulic resistance of the fuel assembly at the same level. The nuclear reactor's fuel assembly comprises a head, a fuel elements bundle, spacer grids and the filter for retention of the foreign objects. The filter is installed in the bottom nozzle of a fuel assembly and is made in the form of rectilinear plates' groups, located in the cross section of the bottom nozzle.

Abstract: A neutron activator includes a neutron source and a reflector-moderator. The neutron source has a housing extending along a longitudinal axis (B). A metallic target as part of the neutron source is provided to produce neutrons through the interaction with a proton beam, the metallic target having a plurality of plates arranged transversally with respect to the longitudinal axis (B). The neutron source also includes a cooling circuit to cool the metallic target. The reflector-moderator has an activation area configured to accommodate the neutron source and the material to be activated.

Abstract: Nuclear propulsion fission reactor structure has an active core region including fuel element structures, a reflector with rotatable neutron absorber structures (such as drum absorbers), and a core former conformal mating the outer surface of the fuel element structures to the reflector. Fuel element structures are arranged abutting nearest neighbor fuel element structures in a tri-pitch design. Cladding bodies defining coolant channels are inserted into and joined to lower and upper core plates to from a continuous structure that is a first portion of the containment structure. The body of the fuel element has a structure with a shape corresponding to a mathematically-based periodic solid, such as a triply periodic minimal surface (TPMS) in a gyroid structure. The nuclear propulsion fission reactor structure can be incorporated into a nuclear thermal propulsion engine for propulsion applications, such as space propulsion.

Abstract: A method of fragmentation of elements of a nuclear reactor includes placement of elements inside a cask and subsequent cutting, the cask being perforated. Each element is lowered into the cask by a full internal height of the cask using a gripper having clamping jaws. The element is intercepted at an upper edge of the cask, lifted, and positioned using video surveillance and artificial lighting so that a hydraulic cutter is directly under the clamping jaws. The element is cut at a point corresponding to a level of the upper edge of the cask, separating from the element a fragment equal to the internal height of the cask. Then the upper part of the element remaining after cutting is lowered inside the cask by the full internal height of the cask and the cutting of the element into fragments is repeated until the element is fully cut to fragments.

Abstract: A method of producing actinium by using liquefied radium includes producing Ac-225 using Ra-226 of a liquefied state, moving the produced Ac-225 in a liquefied state after Ac-225 is produced, and separating Ac-225 and reusing Ra-226. As a result, a nuclear reaction process of Ac-225 may be performed and loss of Ra-226 may be minimized. Further, such a method may improve safety by including a radon collection unit which is capable of discharging and isolating radon produced from Ra-226, thereby preventing radiation exposure due to radon.

Abstract: Methods for rapid isolation of radionuclides (e.g., 68Ga) produced using a cyclotron and methods for recycling of the parent isotope (e.g., 68Zn) are disclosed. In one version of the method, a solution including a radionuclide (e.g., 68Ga) is created from a target including cations (e.g., 68Zn). The solution including the radionuclide is passed through a first column including a sorbent comprising a hydroxamate resin to adsorb the radionuclide on the sorbent, and the radionuclide is eluted off the sorbent. The cations (e.g., 68Zn) are recovered from a recovery solution that has passed through the first column by passing the recovery solution through a second column including a second sorbent comprising a cation exchange resin.