Abstract: Plutonium is effectively and economically rendered unsuitable for employment in a device for creating a nuclear detonation. Weapons-grade plutonium is made into ceramic fuel in the form of spheroids of submillimeter size, coated with multi-layer fission-product-retentive coatings and disposed in sealed fuel chambers in graphite block fuel elements. These elements are used to form a core for a modular helium-cooled high temperature nuclear reactor which is operated to efficiently generate power by causing the hot high pressure helium coolant to drive a gas turbine directly connected to an electrical generator, which nuclear fuel core has about a 3-year lifetime. Spent nuclear fuel elements are removed at the end of 3 years and shifted to form the core for an accelerator-driven helium-cooled reactor wherein a subcritical core of spent fuel elements is safely caused to effectively continuously fission by a neutron flux created by a Linac which bombards a lead target with a beam of high energy protons.

Abstract: A fuel bundle and lower tie plate assembly for a nuclear reactor includes a plurality of fuel rods supported between an upper tie plate and a lower tie plate assembly, the lower tie plate assembly including an upper grid portion and a lower body portion, the upper grid portion having a plurality of fuel rod supporting bosses interconnected by a plurality of webs thus forming flow openings between the bosses. The body portion includes an inlet nozzle and a peripheral wall extending between the bottom nozzle and the upper grid portion to define a flow volume therein. A debris catcher, including a plurality of perforated tubes, is incorporated into the lower tie plate assembly, such that one of the tubes is in abutment with a respective lowermost end of each of the plurality of fuel rod supporting bosses.

Abstract: Provided herein is a process for producing methanol which was developed to reduce the emission of carbon dioxide which is responsible for global warming. The process involves the steps of generating steam by the use of nuclear heat of a high-temperature gas-cooled nuclear reactor, decomposing the steam into hydrogen by means of a steam electrolyzer, and synthesizing methanol from this hydrogen and carbon dioxide obtained from a carbon dioxide source. The process also involves the steps of converting carbon dioxide and hydrogen into carbon monoxide and steam by means of a reverse shift reactor, forming hydrogen and carbon monoxide of almost the same composition as the conventional one, and reacting said hydrogen and carbon monoxide into methanol by means of a methanol synthesis column. The process permits the use of an existing methanol production facility.

Abstract: A fuel assembly for a light-water nuclear reactor includes a plurality of vertical fuel rods (10) which are arranged, in spaced relationship in the lateral direction, between a bottom tie plate (11) and a top tie plate (12). The bottom tie plate and the top tie plate are provided with through-holes (35) for inlet and outlet of coolant for the fuel rods. Below the bottom tie plate, in the flow path of the water, a debris catcher (36) is arranged which includes helical springs (40) that are arranged in a frame having at least two ends (37, 38) in the form of substantially parallel plates, the flat sides of which are interconnected via pins (39). The pins are arranged in spaced relationship in at least two rows between the ends in such a way that the springs, in spaced relationship or adjacent to each other, can be fixed between the rows of pins in one or more layers.

Abstract: A fuel assembly for a light-water nuclear reactor includes a plurality of vertical fuel rods (12) which are arranged, in spaced relationship in the lateral direction, between a bottom tie plate (13) and a top tie plate (14). The bottom tie plate and the top tie plate are provided with through-holes (17a) for inlet and outlet of coolant for the fuel rods. Below the bottom tie plate, in the flow path of the water, a debris catcher (18) is arranged. The debris catcher includes at least one helical spring (19) which is fixed in a holder permeable to the coolant and defining at least one slot which is formed as a plane spiral (30) or several concentric annular slots (23, 27) in which slot/slots the helical spring/helical springs is/are arranged.

Abstract: The invention provides a heterogeneously loaded type of fast reactor core in which a reduced number of target fuel assemblies containing minor actinide nuclides are heterogeneously dispersed and loaded. A wrapper tube for each of the target fuel assemblies is of the same shape and size as a hexagonal wrapper tube for an ordinary core fuel assembly. Each of target fuel rods within the wrapper tube contains 20 to 50% of minor actinide nuclides, and has a diameter more reduced than that of an ordinary core fuel rod. The number of the ordinary core fuel rods loaded in the ordinary core fuel assembly is 271 while the number of the target fuel rods loaded in the target fuel assembly is 331 or 397. Thirty to 50 such target fuel assemblies are heterogeneously dispersed and loaded in the fast reactor core.

Abstract: This neutron detector device includes a containment inside of which there is mounted a detector and which contains a neutral gas. The detector is formed by a fission type chamber comprising a cylindrical-shaped external electrode, coated with a lining of uranium in metal form, enriched as isotope 235, and a cylindrical-shaped internal electrode coaxial to the external electrode. The containment is of annular shape and arranges a cylindrical center space open at both ends to house a moderator to slow down the fast neutrons with great efficiency with respect to detection. The present invention provides an advantage of making it easy to replace the moderator. It is favorable to use cylindrical electrodes of large diameter thus increasing the sensitivity.

Abstract: Fuel pellets for use as targets in a device employing thermonuclear fusion by inertial confinement (Laser fusion) are manufactured from high polymer hydrocarbons in which bound hydrogen has been replaced with tritium. The required polymer is prepared by polymerizing monomer(s) which contain carbon and tritium. The hollow pellets are filled with thermonuclear fuel, e.g., a mixture of deuterium-tritium. To improve the sphericity of the pellets and the uniformity of their wall thickness, manufacture of the pellets is contemplated in the near-zero gravity of space.

Abstract: A process for simultaneously producing PET-usable quantities of [.sup.13 N]NH.sub.3 and [.sup.18 F]F.sup.- for radiotracer synthesis is disclosed. The process includes producing [.sup.13 N]NO.sub.2.sup.- /NO.sub.3.sup.- and [.sup.18 F]F.sup.- simultaneously by exposing a low-enriched (20%-30%) [.sup.18 O]H.sub.2 O target to proton irradiation, sequentially isolating the [.sup.13 N]NO.sub.2.sup.- /NO.sub.3.sup.- and [.sup.18 F]F.sup.- from the [.sup.18 O]H.sub.2 O target, and reducing the [.sup.13 N]NO.sub.2.sup.- /NO.sub.3.sup.- to [.sup.13 N]NH.sub.3. The [.sup.13 N]NH.sub.3 and [.sup.18 F]F.sup.- products are then conveyed to a laboratory for radiotracer applications. The process employs an anion exchange resin for isolation of the isotopes from the [.sup.18 O]H.sub.2 O, and sequential elution of [.sup.13 N]NO.sub.2.sup.- /NO.sub.3.sup.- and [ .sup.18 F]F.sup.- fractions. Also the apparatus is disclosed for simultaneously producing PET-usable quantities of [.sup.13 N]NH.sub.3 and [.sup.18 F]F.sup.

Abstract: Provided is a method for making high-temperature high-performance fuel particles wherein fertile or fissile metal carbides are dispersed in spherical graphite skeletons. That is, a fissile metal salt, such as uranyl nitrate, is added to an aqua-mesophase in alkaline solution, to form a fuel solution. The fuel solution is added to an oil bath to form an emulsion of aqueous pitch-derrived spheres in oil. The emulsion is heated and stirred to drive water from the spheres to dry them into solid spheres which contain the above metal salts. The solid spheres are then heated to between 700-1100 C. to carbonize them and convert the metal salts to metal oxides and then the spheres are further heated to between 2000.degree.-3000.degree. C., to carburize the metal oxides to metal carbides and graphitize the carbon. The resulting fuel spheres are then preferably coated by deposition thereon, of a carbon or carbide coating to contain the future reaction products thereof.

Abstract: A unitary one-piece lower tie plate grid has a lower portion and an upper portion for supporting the fuel rods. The lower tie plate grid includes cylindrical boss portions arranged in square matrices for receiving the lower end plugs of the fuel rods. Web portions interconnect the boss portions along the sides of the matrices. The lower grid portion includes a plurality of openings which open into the flow spaces defined by the convex portions of the bosses and the webs within each square matrix of the upper portion of the tie plate. Coolant flows through the lower flow openings into the flow spaces for further flow upwardly about the fuel rods. The openings are defined by the convex lower portions of the bosses and webs, as well as projections which extend laterally inwardly from the convex surfaces of the lower boss portions toward a central region in the middle of the square matrix.

Abstract: Fast neutrons from a moving source are thermalized by travel through water to a soil embedded body of nitrogen-rich material causing emission of gamma rays therefrom. Emitted gamma rays are detected at a location adjacent the neutron source for measurement of radiation energy from which location of nitrogen-rich materials in the soil is mapped, based on a predetermined signature energy level of the measured radiation.

Abstract: A hydrogenous moderated thermionic nuclear reactor operating in the thermal neutron energy region. Thermionic fuel elements are formed from multiple concentric cylinders. The center cylinder is a combination heat pipe and thermionic converter collector. The second cylinder is the converter emitter. The third cylinder is the nuclear fuel. The outer cylinder is the physical barrier between the fuel element and moderator. Between the outer radius of the fuel and outer cylinder is a gap containing multi-foil insulation. The insulation acts as a thermal barrier between the fuel and the outer cylinder and accommodates fuel expansion. This also causes heat flow to be radially inward from the fuel to the center converter/heat pipe.

Abstract: For use in the manufacture of gas tags such as employed in a nuclear reactor gas tagging failure detection system, a method for designing gas tagging compositions utilizes an analytical approach wherein the final composition of a first canister of tag gas as measured by a mass spectrometer is designated as node #1. Lattice locations of tag nodes in multi-dimensional space are then used in calculating the compositions of a node #2 and each subsequent node so as to maximize the distance of each node from any combination of tag components which might be indistinguishable from another tag composition in a reactor fuel assembly. Alternatively, the measured compositions of tag gas numbers 1 and 2 may be used to fix the locations of nodes 1 and 2, with the locations of nodes 3-N then calculated for optimum tag gas composition.

Abstract: The device includes a removable supporting end piece (26) which comes to rest on the top end part of a support assembly (21) fixed to the end of a port adapter of the head of the vessel of a nuclear reactor, and a pressure plate (28) including an odd number of lifting screws (31), so as to move the instrumentation column (22) upward and to clamp it against a support surface (24). A tightening assembly (35) for the lifting screws includes a tightening spindle (42a) having an end part (45) shaped to receive a tool (40) for rotating the spindle, and in turn rotates tightening spindles mounted so as to idle in the mounting plate (38) of the tightening assembly (35). The tightening spindles comprise shaped end parts (46a) coming into engagement with drive parts (31b) of the lifting screws (31) of the pressure plate (28), so as to tighten all the lifting screws simultaneously.

Abstract: A debris catching arrangement is disclosed for incorporation within the flow plenum up stream or below the rod supporting grid of the lower tie plate assembly. The device is preferably placed within the lower tie plate flow plenum between the fuel bundle inlet orifice and the rod supporting grid structure supporting the fuel rods; alternate placement can include any inlet channel upstream of the fuel rods including the fuel support casting. The disclosed debris catching designs include successive side-by-side coil springs placed in layers across the tie plate plenum. Preferably, the respective tie plates are placed in alternating directions with a first layer of springs oriented at 90.degree. to an alternate and underlying layer of springs. Multiple layers of such springs are used with four layers being preferred. At their respective crossing points, the springs of adjacent layers are joined--as by welding--with the result that the filter is a solid unitary mass.

Abstract: During operation of a light water moderated and cooled nuclear reactor, rods varying the neutron energy spectrum are introduced into the core of the reactor in the course of a first phase of the cycle in order to reduce the ratio of the volume of moderator to the volume of fissile material in the core. In a second phase of the cycle the spectrum displacement rods are extracted. The rods are of a mixture of thorium energy neutrons. The rods may be of fertile material and--depleted uranium. The invention is of particular interest in PWRs.

Abstract: An integral reusable locking arrangement between the guide tube and upper end fitting of a reconstitutable fuel assembly that eliminates all loose fastener components at the reactor site. A retainer sleeve is fabricated as an addition to or part of the upper end sleeve of the guide tube assembly. The retainer sleeve is formed from a cylindrical tube that has a plurality of flexible tabs spaced around the circumference of the tube at the lower end and substantially at the mid section of the tube. The lower tabs serve to center the guide tube in a hole in the upper end fitting or top nozzle. The mid section tabs extend beyond the shoulder of a counterbore in the hole in the upper end fitting or top nozzle and serve to retain the guide tube and upper end fitting in the installed position. A sleeve or collet may be inserted into the counterbore to force the tabs inward and unlock the retainer and guide tube from the upper end fitting.

Abstract: A nuclear fuel assembly lower end fitting. Two plates each having a network of diagonal and lateral ribs in conjunction with hubs for the guide thimble hole pattern are provided. The pitch between ribs corresponds to one-half of the fuel rod pitch. This allows for the fuel rods to be supported by every other rib. One plate is rotated horizontally ninety degrees relative to the other plate so that the lateral ribs of the plates are at right angles. A screen formed from approximately 0.03 inch diameter wire with 0.100 inch pitch is provided with guide tube bosses. The plates and screen are rigidly attached to each other to form a debris filtering lower end fitting.

Abstract: An integral, reusable locking arrangement between the guide tube assembly and upper end fitting of a reconstitutable fuel assembly that eliminates all loose fastener components at the reactor site. A retainer sleeve is fabricated to cooperate with the upper end sleeve of the guide tube assembly. Slots adjacent to the upper end of the sleeve receive rigid tabs on the upper end sleeve to hold the retainer sleeve and upper end sleeve together. The retainer sleeve is formed from a cylindrical tube that has a plurality of flexible curved tabs spaced around the circumference of the tube substantially at the mid section of the tube. Optional lower tabs serve to center the guide tube assembly in the upper end fitting and provide a more rigid connection. The mid section tabs are received against the shoulders of slots provided along the walls of the hole in the upper end fitting and serve to retain the guide tube assembly and upper end fitting in the installed position.