Abstract: Installation and method to regenerate cold traps loaded with the hydride and oxide of a metal, such as sodium, in its liquid state. A forced circulation of the orginal liquid metal of a tank (11) is created at a temperature sufficient to dissolve the solid deposits. The hydrogen and tritium ions are filtered and end up at a storage tank (42) where they are fixed, whereas the oxygen ions recombine so as to form a new oxide deposit in another trap (23) cooled to a temperature enabling only the oxide to be deposited. An application is for fast neutron nuclear reactors and fusion reactors.

Abstract: Fresh fuel bundles are inserted into core locations with small coolant flow orifices, while mid-life fuel bundles are inserted into core locatiosn with large coolant flow locations. Thus, fissile fuel production is promoted at the expense of fissioning early in a bundle lifetime, increasing the effective quantity of fuel available for energy production. Moreover, fissioning is promoted at the expense of conversion later in the bundle lifetime to enhance reactivity of the remaining fissile material and to minimize the further production of fissile fuel. The net result is longer fuel lifetimes and reduced radioactive waste.

Abstract: Water rod configurations, such as for a boiling water nuclear reactor, are provided. An efficiency parameter is defined which relate to how well-used the sacrificed fuel rod positions are. Four particular water rod configurations are described, which produce high efficiency, such as having a water rod efficiency greater than about 0.6, preferably greater than about 0.7. Desired moderation is achieved by providing for sacrifice of more than four and less than nine lattice positions. The first "peanut" configuration has a cross-section with two round-cornered triangular regions, integrally connected by a constricted portion. The second configuration has a substantially rectangular cross-section. The third "clover" configuration has a four-lobed shape. The fourth "figure 8" configuration has two substantially circular cross-sectional portions. A method for analysis and design, using a new efficiency parameter, is provided.

Abstract: A cermet alloy having a structure including a hard phase and a bonding phase which is composed of at least one ferrous metal, said bonding phase containing fine hard grains of a mean grain size not greater than 2000 .ANG. dispersed therein. The structure has a composition consisting of 10 to 70 wt % of TiCN, 5 to 30 wt % of WC, 5 to 30 wt % of NbC, 1 to 10 wt % of Mo.sub.2 C, 0.5 to 5 wt% of VC, 0.05 to 3 wt % of ZrC, 5 to 25 wt % of (Ni, Co), and not smaller than 2.5 wt% of total nitrogen and incidental impurities.

Abstract: A fuel assembly for a nuclear reactor with a number of parallel fuel rods which are retained by means of spacer lattices and guide tubes (3), which guide tubes (3) are also fixed to the spacer lattices, a top tie plate (4) and a bottom tie plate between which the guide tubes (3) with associated fuel rods are fixed. The top tie plate (4) has been provided with through-holes (10) for connection to a top sleeve (7) joined to the upper end surface of the respective guide tube (3). According to the invention, there is arranged inside the top sleeve (7) a first locking element (9) for cooperation with a second locking element (13). This is arranged on a guide sleeve (11) which is insertable through a hole (10) in the top tie plate (4), which hole corresponds to the respective top sleeve (7).

Abstract: A nuclear reactor core has a first group of fuel rods containing fissionable material and no burnable absorber, and a second group of fuel rods containing fissionable material and two burnable absorber materials. The groups of fuel rods are arranged in the core for controlling power peaking and moderator temperature coefficient. The number of fuel rods in the first group are greater than the number in the second group. The two burnable absorber materials can be provided as separate coatings or a mixture. One burnable absorber material is an erbium-bearing material such as erbium oxide and the other is a boron-bearing material such as zirconium diboride. Alternatively, the erbium-bearing material can be interspersed or mixed with the fissionable material.

Abstract: A self-contained and self-supporting cell for generating ozone by corona discharge which consists basically of two open-ended straight tubes. An inner metal tube serves as a first electrode and is cooled by a fluid flowing through its core. An outer glass or ceramic tube concentrically surrounds and is shorter than the inner tube, carries a second electrode on its outer surface, and is cooled by a flow of fluid across its outer surface. The inner metal tube serves as a supporting column on which all other components are mounted and aligned. It carries a collar near each of its ends, and across each collar are clamped outer end-pieces carrying coolant seals and fittings, the inner side of the clamp assembly comprising flat aligning plates. Short cylinders of non-conductive inert material, bearing seals on each face and dry gas inlet/ozone outlet ports, fit concentrically around the inner tube and are clamped between the surfaces of clamping-plates.

Abstract: A process of separating transuranium actinide values from uranium values present in spent nuclear oxide fuels which contain rare earth and noble metal fission products. The oxide fuel is reduced with Ca metal in the presence of CaCl.sub.2 and a U-Fe alloy containing not less than about 84% by weight uranium at a temperature in the range of from about 800.degree. C. to about 850.degree. C. to produce additional uranium metal which dissolves in the U-Fe alloy raising the uranium concentration and having transuranium actinide metals and rare earth fission product metals and the noble metal fission products dissolved therein. The CaCl.sub.2 having CaO and fission products of alkali metals and the alkali earth metals and iodine dissolved therein is separated and electrolytically treated with a carbon electrode to reduce the CaO to Ca metal while converting the carbon electrode to CO and CO.sub.2. The Ca metal and CaCl.sub.2 is recycled to reduce additional oxide fuel.

Abstract: There is disclosed a grid in a nuclear fuel assembly for supporting fuel rods and thimbles, which includes a plurality of elongated straps intersecting perpendicularly with each other to define a plurality of first grid cells for supporting the fuel rods and a plurality of second grid cells for supporting the thimbles. Each grid cell has a prescribed intervening distance defined between the opposed straps. A cylindrical sleeve is arranged on at least one of the opposite ends of the strap portions defining the second grid cell and has an inner diameter generally identical to the intervening distance. There is provided an engaging unit for securing each sleeve to the strap portions. The engaging unit includes at least one first engaging portion provided on the strap portions and at least one second engaging portion provided on the sleeve. The first and second engaging portions are held in resilient engagement with each other.

Abstract: In ozone generators having segmented inner electrodes (7), the electric connection of the segments is effected by means of plane contact areas (10) applied to the ends of the segments. A tension rod (11) passing through all segments ensures cohesion and, at the same time, is used as the connecting element for supplying the ozone generator with power.

Abstract: An automated system for examining incore housing welds in a nuclear reactor from above is disclosed. The probe uses both ultrasonic and eddy current non-destructive inspection coils to examine the weld for indications, or flaws. It is inserted into the incore housing tube from above because of the high radiation exposure workers experienced using the prior method of inserting a probe into the incore housing from below. This is conveniently done when the incore flux monitors are removed during standard maintenance, and is performed from the refueling bridge.

Abstract: A conversion cell for an ozone generator comprises a first electrode that is hollow and has a right cylindrical internal surface, a second electrode that has a right cylindrical external surface of smaller radius than the internal surface of the first electrode, and an insulator sleeve having coaxial right cylindrical internal and external surfaces. The insulator sleeve is disposed coaxially within the first electrode and the second electrode is disposed coaxially within the insulator sleeve, whereby first and second gas spaces are defined between the insulator sleeve and the first and second electrodes respectively. The first and second gas spaced are sealed at opposite respective ends of the conversion cell and are in open communication with each other.

Abstract: Ceramic metal compositions are described that include a ceramic phase content of at least 60 percent by volume of said composition and a copper metal phase permeating the ceramic phase. The resulting composition is substantially fully densified, having a connected or isolated ceramic grain structure, preferably of fine B.sub.4 C grains of less than 3 micrometers. Flexure strength and fracture toughness for 80 volume percent B.sub.4 C-20 volume percent Cu cermets are 6.62 MPa.multidot.m1/2 and 725 MPa, respectively. The process of the invention includes as a key element, contacting a porous article of ceramic phase with copper metal followed by heating to above melting and subjecting said article to pressure of at least 200 MPa, such that the porous body is filled with metal and the composition is substantially fully densified.

Abstract: A consolidated tungsten alloy body consisting essentially of from about 88% to about 98% by weight of tungsten, balance, nickel and iron, produced by liquid phase sintering, containing a continuous phase of a tungsten, nickel and iron alloy and a discontinuous phase of elongated grains of tungsten having an aspect ratio of at least 4:1 relatively uniformly distributed throughout the continuous phase and wherein said body has a recrystallization temperature of from about 1000.degree. C. to about 1200.degree. C. A process for producing the consolidated bodies comprises working and annealing at controlled temperatures to achieve the desired properties. The working temperatures are from about 700.degree. C. to about 900.degree. C. and the annealing temperature is preferably 1200.degree. C.

Abstract: A high conversion nuclear reactor core has fuel assemblies made up from large numbers of axially-extending uranium-plutonium mixed oxide fuel rods. The fuel rods are densely packed so as to give a high conversion ratio of fissile substances, preferably approaching unity. The average plutonium enrichment in the assemblies is higher in their bottom, upstream halves, than in their top downstream halves. This has the effect of reducing a potentially dangerously high void coefficient in the core.

Abstract: A method of solidifying a radioactive waste of an atomic power plant, for example, begins with concentrating the liquid waste to powder or pellet form to reduce its volume. Prior to reducing its volume, an estimation is made of what the concentration will be once the liquid waste is converted into powdered or pelletized form. The powdered or pelletized waste is charged into a container, and a solidifying agent is poured over the contents to form a solidified body. The solidifying agent is prepared to have a desired coefficient of distribution that is determined in accordance with the estimated concentration of the reduced volume solidified waste so that the amount of leaching of the solidified body that is produced will be less than or equal to a predetermined value, such as the known value of leaching for a conventional cement-solidified waste that is not processed to reduce its volume before being solidified.

Abstract: A fuel assembly for a boiling water reactor includes an elongated case having an interior and inner surfaces. A base part has inlet openings discharging into the interior of the case for coolant flowing in a given flow direction and a head part has outlet openings leading out of the interior of the case for the coolant flowing in the given flow direction. Mutually parallel fuel rods containing nuclear fuel are disposed in the case between the base and head parts. The inner surfaces of the case have a profile with a rectilinear alignment as seen in the given flow direction and flow trippers extending transversely to the alignment in the form of bulges protruding inward in the given flow direction. Each of the bulges has a sloped surface facing toward the coolant with an impact surface substantially perpendicular to the given flow direction.

Abstract: The invention relates to a process for immobilizing, by an hydraulic binder, radioactive ion exchange resins or IER, which can contain borates in a quantity which can reach up to the equivalent of 1000 g H.sub.3 BO.sub.3 /kg of dry IER, wherein the IER are decanted and then placed in contact for a maximum of three hours with an eluant solution of 100 to 300 g/l in Ca(NO.sub.3).sub.2 in the proportion of 1 to 2 l/kg of decanted IER, an hydraulic binder of low hydration heat being added to the medium of pH.gtoreq.9 so that the ratio of the water of the eluant solution to the binder (by weight) is between 0.3 and 0.5 and that the incorporation rate:dry IER/final product (by weight) is between 3% and 10%.

Abstract: Substantially dense, void-free ceramic-metal composites are prepared from components characterized by chemical incompatibility and non-wetting behavior. The composites have a final chemistry similar to the starting chemistry and microstructures characterized by ceamic grains similar in size to the starting powder and the presence of metal phase. A method for producing the composites requires forming a homogeneous mixture of ceramic-metal, heating the mixture to a temperature that approximates but is below the temperature at which the metal begins to flow and pressing the mixture at such pressure that compaction and densification of the mixture occurs and an induced temperature spike occurs that exceeds the flowing temperature of the metal such that the mixture is further compacted and densified. The temperature spike and duration thereof remains below that at which significant reaction between metal and ceramic occurs. The method requires pressures of 60-250 kpsi employed at a rate of 5-250 kpsi/second.

Abstract: A method for dissipating static electrical energy from air cushion vehicles hen operating more particularly in cold, low humidity environments, which method involves fabricating the skirt assembly from a flexible sheet material of at least semiconductive character which will provide a suitable dissipating grounding pathway to discharge potential static electrical energy generated during the aforesaid operation thereof. The method includes utilizing a coated flexible fabric material having at least one of its opposite surfaces coated with an elastomeric abrasion-resistant material, and embedding a plurality of electrically conductive flexible strands at least partially within said flexible fabric material, or alternatively embedding electrically conductive particles or fibers in a generally uniformly manner throughout a forming of its elastomeric composition.