Abstract: A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference.

Abstract: A bimodal nuclear power and propulsion system for space is disclosed. Closed cycle heat engines are in operative association with each sector of a sectored reactor core. Heat exchangers employing waste heat, electric power and reactor heat are used to heat propellant to increase Isp. Non-nuclear ground testing of the system is also disclosed.

Abstract: A self-aligning seal system for use in carrying out maintenance services in a nuclear fission reactor plant is disclosed. The self-aligning seal system enables an operator to block off openings in the lower portion of a water filled reactor pressure vessel for maintenance service in an underlying dry field without draining the coolant water from the reactor pressure vessel.

Abstract: The invention relates to a process fop trapping gaseous ruthenium on polyvinyl pyridine, more particularly usable for recovering radioactive ruthenium from irradiated nuclear fuels.This process consists of contacting a gas containing ruthenium in gaseous form with an adsorbent (11b) constituted by a vinyl pyridine polymer or copolymer for fixing the ruthenium to the latter. The gas can be constituted by yapours from a concentrate of fission products containing ruthenium, which has been heated (at 31) in the presence of an oxidizing agent for volatilizing the ruthenium.

Abstract: A method and apparatus for positioning stud affecting apparatus comprising: sequentially positioning a plurality of flange cover sectors about the flange of a nuclear pressure vessel; rotating each flange cover sector until the entire flange is covered by said flange cover sectors; moving a caddy containing stud affecting tools including stud tensioners and stud drive tools into a position adjacent a point on the flange of the nuclear reactor pressure vessel; moving apparatus sector vessels containing stud affecting apparatus to a point on the flange of the nuclear pressure vessel and positioning them on a specific flange cover sector; rotating all flange cover sectors to bring another flange cover sector into registration with the caddy; sequentially moving the apparatus sectors onto each flange cover sector by rotating the flange cover sectors; and actuating the stud affecting tools to perform the appropriate function to tension or untension the studs and/or to remove and/or to insert studs into the pressur

Abstract: A boiling water reactor includes a pressure vessel containing a reactor core, chimney, steam separator assembly, and steam dryer assembly therein, with the vessel being filled with reactor water to a normal water level through the steam separator assembly. A plurality of control rod drives extend downwardly from the bottom of the pressure vessel and are operatively joined to control rods extending downwardly into the reactor core. The chimney includes a plurality of channels disposed above the core and laterally spaced apart to define guide slots for receiving the control rods as they are selectively translated upwardly out of the core by the control rod drives. The chimney has a vertical height for increasing the normal water level above the reactor core and for providing a space for the control rods withdrawn from the reactor core by the bottom-mounted control rod drives.

Abstract: In a fuel assembly, rods are disposed in meshes of a grid. Crossing points of the grid are distributed in a checker-board-like manner, partly in an upstream crossing plane and partly in a downstream crossing plane. Webs of the grid run in zigzag form between the two planes. As a result, flow resistance which is produced by the webs and/or by mixing vanes disposed thereon and by flow turbulences is shifted into different axial planes and is considerably reduced.

Abstract: A water chemistry factor which is specific to a specific portion of a primary cooling system and universal is decided to be a standard target. The concentration of an agent for mitigating corrosion damage of structural material of the primary cooling system is controlled so that the target will be in a desirable range. All sensor groups provided in the primary cooling system are separated into sensor groups in different lines, of which a specific sensor group are connected to an arithmetic unit and a data base and are for always monitoring a plant process. For example, concentration distribution agreed with measured value oxidation component in the reactor water at the measurement points is selected from the data base, and it is used to estimate the standard target.

Abstract: An automated monitoring system and method of operation is provided for a nuclear reactor having a pressure vessel containing a reactor core for boiling water to generate steam. A plurality of monitors provide signals for respective monitoring parameters for monitoring operation of the reactor, and a computer includes a data base therein containing predetermined setpoints for the monitoring parameters. The computer identifies abnormal and normal behavior of the monitoring parameters based on the data base, and determines the cause of abnormal behavior of the monitoring parameters using artificial intelligence. A warning is also provided to identify the cause of the monitoring parameter abnormal behavior. And, automatic mitigation action may also be effected.

Abstract: A detector structure adjacent an opening in a cavity structure for detecting explosives in objects within such opening including a plurality of thin nonchlorinated hydrogenous wall members forming a passageway to define such opening. A source of high energy neutrons located adjacent the passageway to direct neutrons into the passageway. A premoderator formed by nonchlorinated hydrocarbon material surrounding the source of high energy neutrons to reduce the energy in at least a portion of the neutrons. A first moderator formed by heavy water surrounding the source of neutrons and the premoderator to reduce the energy in at least a further portion of the neutrons. A second moderator formed by carbonaceous material at least partially surrounding the plurality of thin hydrogenous wall members and the first moderator to reduce the energy in at least an additional portion of the neutrons and reflect back the additional portion of neutrons into the opening.

Abstract: An object of the present invention is to provide a boiling water reactor wherein two phase flow instability in a fuel assembly occurs scarcely.A bottom flow path is formed beneath a partition plate which is supported by control rod driving mechanism housings in a reactor pressure vessel, and coolant guide tubes which open beneath the partition plate stands perpendicularly on the partition plate. An upper end portion of the coolant guide tube is restrained at outer periphery by a fixing portion of a square grid, and a coolant entrance of a fuel assembly is connected through to the coolant guide tube.Pressure loss of the coolant decreases and flow instability of the coolant in the fuel assembly occurs scarcely, lowering of a critical power ratio at a pump trip can be suppressed.

Abstract: A process for extracting uranium from uranium-containing waste residues. The process dissolves the residue in hot nitric acid, and precipitates the resulting solution with sodium carbonate/sodium bicarbonate.

Abstract: The process for recovering Ta/Nb values from highly flourinated ore materials by the process of;(a) contacting the materials with one or a mixture of HNO.sub.3 or HCl, and H.sub.3 BO.sub.3 wherein the H.sub.3 BO.sub.3 to other acid molar ratio is from about 1/10 to about 1/1,(b) maintaining the temperature between about 55 C. and about 85 C.,(c) reacting for a sufficient period to substantially solubilize the major portion of the materials and to substantially insolubilize all Ta/Nb values, and(d) separating the solids containing the Ta/Nb values from solution.

Abstract: The present invention provides a cladding having an outer circumferential substrate, a zirconium barrier layer metallurgically bonded to the inside surface of the substrate and an inner circumferential liner metallurgically bonded to the zirconium barrier. The inner circumferential liner is more ductile than conventional Zircaloy. The low ductility of the inner circumferential liner is obtained by using a zirconium alloy containing a low tin content (e.g. less than 1.2% by weight) and/or a low oxygen content (e.g. less than 1000 ppm). The inner circumferential liner is less than about 25 micrometers thick.

Abstract: A second fuel rod positioned at each corner of a channel box and second fuel rods adjacent to the former are formed to have a smaller outer diameter than that of ordinary first fuel rods, so that a pitch between the second fuel rods is narrower than a pitch between the first fuel rods. Making the outer diameter of the second fuel rods smaller than that of the first fuel rods reduces the power per unit length of the second fuel rods. The narrower pitch between the second fuel rods than the pitch between the first fuel rods provides two effects. First, a unit lattice cell becomes so small as to avoid an increase in the H/U ratio. Secondly, a new moderator region is formed between the second fuel rods and the first fuel rods adjacent thereto, the moderator region acting to intensify thermal neutron flux around those first fuel rods. These two effects enable a further reduction in the power per unit length of the second fuel rods.

Abstract: A method for generating an on-line trip signal when a measured one (p1') of a plurality of operating parameters (p1, p2, p3, . . . pN) which define a limit surface on a multidimensional reactor operating space, exceeds a limit value (*p1) on the limit surface. The method includes the steps of storing in an array having at least three dimensions, a set of discrete limit surface values *p1(r) of parameter p1 in ordered triplets, [*p1(r), p2(r) and p3(r)] under reference conditions in which parameters p2 and p3 vary discretely and parameters p4 . . . pN are deemed constant. While operating the reactor, the on-line values p1', p2', p3' of the parameters p1, p2 and p3 are measured. An interpolation is made among the selected triplets to estimate the surface limit value *p1' corresponding to the measured values of p2' and p3'. Preferably, the method includes measuring the operating parameters p4, p5 to obtain values p4' and p5'.

Abstract: The reactor coolant system (RCS) of a pressurized water reactor (PWR) is chemically decontaminated and cleaned utilizing apparatus which is comprised of components designed to operate at low pressures while still utilizing installed reactor coolant pumps and/or the residual heat removal pumps to generate the high flow rates required for the process. A high volume diverted flow of reactor coolant from the RCS is passed through letdown valves to reduce the high pressure produced by the installed pumps. Chemical decontamination and cleaning agents are mixed with the low pressure diverted flow and returned to the RCS by high head injection pumps. Contamination solubilized by the decontamination and cleaning agents is removed as the reactor coolant is recirculated through demineralizers. Filters remove particulates, and fines from the demineralizer resins.

Abstract: An object of the present invention is to provide a method and a nuclear plant capable of preventing deposition and activation of crud to a nuclear fuel rod and decreasing the radioactivity level in reactor water. Metal ions solely having a low deposition rate coefficient are made to coexist to prevent or decrease deposition of radioactive corrosion products to the nuclear fuel rod. A method and a nuclear plant capable of preventing deposition and activation of crud to the nuclear fuel rod and decreasing the radioactivity level in reactor water can be provided.

Abstract: An improved system for transferring fuel bundles and control blades between a fuel storage pool and a fuel core of a nuclear reactor. The transfer system includes a carriage which is movable horizontally along a track which is submerged in a transfer pool. The carriage has a slot for receiving interchangeable baskets of different configurations and capacities. One basket is designed to receive a fuel bundle assembly; another basket is designed to receive a control blade. These baskets have the same mounting hardware. The basic construction of the carriage and baskets is aluminum with accessories of stainless steel. Each basket can be hung on the carriage and locked in place with a bolt. Each basket has a bail for handling with existing grapples. When not in use, the baskets are stored and locked in place on a storage rack.

Abstract: A radial flow nuclear thermal rocket fuel assembly includes a substantially conical fuel element having an inlet side and an outlet side. An annular channel is disposed in the element for receiving a nuclear propellant, and a second, conical, channel is disposed in the element for discharging the propellant. The first channel is located radially outward from the second channel, and separated from the second channel by an annular fuel bed volume. This fuel bed volume can include a packed bed of loose fuel beads confined by a cold porous inlet frit and a hot porous exit frit. The loose fuel beads include ZrC coated ZrC-UC beads. In this manner, nuclear propellant enters the fuel assembly axially into the first channel at the inlet side of the element, flows axially across the fuel bed volume, and is discharged from the assembly by flowing radially outward from the second channel at the outlet side of the element.