Abstract: A gun having a slightly curved bore for discharging a frangible generally spherical projectile creating an improvement in trajectory of the projectile. The slightly curved bore applies a spin onto the spherical projectile without causing the projectile to rupture.

Abstract: A seal assembly for sealing a space between an annular flange on a nuclear reactor vessel and a surrounding ledge of a refueling canal to provide a temporary water barrier during refueling operations. The seal assembly includes an annular closure plate having an outer portion secured to the surrounding ledge and an inner portion supporting a first sealing surface. A second sealing surface opposing the first sealing surface is formed on or secured to the annular flange of the reactor vessel. An annular space between the first and second sealing surfaces provides a ventilation path from the reactor cavity during normal plant operation. The annular space is sealed by an inflatable seal during refueling operations to provide a water barrier between the refueling canal and the reactor vessel. The inflatable seal is secured to and supported by an annular support structure that straddles the annular space.

Abstract: Permanent safety device for preventing the accidental firing of a weapon whose firing mechanism comprises a trigger, a hammer, a loaded spring which exerts a force along a given line of action on said hammer, retention means which hold the hammer in opposition to said spring and, inserted between the trigger and said hammer retention means, a lever which disengages these latter at the time of firing as a result of the trigger being pulled. The abovementioned firing mechanism includes a stop piece which can be moved between an interference position in which it interferes with the action of said spring on the hammer and a position in which it does not interfere with said action, and vice versa, and a mechanism, connected to the trigger, which is designed to move said stop piece out of said interference position only if the trigger is pulled.

Abstract: A new design concept of boiling water reactor fuel assembly water channels is disclosed. The new design utilizes parallel flow paths guided inside an outer conduit without reversing flow. The different flow paths discharge water into the coolant stream, which is the objective of this invention, and resulting in improvements in thermal efficiency and stability of the fuel assembly. The thus diverted flow paths discharge water evenly into the coolant stream, which is the objective of this invention, with the result of improving the thermal efficiency and stability of the fuel assembly.

Abstract: A reactor-internal equipment handling apparatus which is capable of reducing work required to load/unload control rods, fuel supports, and control rod guide tubes, includes a control rod holding unit (16) for releasably holding a control rod (7) which is loaded into a reactor vessel (1), and fuel support/control rod guide tube holding unit (17) for releasably holding a fuel support (8) which supports a bottom end of a fuel assembly (10) and a control rod guide tube (6) on which the fuel support (8) is placed. The control rod holding unit (16) and the fuel support/control rod guide tube holding unit (17) are fitted to a main body frame (26) which can be hoisted down inside the reactor vessel (1).

Abstract: The invention provides a device for reducing the danger of harm caused by the accidental discharge of a bullet from a firearm, including an attachment for engaging the muzzle end of a firearm barrel; a substantially tubular body having a cavity and coaxially attachable at one of its ends to the barrel via the attachment; an impact disc having upper and lower surfaces, slidably disposed in the cavity of the tubular body; an energy-absorbing and storing element interposed in the tubular body between the upper surface of the impact disc and an abutting member, the absorbing and storing element acting on the impact disc to maintain contact with the abutting member inside the body, and a body made of a material at least as hard as the material of the bullets to be used with the fiream, the body being affixed at the lower surface of the impact disc, for substantially preventing a bullet from piercing through the impact disc; whereby, upon the discharge of a bullet, the bullet impacts the body, transferring some of

Abstract: The invention relates to a sensor for a measuring an electrochemical corrosion potential comprising a sensor tip, a conductor electrically connected to the sensor tip, an insulating member which surrounds the conductor, a connecting member which surrounds the conductor; and a sleeve which fits over the sensor tip, the insulating member, and the connecting member, the sleeve having inner threads which engage with corresponding outer threads on at least one of the sensor tip and the connecting member.

Abstract: A control rod drive mechanism includes a first tubular member having a first threaded portion and a first generally cylindrical outer surface, the first tubular member including a first plurality of slots spaced circumferentially on the first outer surface and extending in a direction parallel to the axis of the first tubular member, and a second tubular member having a second threaded portion and a second generally cylindrical outer surface, the second tubular member including a second plurality of slots spaced circumferentially on the second outer surface and extending in a direction parallel to the axis of the second tubular member. The first and second tubular members are axial aligned with the first and second threaded portions being engaged with each other to form a threaded joint therebetween. A locking sleeve overlaps at least a portion of the first outer surface of the first tubular member and at least a portion of the second outer surface of the second tubular member.

Abstract: An incore piping section maintenance system of a reactor comprises a maintenance system main body which is fixed to a maintenance target portion in a reactor pressure vessel or in the vicinity thereof to which a preventive-maintenance operation is executed, a support mechanism provided for the maintenance system main body so as to be movable in a reciprocal manner towards the maintenance target portion, a laser generator for generating a laser beam, a laser de-sensitization treatment apparatus which is rotatably supported around an axis of the support mechanism and which includes a laser irradiation section for irradiating the laser beam to the maintenance target portion, and an optical transmission element which guides the laser beam outputted from the laser generator to the laser de-sensitization treatment mechanism.

Abstract: Detectors are used to monitor the status of spent nuclear fuel storage containers non-invasively while they remain in storage casks. The detectors measure neutron flux and &ggr;-ray flux and may also measure temperature variations of the spent nuclear fuel. The measurements can be accomplished actively or passively, with minimal exposure of individuals to radiation fields or other hazardous conditions. Preferred neutron and &ggr;-ray detectors have a semiconductor active region that is resistant to neutron damage. Incipient structural failures may also be detected using measurements based on electrical continuity, with data being transmitted to an external pickup coil.

Abstract: An improved fuel element for use in a nuclear reactor comprised of a central core of nuclear material, which is surrounded by a composite cladding. The cladding has an outer metallic tubular portion comprised of well-known cladding alloys used for such purposes. Metallurgically bonded to the outer metallic tubular portion is a commercially pure zirconium microalloyed with a controlled quantity of iron. The zirconium microalloyed with iron produced an inner metallic barrier having a beneficial balance between stress corrosion crack resistance and corrosion resistance while retaining other beneficial properties of pure zirconium, such as ductility.

Abstract: A method of handling an internal structure of a nuclear reactor utilizing a receptacle such as a container or a cask. A cask, for example, is lifted from outside of a nuclear reactor building through an opening which is opened at a portion of the nuclear reactor positioned just above a nuclear reactor pressure vessel. While maintaining the cask under a lifted condition, a shroud, which is an internal structure of the nuclear reactor, is transferred and inserted to the cask from the nuclear reactor vessel. Thereafter, an inlet port of the cask is closed so that the cask substantially surrounds the shroud and substantially prevents radiation from the shroud passing therethrough. The cask together with the shroud is lifted outside of the nuclear reactor building through the opening. The internal structure of the nuclear reactor can be speedily carried from the nuclear reactor building with reduced exposure of operators to radioactivity from the radioactive internal structure.

Abstract: An anti-radiation device for a container adapted to receive radioactive materials, the device including a plurality of individual and adjacent tubular metal housings, each of the housings having an internal wall shaped to enable flush contact with an outer wall of the container, side walls shaped to enable flush contact with an adjacent tubular housing and an external wall. Each metal housing of the device is fastened to the outer wall of the container.

Abstract: A seismically isolated liquid metal reactor power block is described. In one embodiment, the liquid metal reactor power block is a substantially rectangular nuclear plant with two nuclear islands and a common liquid metal service facility commonly supported on a seismic isolation platform near grade level. The seismic isolation platform supports the nuclear islands in a mirror-symmetric arrangement on opposite sides of a shared liquid metal service facility. A containment pressure suppression system connects the primary pressure relief volumes of the containment structures of each nuclear island to that of the other and also to a common pressure relief volume in the liquid metal service facility, thereby reducing the pressure load on each individual containment structure.

Abstract: The reactor start-up monitoring apparatus is provided with an SRNM detector, an analog amplifier, an N/D converter, a pulse measurement system, a Campbell measurement system and reactor power monitoring means. The pulse measurement system is provided with pulse counting means for counting the pulse number of output pulses of the detector from the first digital data from the converter, and pulse measurement evaluating means for converting the measurement value to reactor power and evaluating the reactor power. The Campbell measurement system is provided with sum operating means for adding a plurality of sampling values forming the first digital data from the converter and acquiring the second digital data having accuracy of bits more than those of the first digital data, power operating means for obtaining mean square values based on the second digital data and Campbell measurement evaluating means for converting the mean square values to reactor power and evaluating the reactor power.

Abstract: The invention relates to a sensor for a measuring an electrochemical corrosion potential comprising a sensor tip, a conductor electrically connected to the sensor tip, an insulating member which surrounds the conductor, a connecting member which surrounds the conductor; and a sleeve which fits over the sensor tip, the insulating member, and the connecting member, the sleeve having inner threads which engage with corresponding outer threads on at least one of the sensor tip and the connecting member.

Abstract: A primary containment vessel comprises an outer peripheral concrete wall surrounding a reactor pressure vessel, a pipe arrangement of a reactor water recirculation system and other reactor systems and equipments, a mat concrete wall positioned below the outer peripheral concrete wall, a reactor pressure vessel (RPV) pedestal supporting the reactor pressure vessel, a horizontal wall joining the outer peripheral concrete wall and the RPV pedestal, upper and lower dry wells, a wet well having a suppression pool in which water is stored, an isolation member for air-tightly isolating the upper dry well and the lower dry well at a position supporting the reactor pressure vessel, vent pipe arrangement used for the upper dry well communicating the upper dry well with the suppression pool, a high pressure gas inflow member used for the upper dry well located in a communicating hole formed to the RPV pedestal so as to communicate the vent pipe used for the upper dry well with a gas phase section of the wet well, anothe

Abstract: A power oscillation monitoring system and method for indicating instability of a nuclear reactor. The monitoring system facilitates monitoring reactor instability and maintaining a nuclear reactor in the stable state. In one embodiment, the monitoring system is implemented in a computer workstation having memory and a processor. The workstation is electrically coupled to neutron detectors, and a period based algorithm and a confirmation density algorithm are stored in the workstation memory. The processor contains a Period Based Algorithm (PBA) and a Confirmation Density Algorithm (CDA). Under the control of the system the PBA algorithm evaluates the periodicity of the neutron detector output signals to identify the presence of density waves in the reactor. The CDA utilizes the PBA output signals to identify confirmation density, which is the fraction of active neutron detectors in the core that reach a target successive oscillation period confirmation count.

Abstract: A cyclotron and a target system containing rotating foils composed of target nuclide to undergo nuclear reactions with the beam from the cyclotron are integrated into one unit such that the foils intercept the orbit of the accelerating beam in the cyclotron. Accordingly, the beam strikes the foils to undergo nuclear reaction therein and to correspondingly lose a small portion of its energy in its passage through the foils. The transmitted beam from the foils gains the lost energy to the foils as it circulates in the accelerating zone of the cyclotron and subsequently re-strikes the foils. This process of continuing strikes results in accumulation of the beam current striking the foils and proportionally increases the rate of nuclear reactions. Since the beam after striking the foils is re-circulated and regains the energy loss to the foils, the integrated unit is termed the Recyclotron. The targets are designed to dissipate the heat from the beam load primarily by radiation.