Abstract: The invention relates to a gas cooled high temperature reactor located in the cavity of a pressure vessel, with spherical fuel elements, and removal apparatus for fuel elements. The latter is made of at least one ceramic pebble outlet tube extending through the graphite structural parts of the nuclear reactor (bottom reflector, bottom layers) and a number of metal pebble outlet tubes installed through the bottom of the pressure vessel. They are arranged coaxially in the liner of the passage through the vessel. To be able to dismantle the metal pebble outlet tubes, they are constructed of several releasably interconnected tube segments. Between the uppermost tube segment and the corresponding ceramic pebble outlet tube a compensating tube is provided and connected with the tube segment by means of a sliding joint. The other end of the compensating tube is fastened to the thermal bottom shield.

Abstract: A water level control for a steam generator of a pressurized water type of nuclear steam supply system varies the water level demand as a function of power. The control also varies the water feed rate after a reactor trip initially as a function of reactor coolant average temperature.

Abstract: In a steam generator for a pressurized water type nuclear reactor, for the purpose of isolating a water chamber in the steam generator from a coolant piping communicating with the water chamber, a plug is disposed in a nozzle section of the coolant piping, the plug is supported by a support arm having an angle adjusting screw and fixedly secured to a mount seat at a manhole communicating with the water chamber, and preferably, a cover is provided on the mount seat at the manhole.

Abstract: The reactor comprises a vessel closed by a lid and containing a core formed of fuel assemblies. The reactor comprises control clusters of two different types and an internal structure fixed inside the vessel, placed above the core and comprising means for guiding the clusters. The mechanisms associated with clusters of a first type each comprise a vertical cylinder belonging to the internal structure of the reactor, defining, with a piston from which is suspended a group of rods belonging to a cluster or forming a cluster, a work chamber. That chamber is connected by a duct, passing through the lid, to a valve for optional connection with a space at a pressure lower than that which prevails in the vessel.

Abstract: A modular tokamak system comprised of a plurality of interlocking moldules. Each module is comprised of a vacuum vessel section, a toroidal field coil, moldular saddle coils which generate a poloidal magnetic field and ohmic heating coils.

Abstract: A nuclear reactor steam generating plant having a pressurized water reactor with a single discharge line to a steam generator, with the primary coolant passing through the steam generator tubes divided into two streams in the channel head outlet section that is divided into two subsections. Discharge nozzles on the outlet subsections direct the streams of coolant to hermetically sealed pumps directly attached to the discharge nozzles, with the pumps directing the cooled primary coolant back to the reactor vessel. A single removable closure is provided for access to both subsections of the outlet section of the channel head, with a removable portion provided on the divider plate that forms the subsections.

Abstract: A disassembleable and reassembleable sealing device for pipelines, includes a cylindrical sealing insert being insertable into a pipeline in a given direction, the sealing insert having a front cup part with a closed cross section and a rear ring part, as seen in the given insertion direction, the cup and ring parts being annular, coaxial and slideable into each other in axial direction of the sealing insert, the cup and ring parts having corresponding peripheral surfaces and ring shoulder surfaces at the outer periphery of the cup and ring parts defining at least one ring seat, at least one sealing ring inserted into the ring seat between the cup and ring parts, the sealing ring being bulged outward by deformation forces exerted on the sealing ring by the ring seat when the cup and ring parts slide toward each other, increasing the diameter of the sealing ring for pressing the sealing ring against the ring seat and forming a ring bead on the sealing ring resting against the inner periphery of the pipeline fo

Abstract: An apparatus and method for maintaining a steady-state current in a toroidal magnetically confined plasma. An electric current is generated in an edge region at or near the outermost good magnetic surface of the toroidal plasma. The edge current is generated in a direction parallel to the flow of current in the main plasma and such that its current density is greater than the average density of the main plasma current. The current flow in the edge region is maintained in a direction parallel to the main current for a period of one or two of its characteristic decay times. Current from the edge region will penetrate radially into the plasma and augment the main plasma current through the mechanism of anomalous viscosity.In another aspect of the invention, current flow driven between a cathode and an anode is used to establish a start-up plasma current.

Abstract: A probe for determining the energy and flux of particles in a plasma comprises a carbon film adapted to be exposed to the plasma, the film havinmg an electrical resistance which is related to the number of particles impacting the film, contacts for passing an electrical current through the film, and contacts for determining the electrical resistance of the film. An improved method for determining the energy or flux of particles in a plasma is also disclosed.

Abstract: A die cylinder assembly is designed for use in an environment which has contaminants outside the assembly. The die cylinder assembly includes a piston disposed in a cylinder and having an outer end surface. The piston is moved in one direction by forces applied to the outer end surface of the piston. The piston is moved in an opposite direction by a working fluid pressure in a head end chamber of the cylinder. The cylinder includes a rod end variable volume chamber which is connected in fluid communication, through a first passage in the piston rod, with a third chamber located in the piston rod. The fluid pressure in the rod end chamber is always maintained at least as great as ambient fluid pressure to prevent contaminants from entering the rod end chamber. A check valve in a second passage admits outside air to the third chamber when fluid pressure in the third chamber drops below ambient pressure. A relief valve vents the third chamber if fluid pressure therein becomes too high.

Abstract: A liquid metal circulation system is disclosed which is suitable for use in connection with a nuclear reactor. The circulation system of the invention includes an electromagnetic pump having a central core body featuring a helically configured, six pole magnet, optionally directing flow to one or a series of flow couplers, which generates sufficient liquid metal flow to be used as the primary circulation means for the nuclear reactor. The increased safety, design simplicity, and efficiency of such circulation system overcomes many of the drawbacks of conventional circulation systems.

Abstract: An end closure for a nuclear fuel flask in which the gate, which is movable between open and closed positions across an end of the flask, has first and second portions which are urged apart, conveniently by spring-loaded means. A door has upper and lower wedge-shaped members mounted on and releasably connected to the respective gate portions. In use, a displacement of the gate into or out of its fully closed position effects movement of one only of the gate portions and its associated door member. As the door members are wedge-shaped the other door member is urged into or out of sealing engagement with the end of the fuel flask.

Abstract: A pipe end sealing element for use in hydrotesting of plain end pipes, such as instrument tubes of a nuclear reactor, and a method of hydrotesting of such plain end pipes. The pipe sealing element comprises a hollow tubular member with a bevelled flange at one end and a threaded portion at the other end, a hollow conical bushing of decreasable interior diameter having a bevelled surface complementary to the bevelled surface of the tubular member, a sealing plug and threaded bolt engageable with the threaded portion of the hollow tubular member. The hollow tubular member is placed about the open end of the pipe, with the threaded portion thereof adjacent and beyond the pipe end, and inserting the conical bushing into the hollow tubular member about the pipe wall. The sealing plug is placed on the pipe end and the threaded bolt engaged with the threads of the hollow tubular member.

Abstract: An entirely passive auxiliary core cooling system for a liquid-metal reactor wherein a path for natural circulation through a radial plenum and radially outermost core assemblies to the heat generating inner core assemblies is provided, the flow being cooled by a totally passive heat exchanger.

Abstract: Synthetic Crandallites of the general composition MeAl.sub.3 (PO.sub.4) (OH).sub.5.H.sub.2 O (Me=alkaline earth metal) are used for the separation of cations, especially alkaline earth metals, lanthanides and actinides, at a pH greater than 6 and temperature above 40.degree. C.

Abstract: The coil arrangement of a nuclear fusion apparatus according to the present invention comprises a return conductor divided into two lines, one of which is connected to resistance-inductance adjuster. The resistance-inductance adjuster is adapted to adjust the current distribution, thereby considerably reducing the error magnetic field generated to improve the characteristic of plasma confinement.

Abstract: A swing gate closure assembly for nuclear reactor tipoff assembly wherein the swing gate is cammed open by a fuel element or spacer but is reliably closed at a desired closing rate primarily by hydraulic forces in the absence of a fuel charge.

Abstract: A coil arrangement for a nuclear fusion apparatus comprises a return conductor radially penetrating through a coil at a portion having a transition between turns and a feed conductor symmetrically arranged with regard to the axis of the return conductor. The coil arrangement practically reduces current loops generated by the transition current, thereby practically reducing the generation of the error magnetic fields and, therefore, better confining the plasma.

Abstract: A thermally activated trigger device 10 comprises a pressurized closed vessel 11 with a piston 12 slideably mounted in it to divide it into two compartments 14 and 16. A fluid such as an inert gas is contained within the compartments at substantially the same pressure. One end of one of the compartments has venting means 24, such as a normally closed pipe which vents the fluid from the compartment once the pipe becomes open by rupture or melting at an elevated temperature. The resulting pressure difference between the compartments on venting of the fluid moves the piston which is connected to an actuator means for performing a desired control or safety shut-down function. The trigger device is useful for performing many control and safety shut-down functions, particularly for rendering a nuclear space reactor subcritical upon reentry to the earth's atmosphere.

Abstract: A novel liquid nuclear reactor is described which comprises a reactor vessel that is connected through upper and lower liquid conduit means to one or more satellite tanks that contain a heat exchanger means and pump means.