Abstract: The leakage of gases in gas cooled nuclear reactors is detected by an arrangement utilizing a flexible material to cover areas of potential leakage and create detection cavities inside the concrete vessel of a nuclear power plant. The detection cavities are connected to the gas collector housed within the concrete vessel by means of gas-tight connecting conduits or lines. A negative pressure is applied to the gas collection device connecting conduits and detection cavities to extract any gas leakage within the power plant. Gas measuring devices and display devices are included in the system to identify, quantify or locate gas leakage.

Abstract: A vaulted cover for an opening in a pressure vessel comprising a vaulted center piece and an annular rim surrounding thermal insulation material of a cover flange. The rim is assembled of two coaxially arranged cylindrical sections. Expansion gaps and sealing disks are provided about pipe fittings in said vaulted cover in a manner that permits release of pressure through gaps formed by said sealing disks.

Abstract: An improved design for shielding the component parts of a gas turbine power plant from radiation in a gas transport conduit is disclosed. The radiation shield and shielded gas conduit utilize a shielding arrangement comprising a displacement body arranged centrally within the conduit and a shielding annulus surrounding the displacement body. A shielding device provides for a first annular flow path for reactor cooling gas between the displacement body and shielding annulus and a second annular flow path for reactor cooling gas between the shielding annulus and the conduit housing. The shielding device provides protection against radiation without significantly disrupting the flow of the cooling gas in the conduits.

Abstract: Disclosed is an angled gas conduit for a gas flowing under high pressure and at an elevated temperature which comprises a first conduit part and second conduit part connected at an angle forming an area of deflection for gas flowing within said conduit parts, an apertured plate arranged at an oblique angle within said conduit in the area of deflection, the apertured plate having a plurality of circular passages for directing the flow of gas in the conduit. A mounting arrangement for the apertured plate is also disclosed.

Abstract: Disclosed is a control system and process for operating same for nuclear reactors, particularly gas cooled nuclear reactors, comprising in the control system a means for measuring the output produced in the reactor core and the output removed by a primary circuit or a secondary circuit, a means for integrating the integral of the core produced output over the output level, during the same time, of the primary or secondary circuit of the reactor and a means for forming a control signal from the value of the integral.

Abstract: Disclosed is a process for reloading the contaminated empty reactor cavity of a nuclear reactor with spherical operating elements forming the core of a high temperature reactor comprising supplying the operating elements to the reactor cavity first through a central loading tube in the roof reflector of the nuclear reactor to a predetermined load level, the loading tube being extended at the onset of the loading process toward the floor reflector and being adjusted upwardly during continued loading with the rising load level and after reaching the predetermined load level, supplying further operating elements through a plurality of auxiliary loading tubes in the roof reflector of the nuclear reactor in concentric circles about the central loading tube with the loading sequence proceeding circle after circle beginning with the circle closest to the central loading tube.

Abstract: Disclosed is a closing arrangement for large passages in a prestressed pressure vessel comprising a cover means for covering the opening of a passage in the prestressed pressure vessel, an annular structural part having an inner boundary surface surrounding the covering means at a distance and defining a space therebetween, a means for securing the annular structural part to the prestressed pressure vessel and a plurality of connecting elements disposed in the space between the annular structural part and the covering means in abutting relationship with the inner boundary surface of the annular structural part and the covering means.

Abstract: The drive for an absorber rod for a nuclear reactor has a drive piston guided in a cylinder combined with the absorber rod forming an absorber unit. In order to compensate the forces exerted by the medium of the pressure vessel on the absorber unit and tending to pressure the absorber rod axially outward, an equalizing surface is arranged in the absorber unit. The equalizing surface is exposed on one side to the medium of the pressure vessel and/or the cooling medium of the absorber rod, so that an equalizing force is acting on the absorber unit. In the event of a failure of the drive medium acting on the drive piston of the absorber unit or during fluctuations and changes of the internal pressure in the pressure vessel, the absorber unit remains in its existing position, i.e. no unintentional withdrawal of the absorber rod from the pressure vessel takes place.

Abstract: Improvements in high temperature gas cooled nuclear reactors is effected by an arrangement of paired absorber elements, each pair comprising a rod shaped absorber element and a tubular absorber element generally surrounding the rod shaped element. With this paired combination in a reactor employing spherical fuel elements, the effective life of the absorber rods is significantly extended by protection of the rod shaped absorber element from excessive amounts of irradiation from thermal neutrons.

Abstract: A plurality of graphite blocks forms a side reflector with an area of each block that allows a certain amount of radiation induced wear in a predefined zone facing the core of the reactor and an area separate from the wear zone for carrying the load bearing function of the side reflector. Most critical is the area of the upper range of the reactor core where radiation induced wear is greatest. The wear is taken into consideration in the design layout of the side reflector in the form of an increment to the thickness of the wall. The load bearing areas of each block provide the load bearing area for the entire side reflector. The side reflector is particularly suitable for high temperature gas-cooled reactors of the pebble bed type.

Abstract: Disclosed is a pressure vessel of a nuclear power plant comprising a generally cylindrical shaped first partial section, a cavity for housing a high temperature reactor within the first partial section, a second partial section forming the lower part of the pressure vessel, a horizontal tunnel for housing a gas turbine assembly within the second partial section and a plurality of recesses for housing components of a heat exchanger apparatus, wherein the cavity for housing the high temperature reactor is eccentrically arranged in the first partial section of the pressure vessel with respect to the cylindrical shape.

Abstract: A gas-cooled high temperature reactor is equipped with a supporting structure for the reactor core having a gas conduit passing through the support structure from a hot gas collecting space beneath the supporting structure. The supporting structure itself rests on a floor plate in a columnar arrangement. The floor plate also rests on support columns and possesses a disk-like center portion indirectly supporting the reactor core and an outer annular portion supporting a lateral thermal shield around the reactor core.

Abstract: The invention concerns a roof reflector suspended from the thermal cover shield of a gas-cooled pebble-bed reactor with a plurality of passages for absorber rods arranged in a triangular lattice, and with channels for the passage of the cooling gas. The roof reflector comprises a plurality of essentially hexagonal graphite blocks arranged in several layers to form vertical, closely-adjacent columns. A process for the disassembly of the roof reflector is further provided.

Abstract: Disclosed is a support structure consisting of several layers of prismatic graphite blocks arranged over each other. The layers are constructed as closed units without expansion gaps and the blocks of one layer are keyed together with the blocks of the adjacent layers. The upper layers are composed of a plurality of preferably hexagonal graphite blocks equipped with passages for the cooling gas, while the bottom layer is formed by a number of support structures, each consisting of several support segments fitted together preferably into a hexagonal cross section, with each support unit resting at its central section on a column head of a round column and carrying a limited number of the hexagonal graphite blocks and that cooling gas channels are provided at the locations of the bottom layer where three support units meet.

Abstract: A heat exchanger apparatus is disclosed comprising a heat exchanger casing having a plurality of box members suspended within the casing, with each box member having a plurality of tubular members disposed within an arrangement which permits the exchange of heat from a hot gas stream flowing outside the tubular members to a cooler gas stream flowing counter-currently within the tubular members. The heat exchanger apparatus is adapted especially for the use in high temperature nuclear reactors and is disposed within a pod in the reactor pressure vessel communicating directly with the reactor core. The suspension of the primary heat exchange components enables the achievement of excellent exchange capability with minimum stress on the exchanger apparatus as a result of thermal expansion. A method of exchanging heat from a primary cooling circuit of a high temperature reactor to an intermediate gas circuit of a heat process plant is also disclosed.

Abstract: A driving apparatus for raising and lowering an absorber rod within a nuclear reactor pressure vessel. The apparatus comprises a driving system which includes a motor-driven flexible support member that is connected to the absorber rod through both a coupling element and a connecting element, and a storage means for storing any excess length of flexible support member. Both the driving system and the storage means are detachably enclosed within a desired gaseous environment that is isolated from the interior of the pressure vessel by a screening plug having a passageway therein through which the connecting element is disposed for movement between an upper end position and a lower end position.

Abstract: Disclosed is a closure combination for pressure vessels comprising a carrier cover in contact with a sealing cover for covering and closing an opening in a pressure vessel by contact with a flange member of a liner element disposed within the opening in the pressure vessel and sealed by a sealing means in communication with the flange member and the sealing cover.

Abstract: Disclosed is a nuclear reactor plant, comprising:a prestressed concrete pressure vessel;a high temperature reactor arranged in a central cavity within the vessel;a closed gas cooling circuit including at least one housed gas turbo unit arranged in a turbine duct in the wall of the vessel, said unit including a turbine and a compressor and having detachable bearings; means for exchanging heat and means for transporting gas in the cooling circuit including hot gas from the reactor to the turbine, said heat exchange means and said gas transport means being arranged in recesses in the wall of the vessel;means for forming a detachable plug-in type connection between the hot gas transport means and each turbo unit;means, positioned at the edge of the turbine duct, for connecting all remaining gas transport means to the turbo unit;means, including peripheral sealing members positioned between the inside wall of the turbine duct and the outer housing of the turbo unit, for separating each of the remaining gas transpo

Abstract: Disclosed is a power plant having a nuclear reactor as a heat source and turbine assemblies comprising turbine, compressor and heat exchanger elements. The nuclear reactor is encased within a thermal barrier which is encased within a liner so as to form a free space between the thermal barrier and the liner. The free space is in communication with a cooling gas source, and the interior of the thermal barrier is in communication with a gas source.Also disclosed is a method of cooling a nuclear reactor plant by passing a cooling gas into the free space between the liner and the barrier which is then passed to a recuperator after which it is passed within the thermal barrier surrounding the reactor.

Abstract: Disclosed are a method and apparatus for regulating and shutting down a gas cooled nuclear reactor having a bed of spherical fuel elements, wherein regulation of the reactor is accomplished by a first set of absorber rods in the side reflector of the reactor, partial shutdown is achieved by a second set of absorber rods movable in the top reflector and in the space above the fuel elements, and total shutdown is accomplished by a third independent set of absorber rods which can be moved downwardly into the fuel elements.