Abstract: A barrier system for a high temperature reactor. The reactor utilizes spherical fuel elements consisting of coated particles of a fissionable material embedded in a graphite matrix, the coating forming a first safety barrier against the release of fissionable material, and the graphite matrix a second such safety barrier. The reactor is surrounded by a prestressed concrete pressure vessel clad on the inside with a metal liner. The metal liner acts as a third safety barrier, while the concrete body of the prestressed concrete pressure vessel forms the fourth, and outermost safety barrier. A plurality of passages are located in the pressure vessel which are closed off by closure means. The closure means provide sealment between the third and fourth barriers in the area of the passages. By utilizing the concrete pressure vessel as a safety barrier in this manner, the need for a separate protective reactor housing is eliminated.

Abstract: A medium power, high temperature pebble bed nuclear reactor, which includes a means for introduction and withdrawal of operating elements. The installation is provided in such a way that it can be more economically built and operated. The installation includes several input stations above a prestressed concrete pressure vessel, and charging hatch blocks positioned on top of the prestressed concrete pressure vessel. The blocks include selectors through which the pebble-shaped operating elements, after traversing helical and meandering charging conduits, reach into the reactor core. The selectors and charging conduits are installed within armored ducts which penetrate the prestressed concrete pressure vessel. Similar armored ducts are provided for exit ducts for withdrawal of pebbles from the core, and a first common exit hatch block is connected to the exit ducts. The block is arranged within foundation walls which support the prestressed concrete pressure vessel.

Abstract: A process and an installation for the securing against excessive pressure in a prestressed concrete pressure vessel of a gas cooled high temperature reactor and for the prevention of activity release into the environment. The process comprises three steps and in each step pressure reducing installations become effective upon the rise of pressure in the prestressed concrete pressure vessel over a predetermined value. In the first step the pressure vessel is relieved by means of the operational gas purification apparatus and a conveying blower into the storage vessels for the cooling gas. In case of a further rise in pressure, in a second step a discharge path equipped with a safety valve and a check valve is opened, which also relieves into the storage vessels while by-passing the gas purification installation.

Abstract: Process for the construction of a nuclear reactor having a reinforced concrete pressure vessel, comprising utilization of a corset frame to support the cavity liner, closing off the reactor cavity and installing the reactor components under "clean conditions", simultaneous to the layer-by-layer pouring of the walls and top of the reinforced concrete pressure vessel. The erection of the supporting corset substantially reduces the overall assembly time of the nuclear power station without involving additional expense.

Abstract: An arrangment for mounting pipes and the like to a concrete wall or slab comprises a fastening device constructed in the manner of building blocks and consisting of prefabricated parts. A specially designed concrete anchor is inserted prior to pouring the concrete in a reinforcing matrix of a concrete slab or wall. It is possible thereby to keep the distance tolerances between the concrete anchors very small and to standardize all of the parts of the fastening construction, which particularly includes supporting rods, beams and diagonal rods.

Abstract: Control regulation and shutdown of gas-cooled, high-temperature nuclear reactors require precise adjustment of core reactivity through the use of absorber rods. Fine adjustment without permanent damage to the reactor core having a bed of spherical fuel elements is accomplished by a process and arrangement of the reactor such that two groups of absorber rods are independently controlled for insertion into the reactor cavity between the roof reflector and the bed of spherical fuel elements and into the fuel element bed itself. Adjustments can be made for rapid shutdown and/or complete shutdown as well as rapid shutdown required due to water or oil penetration into the reactor core.

Abstract: A passage through a reinforced concrete pressure vessel is provided, wherein the tolerance ranges required for the fastening of the components in the passage may be produced safely and without excessive expenditures. This is achieved by an arrangement including a lining having a first, outer tube resting against the concrete and a second tube arranged within the first tube.

Abstract: A support structure for a nuclear reactor is disclosed comprising a primary support element connected with the roof of the pressure vessel and a secondary support element joined with the primary support element. The thermal roof shield and the roof reflector are connected to the secondary support element.

Abstract: It is desirable to being able to vary the temperature of a loop exposed to a flow of hot gases in gas cooled nuclear reactor installations without thereby affecting the gas temperature in the other loops. It should be possible in an extreme case to take the affected loop out of service. This is achieved by arranging under the heat absorbing components in the hot gas channel a means for mixing gas connected with a cold gas line.

Abstract: A gas cooled, high temperature nuclear reactor is provided with a base plate arranged under the reactor core and over the bottom of the prestressed concrete pressure vessel serving as the bottom shield. The bottom shield comprises at least two plates arranged coaxially with respect to each other, one above the other. Each plate comprises several partially interconnected parts with the lower plate being placed at an axial and vertical distance from the bottom liner of the prestressed concrete pressure vessel and also from the upper plate.

Abstract: A concrete anchor is fixedly mounted in a reinforcing grid having a square mesh prior to the pouring of a concrete wall slab. A groove is formed on the concrete anchor between two flanges. The flange and the groove are laid out with respect to their dimensions so that the concrete anchor may be inserted in a mesh and fastened therein by rotation. A connecting nut is capable of being screwed into the concrete anchor. The connecting nut is movable while mounted in the concrete anchor enabling compensation for oblique positions with respect to the external surface of the concrete wall.

Abstract: A closure for a prestressed high-pressure vessel comprises an anchoring ring surrounding the opening of the prestressed concrete pressure vessel, a plurality of axial stressing cables and a plurality of cover stressing cables. The cover is separately prestressed and simultaneously anchored to the prestressed concrete pressure vessel. The anchoring rings on the concret need for releasing the axial stressing cables of the prestressed concrete pressure vessel.

Abstract: A pressure vessel for a nuclear reactor comprises a reinforced concrete vessel with at least one open area located in the wall of the concrete vessel, a lining means anchored on the inside surface of the concrete vessel and the opea area for protection of the surfaces and at least one expansion space in the concrete vessel immediately adjacent the lining means to permit movement of the lining means and distribution of the stresses in the lining means under various reactor conditions.

Abstract: A support structure for a nuclear power station having a prestressed cylindrical vessel comprising an annular ring of supports on a support wall and foundation wherein the prestressed cylindrical vessel rests on the ring of supports is disclosed. The supports, through their defined distances from each other, provide a constant cooling flow of the supports and a constant temperature over the entire operating period of the power station. This results in supports that are maintenance-free. The supports are constructed of plastic washers with steel inserts and are of sufficient height such that in the case of earthquakes, maximum vibrations of the reinforced concrete pressure vessel may be absorbed within an accurately set terminal boundary of the annular support wall.

Abstract: A support structure for the core of a gas cooled high temperature reactor utilizes a plurality of compression members arranged in an annular space between a plurality of graphite blocks forming the roof, bottom and cylindrical side walls of a reflector surrounding the reactor core and a thermal shield surrounding the reflector. Each compression member comprises a compression body, a first bolt part having the configuration of a threaded rod, a threaded area on the inner surface of the compression body for receiving the threaded bolt part, a second bolt part having the configuration of a piston, a sliding area on the inner surface of the compression body for receiving the piston bolt part, and means for producing a compressive force between the piston bolt part and the compression body. The plurality of compression members are attached to the reflector and thermal shield by way of a plurality of ball-and-socket joints.

Abstract: A supporting floor for the core of a nuclear reactor utilizes a plurality of independent support columns forming the floor of the reactor and resting on the bottom layers of the reactor. The support columns are surrounded by a side reflector which is in turn surrounded by a thermal side shield. Between the thermal side shield and the side reflector are disposed retaining means for maintaining the columns close together and preventing the formation of large gaps during operation.

Abstract: An inspection device for the inspection of internal spaces in nuclear reactor installations requires extremely small dimensions while being capable of use at high temperatures and exposures to radiation during shutdown periods of the reactor. The device is designed so that it is readily adapted to a particular inspection purpose. The particular device meeting these requirements comprises a camera arranged in a tube and cooled in such tube. The objective of the camera and/or a mirror are each connected with means for relative movement. A source light and the movement means are designed as separate structural elements which may be assembled in different combinations in a modular fashion.

Abstract: An apparatus for measuring the flow of gas in a blower of a gas cooled high temperature nuclear reactor comprising a blower, a blower shield communicating with the blower, an inlet conduit in the blower shield for conducting gas flow to the blower, an exit conduit in the blower shield for conducting gas flow from the blower and means for measuring the flow of gas in the exit conduit. The measuring means includes a venturi tube having a narrowed area in the exit conduit, a first measuring channel in communication with the gas flow in the narrowed area, a second measuring channel in communication with the gas flow in the exit conduit upstream from the narrowed area, and means for comparing the relative gas flow in the first and second measuring channels. A transducer connected to the first and second measuring channels performs the comparing and measuring steps.

Abstract: A mounting for power conductor and instrument lead penetrations in nuclear reactors provides a device that is simple, compact and at the same time easily installed, repaired or replaced. The mounting comprises a cylinder like, stepped housing which is to pass through the pressure vessel wall of the nuclear reactor and house at least one and preferably a plurality of electrical conductors.

Abstract: The invention concerns a vaulted cover to close a vertical recess in a pressure vessel with a plurality of fittings welded to the cover for the passage of steam pipes and with heat insulation applied to the inside of the cover consisting of a thermally insulating material and a plurality of rectangular cover plates arranged on the thermally insulating material, wherein the cover plates are fastened to the cover by means of holding bolts penetrating the entire insulation.