Hochtemperatur-reaktorbau Gmbh

Claus Elter

Josef Schoening

Wilfried Stracke

Hans-Georg Schwiers

Hermann Schmitt

Ulrich Weicht

Winfried Wachholz

Edgar Hornischer

Hubert Handel

Josef Schoning

Heinrich Stach

Rolf Fritz

Hans-Juergen Kolodzey

Jurgen Rautenberg

Siegfried Brandes

Gerhard Becker

Dietrich Leithner

Karl-Friedrich Kissel

Reinhard Mauersberger

Hans G Schwiers

Walter Theymann

Hans-Juergen Heiland

Gerhard Noll

Karl U Schneider

Guenter Rohark

Franz Grossert

Harald Dorweiler

Herrmann Schmitt

A process is provided for the long term shutdown of a high temperature nuclear reactor comprised of a pile of spherical fuel elements in a core by means of a neutron absorbing absorber material wherein the absorber material consisting of spherical absorber elements is introduced in the core of spherical fuel elements in the form of a column, but wherein the intermixing of the absorber material with the fuel elements is prevented. An apparatus for practicing the process is also provided comprised of a graphite side reflector concentrically surrounding a circular cylindrical core filled with a pile of spherical fuel elements of a high temperature nuclear reactor, into which at least two nose shaped projections distributed uniformly about the circumference radially project, with each of the projections comprising a vertical cavity to contain the absorber material. The vertical cavity is located in the vicinity of the core in the area of the frontal side facing the core of each projection. Pourable absorber material provided by means of a reservoir located above the core and introduced into the vertical cavity penetrates the pile of spherical fuel elements in the form of a column, thereby absorbing neutron radiation.

Shutdown of a high temperature reactor

A roof reflector comprising at least three individual layers of tapered layer elements combined in the form of vertical columns. Each column rests on a block column of the lateral reflector. Individual elements are secured by wedges and dowels to permit vertical column movements without constraint. The top and bottom layers comprise gas collector spaces communicating with each other by passage openings in the middle layer. In the top and bottom layers are also slot-shaped passage openings leading to an from the collector spaces. Preferably, they are radially offset relative to the passage openings in the middle layer to obtain good gas mixing as it rises through the reflector. Such a roof reflector is useful for avoiding roof reflector element damage if one element is vertically displaced relative to an adjacent element. The roof elements are carefully designed to achieve this end and maintain cover utility.

Roof reflector for a nuclear reactor

An absorber rod for nuclear reactors with a pile of spherical fuel elements, which is inserted directly into the pile, in order to affect the prevailing neutron flux by absorber material located in an annular gap between two concentric cylindrical rod elements. The absorber rod has concentric rod elements arranged in pairs, a common rod tip and common connecting pieces. The rod elements are cooled by flow of gas and the inner cylindrical rod element performs the support function, i.e., it absorbs and transmits forces and moments originating in the movements of the rod during insertion and extraction.

Absorber rod

A gas-cooled high temperature reactor having a core filled with spherical fuel elements is provided comprising a graphite side reflector including at least one nose-like projection comprised of a plurality of graphite nose stones stacked one upon the other, said nose stones each including at least one vertically disposed continuous cavity aligned with at least one vertically disposed continuous cavity in adjacent nose stones, said cavity adapted to receive discrete absorber material elements introduced into the reactor core, said nose stones further including at least one vertically aligned continuous gap which extends into said nose stones from a front portion thereof and is aligned with a corresponding continuous gap in adjacent nose stones, communication between said continuous gap and said cavity being prevented, said nose stones also comprising in top and bottom surfaces thereof sealing means which enable adjacent nose stones to be stacked in a manner sufficient to seal said at least one cavity in a gas-tight manner, thus preventing communication between said cavity and said core.

Ceramic installations

A gas-cooled high temperature reactor is provided having a core filled with spherical fuel elements, in combination with a graphite side reflector including at least one nose-like projection protruding radially into the reactor core from said graphite said reflector, the at least one nose-like projection including at least one vertically disposed cavity adapted to receive discrete absorber material elements introduced into said reactor core as well as a vertically disposed continuous opening which permits communication between said cavity and the core of the reactor, said opening having a maximum width adjacent said cavity which is less than the minimum dimension of said discrete absorber material elements in order to prevent passage of said elements into said continuous opening from said cavity.

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. Relative movements caused by the thermal expansion of the bottom shield and the pebble outlet tubes are compensated by the slide joints. Simultaneously, the necessary tight sealing is assured.

Gas cooled high temperature reactor charged with spherical fuel elements

A gas cooled high temperature reactor with spherical fuel elements surrounded by a reflector utilizes at least one ceramic tube and at least one metal tube for removal of pebbles from the core of the reactor. Each cermaic tube is surrounded directly by a ring of graphite columns wherein a plurality of recesses house a number of rod-shaped boron bodies. Additional plate-shaped boron bodies may advantageously be located in the bottom layes of the reflector.

A gas cooled high temperature nuclear reactor utilizes an independent cooling system for the safety enclosure surrounding the reactor vessel. The cooling system comprises means for circulating cooling medium at least on the reactor side of a concrete safety enclosure shell and a separate closed cooling loop for circulation of separate cooling medium through a reservoir of the first cooling medium and to the outside of the entire nuclear reactor installation.

Safety enclosure cooling system for gas cooled high temperature reactors

A nuclear reactor installation with a high temperture, gas cooled nuclear reactor supported in a cavity on a segmented bottom plate held by a centered point of fixation. The first heat exchangers of the primary circulation loop are arranged in the cavity around the nuclear reactor, with the associated first blowers being supported in first passages of the pressure vessel roof. The second heat exchanger for the removal of the decay heat are arranged similarly, with the associated second blowers located in passages of the pressure vessel bottom. The blowers are equipped with contactless magnetic bearings for the rotors. The drives of the core rods and the reflector rods are designed for a banking operation. Simultaneously, the side reflector is supported by means of radial supports on the thermal side shield elastically and secured against rotation. The measures described provide a simplified configuration without affecting safety.

Nuclear reactor installation

A nuclear reactor plant housed in a steel pressure vessel with a small high temperature reactor, together with a steam generator arranged over said reactor and with at least two circulating blowers connected in parallel with each other and following the steam generator in line and is provided with a decay heat removal system located in the primary loop. This system is arranged above the steam generator and a shut-off device is provided between the two component. The shut-off device, which may actuated both passively--by difference pressure--and actively, by means of a drive, is designed so that in normal operation no hot gas may enter the decay heat removal system. In the decay heat removal mode the hot gas is conducted into the decay heat removal system and the steam generator is closed off the hot gas. Simultaneously, the cold gas coming from the decay heat removal system is returned through the steam generator or a gas conduit parallel to it, to the reactor core. In the plant according to the invention the operating installations are rigorously separated from the installations serving the removal of decay heat, whereby a high degree of availability is obtained for the decay heat removal system.

Nuclear reactor plant housed in a steel pressure vessel, with a gas

A nuclear reactor plant housed in a steel pressure vessel comprises a small high temperature reactor and a He/He heat exchanger located above the reactor, preferably followed by two circulating blowers connected in parallel. The installation further comprises at least one decay heat removal system, following in line the He/He heat exchanger in the direction of flow and with the entire flow of primary helium constantly flowing through it. In a preferred embodiment, the He/He heat exchanger is made up of two concentrically arranged coil bundles connected in succession, through which both the primary and the secondary helium are flowing in opposing directions.

Nuclear reactor plant housed in a steel pressure vessel with a gas

Disclosed is a prestressed concrete pressure vessel having a vessel opening which is closed by a concrete cover. Two separate gaskets are disposed between the cover and the pressure vessel, and bordering on an annular channel. The annular channel is connected with a gas detector by means of a connecting channel. At the same time, the inner area of the cover rises from the pressure vessel at a slight angle. The vertical prestress by which the cover is pressed down is larger than the force acting against it (the internal pressure). Additionally, the horizontal annular prestress of the cover is larger in its upper region than in the lower region. In this manner, a constant seal is combined with means for monitoring the seal.

Prestressed concrete pressure vessel, in particular for a nuclear

The invention concerns a steam generator heated by the cooling gas of a nuclear reactor and arranged in the reactor pressure vessel within a vertical shaft. A blower associated with the steam generator is installed above it. The hot gas is conducted to the steam generator in the form of a helical bundle in the downward direction, with the hot gas being conducted initially downward through an annular channel and entering the bundle of heat exchanger tubes at a uniform velocity. The annular channel is sealed in upward direction by means of a sliding seal, which also serves as an earthquake support. In order to provide access to the feed water and live steam lines in view of the blower arranged on top, the two lines are conducted laterally out of and through the reactor pressure vessel. By means of the special fixation of the individual tubes of the heat exchanger bundle in vertical plates and the presence of an expansion zone for the recycling pipes, differential thermal expansion may be kept small.

Steam generator heated with the cooling gas of a nuclear reactor

A cost-effective configuration of a metal liner for a reinforced concrete pressure vessel is disclosed wherein only stud shear connectors and cooling tubes of the liner cooling system are used to anchor the liner and the passages provided in the liner and the wall of the vessel. In the areas of the introduction of forces, stud connectors of different stud rigidities are used. In the anchoring of loads which is again effected by stud connectors only, further transmission is obtained by means of reinforcing rods.

Metal liner for the lining of the cylindrical cavity of a reinforced

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.

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Bad Durkheim, Germany

Claus Elter