Nukem Limited

Hobeg Hochtemperaturreaktor-brennelement Gmbh

Degussa Aktiengesellschaft

Gfo - Gesellschaft F/u/ R Oberfl/a/ Chentechnik M.b.h.

Lothar Rachor

Milan F Hrovat

Hans Huschka

Thomas Schmidt-Hansberg

Willi Wolff

Peter Scheyrer

Dieter Vollath

Karl G Hackstein

Rudolf Seif

Heinrich Porth

Reinhard Kroebel

Erwin Eichinger

There is described a process for the production of high temperature resistant, high density ceramic molded articles at a temperature above 1300.degree. C. and at high pressure in a mold. For this purpose, the blank is heated outside the mold, transferred with a die at 1 to 10 m/sec into the cold mold, compressed there and ejected in the pressing direction. Thereby, the residence time in the mold must be less than 3 msec and the sum of the transport time of the blank from heating up to the mold and the residence time in the mold so regulated that the temperature drop between the nucleus of the blank and the surface of the blank does not exceed 150.degree. C.

Process for the production of high temperature resistant, high density

There are known molded bodies for the safe, long time fixation of radioactive and toxic wastes which have a matrix of graphite and inorganic binding agent, preferably nickel sulfide. An increased resistance to leaching is obtained with molded bodies that have a waste containing nucleus and a waste free shell made of the same graphite matrix.

Molded body for embedding radioactive waste and process for its

There is described a process for the production of ceramic fuel pellets which contain fission and/or fertile material in oxidized form, by heating porous green fuel pellets in a reducing atmosphere to a temperature below 2500.degree. C., molding in a die, ejecting from the die and cooling the finished pellets. Thereby the heating and cooling is carried out stepwise whereby the heating and cooling speed below 1200.degree. C. is less than 30.degree. C./second and above 1200.degree. C. is greater than 30.degree. C./second.

Process for the production of ceramic fuel tablets

For the longtime fixation of radioactive and toxic waste there are used molded bodies made of graphite with nickel sulfide as a binding agent. The molded bodies show especially good properties if the nickel sulfide is in the form of Ni.sub.3 S.sub.2.

For the loading of evaporators in vapor coating plants with shaped pieces made of vapor coating materials there is used an apparatus which is characterized by rolls having indentations for receiving the shaped pieces, centered on a rotatable shaft and surrounded by a closely fitting housing by a moving part having gradual feed fastened on the shaft and by a swivelable shaft moveable into a resting position and into a loading position, on which there is mounted the shaft having rolls via fastening elements. Thereby the housing of the rolls is provided with a recess corresponding to the shaped pieces, which is located in the loading position directly above the evaporator. Because there is only a short time loading process there is no need to cool and there is avoided influencing of the vaporization by the action of moving.

Means for loading vapor coating materials into an evaporator

Previously the conditioning of radioactive wastes took place through binding the waste in a matrix of glass, silicon carbide, cement, bitumen, synthetic resin or vitreous carbon. These processes have many disadvantages, particularly the matrix has poor heat conductivity, insufficient resistant to extraction or poor heat resistance and radiolysis effects. A remedy is provided through a carbon matrix in which there is employed as the starting material graphite which is molded with a binder at a temperature above 100.degree. C. There have particularly proven good as the binder sulfur in admixture with nickel powder from which nickel sulfide forms.

Process for conditioning radioactive and toxic wastes

A process for producing ceramic fuel pellets for nuclear reactors containing the fissionable material and/or fertile material in the form of the oxide or carbide by heating to a temperature above 1300.degree. C. the crude molded fuel articles compacted to 30 to 60% of theoretical density at room temperature, molding in a die and ejection from the die wherein the heating, molding and ejection take place in a vacuum and the molding and ejection take place within 3 to 300 milliseconds.

Process for the production of ceramic fuel pellets for nuclear reactors

There is provided a process for the production of block fuel elements for gas cooled high temperature reactors by multiple step molding of a granulated graphite material comprising a mixture of natural graphite powder, synthetic graphite powder and binder resin together with coated fissile and fertile fuel particles using a lubricant and a hydrocarbon, alcohol, phenol, amine, aldehyde, ketone or ether as an air displacing agent whereby the outer form and the cooling gas channels are produced by molding and the molding temperature in the last molding step is above the softening point of the binder resin and wherein the binder resin is so chosen that it has a softening point at least 15.degree. C above the melting point of the lubricant used and the block is ejected from the die in the temperature interval between the melting point of the lubricant and the softening point of the binder resin.

Process for the production of block fuel elements for high temperature

Block fuel element for high temperature reactors are produced by hot molding of a granulated graphite material consisting of natural graphite powder, synthetic graphite powder, phenolformaldehyde binder resin and stearic acid as a lubricant together with fissile and fertile coated fuel particles to a hexagonal block shape with cooling channels for helium gas and subsequent heat treatment of the molded block to a max. temperature of about 2000.degree. C. In order to displace the air from the die, an organic compound (air displacement agent) e.g., hydrocarbon, alcohol, phenol, aldehyde, ketone ether of amine is built into the granulated graphite material having a very low vapor pressure at room temperature which increases to about 760 Torr at molding temperature of about 180.degree. C and condensed into a liquid phase while the forming pressure is applied.

Process for the production of block-shaped fuel elements for high

Prismatic graphite molded objects for high temperature fuel elements are prepared by producing the outer geometry and the holes for cooling channels and for receiving fuel and fertile materials in the formation of the carbon object.

Process for the production of prismatic graphite molded articles for

There is provided a process for the production of fuel compacts consisting of an isotropic, radiation resistant graphite matrix of good heat conductivity having embedded therein coated fuel and/or fertile particles for insertion into high temperature fuel elements by providing the coated fuel and/or fertile particles with an overcoat of molding mixture consisting of graphite powder and a thermoplastic resin binder. The particles after the overcoating are provided with hardener and lubricant only on the surface and subsequently are compressed in a die heated to a constant temperature of about 150.degree.C., hardened and discharged therefrom as finished compacts.

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Hanau, Germany

Lothar Rachor