Abstract: Cast-iron bodies are repaired or surface defects corrected by chambering the cast-iron body in the region of the defect and positioning the body with the resulting recess upwardly opening beneath a crane from which the head of an electrode advancing unit is suspended. The cast-iron electrode extends into the recess and is advanced automatically in accordance with detection of the arc length. The welding arc is struck to deposit weldment in the recess while the electrode is swung in a pendulum motion back and forth.

Abstract: Nuclear residues with a Co60 specific activity of 1 to 100 Bq/g, such as concrete or metal parts of a nuclear reactor installation, are used as raw materials for the production of radiation shielding structures for such nuclear installation. The concrete reisdues can be broken up to form an aggregate for concrete which is cast to form such structures and metal objects can be added for the casting of transport and storage vessels for radioactive wastes.

Abstract: Nuclear residues, such as concrete or metal parts of a nuclear reactor installation, are used as raw materials for the production of radiation shielding structures for such nuclear installation. The concrete residues can be broken up to form an aggregate for concrete which is cast to form such structures and metal objects can be added for the casting of transport and storage vessels for radioactive wastes.

Abstract: A method of and apparatus for melting radioactive waste contained in a metal transport vessel and in which the transport vessel is introduced into a container which is closed by a laterally retractable cover and then inverted by rotation through 180.degree. about a horizontal axis to lie above the mouth of a furnace. The mouth of the furnace is provided with a horizontally retractable slider and the cover and the slider are independently retracted to allow discharge of the transport vessel and the radioactive waste contents thereof into the furnace for melting therein. The container and its cover thus form part of the gate allowing transfer of the radioactive waste into the furnace without a hot or radioactive cell shielding the entire unit from vagabond or wayward radioactivity.

Abstract: A nuclear-reactor assembly comprising a pressure vessel for the nuclear reactor and auxiliary vessels disposed in annularly spaced relationship around the reactor pressure vessel and communicating therewith by horizontal passages in the walls between the vessels. According to the invention, the outer surface of the reactor pressure vessel, which is otherwise generally cylindrical, is formed with vertical surfaces in the region of the passages against which complementary vertical planar surfaces of the auxiliary vessels lie. The spaces between the auxiliary vessels are filled in the plane of these passages by support blocks so that the blocks together with the auxiliary vessels form a compound disk which is prestressed inwardly by a peripheral prestressing element passing around the perimeter of the disk.

Abstract: A pressure vessel susceptible to high temperatures, especially for containment of a nuclear-reactor core, is constituted of a cylindrical shell from a cast material such as cast steel, cast iron or concrete, and is prestressed by vertical cables which extend parallel to generatrices of the shell. Peripheral (circumferential) prestressing cables are provided around the shell which can be externally insulated. The peripheral tensioning cables are exposed externally of the insulation material and bear upon the shell of the vessel with heat-resistant elements of high compressive strength which extend through the external insulation.

Abstract: An erect cylindrical pressure vessel, especially for a nuclear reactor, is constituted from cast-iron or cast-steel elements and is stressed by axially extending angularly spaced axial stressing elements and by axially circumferential peripheral stressing elements or cables. At least one of the axially stressing cables and at least one of the peripheral stressing cables serving for sustaining the operating load of the pressure vessel, i.e. the working elements rather than the addition or additional elements, is provided with a measuring device which triggers an alarm upon the detection of a change in the force developed at the respective stressing element or the length change thereof reaching 90% of the corresponding change at the pressure rating of the vessel.

Abstract: An apparatus for measuring or monitoring changes in the periphery of a vessel, especially a pressure vessel for containment of a nuclear-reactor core, comprises a wire which extends around the periphery of the vessel and is held along this periphery by a plurality of mechanical elements establishing a predetermined spaced relationship between the wire and the periphery. The wire extends polygonally around these elements and is provided with a displacement-measuring device responsive to any tendency of the wire to shift from its original position. According to the invention, the connecting elements between the wire and the periphery of the vessel are constituted as sheet-metal plates or vanes lying in planes substantially perpendicular to the axis of the wire and extending radially with respect to the axis of the vessel. The vanes are elastically deformable laterally or shiftable in the direction of the axis of the wire and are retained under tension by the tension applied to the wire.

Abstract: A cylindrical pressure vessel is placed under an inward prestress to resist outward forces by the application of outwardly spread annular stressing means which are then permitted to bear inwardly upon the vessel. The device includes fluid-pressure means for relieving the inward force during the application of the annular means so that at least one ring of the latter can expand outwardly and then contracted on the periphery of the vessel.

Abstract: A pressure vessel, especially as a containment for a nuclear reactor core, comprises a stack of horizontal cast-metal members which define horizontal joints or seams between them, the stack being held together under pre-stress by a multiplicity of tension elements, e.g. cables or rods. The stack is provided with a liner welded together from steel sections and having, in the region of the seams, a reduced thickness as well as a lower yieldability or tensile strength than the yieldability or tensile strength of the liner sections elsewhere. As a result, rupture of the liner is ensured in the region of the seams which constitute preferred pressure release cracks in the event of an explosion or excessive development of pressure within the vessel.