Abstract: Process and device for locating the ideal screwing position of bolts of large dimensions wherein a bolt (10) is lowered under control until it engages in the tapping recess of an orifice (5), the bolt (10) is rotated in the opposite direction to screwing, the point of engagement of the threads (11) of the bolt (10) in the threads of the tapped orifice (5) is detected, screwing is started under control by the rotation of the bolt in the normal direction, successive seizures are detected during the screwing, and after each seizure the ideal screwing position is located by means of a suitable path from the center corresponding to the preceding stop previously recorded, screwing is resumed after each detection of the new ideal screwing center, and the screwing of the bolt (10) is continued at a high speed until the end of screwing is detected.

Abstract: A high pressure seal fitting with a built-in low pressure seal arrangement for sealing a space defined by an inner diameter of a pipe and a rod slidably disposed within the first pipe and extending beyond and end of the first pipe. The fitting includes a fitting body provided with an axial passage for slidably accommodating the rod and having a first end region constructed for engaging the end of the pipe for forming a high pressure seal between the pipe and the fitting body, and a second end region opposite the first end region and including an outer circumferential protrusion having the shape of a ferrule for cooperating with components utilized to form a compression seal to form a releasable high pressure seal. The fitting body further includes a low pressure sealing device disposed in the axial passage at the second end region of the fitting body for maintaining a low pressure seal between the fitting body and the rod when the releasable high pressure seal is disconnected.

Abstract: A remotely controlled tooling apparatus is disclosed for supporting and selectively disposing a tool with respect to a workpiece illustratively taking the form of a core barrel of a nuclear reactor. Illustratively, a core barrel is of a substantially cylindrical configuration and has a plurality of flow holes disposed therethrough. The remotely controlled apparatus comprises a tool carriage, a support table carried thereby for receiving the tool, a strongback assembly for supporting and guiding the tool carriage with respect to the core barrel, and a pair of clamps affixed to the strongback assembly for engaging the core barrel for suspending the strongback assembly upon the core barrel. The tool carriage and its support table carried thereby are selectively disposed with respect to the core barrel, whereby the tool may be engaged and disengaged with and from the core barrel.

Abstract: A fast neutron nuclear reactor having a vessel filled with liquid metal and sealed in its upper part by a box slab having a central opening in which is placed a plug-cover-core overhanging the core of the reactor. The central opening is surmounted by a cell containing the handling and storage mechanism for the plug-cover-core and a mechanism for handling the assemblies. The latter can be moved on annular rails and can be collapsed against the wall of the cell, in order to permit the manipulation of the plug-cover-core. A radial passage connects the cell to a transfer station.

Abstract: During unrodded refueling, the drive rods and the control rods and coolant-displacement rods, attached to the drive rods, are removed from a fuel assembly, preliminary to the transfer of the fuel assembly, and are reinserted in the reactor after a replacement fuel assembly has been positioned in the reactor. Prior to the transfer of a fuel assembly, a lifting rig is secured to the upper-internals support. A lift plate is removeably mounted on latches in a lower position of the lifting rig. The latches are released and the lift plate is connected to the drive rods. The lift plate is then raised and removeably mounted on latches in an upper position on the lifting rig. In this position, the control rods and coolant-displacement rods are in the guides in the upper internals of the reactor. During the lift-plate raising operation, the loading on the drive rods is monitored and if the loading exceeds a predetermined magnitude, the excess loading is indicated.

Abstract: A tool for removing split pin remnants which remain in anchor bores in the upper core plate of a nuclear reactor vessel after removal of guide tube assemblies therefrom, includes an elongated mast having parallel tubular members with handle apparatus at the upper end thereof and carrying at the lower end thereof a ram platform having an upstanding pin removal member. The ram platform is dimensioned to be lowered through any one of the guide tube seating apertures in the upper core plate. A locating plate mounted on the mast above the ram platform seats in the seating aperture and accurately positions the ram platform below the upper core plate with the pin driving member in registry with the pin bore. A hydraulic cylinder is mounted on the mast above the locating plate and has a piston rod extending through the locating plate and fixedly secured to the ram platform for moving it up and down to drive the pin from the bore. Hydraulic fluid is carried to and from the cylinder through the mast tubes.

Abstract: A concrete pressure vessel (1) for a nuclear reactor is formed with an arch (6) arranged above the cover (4) of the pressure vessel, said arch having a horizontally directed opening permitting horizontal transport of the cover. The cover (4) is retained by a plurality of compressive force transmitting elements (11) arranged between the cover and the arch (6).

Abstract: The invention provides an automatic channel box fitting position adjusting apparatus to facilitate positional adjustment of a channel box for fitting onto a nuclear fuel assembly. The apparatus comprises a position adjusting mechanism and a jig having a rod for controlling the position adjusting mechanism. The position adjusting mechanism includes guide rollers to guide the channel box to a correct fitting position. The guide rollers are tapered toward outer ends and are cantilevered at inner ends thereof.

Abstract: Gas-cooled high temperature reactor asembly, including a safety container, a chamber disposed in the safety container, a reactor vessel disposed in the chamber for receiving a charge of spherical fuel elements at a given location therein, the reactor vessel being formed of blocks of at least one material from the group consisting of carbon and graphite, a steel shell surrounding the reactor vessel, a metallic base plate supporting the reactor vessel, the base plate having openings formed therein for passing cooling gas blown in the chamber into the given location for a fuel element charge, at least one downwardly extended pipeline having a connection to the base plate for discharging heated gases, the connection being detachable by axial motion of the reactor vessel, a removable cover disposed on top of the chamber, and means disposed on the reactor vessel for connecting the reactor vessel to hoisting apparatus.

Abstract: In a nucler reactor containment structure, a fuel transfer arrangement including a bridge, trolley, and grapple, each of the latter having a position sensor mounted thereon, and control means for determining the position of bridge, trolley, and grapple in response to signals from said position sensors, whereby fuel assemblies may be transferred between locations in the containment structure.