Abstract: A nuclear reactor containing assemblies having two caps and a framework inside which fuel rods are disposed vertically is reloaded by first inverting the assembly to be removed into a vertical position permitting the then lower cap to be demounted. The spent fuel rods are then identified and removed in sets and deposited in a suitable storage area, and replacement rods are placed in sets in the framework of the fuel assembly. Finally, the lower cap is replaced and the assembly is conveyed into the reactor vessel at its new location.

Abstract: In an installation for a nuclear power station comprising a "reactor building" with a first swimming pool for handling of fuel units and a fuel building with a second swimming pool for the transfer, storage and deactivation of the units, the second swimming pool is located at a lower level than that of the first and is connected to the first by an intermediate auxiliary chamber filled with water and located under the first swimming pool. The auxiliary chamber is connected by a vertical pipeline to the first swimming pool and by a horizontal connecting pipeline to the second swimming pool. Each of the pipelines is provided with a shut-off valve, with interlocking means which prevents the simultaneous opening of the two valves. There is negligible dead space around a conveyor basket for fuel units when it is in the vertical or horizontal pipelines.

Abstract: The invention relates to an assembly for passage through a containment slab for transferring irradiated nuclear fuel, comprising a sleeve passing through the slab and fast therewith and a guide ramp passing through the sleeve and in which moves a handling pot carrying the fuel, wherein said assembly further comprises a device for evacuating the residual heat dissipated by the fuel, this device comprising a bundle of caloducts disposed parallel to the ramp over a length at least equal to that of the sleeve, and means for evacuating the flow of heat directed above the slab by the caloducts.

Abstract: A reactor unit and a nuclear installation which uses said reactor unit and method of fitting up such an installation. Said installation includes mainly a reactor unit (2) which constitutes a shiftable module formed by a casing (7) and a stand (8), by a container unit (1) designed to accommodate the reactor unit (2) and by a module (3) for closing the container unit (1) and forming, for example, a swimming bath type storing unit for the used nuclear fuel. The installation of the invention may constitute a nuclear boiler which can be transported to the operation site in the form of an integral assembly or in separate components.

Abstract: A reactor refueling method utilizing a vibrating fuel grapple for removing spent fuel assemblies from a reactor core which incorporates a pneumatic vibrator in the grapple head, enabling additional withdrawal capability without exceeding the allowable axial force limit. The only moving part in the vibrator is a steel ball, pneumatically driven by a gas, such as argon, around a track, with centrifugal force created by the ball being transmitted through the grapple to the assembly handling socket.