Abstract: An apparatus for inserting rods of a rod bundle from a nuclear reactor fuel assembly into a vessel includes a dense-setting device including: a holding cage for laterally holding the rods together in a given dense packing with mutually parallel longitudinal axes, the cage having a bottom on which one end of each of the rods stand; an insert associated with the holding cage having two ends and guide channels receiving the rods, the guide channels defining an outlet cross section at one end near the bottom with outlet openings disposed according to the given dense packing, and the guide channels defining an inlet cross section at the other end at which the rods are inserted with inlet openings disposed according to the position of the rods in the rod bundle, the insert including a plate having the inlet openings formed therein defining the inlet cross section, the plate being movable toward the outlet cross section against a spring up to a stop; and a pulling tool for pulling the insert out of the holding cage

Abstract: Fuel assembly for fast nuclear reactors includes a cluster of parallel-disposed fuel rods, and a casing surrounding the fuel rods and defining a coolant flow configuration, the fuel rods being disposed in a manner that the axes thereof intersect imaginary coaxial circles, and the casing being of circular cylindrical shape.

Abstract: A gas-cooled nuclear reactor, having a tight connection with an intentionally provided leak site between a fission-gas discharge channel formed in a reactor core carrying plate as well as in a head portion of encased fuel elements that are suspended in receiving bores formed in the core carrying plate, the tight connection being formed by an annular member having a sealing surface engaging the core carrying plate at a region thereof in which an opening to the fission-gas discharge channel formed in the core carrying plate is located, a gas-tight, elastic and substantially cylindrical member, variable in length, connecting the annular member to the fission-gas discharge channel formed in the head portion of the fuel element, compression spring means biasing the annular member in a direction away from the fission gas discharge channel formed in the fuel-element head portion, and a sealing abutment plate secured to a central pin and limiting clearance for play of the annular member with respect to an annular zon

Abstract: A nuclear reactor fuel rod is disclosed in which fission gases from the nuclear reaction are retained for a short time period to permit decay of the radioactivity present in the gases and then permit the removal of the gases from the rod. To accomplish this one of the end caps of the rod has a hole drilled in it and is connected to a fission gas removal system in the reactor. A separate container, containing pressed filter material such as, activated carbon, is metallurgically connected to the perforated end cap. At least on the side of the filter into which the fission products initially pass, a porous element is used to permit the fission products to pass into the filter material in a finely divided state without a large pressure drop.