Abstract: A shipping container is provided for use in containing and supporting a nuclear core component assembly, such as a control or poison assembly. The shipping container includes a separate rigid cylindrical body and lid of plastic material, a plurality of elongated tubes of plastic material, and foam plastic rigid flat cylindrical spacer plates. The tubes are inserted into the body for receiving and stabilizing elongated rods of the core component assembly. The spacer plates are disposed stationarily within and transversely across the body and spaced apart from one another axially along the body. Each plate has a plurality of openings therethrough for receiving and disposing the tubes in transverse side-by-side spaced relationship with respect to one another in, and extending between a closed bottom and an open top of, the body. The plates thus laterally space and support the rods when received in the tubes.

Abstract: The leaf springs mounted in the upper nozzle of a prior art fuel assembly, which are compressed by the upper core plate to restrain the upward movement of the fuel assembly under the pressure of upwardly-flowing coolant, as dispensed with. Instead the fuel assembly is permitted to rise in a controlled manner into engagement with the upper core-support plate. The lower nozzle is provided with snubbers which engage, and exert low pressure, as required by the specifications governing a reactor, on the lower core plates when the fuel assembly is raised into engagement with the upper core plate by the force of the flowing coolant. In addition springs are provided between the pins extending from the upper and lower core plates and the walls of the holes in the upper and lower nozzles to suppress vibration under the transverse forces impressed by the flowing coolant.

Abstract: A fuel assembly in a nuclear reactor has a spectral shift apparatus including a plurality of displacer rods for controlling reactivity in the assembly and an apparatus for refurbishing the displacer rods for reuse. Each displacer rod contains a quantity of water equivalent to a small fraction of the rod volume. Also, the spectral shift apparatus includes a manifold with a central plenum and a rupturable disk connected to the manifold. The manifold is connected in flow communication with the displacer rods. The disk which seals the displacer rods as well as the manifold plenum is rupturable at a given pressure differential thereacross so as to allow entry of the moderator/coolant liquid into the manifold and rods. Also, a screen adjacent the disk restricts it to rupturing in one direction only.

Abstract: A fuel assembly in a nuclear reactor has a spectral shift apparatus including a plurality of displacer rods for controlling reactivity in the assembly and an apparatus for refurbishing the displacer rods for reuse. Each displacer rod contains a quantity of water equivalent to a small fraction of the rod volume. Also, the spectral shift apparatus includes a manifold with a central plenum and a rupturable disk connected to the manifold. The manifold is connected in flow communication with the displacer rods. The disk which seals the displacer rods as well as the manifold plenum is rupturable at a given pressure differential thereacross so as to allow entry of the moderator/coolant liquid into the manifold and rods. Also, a screen adjacent the disk restricts it to rupturing in one direction only.