Abstract: A spent fuel rack for storing fresh fuel assemblies, or spent fuel assemblies removed from a nuclear reactor, which includes a base plate having multiple cells of modular construction welded at their bottom ends to the plate. The cells are formed of L-shaped sections having walls which support neutron absorbing material, and the walls of one cell are common to the adjacent cells. The base plate includes openings primarily for receiving the bottom nozzle of a fuel assembly, but they further serve as access openings for apparatus used for leveling the base plate. There is also means for receiving and locking the engaging mechanism of lifting apparatus which means is wholly within the periphery of the base plate.

Abstract: A method of making a rack for storing a maximum number of fuel assemblies in spent-fuel storage locations in a minimum space. The rack has locations each formed by bending a stainless-steel sheet into a hollow body of the generally rectangular cross section and with each side shaped so that the apices of the body project outwardly. Except for bodies along the outer periphery of the rack, the apex of each body is contiguous to the apex of an adjacent body. These contiguous apices are joined by spaced welds longitudinally along the bodies. The welds are spaced so as to maximize the resistance of the rack to seismic acceleration and spent-fuel storage locations are thus formed. Four storage locations extend radially from the apices of each location. A wrapper plate is secured to each side of each of these four locations providing a pocket for neutron-absorbing material. An additional storage location is formed having pockets in common with the locations which bound it.

Abstract: A spent fuel rack for storing fresh fuel assemblies, or spent fuel assemblies removed from a nuclear reactor, which includes a base plate having multiple cells of modular construction welded at their bottom ends to the plate. The cells are formed of L-shaped sections having walls which support neutron absorbing material, and the walls of one cell are common to the adjacent cells. The base plate includes openings primarily for receiving the bottom nozzle of a fuel assembly, but they further serve as access openings for apparatus used for leveling the base plate and for lifting and transferring the base plate with or without cells thereon, to a different area.

Abstract: A rack for storing a maximum number of fuel assemblies in spent-fuel storage locations in a minimum space. The rack has locations each formed by bending a stainless-steel sheet into a hollow body of the generally rectangular cross section and with each side shaped so that the apices of the body project outwardly. Except for bodies along the outer periphery of the rack, the apex of each body is contiguous to the apex of an adjacent body. These contiguous apices are joined by spaced welds longitudinally along the bodies. The welds are spaced so as to maximize the resistance of the rack to seismic acceleration and spent-fuel storage locations are thus formed. Four storage locations extend radially from the apices of each location. A wrapper plate is secured to each side of each of these five locations providing a pocket for neutron-absorbing material.

Abstract: Spent fuel racks for housing new or spent fuel assemblies at a nuclear reactor site. The racks are made to modular design and include upper and lower grid structures which provide aligned square openings. A container or cell shaped to the size of a fuel assembly fits in each of the aligned square openings. To provide verticality to the aligned and uniformly spaced cells, leveling pads beneath the base plate supporting the cells are adjustable vertically to cause the base plate to assume a horizontal plane and thereby align cell longitudinal axis with a vertical plane.

Abstract: A spent fuel storage cask for long-term storage of spent nuclear fuel following short-term storage in a pool of water. The cask includes a grid basket assembly, resembling a matrix of pigeonholes, for accommodating cells which in turn accommodate spent fuel assemblies. The grid basket assembly is formed by metal plates which transmit heat to channel sections affixed to the interior walls of the cask. The edges of the plates movably fit into the channel sections in order to permit radial movement of the grid basket assembly with respect to the walls of the cask as temperature changes. During storage the cask can be flooded with helium, which readily transmits heat through narrow gaps between the edges of the plates and the walls of the channel sections. Several embodiments of cells having material for moderating neutrons emitted from spent fuel assemblies are also enclosed, some of these embodiments permitting easy conversion of the cask for storing consolidated fuel rather than intact fuel assemblies.

Abstract: A cask for storing spent nuclear fuel after removal from a pool of water includes a container with a cylindrical cavity and a basket which is inserted into the container. The basket includes disk-like grid assemblies which provide spent fuel storage slots and which are coaxially mounted at spaced-apart positions, each grid assembly having a diameter that is slightly less than the one above it. If fuel assemblies are to be stored, hollow cells are affixed to one of the grid assemblies and positioned in the others by heat-conducting wedges which permit the basket and cells to expand at different rates. Rings which project slightly into the interior of the container are provided on the container walls, each ring being positioned to be in alignment with the periphery of a corresponding grid assembly after the basket is inserted into the container.

Abstract: A cooling fin for a spent nuclear fuel storage cask is fabricated by bending an elongated composite sheet, formed by cladding a stainless steel sheet onto a carbon steel sheet, along its axis to provide two sides joined at a curved apex. The free ends of the sides are welded to the base element of the cask. A pocket is formed between the sides of the fin by welding an end plate to the bottom of the fin, and thereafter resinous neutron absorbing material is poured into the pocket. After the pocket is filled an end plate is welded to the top of the fin.

Abstract: A baffle-former arrangement for the reactor vessel internals of a nuclear reactor. The arrangement includes positioning of formers at the same elevations as the fuel assembly grids, and positioning flow holes in the baffle plates directly beneath selected former grid elevations. The arrangement reduces detrimental cross flows, maintains proper core barrel and baffle temperatures, and alleviates the potential of overpressurization within the baffle-former assembly under assumed major accident conditions.

Abstract: An arrangement for cooling the fasteners affixing a core barrel to a core former and a core baffle to a core former in the reactor vessel internals of a nuclear reactor. The arrangement allows the flowing reactor coolant to contact the fasteners, preferably bolts with an elliptical neck, and maintain lower bolt operating temperatures than previously experienced.