Abstract: The invention relates to a storage device (1) for storing and transporting nuclear fuel assemblies, the device comprising a plurality of adjacent compartments, each having a lateral wall and being capable of receiving a nuclear fuel assembly, the lateral walls being made using notched structural units (6a, 6b) that are stacked and crisscrossed. According to the invention, each unit (6a, 6b) comprises two spaced-apart flats (16, 18) made of a neutrophage material, as well as an intermediate structure (119) situated between the flats (16, 18) and in contact with them.

Abstract: Transport and storage of nuclear fuel assemblies may require double confinement depending on the circumstances. A device and a method are described to perform this double conditioning without the need of a hot containment, and in which the loading and pre-positioning steps can take place in a pool. The device (10) includes a metallic inner leak tight conditioning receptacle (20) and a metallic outer leak tight receptacle (30). When the inner receptacle (20) is located in the outer receptacle (30), a passage (15, 25) remains free between the two receptacles, from the open end to the bottom of the outer receptacle. The outer receptacle (30) can be drained through this passage, particularly by a dip tube (33).

Abstract: The invention concerns a neutron shielding material for maintaining sub-criticality based on unsaturated polymer: Said material comprises an unsaturated polyester resin, at least an inorganic boron compound, and at least a hydrogenated inorganic compound, in amounts such that the boron concentration is 4.1021 to 25.1021 atoms per cm3 and the hydrogen concentration is 3.1022 to 5.5.1022 atoms per cm3.

Abstract: The invention relates to a shielding wall (12) with a puncture-resistant shield for a container (1), said wall (12) comprising support means (20) as well as the following respective stacked elements (24, 26, 28, 30, 32): an outer plate (24); a first dampening layer (26); an intermediate plate (28); a second dampening layer (30); an inner plate (32). According to the invention, the intermediate plate (28) is positioned non-rigidly with respect to the support means (20). The invention likewise relates to a container (1) comprising at least one shielding wall (12) such as the one described above. Application to the field of transporting/storing nuclear materials.

Abstract: The invention relates to a storage device (1) for storing and transporting nuclear fuel assemblies, the device comprising a plurality of adjacent compartments, each having a lateral wall and being capable of receiving a nuclear fuel assembly, the lateral walls being made using notched structural units (6a, 6b) that are stacked and crisscrossed. According to the invention, each unit (6a, 6b) comprises two spaced-apart flats (16, 18) made of a neutrophage material, as well as an intermediate structure (119) situated between the flats (16, 18) and in contact with them.

Abstract: The invention relates to a material for neutron shielding and for maintaining sub-criticality, and a process for preparation of this material and applications of the said material. The material comprises a matrix based on a vinylester resin, at least one polyamide and an inorganic filler capable of slowing and absorbing neutrons. Applications: manufacturing of neutron shields in packagings for transport, interim storage and/or ultimate storage of radioactive materials, particularly packagings for new nuclear fuels.

Abstract: A method and device for blocking a fuel assembly in a housing of a transport basket. An attachment system is placed between an upper end piece of a fresh fuel assembly that it is to be transported and the open end of a housing in which the assembly is placed, to make a rigid connection between them. The attachment system holds the lower end piece of the assembly far from the bottom of the housing and puts the upper end piece in contact laterally with the corner of the housing designed to face downwards during subsequent transport of the assembly in the horizontal position. Furthermore, the lower end piece of the assembly is maintained laterally by a part of the housing with a smaller section.

Abstract: Transport and storage of nuclear fuel assemblies may require double confinement depending on the circumstances. A device and a method are described to perform this double conditioning without the need of a hot containment, and in which the loading and pre-positioning steps can take place in a pool. The device (10) includes a metallic inner leak tight conditioning receptacle (20) and a metallic outer leak tight receptacle (30). When the inner receptacle (20) is located in the outer receptacle (30), a passage (15, 25) remains free between the two receptacles, from the open end to the bottom of the outer receptacle. The outer receptacle (30) can be drained through this passage, particularly by a dip tube (33).

Abstract: The invention relates to a container (1) intended for transport/storage of radioactive materials, the container comprising a container body (2) and at least one handling device (8) mounted using attachment screws (38) in a base housing (30) delimited by a base housing wall (32). According to the invention, a sealing plate (50) covering the attachment screws is installed removably in a plate housing (52) delimited by a plate housing wall (56) provided on the handling device and by a portion (58) of the base housing wall. Furthermore a seal (66) is provided inserted between a peripheral wall (60) external to the plate and the portion (58) of the base housing wall, and a seal (74) inserted between a peripheral wall (68) external to the plate and the plate housing wall (56).

Abstract: This invention relates to a composite material for neutron shielding and maintenance of sub-criticality comprising a matrix based on vinylester resin and an inorganic filler capable of slowing and absorbing neutrons. The vinylester resin may be an epoxymethacrylate resin and the inorganic filler may contain a zinc borate and an alumina hydrate or magnesium hydroxide.

Abstract: A method of treating aqueous salt solutions to provide a solution suitable for vitrification to a stable glass matrix for long term storage is described. In particular, salt solutions composed of aqueous nuclear waste materials are suitable for treatment by the described method. Specifically, salt solutions which have a sulfate to sodium mole ratio that does not permit easy vitrification into stable glasses may be treated by the present invention. The present method decreases the volume of vitrified glass.

Abstract: A method of treating aqueous salt solutions to provide a solution suitable for vitrification to a stable glass matrix for long term storage is described. In particular, salt solutions composed of aqueous nuclear waste materials are suitable for treatment by the described method. Specifically, salt solutions which have a sulfate to sodium mole ratio that does not permit easy vitrification into stable glasses may be treated by the present invention. The present method decreases the volume of vitrified glass.

Abstract: The invention relates to an arrangement device (1) for the storage and/or transport of nuclear fuel assemblies, the device (1) comprising a plurality of compartments (2) capable of receiving at least one nuclear fuel assembly, each compartment (2) being made of a plurality of wall elements (6, 8, 10) that form the sidewall of the compartment (2), at least one connection between two elements (6, 8) of the compartment (2) wall being made using one engagement portion (12) and a complementary engagement portion (14), respectively formed on said two wall elements (6, 8) of the compartment (2). According to the invention, the engagement portion (12) and the complementary engagement portion (14) each contain a dovetail-shaped part that fits into the other, along a direction approximately parallel to a longitudinal axis (4) of the compartment.

Abstract: An automated machine for loading nuclear reactor fuel, BP, or APSR pellets from small trays having rows of pellets into reactor rods of long length wherein the pellets are individually counted and loaded into rows of a loading tray according to the desired number of pellets per row and total number of pellets per tray with the loading tray controls being moved to a que tray where they may be weighted and there from to an unloading tray for sequential row loading into the reactor rod.

Abstract: The top nozzle (6) of the fuel assembly includes a transverse adaptor plate (6a) penetrated by openings (8) for fastening the guide tubes (4) and by openings (9) for water to pass through. The water passage openings (9a) in the adaptor plate (6a) of the top nozzle (6) which are arranged in a central part of the adaptor plate (6a) have a triangular shape with rounded corners and are distributed regularly around at least some of the openings (8) for fastening the guide tubes (4).

Abstract: Surface preoxidation of the substrate is carried out by bringing the substrate into contact with an oxidizing gas excited by a cold plasma, the substrate being situated in the flowing afterglow of the cold plasma used to excite the oxidizing element and being heated to an oxidation temperature of less than 500.degree. C. A metal oxide is formed at the surface of the preoxidized substrate by heterogeneous oxidation of a metal halide with a gas mixture including an oxidizing element activated by a cold plasma. The oxidizing gas mixture is brought into contact with the halide as directly as possible in the vicinity of the substrate arranged in the far flowing afterglow of the cold plasma. The cold plasma is preferably generated by microwaves. The process can be used in particular for producing a protective coating on a cladding tube of a nuclear fuel rod.

Abstract: The fuel assembly includes an arrangement for quickly fixing the guide thimble into an opening passing through the adaptor plate of a dismountable nozzle of the assembly. This arrangement includes at least two bearing stops inside the opening of the nozzle, a bearing sleeve integral with the end of the guide thimble and a locking ring which includes stops for bearing on bearing surfaces of the stops inside the opening of the nozzle and deformable elastic parts capable of being accommodated in cavities of the opening of the adaptor plate or of the bearing sleeve, in order to place the ring in a position in which the guide thimble is locked or unlocked. The sleeve includes a rim for bearing on a bearing surface of the adaptor plate at the periphery of the opening.

Abstract: The spacer grids consist of interlaced metal straps defining a regular lattice of cells. A spring for holding a fuel rod against bearing stops is fixed on at least one wall of each of the cells. In its part which constitutes the wall of the cell, the strap includes at least one stop produced by cutting and pushing the metal of the strap into the cell, so as to limit the displacement of a fuel rod housed in the cell. Stops for limiting the displacement of the fuel rod are placed preferably o the walls of the peripheral cells or corner cells of the spacer grid, opposite a peripheral belt of the spacer grid. The invention also relates to a fuel assembly which includes, in addition to structural spacer grids, end grids and additional mixing grids interposed between the structural spacer grids.

Abstract: The fuel assembly includes an arrangement for quickly fixing the guide thimble into an opening passing through the adaptor plate of a dismountable nozzle of the assembly. This arrangement includes at least two bearing stops inside the opening of the nozzle, a bearing sleeve integral with the end of the guide thimble and a locking ring which includes stops for bearing on bearing surfaces of the stops inside the opening of the nozzle and deformable elastic parts capable of being accommodated in cavities of the opening of the adaptor plate or of the bearing sleeve, in order to place the ring in a position in which the guide thimble is locked or unlocked. The sleeve includes a rim for bearing on a bearing surface of the adaptor plate at the periphery of the opening.

Abstract: Each of the square top nozzles (26) of the fuel assemblies of the core includes four locating openings (40) in the vicinity of the vertices of the nozzle. The set of locating pins (35) of the upper core plate (32) includes four pins at each of the positions of fuel assemblies which are intended to be engaged in the four openings (40) of the top nozzle (26). The locating openings (40) of the nozzle may consist of the internal bores of sleeves (36) which are fixed on the nozzle in an axial arrangement and holds the spring leaves (38) of the nozzle. The locating openings may also be machined inside four bosses, projecting at the upper part of the assembly, and each arranged in one corner of the assembly.