摘要:
A control rod assembly for a boiling water reactor comprises a tie-rod of a cross-shaped section, and four sheaths. Each of the sheaths is of a U-shaped section and mounted to the respective arms of the tie-rod. One or more neutron absorber materials are disposed within a space defined by the arm and the sheath. The neutron absorber material is axially separated into two portions. One of two portions is supported by a supporting member. The other portion is suspended by a handle.
摘要:
A fuel assembly comprises a plurality of fuel rods supported by an upper tie plate and a lower tie plate respectively at each of upper end portion ad lower end portion, and a channel box surrounding a bundle of the fuel rods and the lower tie plate. The fuel assembly forms a natural uranium region at lower end portion of effective fuel length portion. A wall thickness at a lower thick wall region of the channel box is thicker than the wall thickness at a region disposed upwardly from the lower thick wall region and between corner portions of the channel box. An upper end of the lower thick wall region is disposed from an upper side of the lower tie plate and downwardly from an upper end of the natural uranium region. A wall thickness at the corner portion of the channel box is thicker than the wall thickness at a middle portion of the side wall between the corner positions at the region locating upward from the lower thick wall region. The fuel assembly is able to reduce stresses caused in the channel box during an earthquake, and, is able to improve fuel economy.
摘要:
A nuclear fuel assembly has a plurality of fuel rods and a lower tie plate supporting their lower ends. Coolant apertures extending through the lower tie plate. A channel box surrounds the fuel rods and receives the lower tie plate, to confine the coolant. To restrict leakage of coolant between the tie plate and the channel box, the coolant apertures include, adjacent the periphery of the lower tie plate, a plurality of peripheral apertures which are located at least partly outside the outermost fuel rods. The peripheral apertures each provide a coolant velocity peak located further from the axial center line of the tie plate than the axial center lines of the closest neighboring fuel rods. The invention also provides venturis in the leakage path between the channel box and the tie plate, to restrict deformation of the tie plate.
摘要:
A fuel assembly has a fuel spacer consisting of a water rod having an outer diameter greater than that of fuel rods and a large number of circular sleeves into which the fuel rods are inserted. The fuel spacer has four bridge members. Both ends of these bridge members are fitted to two of eight circular sleeves which are adjacent one another in the diagonal direction of the fuel spacer. Both ends of each bridge member are bent so that its center projects outwardly away from the water rod.
摘要:
To reduce the manufacturing processes of a control rod and shorten the time required for manufacturing a control rod, for the lower part support member 7, the thin parts 11A and 11B are formed in the neighborhood of each of the left and right sides of the window 8. In the left and right sides of the pull-up handle 9, the grooves 17A and 17B are formed respectively. The groove 17B is deeper than the groove 17A. The thin part 11A is fitted into the groove 17A and the thin part 11B is fitted into the groove 17B. The gap formed between the end of the thin part 11B and the bottom of the groove 17B is larger than the gap formed between the end of the thin part 11A and the bottom of the groove 17A. Therefore, the thin part 11A can be simply fitted into the groove 17A.
摘要:
A fuel assembly, particularly, a fuel assembly including short-length fuel rods and fuel spacers, is used for a boiling water reactor, which is capable of sufficiently reducing the pressure loss of at least one of the fuel spacers positioned above the upper ends of the short-length fuel rods, irrespective of the arrangement of the short-length fuel rods, and also ensuring the structural strength of the fuel spacer. The fuel assembly includes fuel rods located in a square lattice array, two water rods arranged in a region in which seven of the fuel rods are arrangeable, two fuel spacers for holding the fuel rods and the water rods with mutual intervals kept immovable. Each of the fuel spacers includes cells which are connected to each other and in which the fuel rods are to be inserted, respectively, and a band for surrounding the outermost peripheries of the cells. The short-length fuel rods include four first short-length fuel rods arranged in the outermost peripheral region of the square lattice array. One of the fuel spacers, positioned upward from the upper ends of the short-length fuel rods, is configured such that the cells located at lattice positions associated with the first short-length fuel rods are removed and instead supporting members, each being adapted to connect two of the cells adjacently located on both sides of each of the lattice positions in the outermost peripheral region to the band, are provided at the lattice positions.
摘要:
A fuel assembly having a plurality of fuel rods arranged in a square lattice array. The fuel rods include a plurality of short-length fuel rods each having a fuel active length shorter than that of each of remaining ones of the fuel rods. At least one water rod is arranged in a region in which one or more of the fuel rods are arrangeable in the array, and a plurality of fuel spacers are provided at a plurality of positions in the axial direction for holding the plurality of fuel rods and the at least one water rod, with mutual radial intervals therebetween being kept immovable. The plurality of short-length fuel rods include at least one first short-length fuel rod arranged in the outermost peripheral region of the square lattice array. Each of the plurality of fuel spacers include a plurality of cylindrical members.
摘要:
A photoreactive agent is provided for removing harmful materials which comprises a substrate and a layer containing a photoreactive semiconductor and organic fine particles coated with inorganic fine particles which is formed on at least one side of the substrate. A photoreactive agent is provided for removing harmful materials which comprises a substrate, a layer containing a photoreactive semiconductor and a layer containing organic fine particles coated with inorganic fine particles which layers are formed in that order on at least one side of the substrate. A photoreactive agent is provided for removing harmful materials which comprises a substrate, a layer containing a photoreactive semiconductor and a layer containing film-forming inorganic fine particles and a water repellent which layers are formed in that order on at least one side of the substrate. A photoreactive agent is provided for removing harmful materials which comprises a substrate, a layer containing a photoreactive semiconductor, a layer containing film-forming inorganic fine particles and a layer containing a water repellent which layers are formed in that order on at least one side of the substrate. The photoreactive agents for removing harmful materials are excellent in ability to remove harmful materials such as malodor, are water-resistant, are not changed in characteristics over a long period of time, and can easily be produced.
摘要:
The industrial production of 4-(2-methyl-1-imidazolyl)-2,2-diphenylbutanamide, a urinary incontinence remedy, necessitates elimination of problems concerning the use of a synthetic adsorbent, e.g., HP-20, the efficiency of operation with the same, purification efficiency, etc. An acid salt, e.g., hydrochloride or phosphate, of 4-(2-methyl-1-imidazolyl)-2,2-diphenylbutanamide or a hydrate of any of these salts is used as an intermediate. This intermediate is neutralized and then purified. Thus, high-purity 4-(2-methyl-1-imidazolyl)-2,2-diphenylbutanamide is easily obtained in satisfactory yield. The industrial-scale production process has been thus established.
摘要:
Photographic light-sensitive materials having a coating layer containing a cation modified colloidal silica on one surface of a hydrophobic support have markedly improved antistatic properties.