[en] The invention relates to a sealing device in a graphite-moderated light water-cooled nuclear reactor. The reactor comprises a plurality of fuel channels and each fuel channel at its upper part encloses a plug. A gap is provided between said fuel channel and said plug and sealing surfaces are arranged correspondingly on the inner part of the fuel channel and the outer part of the plug, respectively. The sealing device is arranged in the gap between said sealing surfaces, and is characterized in that it comprises one or more annular bodies arranged in the axial direction one after the other and making direct contact with each other. Each body is plastically deformable for transforming the force in the axial direction obtained via the plug into a sealing pressure in the radial direction whereby it achieves a sealing effect of the sealing device. Further, the sealing device is characterized in that at least that part of it, which faces the sealing surfaces, is monolithic. (author)

[en] Describes a design of the feed water tubes. The new design has a second air coolant channel placed near the inner side of the biological shield. By this arrangement the cooling of the feed water tube is improved

[en] A water inner circulation device for a reactor vessel comprising a pump mounted in the reactor vessel and driven by a water-cooled electric motor mounted in a housing outside the reactor vessel, the shaft of the pump passing through the reactor-vessel bottom and being coupled to the motor shaft in a member mechanically connected to the bottom of the reactor vessel in the vicinity of the motor housing, the pump shaft being surrounded by a resilient sealing ring, the reactor vessel communicating with the cooling channels of the pump, when the latter is operating, via a slot surrounding the pump hollow cylindrical shaft, characterized in that the slot inner end is used for/forming a circular space surrounding the pump shaft and surrounded by the motorhousing, in which is coaxially mounted a separating cylindral wall, the upper edge of which is tightly applied against the inner wall of the motor-housing to which it is fastened vertically, the inner surface of said wall being turned towards the outer surface of a circular packing-box, the outer surface of said separating wall constituting a separating radical inner surface for a circular chamber through which flow the motor cooling water. (author)

[en] The inner surface of the cylindrical biological shielding surroundin the reactor pressure vessel is provided with a steel liner cast into the concrete and provided with vertical ducts for cooling air which enters through a number of pipes at the upper end of the shielding, and is exhausted at the lower end. The liner is divided into a number of segments of steel plate. Each segment includes one cooling duct and fins which are cast into the concrete. The segments are held in place by bolts and square washers attached to vertical steel channels, also cast into the concrete. Extensions to these bolts form the fasteners for holding the thermal insulation in place against the inner surface of the liner. (J.I.W.)

[en] The report treats ideas and perspectives and its aim is to broaden the views. Thus it might be possible to make the choice between different futures. The roads and the mechanisms of choice are discussed. The existing technical-economical, system-theoretical investigations which characterize the energy policy are considered to have a limited scope

[en] In that nuclear reactor core, several fuel assemblies are enclosed in a moderator vessel and fixed by an assembly-carrying grid, whereas each fuel-assembly comprises a polygonal can and several control-rod guide-tubes surrounded by said can. The assembly-carring grid is fixed to the vessel-cover and is so arranged that it provides a mechanical contact with the upper edges of the can-walls, so that the surfaces of fuel assembly cans located in vertical planes are intersected by vertical planes along the surfaces of the assembly-carrying grid. Such mechanical contact is established at places where the grid is provided with means for immobilizing the cans

[en] This is the final report for a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This project sought to study of unusual magnetic and structural properties of rare earth, actinide, and transition metals through high-precision electronic structure calculations. Magnetic moment anisotropies in bulk and surface systems were studied, with emphasis on novel surfaces with unusual magnetic properties with possible applicability in magnetic recording. The structural stability, bonding properties, and elastic response of the actinides, as well as transition and rare earth elements and compounds, were also studied. The project sought to understand the unusual crystallographic and cohesive properties of the actinides and the importance of correlation to structural stability and the nature of the delocalization transition in these elements. Theoretical photoemission spectra, including surface effects, were calculated for rare earths and actinides

[en] A description is given of a core for a nuclear reactor which includes a moderator tank and fuel assemblies within the moderator tank. The tank has a lid. The fuel assemblies are fixed by an assembly grid shaped as a lattice, each fuel assembly including a polygonal shroud and a plurality of control rod guide tubes surrounded by the shroud. The walls of the shrouds extend upwardly above the control rod guide tubes. The grid is secured in place by the lid of the moderator tank. The grid has mechanical contact with the upper edges of the shrouds, the vertical planes along the surface of the grids crossing the planes along the surfaces of the shrouds. The mechanical contact is made by downwardly open slots in the sheet metal parts constituting the grid which engage the upwardly extending edges of the shroud

[en] We have used the linear muffin-tin-orbital method, without geometrical approximations, to calculate the electronic structure of tetragonal BaTiO₃ and cubic SrTiO₃. Using our self-consistent potential, we have calculated the frequency-dependent dielectric function and the reflectivity spectrum. For tetragonal BaTiO₃ the anisotropic optical properties are calculated. We compare our calculations with experimental data and find good agreement. We analyze the origin of the different calculated features in the optical spectra by means of our energy-band structure. copyright 2001 American Institute of Physics

[en] Ti₃Sn forms an orthorhombic metal hydride phase at 25-kPa deuterium pressure and 650 deg. C. The unit cell parameters were determined to be a=6.179(1) A, b=9.877(2) A and c=4.7898(6) A and the space group to be C222₁. The crystal structure was determined from neutron powder diffraction data with the Rietveld method. Three phases are formed in the Ti₃Sn-D system upon hydrogenation, and appear in the following order at increasing deuterium pressures: an orthorhombic structure (Ti₃SnD_0.80), a hexagonal phase and a cubic metal hydride phase (Ti₃SnD). The cubic phase, Ti₃SnD, crystallises in the CaTiO₃-type structure, space group Pm3m, with the unit cell parameter a=4.1776(2) A. The stability of the three Ti₃SnD_x phases is in agreement with calculated total energies, based on first principles theory