Abstract: The present invention relates to a radioactive electron emitting microchannel plate. More particularly, to a radioactive electron generating microchannel plate comprising (a) a pair of parallel substrates; (b) at least one radioactive material layer deposited on an inner surface of the substrates; and (c) at least one electron ray-amplifying layer deposited on the surface of the radioactive material layer. The emitted electron ray is amplified by penetrating into the cavity formed by a pair of parallel substrates and is further amplified by reflecting from the electron ray-amplifying layer. As the substrate in the microchannel plate, use can be made of a capillary tube or a thin plate. The microchannel plate of the present invention can be applied as an electron ray source in an electron ray-generating device, an image display device, and electron ray-etching device.

Abstract: The present invention relates to a zirconium alloy having excellent corrosion resistance and mechanical properties and a method for preparing a nuclear fuel cladding tube by zirconium alloy. More particulary, the present invention is directed to a zirconium alloy comprising Zr-aNb-bSn-cFe-dCr-eCu (a=0.05-0.4 wt %, b=0.3-0.7 wt %, c=0.1-0.4 wt %, d=0-0.2 wt % and e=0.01-0.2 wt %, provided that Nb+Sn=0.35-1.0 wt %), and to a method for preparing a zirconium alloy nuclear fuel cladding tube, comprising melting a metal mixture comprising of the zirconium and alloying elements to obtain ingot, forging the ingot at &bgr; phase range, &bgr;-quenching the forged ingot at 1015-1075° C., hot-working the quenched ingot at 600-650° C., cold-working the hot-worked ingot in three to five passes, with intermediate vacuum annealing and final vacuum annealing the worked ingot at 460-540° C.

Abstract: A lips-type multi-purposed spacer grid for supporting fuel rods within a nuclear fuel assembly is disclosed. In the spacer grid, the fuel rods are in contact with dimples and water strider-type springs in an equiangular surface contact manner. The spacer grid distributes load, applied to the springs, to the entire structure of its inner strips, thus reducing peak stress at the contact surfaces between the fuel rods and the springs and diminishing vibration of the fuel rods, and thereby reducing possible fretting wear of the fuel rods due to hydraulic vibration of the fuel rods. The spacer grid also enlarges the allowable elastic range of the springs, and allows the springs to soundly support the fuel rods by using residual spring force. The spacer grid has mixing blades capable of minimizing pressure loss and flow interference, so that the fuel rod cooling efficiency of the nuclear fuel assembly is improved.

Abstract: Disclosed are a method and an apparatus for continuously casting a uranium rod so that impurities generated in melting the metallic substance reduced from nuclear spent fuel are easily removed, the molten metal is easily degassed, the oxidation of uranium is prevented, and the molten metal does not remain in a crucible, thereby completely removing the noxious gas, improving the safety of work, allowing the workers to be close to the apparatus, reducing the consumption rate of the inert gas, completely preventing the oxidation of uranium, and being remotely controlled.

Abstract: The present invention provides a remote-controlled in-pile creep test system used in in-pile creep tests for measuring and determining mechanical properties of nuclear materials irradiated in research reactors.

Abstract: A side-slotted nozzle type double sheet spacer grid for nuclear fuel assemblies is disclosed. The spacer grid includes intersecting inner strips and four perimeter strips. Each inner strip has unit strip parts, each fabricated by integrating two unit sheet parts together into a single structure, such that the two unit sheet parts face each other and a nozzle type coolant channel is defined between the two unit sheet parts. Each perimeter strip is fabricated by integrating an inner thin sheet having the unit sheet parts with a flat outer thin sheet having a width corresponding to the width of the inner thin sheet into a single structure. The coolant channel has one or more outlets formed by cutting an upper portion of one of the two unit sheet parts of each unit strip part. Each unit sheet part has a slot longitudinally formed on each side surface of a spring that is projected from the unit sheet part to support a fuel rod within a four-walled cell.

Abstract: A spacer grid for nuclear fuel assemblies is disclosed. This spacer grid has a plurality of side weld supports, that is, main supports, upper sub-supports and lower sub-supports, on its interlaced inner straps, with two flow mixing vanes integrally extending upward from each of the main supports. This spacer grid is fabricated by seam-welding the interlaced first and second inner straps to each other along the upper axial junction lines of the crossing main and upper sub-supports at the top of the intersections, and along the lower axial junction lines of the crossing lower sub-supports at the bottom of the intersections, thus forming side weld lines at the intersections.

Abstract: A spacer grid for use in a nuclear fuel assembly has double-deflected vanes that guide an axial flow of coolant around fuel rods and thereby generate swirl flow. The vanes each have a double bend projecting upwardly from first inner straps and projecting toward one fuel rod. The vanes are sufficiently wide at their bases to prevent inadvertent deformation due to contact with fuel rods during an insertion of fuel rods into the cells. The vanes also make a smooth variation in the cross-sectional area of the coolant channel at the outlet of the spacer grid, thus reducing a loss of pressure during reactor operation.

Abstract: A spacer grid used for placing and supporting fuel rods in nuclear reactor fuel assemblies is disclosed. The spacer grid of this invention has a plurality of grid springs designed to have an optimal shape of their vertical support parts, thus reducing fretting wear of the fuel rods caused by contact of the fuel rods with the grid springs. The grid spring has a vertical support part and a fuel rod support part. The vertical support part includes upper and lower base parts extending downward and upward from the central portions of the top and bottom edges of an opening formed at the central portion of a unit strip, and two bridge parts branched from the upper base part and extending symmetrically downward until they are united at the lower base part. The fuel rod support part includes a conformal support part brought into surface contact with the external surface of a fuel rod.

Abstract: Disclosed are a dermal scaffold comprising alkaline pre-treated free amine-containing chitosan matrix, alkaline pre-treated free amine-containing chitosan and alkaline pre-treated collagen mixed matrix, or alkaline pre-treated free amine-containing chitosan and alkaline pre-treated collagen mixed matrix containing chitosan fabrics, which has excellent wound healing effect by constituting microenvironments suitable for migration and proliferation of fibroblasts and vascular cells surrounding the wound to be extremely useful as wound healing dressings, and a bioartificial dermis comprising the dermal scaffold and human fibroblasts, particularly useful for healing broad wound sites such as burns.

Abstract: An instrumented capsule for material irradiation tests in research reactors. The instrumented capsule performs an optimum material irradiation test under a testing environment similar to the operational environment of a real reactor. The capsule minimizes the influence of flow-induced vibration caused by forced-circulation-type coolant flow in a research reactor, and overcomes the problems experienced in the conventional breakable parts of instrumented capsules which may be broken during the process of loading/unloading the capsules in vertical irradiation holes of reactor pools. The instrumented capsule includes a capsule main body installed in the vertical irradiation hole. The capsule main body consists of a shell and several instruments, such as thermocouples, dosimeters, a vacuum control pipe, and heaters housed in the shell.

Abstract: Disclosed herein is a method of discriminating a through-wall crack and measuring the through-wall length of the crack in a steam generator tube of a nuclear power plant. The method of the present invention is characterized in that the through-wall crack is discriminated and the through-wall length of the crack is measured in such a way that there are measured the number and positions of inflection points of a graph that is plotted by relating characteristic amplitude values of eddy current signals, which are generated whenever a coil of a motorized rotating probe passes the crack while being spirally rotated, to the positions in the length of the crack.

Abstract: A double strip mixing grid for nuclear reactor fuel assemblies is disclosed. This grid is fabricated by intersecting at right angles a plurality of double strips, each fabricated by welding two thin sheets together into a single structure with coolant channels. The mixing grid, having the channels, effectively mixes low temperature coolant with high temperature coolant within a fuel assembly, thus improving the thermal efficiency of the fuel assemblies. This mixing grid also effectively prevents the coolant from being partially overheated, thus improving the soundness of nuclear reactors. This mixing grid also has swirling flow blades and/or lateral flow blades to further improve the thermal efficiency of the fuel assembly. This mixing grid elastically supports the fuel rods by the sheets of the double strips, collaterally acting as positioning springs.

Abstract: A radiation source assembly and a connector press used in producing such assemblies. In the radiation source assembly, each of the cap connector and the female connector is provided with internal round threads on its pigtail fitting hole, thus engaging with the large-diameter coil of the pigtail at the internal round threads through a thread engagement prior to a compression process of the press. The assembly also allows a person to know whether both ends of the pigtail fully reach desired points within the two connectors, thus securing a precise compressing target portion during a compression process of the press. The inserted lengths of the pigtail relative to the two connectors are maximize accomplishing a desired linearity of the assembly. In the assembly, a target biasing spring is provided on the capsule lid and allows the disc targets within the source capsule to effectively maintain a desired condition as point sources regardless of the number of targets.

Abstract: A remote-controlled mobile cleaning device for removal and collection of high radioactive waste debris in a spent nuclear fuel process and fabrication area, such as a hot-cell, is disclosed. The device includes navigation means for moving it to the desired cleaning location and climbing over such obstacles as electrical cables and pneumatic tubes placed on the hot-cell floor to be cleaned, suction and collection means for dislodging, filtering, and capturing high radioactive waste debris, and cover means for protecting suction and collection means. The device that is operated by remote control cleans and collects loose dry spent nuclear fuel powder and other high-radioactive waste debris adhered to both the contaminated in-cell floor and the in-cell spent nuclear fuel process and fabrication equipment, without spreading inside the hot-cell.

Abstract: Disclosed are a method and an apparatus for producing a uranium foil with fine crystalline granules by forming the foil by the gravitational dropping of molten uranium or uranium alloy and rapidly cooling the foil by the contact with cooling rolls, and a foil produced thereby. In accordance with the present invention, a high-purity and high-quality uranium foil with an isotropic structure and fine crystalline granules is easily produced via a simple process without requiring hot rolling and heat treatment processes. The surface of the foil is prevented from oxidizing and residual stress is not imparted to the foil. The productivity and the economic efficiency of the foil are improved.

Abstract: A duct-type spacer grid for nuclear fuel assemblies is disclosed. In this spacer grid, a plurality of duct-shaped grid elements, individually having an octagonal cell, are closely arranged in parallel and are welded together, thus forming a matrix structure. The grid elements do not pass across the center of the subchannel of the assembly, thus effectively reducing pressure loss. Each of the grid elements is formed as an independent cell, and so they effectively resist against a lateral impact. A plurality of integral type swirl flow vanes, having different heights or same height, axially extend from the top of the grid to be positioned within each subchannel. The swirl flow vanes are bent outwardly, and so they do not contact the fuel rods during an insertion of the fuel rods into the cells. In the spacer grid, the fuel rods are supported within the cells by line contact springs without using any dimple.

Abstract: Disclosed are a CaSO4 based TL detector bonded with phosphorous compound and a method for fabricating thereof. The CaSO4 based TL detector can be fabricated by mixing CaSO4 based TL powder with a phosphorous precursor; molding the mixture powder under pressure; and sintering the molded body. The TL detector has so high TL sensitivity as to effectively measure personnel dose equivalent and low dose detection. It can be also manufactured in various forms and is easily handled, finding numerous applications in personnel and environmental monitoring fields.

Abstract: Disclosed is a method for manufacturing a catalytic oxide anode using high temperature sintering, which can increase a decomposition efficiency of an organic substance by improving a performance of the catalytic oxide anode (Ru oxide anode, Ir oxide anode) used in a water treatment, and in particular, to a method for manufacturing a catalytic oxide anode, in which the oxide anode is sintered at 600° C. or higher, and a TiO2-screening layer is formed between a titanium base metal and a catalytic oxide layer to prevent a lowering of the oxide anode activity owing to an oxidation of the titanium base metal caused by sintering the oxide anode at high temperature and a solid diffusion of an oxide into an anode surface.

Abstract: The present invention relates to a polysaccharide composition having the hematopoietic, myeloprotecting, antitumor immune cell generating, and radiosensitizing activities extracted from the roots of Panax ginseng prepared by the steps of: i) obtaining the residue by extracting 1 wt part of ginseng roots with 2˜4 wt part of methanol; ii) extracting and obtaining the water soluble fraction from the residue in step i) using 3˜5 wt part of distilled water; iii) freeze-drying the obtained water soluble fraction in step ii); iv) obtaining the inner fraction using the dialysis membrane after obtaining the insoluble fraction to the 40% of ethanol from freeze-dried fraction in step iii); v) obtaining the 6 fractions by sephacryl S-500 gel chromatography; and vi) purifying the polysaccharide by DEAE-sephadex A-50 chromatography.