Abstract: A dose distribution-measuring method capable of grasping a three-dimensional form of an object to be measured or evaluating a three-dimensional dose distribution thereof. The method comprises providing a multiple-eye type radiation meter probe in which at least two directional radiation detectors are arranged so as to be spaced from each other and directed toward a point to be measured; and carrying out dose measurement by directing the radiation meter probe toward an object to be measured from different positions to thereby determine a three-dimensional dose distribution of the object to be measured. Each of the radiation detectors has a structure in which a periphery of the radiation detector main body, except for a detection surface thereof, is surrounded by a radiation shield to reduce the effect of radiation from other than the object to be measured and from Compton scattering.

Abstract: The present invention is used to reduce thermal load itself, being the cause to generate stress, which develops near liquid surface in a nuclear reactor wall and to contribute to further improvement of safety. A partition member (5) is arranged above a coolant liquid surface (9) in an annulus space (3) between a reactor vessel (1) and a guard vessel (2), a low-temperature gas is circulated through the annulus space above the partition member to cool down, the gas is circulated through the annulus space from under the coolant liquid surface to the partition member, and the high-temperature gas heated under the coolant liquid surface is used to raise the temperature above the coolant liquid surface.

Abstract: A heat exchanger having an intermediate heating medium has a shell of the heat exchanger, a plurality of cylindrical partition tubes each of which has an annular space therein and is closed at both end portions thereof with annular walls, the cylindrical partition tubes being arranged concentrically in a mutually spaced manner in the shell, and helical coil-shaped heat exchanger tubes each of which is disposed in the annular space in the cylindrical partition tube. A high-temperature heating medium flows in the shell through clearances among the helically arranged multiple cylindrical partition tubes, a low-temperature heating medium flows in each of the helical coil-shaped heat exchanger tubes, and an intermediate heating medium chemically inactive with respect to both the high-temperature heating medium and the low-temperature heating medium and excellent in the heat transferring performance is passed through each of the annular spaces in the cylindrical partition tubes.

Abstract: The present invention is used to reduce thermal load itself, being the cause to generate stress, which develops near liquid surface in a nuclear reactor wall and to contribute to further improvement of safety. A partition member (5) is arranged above a coolant liquid surface (9) in an annulus space (3) between a reactor vessel (1) and a guard vessel (2), a low-temperature gas is circulated through the annulus space above the partition member to cool down, the gas is circulated through the annulus space from under the coolant liquid surface to the partition member, and the high-temperature gas heated under the coolant liquid surface is used to raise the temperature above the coolant liquid surface.

Abstract: A heat exchanger having an intermediate heating medium is provided. A multiplicity of inner tubes 2 are disposed in a shell 1 of a heat exchanger 10. A low-temperature heating medium Y (water) flows in these inner tubes and a high-temperature heating medium X (liquid sodium) flows in the shell. These inner tubes are divided into a plurality of groups so that each group has a plurality of said inner tubes. The plural inner tubes constituting one group are disposed in one outer tube 3, and an intermediate heating medium Z chemically inactive with respect to both the high-temperature heating medium and the low-temperature heating medium and excellent in heat transferring performance is passed through each outer tube. The possibility that the high-temperature heating medium and the low-temperature heating medium contact each other can be reduced to an extremely low level.

Abstract: This invention is provided for improvement of corrosion-resistant property of a crucible and for promotion of safety in a pyrochemical reprocessing method for the spent nuclear fuel. The spent nuclear fuel is dissolved in a molten salt placed in the crucible. In a pyrochemical reprocessing method, the nuclear fuel is deposited, and the crucible (2) is heated by induction heating. Cooling media (5, 6) are supplied to cool down, and a molten salt layer (7) is maintained by keeping balance between the heating and the cooling, and a solidified salt layer (8) is formed on inner wall surface of the crucible.

Abstract: A method of melting treatment of radioactive miscellaneous solid wastes wherein, even when the wastes contain various kinds of substances in a mixed state, each of the substances is efficiently induction-heated and the whole of the wastes can be melted quickly. The radioactive miscellaneous solid wastes are charged into a water-cooling type cold crucible induction melting furnace disposed within a high-frequency coil. A plurality of high-frequency currents each having a frequency suitable for induction-heating each of the various kinds of substances contained in the radioactive miscellaneous solid wastes are supplied to the high-frequency coil to melt the solid wastes by being induction-heated. The high-frequency currents of different frequencies may be simultaneously supplied to a single high-frequency coil or may be supplied to a plurality of high-frequency coils, respectively.

Abstract: In a material feeding mechanism in association with a continuous sintering apparatus, a material (S) carried by a transporting conveyer (1) into an atmosphere-displacement chamber (2) is fed into a furnace casing (4) of the continuous sintering apparatus by using a loading pusher (3). The transporting conveyor, the atmosphere-displacement chamber, and the loading pusher are arranged in such a manner that a direction in which the material is carried by the transporting conveyor and a direction in which the material is fed from the atmosphere-displacement chamber into the furnace casing by the loading pusher are linearly aligned, and the loading pusher and a drive unit thereof are installed under a floor of the atmosphere-displacement chamber so that the loading pusher moves up over the floor surface of the atmosphere-displacement chamber and moves forward and backward on the floor surface of the atmosphere-displacement chamber when the material is fed into the furnace casing.

Abstract: Abnormal flows in an extractor are simulated, with a flow divider model and a flow merger model being introduced. Overflow state, entrainment occurrence state, and reflux state in the extractor are simulated. Moreover, abnormal flows under a variety of conditions are simulated efficiently by using object-oriented software as the simulation program.

Abstract: An airtight adapter to be mounted to an airtight unit requiring airtightness, e.g. a glove box, with which it is possible to easily replace a part of the airtight adapter while maintaining airtightness. The adapter has an outer-cylinder adapter body, an internal adapter body inserted into and fitted in the outer-cylinder adapter body and at least two annular sealing members positioned between the internal adapter body and the outer-cylinder adapter body.

Abstract: A microcomputer usable for a long period of time even when disposed in a high dose radiation-exposed environment, and its access speed control method are provided. According to the microcomputer and the method, the total dose of radiation that the microcomputer receives is determined on the basis of detection signals from a radiation detecting element. Based on the determined total dose of radiation, and table data preset by tests and stored into a memory unit, a CPU controls an access speed. Moreover, the CPU, and the memory unit and a circuit interface unit that access the CPU are integrated on a single chip (ASIC) These units on the same chip are deteriorated and changed in the same direction, without fail, on exposure to radiation.

Abstract: A method of producing an iron-based dispersion-strengthened alloy tube (2-1) by utilizing a rolling machine having grooved rolls (5, 5-1) and a mandrel (9)for forming the tube (2-1) from a raw rolling tube (2). In the method, a length of contact between a rolling surface (6, 6-1) of a caliber formed by the grooved rolls and an outer circumference of the rolling tube is set to be 0.9 times or more of a circumferential length of the rolling tube over the entire area of the rolling region. It is preferred that the method be performed by a Pilger type rolling machine.

Abstract: A cylindrical thin-wall sleeve including an SiC fiber-reinforced SiC composite material (SiC/SiC), which has a porosity of 40% or less and a wall thickness of 5 mm or less.

Abstract: A new transmutation assembly permits an efficient transmutation of a long-lived radioactive material (long-lived FP nuclides such as technetium-99 or iodine-129) which was produced in the nuclear reactor. Wire-type members of a long-lived radioactive material comprised of metals, alloys or compounds including long-lived FP nuclides are surrounded by a moderator material and installed in cladding tubes to form FP pins. The FP pins, and nothing else, are housed in a wrapper tube to form a transmutation assembly. The wire-type members can be replaced by thin ring-type members. The transmutation assemblies can be selectively and at least partly loaded into a core region, a blanket region or a shield region of a reactor core in a fast reactor. From a viewpoint of reducing the influence on the reactor core characteristics, it is optimal to load the transmutation assemblies into the blanket region.

Abstract: A compressive/tensile-load-type lead damper absorbs vibration energy by elastic-plastic deformation through bending of lead. The lead damper has a semicircular structural portion at a central portion, and compressive/tensile load input points at opposite ends of the semicircular structural portion. The center of an imaginary circle that overlaps the semicircular structural portion is located on a line connecting the load input points. The lead damper deforms by only a small amount upon receipt of compressive/tensile load and has a compact structure.

Abstract: A method for homogeneously mixing a uranium/plutonium mixed oxide which is used for the preparation of a uranium/plutonium mixed oxide fuel. The method comprises weighing a uranium oxide powder, a plutonium oxide powder, and a dry recovered powder prepared by grinding a uranium/plutonium mixed oxide sinter so as to give a predetermined plutonium enrichment; roughly mixing these powders together by means of a mixer; pulverizing and homogeneously mixing the roughly mixed powder by means of a jet mill; discharging the homogeneously mixed powder together with compressed air from the jet mill; and separating the mixed powder from the air by means of a first-stage cyclone to recover at least 90% of the discharged powder.

Abstract: A three-dimensional object data processing method and system reduces the number of coordinate calculations of the objects when an eyepoint changes during CG processing. A workstation (2) comprises a space searching module (6) which searches for the objects included in a view volume, a rasterizing module (12) which displays the view volume, and a texture data generating module (10) which groups a plurality of objects according to a user's request and generates two-dimensional texture data. Each object is drawn as texture data.

Abstract: In a dry chemical reprocessing method, uranium type elements are electrolytically refined continuously. Molten cadmium in which these uranium type elements are dissolved is transferred to a rotating cathode electrolysis tank 30 for performing electrolytic refining. The rotating cathode electrolysis tank 30 is filled with molten cadmium, and a mixture of potassium chloride and lithium chloride. In the salt phase are placed a rotating cathode 32 and a receiving dish 36 for uranium type elements which deposit at the cathode, while in the molten cadmium phase a fixed anode 42 is installed. When uranium type elements deposited at the rotating cathode 32 have grown to at least a predetermined size, they are scraped off by a scraper 34 and collect in a receiving dish 36. These uranium type elements are sent to a U/salt separating tank 50 where uranium is separated from salts.

Abstract: A laser decontamination method includes the steps of incorporation of a condenser lens in a gas supply nozzle, supplying a gas toward a contaminated member while moving the gas supply nozzle relatively to and along a surface of the contaminated member with a laser beam which is condensed by the condenser lens applied thereto, and thereby continuously melting or evaporating a contaminated surface layer so as to remove the same to clean the contaminated member. The gas is supplied asymmetrically with respect to the axis of the laser beam.

Abstract: A continuous sintering apparatus to be used for sintering nuclear fuel pellets includes a casing integrally constructed to have an upper portion enclosed in a maintenance glove box. The furnace casing includes a casing body and a ceiling cover removably mounted on the casing body, and the ceiling cover can be opened in the glove box while retaining containment. A furnace member to be accommodated in the casing body comprises a combination of a plurality of divided furnace member units, and the furnace member units can be maintained by glove operations when they are delivered from the inside of the casing body into the glove box. A ceiling crane is disposed at an upper portion of the inside of the glove box, and a ceiling cover tentative space and a maintenance working space are provided in the glove box. A turntable for placing the delivered furnace member unit is preferably disposed in the maintenance working space.