Abstract: The invention relates to nuclear technology, and to irradiation targets and their preparation. One embodiment of the present invention includes a method for preparation of a target containing intermetallic composition of antimony Ti—Sb, Al—Sb, Cu—Sb, or Ni—Sb in order to produce radionuclides (e.g., tin-117 m) with a beam of accelerated particles. The intermetallic compounds of antimony can be welded by means of diffusion welding to a copper backing cooled during irradiation on the beam of accelerated particles. Another target can be encapsulated into a shell made of metallic niobium, stainless steel, nickel or titanium cooled outside by water during irradiation. Titanium shell can be plated outside by nickel to avoid interaction with the cooling water.

Abstract: The invention provides at least two electrochemical sensors positioned in a nuclear reactor or in a system adjacent to the nuclear reactor, wherein at least one of the at least two electrochemical sensors has a heated zirconium electrode, and the at least two electrochemical sensors produce voltages proportional to an electrochemical corrosion potential for a surface that each of the at least two electrochemical sensors are installed upon. The invention also provides an arrangement configured to accept the voltages produced by the at least two electrochemical sensors, wherein the arrangement is configured to determine an electrochemical corrosion potential of a zirconium fuel rod in the nuclear reactor based upon the voltages of the at least two electrochemical sensors.

Abstract: Disclosed herein is a guide thimble of a nuclear fuel assembly, which is capable of improving the cooling performance and the stability of a nuclear fuel, preventing a flow split in dual-cooling nuclear fuel rod and guide thimble sub channels for obtaining high combustion degree and high power, and minimizing a neutron absorption section in a reaction degree region. Since the guide thimble having the dual tube type structure is adopted, a flow split in the fuel rod and guide thimble sub channels can be reduced, and the degradation in performance of nuclear fuel due to increase of a neutron absorption section can be prevented. In order for compatibility with an existing control rod, a typical guide tube is used as an inner guide thimble, and an outer guide thimble is provided outside the inner guide thimble.

Abstract: A cylindrical gamma generator includes a coaxial RF-driven plasma ion source and target. A hydrogen plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical gamma generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which has many openings. The plasma generator emanates ions radially over 360° and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired.

Abstract: A perforated plate support supports dual-cooled fuel rods, each of which has concentric outer and inner tubes and is coupled with upper and lower end plugs at upper and lower ends thereof, and guide thimbles, each of which is used as a passage for a control rod. The perforated plate support is formed as a support plate having the shape of a flat plate, which includes internal channel holes, each of which has a diameter corresponding to an outer diameter of the inner tube, guide thimble holes, each of which has a diameter corresponding to an outer diameter of the guide thimble, and sub-channel holes around each internal channel hole. The upper or lower end of the dual-cooled fuel rod is coupled to the support plate such that the outer diameter of the inner tube is matched with the diameter of the internal channel hole.

Abstract: An apparatus for forming stress corrosion cracks comprises a heating unit which includes a conductive member and a heating coil disposed adjacent to the conductive member to generate steam pressure in the tube specimen, an end holding unit, and a control unit for controlling the heating unit and the end holding unit. The stress corrosion cracks occurring in the equipment of nuclear power plants or apparatus industries during operation can be directly formed in a tube specimen using steam pressure under conditions similar to those of the actual environment of nuclear power plants, thus increasing accuracy for analysis of properties of stress corrosion cracks which are in actuality generated, thereby improving reliability of nuclear power plants or apparatus industries and effectively assuring nondestructive testing capability, resulting in very useful industrial applicability.

Abstract: Methods of producing cesium-131. The method comprises dissolving at least one non-irradiated barium source in water or a nitric acid solution to produce a barium target solution. The barium target solution is irradiated with neutron radiation to produce cesium-131, which is removed from the barium target solution. The cesium-131 is complexed with a calixarene compound to separate the cesium-131 from the barium target solution. A liquid:liquid extraction device or extraction column is used to separate the cesium-131 from the barium target solution.

Abstract: In various embodiments, the system comprises a system for storing radioactive material, wherein the system includes a storage pool for storing a plurality of radioactive objects submersed in a radiation shielding and cooling liquid. The system additionally includes an assembly building located above the storage pool for constructing one or more radioactive articles using the radioactive objects transferred from the storage pool. Furthermore, the system includes at least one transfer shaft connecting the storage pool and the assembly building. The transfer shaft(s) are used for transferring the radioactive objects directly from within the storage pool to an interior of the assembly building and directly from the interior of the assembly building into the storage pool.

Abstract: A debris trap catches debris falling through a fuel bundle orifice in a nuclear reactor. The debris trap includes a shaft and a debris capture tray attached to an end of the shaft. The debris capture tray includes a tray cavity sized larger than the fuel bundle orifice.

Abstract: A formic acid aqueous solution that contains Fe (II) ions is produced by dissolving metal iron in a formic acid aqueous solution. Nitrogen is supplied from a nitrogen supply device to a chemical liquid tank and then discharged from a discharge line to reduce the dissolved oxygen concentration in the aqueous solution. The chemical liquid tank is filled with the formic acid aqueous solution sealed with nitrogen, and transferred from a factory to a nuclear reactor building designated as radiation-controlled areas. Inside the nuclear reactor building, the chemical liquid tank is installed in a film deposition apparatus connected to a reactor water recirculation pipeline. The formic acid aqueous is supplied from the chemical liquid tank to the inside of the reactor water recirculation pipeline, and then a ferrite film is formed on the inner surface of the reactor water recirculation pipeline.

Abstract: A container including a support having at least one first longitudinal support surface defining a longitudinal housing for receiving a nuclear fuel assembly, and a door having a second longitudinal support surface. The door is movable between a position of holding the nuclear fuel assembly between the two longitudinal surfaces and a released position in which the assembly is free with respect to the support. The container includes means for adjusting the transversal separation between the first and second surfaces in the holding position of the door.

Abstract: A dynamic port that extends from the bottom wall of an oil reservoir that surrounds the lower guide bearing of a reactor coolant pump and is in fluid communication within an oil level gauge. The dynamic port is rotatable into and out of the oil flow path to adjust the dynamic oil level shown by the oil level gauge when the pump is at operating speed to be substantially equal to the static oil level when the motor is at rest.

Abstract: A cooling device component of monobloc design has a heat shield made from tungsten, a tungsten alloy, a graphitic material or a carbidic material provided with a through-hole. A cooling pipe for carrying coolant is joined in the through-hole. The heat shield is in turn joined or metallurgically joined to a structural part made from a material with a tensile strength at room temperature of >300 MPa and an electrical resistivity of >0.04 Ohm mm2m?1.

Abstract: A method for attaching a core spray sparger T-box clamp for a sparger T-box in a shroud of a nuclear reactor pressure vessel assembling the anchor plate, bearing plate and saddle bracket; positioning the assembly of the anchor plate, bearing plate and saddle bracket in front of the T-box such that the saddle bracket is below a sidewall of the T-box; elevating the assembly to seat the saddle bracket against a lower surface of the sidewall and sliding a locating pin on the saddle bracket into an aperture in the sidewall; lowering a carrier plate onto an upper surface of the sidewall and attaching the carrier plate to the anchor plate, wherein a locating pin on the carrier plate slides into an aperture on the upper surface, and advancing the bearing plate to the T-box to bias a bearing plate against a cover plate of the T-box.

Abstract: The invention relates to a novel design and production of fuel element pebbles which satisfy the requirements of high temperature pebble bed nuclear reactors of the next generation. The invention uses a shell of the fuel element pebbles that is devoid of fuel and consists of silicon carbide (SiC) and/or zircon carbide (ZrC), in addition to natural graphite and graphitized petroleum coke, said shell having a maximum average nominal thickness of 5 mm and preferably only 3 mm.

Abstract: Disclosed is an apparatus for removing a thermal sleeve from a cold leg of a reactor coolant system, which removes an unintentionally separated thermal sleeve without pipe cutting, preventing invasion of impurities into pipes and achieving reliable pipe re-welding. The apparatus includes a sleeve removal tool including a corn head formed at a shaft, a pressure plate below the corn head to maximize hydraulic pressure inside a safety injection pipe, a spring connected to the pressure plate to keep the pressure plate unfolded, and a guide wheel to guide the sleeve removal tool into the safety injection pipe, a horizontal movement carrier including bodies connected to each other by a link, a seating rod for seating of the sleeve removal tool, and moving wheels for movement of the horizontal movement carrier, and a vertical movement carrier including first and second anti-separation bars to prevent separation of the horizontal movement carrier.

Abstract: A spacer grid can be applied to close-spaced nuclear fuel rods. The spacer grid is directed to solve the problem in which, as the outer diameter of each nuclear fuel rod increases due to the use of dual-cooled nuclear fuel rods for improving cooling performance and obtaining high combustion and high output power, the gap between the neighboring nuclear fuel rods is narrowed to thus make it impossible to use an existing spacer grid. The spacer grid is a combination of unit grid straps, each of which has supports for supporting each of the nuclear fuel rods set in a narrow array and has a sheet shape, which are combined with each other. The supports are located at positions shifted from the longitudinal central line of each unit grid strap toward sub-channels.

Abstract: A method of calibrating a nuclear instrument using a gamma thermometer may include: measuring, in the instrument, local neutron flux; generating, from the instrument, a first signal proportional to the neutron flux; measuring, in the gamma thermometer, local gamma flux; generating, from the gamma thermometer, a second signal proportional to the gamma flux; compensating the second signal; and calibrating a gain of the instrument based on the compensated second signal. Compensating the second signal may include: calculating selected yield fractions for specific groups of delayed gamma sources; calculating time constants for the specific groups; calculating a third signal that corresponds to delayed local gamma flux based on the selected yield fractions and time constants; and calculating the compensated second signal by subtracting the third signal from the second signal. The specific groups may have decay time constants greater than 5×10?1 seconds and less than 5×105 seconds.

Abstract: A protector bottom grid for a nuclear fuel assembly that includes three laterally staggered and horizontally oriented protrusions that extend into the fuel rod cell of a support grid below a vertically oriented spring. The three staggered protrusions extend into the cell a distance that maintains a space between the protrusions and the fuel rod. The vertically oriented spring biases the fuel rod against a dimple extending from the opposite cell wall that is at an elevation just above the spring. The protrusions below the spring trap incoming debris in the area of the fuel rod end cap and protect the fuel rod cladding from fretting.

Abstract: The present invention relates generally to a process for a pressurized water reactor. The pressurized water reactor includes a primary circuit and a reactor core. The process includes adding a sufficient amount of an organic compound to coolant water passing through the primary circuit of the pressurized water reactor. The organic compound includes elements of carbon and hydrogen for producing elemental carbon.