Abstract: A method and apparatus is disclosed for very rapidly cleaning very small, colloidal particles from nuclear reactor water subjected to a high-energy waterjet cutting of metal using metal shot particles for cuffing such as garnet particles with the cutting causing fracturing of the metal shot as well as the cut metal fines into a negatively charged colloidal suspension having a large area. This colloidal suspension causes water turbidity and makes known filtration techniques impractical for rapid removal of such suspensions for recycling to the reactor.

Abstract: The measurement device comprises a real-time measurement-signal acquisition module (25) and means (23, 24) for connecting the cables for picking up the voltage from electrical windings for measuring the movement of the control rods to the acquisition module (25), in order to deliver, to the acquisition module (25), voltage signals corresponding to the voltage induced in the windings while the control rods are being dropped. The signal acquisition module (25) is thus permanently connected to the voltage-signal pickup cables (29) and the signals relating to the set of nuclear reactor control rods may be recorded simultaneously. Means (26, 27) for using the voltage signals delivered by the acquisition system (25) allow the drop times of the control rods to be determined.

Abstract: In a boiling water fuel assembly, some of the fuel rods are shortened. It is necessary to establish a sufficiently high maximum power for transition to boiling. To optimize this power, spacers are at a constant distance at a bottom and are at a shorter distance at a top. The spacers belonging to upper group have turbulence-generating vanes which, however, do not project above the shortened fuel rods.

Abstract: For the redistribution of a coolant flow from a first region into a second region, in particular in boiling-water-reactor fuel elements having an eccentrically disposed water passage, a fuel-rod bundle is constructed in a mirror symmetry manner relative to a diagonal. A distance between adjacent fuel rods increases monotonically in particular along a diagonal. In addition, a fuel-rod bundle as an entity may be offset eccentrically along the diagonal. To compensate for asymmetry in the reactor core, a redistribution of coolant is provided which is advantageous in pressurized-water-reactor fuel elements.

Abstract: The present invention provides an apparatus and method for measuring nonferrous electrical resistance measurement. The method includes providing a nonferrous material, inducing a magnetic field on the nonferrous material, measuring the remote magnetic field of the nonferrous material, and comparing the measured remote magnetic field to a standard.

Abstract: A method for inspecting an irradiated fuel element in a nuclear power plant includes the step of measuring, with a measuring device, a spacer of a fuel element for providing measurements of the spacer. The measuring device also measures a calibration rod for providing measurements of the calibration rod, the calibration rod having known dimensions. The measurements of the spacer are calibrated by using the measurements of the calibration rod. It is possible thereby to measure at least the maximum width of the spacer with a measuring error of less than 20 &mgr;m. A device for inspecting an irradiated fuel element in a nuclear power plant is also provided.

Abstract: The present invention relates to a method for making flat, thin elements which consist of: producing a zirconium alloy blank also containing, besides the inevitable impurities, 0.8 to 1.3% of niobium, 1100 to 1800 ppm of oxygen, and 10 to 35 ppm of sulfur; carrying out a &bgr; hardening and hot rolling to obtain a blank and performing on it at least three cold rolling passes with intermediate annealing heat treatments. One of the intermediate heat treatments is performed for a duration of at least 5 hours at a temperature less than 560° C. and all the optional treatments subsequent to the long treatment are carried out at a temperature of less than 620° C. for not more than 15 minutes.

Abstract: The invention is directed to an apparatus and method for inspecting spring hold down bolts of an upper tie plate of a fuel rod assembly in a nuclear reactor and includes an inspection fixture adapted to be aligned with the upper tie plate of the nuclear reactor fuel rod assembly for placement into a position for rapid and easy insitu inspection of the hold down bolts of the upper tie plate. The fixture is provided with a plurality of ultrasonic transducers which are positioned on the fixture so that when the fixture is placed into the inspection position each transducer will be located proximate to one of the hold down bolts for conducting effective ultrasonic scanning of the bolt while the bolt is in place. A multi-channel ultrasonic flaw detector is connected to each of the transducers for indicating whether there are any flaws in each of the hold down bolts when the fixture is placed into the inspection position and the ultrasonic transducers are activated.

Abstract: A tube testing system consists of two subassemblies, the probe and the applicator. The probe uses a stack of Belleville style washers that when compressed allow the locking fingers to relax and the probe to be inserted into the tube. Once the probe is placed in the correct location using the applicator, the Belleville style washers are allowed to expand, locking in the fingers and engaging the urethane seals. As the water fills the tube, the air is pushed through a bleed hole in the mandrel of the probe. The bleed hole leads to a chamber in the top of the probe that contains a plastic ball. The ball floats on water and as the chamber fills, the ball seals off the leak path and the tube can then be pressurized and the test performed. Once the test is complete, the water is drained and using the applicator, the probe is removed from the tube.

Abstract: A hydrogen/oxygen reaction is initiated in a catalytic recombination or ignition device. The device has one or more catalyst bodies with a predetermined catalytic surface. Only a small portion of the entire available catalytic surface, preferably less than 5% of the surface, is permanently maintained at a temperature level above ambient temperature. The temperature is raised by introducing energy with a heater. The heated surface portion acts as an initial igniter.

Abstract: A fuel assembly mechanical flow restriction apparatus for detecting failure in situ of nuclear fuel rods in a fuel assembly during reactor shutdown.

Abstract: The liquid effluent from solvent extraction contains radioactive thorium Th-231 and Th-234. This invention uses an ion exchange process to remove and concentrate the thorium. The process is designed so that the thorium remains on the ion exchange column until it decays to uranium and protactinium. These decay products are subsequently replaced by additional thorium. Therefore, the thorium never reaches break-through and the column can be used continuously without regeneration.

Abstract: A CRUD collection system for removing deposits from a nuclear reactor fuel rod submerged in pool water. The system includes a sealable collection head for containing a portion of the fuel rod. The collection head includes at least one seal positioned to receive the fuel rod. Also provided is a liquid inlet communicating with an interior portion of the collection head, the inlet is configured to inject a liquid into the interior to displace the pool water therefrom. At least one blade is provided that is positionable in scraping engagement with the fuel rod. Also included is a liquid outlet for eliminating a CRUD sample and the liquid to a filter.

Abstract: A method for decontaminating a surface includes the steps of bringing a surface of a component formed of an unalloyed steel or a low-alloy steel into contact with a solution containing an oxalic acid for dissolving a contaminated layer from the component. Ions of divalent iron in the solution instantly form a protective layer on exposed surfaces. Iron(III) oxalate is converted into iron(II) oxalate and carbon dioxide by irradiation with UV light in order to provide ions of divalent iron. Subsequent to dissolving the contaminated layer, the protective layer is dissolved by lowering the level of the ions of the divalent iron in the solution. The ions of the divalent iron and the substance having caused the contaminated layer are bound to an ion exchange resin.

Abstract: A method of removing rib plugs from steam generator tubes in energy producing units such as nuclear reactors includes the removal of the expander element or mandrel from the expanded part of the rib plug, TIG welding a bead on the available internal surface of the plug in a spiral manner from the bottom to the top thereof to relax the rib plug from its forced contact with the tube and removal of the rib plug as a unit from the tube after it has cooled down from the welding process.

Abstract: An in-situ testing apparatus for testing the integrity of rib plugs used to seal faulty reactor boiler tubes consists of a cup-shaped member with a groove on the open end, a tapped hole for attaching a hydraulic hose of known pressure, and a hole through the top of the member. A seal is installed in the groove on the open end of the cup to seal to the primary face of a tubesheet around the tested rib plug. A threaded mandrel goes through the hole in the top of the cup-shaped member and engages the expander member of the rib plug. The threading action of the mandrel into the expander draws the seal against the tubesheet to seal the testing apparatus and allows the rib plug to be in-situ pressure tested.

Abstract: A method for measuring the thickness of an oxide layer formed on the cladding surface of nuclear fuel rods and underlying a crud layer containing ferromagnetic material using eddy current lift-off measurements by exciting a probe coil at a first frequency which penetrates only into the crud layer and by exciting a probe coil at a second frequency which penetrates the crud layer, the oxide layer and into the cladding of a nuclear fuel rod. By subtracting vectorally the complex impedance resulting from exciting the probe coil at the first frequency from the complex impedance resulting from exciting the probe coil at the second frequency, the thickness of the oxide layer formed on the cladding is measured.

Abstract: The apparatus checks the functionality of an electrical drive and/or of a mechanical device associated with the electrical drive. The mechanical device may be an accessory or an actuating element. An electrical unit is associated with the drive and/or with the mechanical device. The unit has connections to which a diagnosis module can be connected. A power supply device is provided for the diagnosis module which can be activated via at least one of the connections to the unit, or via an external signal.

Abstract: An enhanced visibility underwater waterjet cutting system is provided wherein the waterjet cutting assembly and the video camera for remotely viewing the operating system is enclosed within an enclosure spacedly set against the workpiece and a stream of clean water is injected into the enclosure to set up a flow of clean water past the camera and to the waterjet cutting tip to exhaust the cuttings away from the enclosure and camera to allow a continuous view of the cutting surface of the workpiece without clouding up the water in the enclosure.

Abstract: An electrolysis apparatus has a number of membrane electrolysis cells. Each of the cells has a membrane formed on both sides with a contact layer. The apparatus, while it is compact in its design, is also suitable for comparatively high hydrogen production rates and can consequently be used particularly flexibly. A contact plate is respectively arranged on each contact layer. Each of the contact plates is formed, on its surface facing the contact layer assigned to it, with a system of ducts for the transport of water and/or gas.