Abstract: A leakage testing device for testing leakage of a nuclear fuel assembly (18) by sipping. The device includes a collection assembly (32) that is configured to close an upper end (24A) of a cell (24) of a storage rack (22) for storing nuclear fuel assemblies discharged from a nuclear reactor (4). The closing prevents water contained in the cell from escaping via the upper end of the cell. The collection assembly is configured to collect products containing possible fission products released by a nuclear fuel assembly contained in the cell.

Abstract: Provided is mobile equipment for measuring structural deformation of a nuclear fuel assembly, the mobile equipment including: a container; a power means and a loading table disposed inside the container; a pedestal disposed on one side of the loading table of the container, the pedestal being provided with a hinge means and a fixing means configured to fix the nuclear fuel assembly upright; a column seated on the loading table and provided at one end part thereof with a rotating shaft detachably installed to the hinge means, and configured to be erected upright on the fixing means of the pedestal by power of the power means; and a scanner configured to move upward and downward in a longitudinal direction of the column and to measure the structural deformation of the nuclear fuel assembly.

Abstract: It is possible to detect a failure in a temperature sensor while preventing enlarging of a circuit scale. A temperature measurement circuit 10 includes temperature sensors 20 and 30, and a comparator 40. The temperature sensor 20 includes a temperature detection unit 21 including a resistive element, a resistance value of which varies in accordance with temperature changes, and an AD converter which converts a voltage of the temperature detection unit 21 into a temperature digital value D1. The temperature sensor 30 includes a ring oscillator 31 which oscillates at a cycle that is temperature dependent, and generates a digital value D2 based on an oscillating signal output by the ring oscillator 31. The comparator 40 compares the temperature digital values D1 and D2, and outputs a signal indicating whether the temperature sensor 20 is normal or not based on a comparison result.

Abstract: Methods and systems for detecting an individual leaking fuel channel included in a reactor. One system includes a plurality of inlet lines and a plurality of outlet lines. Each of the plurality of inlet lines feeding annulus fluid in parallel to an annulus space of each of a first plurality of fuel channels included in the reactor, and each of the plurality of outlet lines collecting in parallel annulus fluid exiting an annulus space of each of a second plurality of fuel channels included in the reactor. In some embodiments, the system also includes a detector positioned at an outlet of each of the plurality of outlet lines configured to detect moisture in annulus fluid and identify a first position of an individual leaking fuel channel, and an isolation valve positioned at an inlet of each of the plurality of inlet lines operable to stop annulus fluid from circulating through one of the plurality of inlet lines and to identify a second position of the individual leaking fuel channel.

Abstract: A method for determining a leaking nuclear fuel rod that remotely measures the internal pressure in the plenum region of the fuel rod by remotely measuring the thermal response of the rod when a localized heating is imposed on the outside of the rod in the plenum region. The temperature of the cladding at two symmetrically spaced points on either side of the location where the heating is imposed is remotely monitored as a function of time and compared to a standard to determine the internal pressure of the plenum.

Abstract: A system and method for assessing failure of fuel rods are disclosed. The method may include monitoring fuel rod operational conditions, comparing the fuel rod parameters to parameters limits, calculating the fuel rod performance parameters to determine the likelihood of failure of individual fuel rods, and updating plant operating parameters based on the calculated fuel rod parameters. The system may input the calculated fuel rod parameters into a fuel failure model to assess the probability of failure, and predict the probability of failure of individual fuel rods based on fuel rod parameters in the fuel failure model.

Abstract: Methods and systems for detecting an individual leaking fuel channel included in a reactor. One system includes a plurality of inlet lines and a plurality of outlet lines. Each of the plurality of inlet lines feeding annulus fluid in parallel to an annulus space of each of a first plurality of fuel channels included in the reactor, and each of the plurality of outlet lines collecting in parallel annulus fluid exiting an annulus space of each of a second plurality of fuel channels included in the reactor. In some embodiments, the system also includes a detector positioned at an outlet of each of the plurality of outlet lines configured to detect moisture in annulus fluid and identify a first position of an individual leaking fuel channel, and an isolation valve positioned at an inlet of each of the plurality of inlet lines operable to stop annulus fluid from circulating through one of the plurality of inlet lines and to identify a second position of the individual leaking fuel channel.

Abstract: Disclosed is a fuel rod testing apparatus for a nuclear fuel assembly. The fuel rod testing apparatus includes a helium leakage testing chamber having a gate so that a fuel rod is horizontally loaded/unloaded and testing whether or not helium leaks from the fuel rod, a fuel rod upward/downward transfer unit that has first and second transfer sections located in front of the gate and horizontally installed apart from each other in order to guide the fuel rod loaded into or unloaded from the helium leakage testing chamber, and that vertically drives the first and second transfer sections, and a main frame that has a upper transfer section disposed in parallel in a lengthwise direction of the fuel rod upward/downward transfer unit and having an inclined face and a lower transfer section installed at a lower portion of the upper transfer section and having an inclined face.

Abstract: A method to assess light water reactor fuel integrity is presented having the steps of granting access in a nuclear reactor fuel pool to at least one of a discharged fuel rod and a nuclear fuel assembly, calculating an operating flux for the fuel rod, measuring a thickness of CRUD on the fuel rod, measuring a thickness of oxide on the fuel rod, calculating a maximized flux for the at least one fuel rod for a position of the one fuel rod in a nuclear reactor, calculating a maximized deposit for the fuel rod, calculating a maximized oxide thickness for the fuel rod, calculating a fuel condition index of the fuel rod, comparing the fuel condition index to an index constant, and removing the fuel rod from operation when the fuel condition index is greater than the index constant.

Abstract: Method including: inducing, with antiprotons, nuclear fission in a material, such as depleted uranium; measuring leakage of radioactive byproduct produced by the fission; and producing, responsive to the measuring, a design for the nuclear fuel element. Apparatus, manufactures, and products produced by the method can be encompassed.

Abstract: Systems and methods for servicing a fuel assembly in a light water reactor include those for controlling flow through a fuel assembly to maintain debris in the fuel assembly during removal and transportation of the fuel assembly, those for discharging debris from the fuel assembly, and those for isolating and sampling the water chemistry of a fuel assembly. An exemplary system includes a closure device configured to seal a mast to a fuel assembly to surround the upper opening of the fuel assembly and provide a flow control channel between a void in the mast and a lower opening in a lower tie plate.

Abstract: Fuel rods of fuel assemblies of a boiling water reactor are tested for leaks. A plurality of fuel assemblies are each arranged adjacent to one another in a cell of the upper core grid of the boiling water reactor. A hood is placed above a plurality of cells A water sample is taken from each of the cells, and the water samples from a plurality of cells forming a group are combined and tested for the presence of radioactive fission products A plurality of groups are analyzed simultaneously in a number, which number corresponds to the number of groups, of measurement channels. Where a result of a group is positive, the cells of the group are tested separately by the measurement channels. Those fuel assemblies of a cell that is found positive are tested individually outside the hood.

Abstract: Methods and apparatus are provided for measuring emissions from radioactive material in a matrix. Consideration is made in the variation in counts observed at different rational positions of the body of material so as to establish the information about the position of the radioactive material within the matrix.

Abstract: A method for determining a leaking nuclear fuel rod that remotely measures the internal pressure in the plenum region of the fuel rod by remotely measuring the thermal response of the rod when a localized heating is imposed on the outside of the rod in the plenum region. The temperature of the cladding at two symmetrically spaced points on either side of the location where the heating is imposed is remotely monitored as a function of time and compared to a standard to determine the internal pressure of the plenum.

Abstract: The present invention relates to a nondestructive method or inspecting defects of the cladding of a nuclear fuel rod, which is featured by a wave emitter obliquely discharging an inspection wave to an inspected tube and a receiver arranged at a side of the inspected tube with respect to the wave emitter. If liquid is accumulated inside the tube, the incident inspection wave will be refracted so that the receiver can receive the refracted inspection wave at a specific location. The method can determine whether liquid is accumulated inside the tube and further is able to detect the level of the liquid.

Abstract: The diameter of a segment of a peripheral rod in a fuel assembly is measured between two successive spacer grids. A measuring tool is positioned at a level situated between the two successive spacer grids, the tool comprising two measuring fingers that are free to move relative to each other in a first horizontal direction and that are urged towards each other by a resilient return arrangement, and that extend in a second horizontal direction perpendicular to the first horizontal direction. The measuring fingers are moved in the second horizontal direction towards a rod so as to put two contact pieces of the measuring fingers into contact with two zones of the rod segment. The measuring fingers are moved in the vertical axial direction of the rod along its segment situated between the two spacer grids and an electromagnetic sensor is used to measure the distance between the measuring fingers in the first horizontal direction while the measuring fingers are being moved axially.

Abstract: The contents of a container 1 are non-intrusively monitored by probing the container with an ultrasonic signal, and measuring changes in the ultrasound signature of the received signal after the signal has passed through the contents of the container.

Abstract: A method for testing whether fuel rods of fuel assemblies resting on a working base and under water, of a nuclear reactor are leaking is disclosed. The method includes heating at least one first fuel assembly of a first division of fuel assemblies for driving radioactive fission products out of a defective fuel rod contained in the first fuel assembly. The first fuel assembly is continuously tested by extracting samples of water and continuously degassing the water removed from an area around the first fuel assembly even during the heating resulting in gas. A radioactivity of gaseous fission products released in the gas is continuously recorded. A fuel assembly belonging to a second division of fuel assemblies is heated only if the first fuel assembly belonging to the first division of fuel assemblies has been tested. An apparatus for implementing the method is also disclosed.

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 invention concerns a method and a device for evaluating the integrity of the nuclear fuel in a nuclear plant having a reactor (1) enclosing a reactor core formed by a number of fuel cladding members (2) arranged to enclose said nuclear fuel. The value of each of a number of parameters including activity data (4) of the off-gases from the reactor is determined. The value of each of a number of second parameters including chemical data and activity data of the liquid (5) flowing through the reactor is determined. The value of each of a number of operational parameters (6) including at least one of the reactor effects, control rod position, actual fuel type, flow of off-gases, and flow of the liquid flowing through the reactor is determined. The value of the first and second parameters are standardized (7, 8) in relation to the values of said operational parameters.

Abstract: According to the present invention, a system for measuring a thermal neutron emission from a neutron source, has a reflector/moderator proximate the neutron source that reflects and moderates neutrons from the neutron source. The reflector/moderator further directs thermal neutrons toward an unmoderated thermal neutron detector.

Abstract: A capsule containing a tag gas in a zircaloy body portion having a hemispical top curved toward the bottom of the body portion. The hemispherical top has a rupturable portion upon exposure to elevated gas pressure and the capsule is positioned within a fuel element in a nuclear reactor.

Abstract: A system and method of the present invention measures the relative stress in the cladding of a nuclear fuel rod caused by the internal gas pressure of the rod. This is done by determining the attenuation ratio of two specific frequencies from a broadband low frequency acoustic energy spectrum. Relative pressure differentials are measurable and therefore any loss of fuel rod gas pressure is a direct indication of fuel rod cladding failure.

Abstract: A method and system for providing nuclear fuel rods with a configuration of isotopic gas tags. The method includes selecting a true location of a first gas tag node, selecting initial locations for the remaining n-1 nodes using target gas tag compositions, generating a set of random gene pools with L nodes, applying a Hopfield network for computing on energy, or cost, for each of the L gene pools and using selected constraints to establish minimum energy states to identify optimal gas tag nodes with each energy compared to a convergence threshold and then upon identifying the gas tag node continuing this procedure until establishing the next gas tag node until all remaining n nodes have been established.

Abstract: The present invention provides a method for identifying failed fuel elements and the scale of damage accurately, quickly and at low cost without disassembling a fuel assembly and without discharging radioactive waste. Radiation detector(s) for measurement of gamma radiation emitted from surface of the irradiated fuel assembly and the fuel assembly are rotated and translated relative to each other, the dectected data of the radiation emitted from the surface of the fuel assembly is acquired, processed, a tomographic image is constructed from the radiation intensity distribution and is prepared and displayed, and a failed fuel element is finally confirmed from the tomographic image of the fuel assembly cross-section.

Abstract: An on-line sipping air delivery system that propels bubbles across the entire surface of the fuel assembly. A pump delivers liquid through an aspirator located near the bottom of the fuel handling mast. Liquid flow through a venturi in the aspirator causes a drop in pressure inside the aspirator and pulls air into the aspirator through an ambient air line that extends above the surface of the liquid. The air is mixed with liquid as it flows through the aspirator and the mixture is injected under the fuel assembly through nozzles positioned at the bottom of the assembly. Suction nozzles above the liquid level at the top of the fuel assembly are used in a conventional manner to capture and deliver the released air and gases to appropriate testing equipment.

Abstract: The invention relates to an arrangement for carrying out leak detection of a fuel assembly for a pressurized-water nuclear reactor. A substantially vertical hollow mast means open in both ends houses the fuel assembly to be examined. The fuel assembly is drawn to the inside of the mast means from its lower side. The part of the mast means housing the fuel assembly is lifted to a position in which the fuel assembly is provided near but below the water surface of water inside the nuclear reactor. Water is sucked from a position inside the mast means above the fuel assembly. A gas separating means separates gases present in water sucked from the inside of the mast means. The separated gas is analyzed in a gas analyzing means regarding its amount of gaseous fission products.

Abstract: A process and a system for detecting defective nuclear fuel assemblies in situ. The system includes two basic subsystems. The first subsystem is a sample collection system consisting of a hood placed over the fuel. A technique whereby a vacuum is drawn across a submerged nozzle of a degas tank is used to draw up the sample of fluid out of a fuel assembly. The second subsystem determines the amount of Kr-85 radioisotope contained in the fluid sample. This information is used to determine whether the fuel assembly contains a defective, i.e., leaking, fuel rod. The measurement values for Kr-85 in the fluid sample extracted from the fuel assembly are compared to the measurement values for Kr-85 in fluid samples taken from the reactor pool prior to fuel assembly testing and fluid samples taken from non-leaking control cells, the latter values representing the background to which the subject fuel assembly is compared.

Abstract: Failed fuel cladding in light water reactors can lead to premature reactor shutdown for removal of the failed fuel bundles from the core. The lost power and associated fuel replacement costs are astronomically high, approaching a million dollars per day in near term costs. Additionally, the long term affect on an operating plant are the release and distribution around the plant of long-lived fission products which increase radiation levels and impose increased radiological protection procedures. A method has been developed which allows for on-line early detection of failed fuel elements while the plant is operating through flowing off-gas through a conduit to a gamma spectrograph with a time delay to allow interfering short lived isotopes to decay and then analyzing for gamma radiation from at least one of the nuclides Kr-85m, Kr-87, Kr-88, Xe-133, Xe-135, Xe-135m and Xe-138.

Abstract: The method and the device are applicable to the penetrations (2) of a pressurised water nuclear reactor vessel head (1) during operation.The device includes a double circuit for picking off two gas samples (100, 16, 17; 12, 13, 14, 15) and a measurement assembly (18) which regularly compares the content, especially of water vapour, in the two samples picked off. The first sample is taken from the volume of a chamber (7) where the possible leak (10) emerges, and the second in proximity to the head (1) outside the region immediately affected by the leak. The assembly (18) makes it possible to generate (19) an alarm in the event of a leak and to distinguish it from operational alarms.Techniques and means are also provided for determining the flow rate of sweeping in the volume of the chamber (7) and for checking the pick-off and detection systems.

Abstract: Leak-detection system and method for detecting a leaking container. The system includes an enclosure defining a cavity therein surrounding the container, which container may be a nuclear fuel rod having fission products leaking through a breach in the exterior surface of the fuel rod. The fission products are capable of adhering to the exterior surface of the fuel rod as the fission products leak through the breach in the fuel rod. A radiation detector is in communication with the cavity for detecting the fission products leaking through the breach. Moreover, a gas injector is in communication with the cavity for injecting a multiplicity of carrier gas bubbles into the cavity to remove any fission products adhering to the exterior surface of the fuel rod and to carry the fission products removed thereby to the radiation detector. In this manner, the detector detects the leaking fission products even though they may tend to adhere to the exterior surface of the fuel rod.

Abstract: During leak detection of fuel assemblies (10) for a boiling water nuclear reactor, water is sucked from an area (12) located above an outlet (11) for water from the fuel assembly and around a gripper (8) for a loading machine (1) for fuel assemblies, which gripper is secured to the fuel assembly above the outlet, while the fuel assembly is lifted in the water (6) in which the fuel assembly is immersed or while the fuel assembly, after having been lifted in the water, is maintained in its lifted position or relowered in the water and while maintaining a flow of the water through the fuel assembly and around the gripper. The sucked-off water is subjected to an analysis with respect to the presence of fission products which, during operation of the reactor, have been formed of the fuel in the fuel assembly.

Abstract: Failure of a fuel element in a nuclear reactor core is determined by a gas tagging failure detection system and method. Failures are catalogued and characterized after the event so that samples of the reactor's cover gas are taken at regular intervals and analyzed by mass spectroscopy. Employing a first set of systematic heuristic rules which are applied in a transformed node space allows the number of node combinations which must be processed within a barycentric algorithm to be substantially reduced. A second set of heuristic rules treats the tag nodes of the most recent one or two leakers as "background" gases, further reducing the number of trial node combinations. Lastly, a "fuzzy" set theory formalism minimizes experimental uncertainties in the identification of the most likely volumes of tag gases. This approach allows for the identification of virtually any number of sequential leaks and up to five simultaneous gas leaks from fuel elements.

Abstract: A method and apparatus of sensing obstructions in a tubular nuclear fuel rod or the like is disclosed. A nozzle is positioned to engage one end of the fuel rod in an air tight sealed relationship. A first gas flows through the nozzle and then into and through the fuel rod. The pressure is sensed and compared with a standardized pressure to determine any excess back pressure in the nozzle indicating an obstruction present therein.

Abstract: An improved short-term autoclave (10) test for ex-reactor evaluation of in-reactor corrosion resistance of zirconium alloy members (16) for use in pressurized water reactors and pressurized heavy water reactors by:providing a heat flux to initiate hydride precipitation close to the metal-oxide interface of the tube outside surface by means of a resistance heater (20) and a directed flow of aqueous coolant in the water phase to only the outside surface which is one of two specimen (16) opposed surfaces; providing the inside surface with access to the coolant from the flow but not in the flow; reducing the distance between the opposed surfaces of specimen (16);regulating coolant flow from inlet port (12) to outlet port (14) and power of autoclave (10) to optimum saturation condition of 360.degree. C..+-. 5.degree. C. and pressure 2700 p.s.i..+-. 100 p.s.i.;providing a coolant chemistry which simulates a rector's;removing most of the oxygen from the coolant.

Abstract: The fuel element is inserted into a cell, under water, in a pool. Compressed air is injected into the cell so as to drain it of water. A pressure lower than atmospheric pressure is established in the cell and then the gases contained in the cell are subjected to a stream of scavenging air and are collected in a fission product detecting unit. Water is introduced into the cell, the water in the cell is sampled, fission products in the water sample are detected and the fuel element is extracted from the cell if the possible presence of a leak from this fuel element is determined. The detection device comprises a cell having an elongate body delimiting a central housing for a fuel element and end parts. One of the end parts, traversed by a channel in the extension of the housing, receives a cap for opening and closing the channel associated with a remotely controllable opening and closing arrangement.

Abstract: In order to detect leaky rods inside a nuclear fuel assembly (24), this assembly is placed inside a pool (36) so that the gases contained inside the rods (10) escape from the leaky rods. By heating the upper part of the assembly by means of a heated sleeve (42) the gases contained inside the leaky rods are expanded. Monitoring the diameter change of the rods (10) at the base of the assembly by means of a measuring device (44) makes it possible to distinguish the sealed rods whose sheaths elastically get out of shape from the leaky rods whose sheaths hardly warp at all.

Abstract: A method of detecting coated fuel particles having a broken ceramic coated layer in coated fuel particles for high-temperature gas-cooled reactor which comprises permeating a liquid into the interior of the coated fuel particles having a broken ceramic coated layer through a broken portion of the ceramic coated layer, thereafter heating it to expand the liquid by evaporation pyrolysis thereby breaking the ceramic coating layer or the whole body of coated fuel particle by pressure generated.

Abstract: An inspection apparatus and method for testing nuclear fuel rods for helium leaks includes the basic operative steps of constantly leaking helium at a predetermined known value into a test chamber containing a fuel rod to be tested, and sampling the atmosphere within the chamber and measuring the helium in the atmosphere. A measured helium value below a preset minimum helium value indicates a malfunction in the inspection apparatus, whereas a measured helium value above a preset maximum helium value indicates the existence of a helium leak from the fuel rods. On the other hand, a measured helium value between the minimum and maximum helium values indicates the absence of a helium leak from the fuel rod.

Abstract: A method of repairing under water a boiling water reactor-fuel assembly having a fuel assembly channel and an upper grid plate by means of a channel stripping machine, disassembling the upper grid plate, determining a damaged fuel rod and exchanging the damaged fuel rod for another fuel rod by means of a fuel rod exchanging device, which includes, after stripping off the fuel assembly channel and disassembling the upper grid plate at the location thereof in the channel stripping machine, placing on the fuel assembly a guide box with which the fuel rods of the fuel assembly are centered, then placing thereon an indicator plate and determining the varying growth of the fuel rods, and replacing the indicator plate by a centering plate to which the fuel rod-exchanging device is coupled and a device for carrying out the method.

Abstract: A system constructed of three tools for manipulating fuel rods with a nuclear fuel assembly is disclosed. The individual tools are adapted for displacing fuel rods upwardly and downwardly along their longitudinal axes and for rotating same 360.degree. without having to remove the fuel rods from their location within a nuclear fuel assembly. The individual tools are operative on-site from a remote location while the nuclear fuel assembly is maintained underwater in a spent fuel pool. By manipulating the fuel rods, those areas previously hidden from visual inspection such as within grids may be inspected for defects and the like.

Abstract: A sipping test for detecting defective sheaths in a nuclear fuel assembly is carried out by increasing the pressure of the gases within the sheaths by increasing the temperature. The fission products are released in case of sheath failure. A mixture of water and inert gas is introduced into a hood containing the fuel assembly. Gas and water are separated at the upper portion of the hood and are circulated in distinct loops for continuous detection of the water-soluble fission products and the gas-driven fission products.

Abstract: A vessel for the long term storage and monitoring of nuclear fuel materials incorporates a device (12) within its interior for providing an externally detectable signal indicating whether any pressure loss has occurred. The device (12) comprises a magnet (32) attracted towards a boundary wall (11) of the vessel and urged in that direction by the internal pressure within the vessel acting on a diaphragm (26). The magnet (32) is subjected to oppositely directed forces by pressurized fluid in chamber (40) bounded by diaphragm (26) and a spring (30), the arrangement being such that these latter forces collectively or individually are effective to drive the magent (32) away from the wall (11) in the event of a pressure loss within the vessel thereby producing an externally detectable change in magnetic flux.

Abstract: A mechanism for testing fuel tubes in nuclear fuel bundles includes a carriage, carrying an elongated probe, and a grooved plate. The grooves are parallel to the probe and are spaced by the same distances as rows of tubes in the fuel bundle. They are connected at at least one end. A pin on the carriage fits in the grooves. A hydraulic cylinder reciprocates the carriage longitudinally of the grooves and a pneumatic cylinder urges it laterally, so that the pin moves from groove to groove at the end of each stroke.

Abstract: A device for the inspection of fuel rods combined into fuel rod bundles in a fuel element of a nuclear reactor includes a frame for supporting a fuel element including a base plate, a cover plate and four supports in the form of four first leadscrew drive mechanisms, two mutually parallel second leadscrew drive mechanisms attached to and extending transversely to the first leadscrew drive mechanism, a third leadscrew drive mechanism jointly supported by and extending transversely to the second leadscrew drive mechanism, and an accessory carrier mechanism disposed on the third leadscrew drive mechanism and movable in a plurality of levels for entering gaps between fuel rods of the fuel element.

Abstract: An end cap with a tag gas capsule adapted to close an end of a cladding tube of a nuclear fuel element and to introduce a tag gas into the fuel element. The end cap is fixed to the tag gas capsule to form a unitary structure. The end cap has a specific shape or description on its outer surface corresponding to information concerning the specific tag gas and the capsule, so that the description or shape of the end cap can identify the specific capsule and the tag gas contained in the capsule.

Abstract: A solid tag material which generates stable detectable, identifiable, and measurable isotopic gases on exposure to a neutron flux to be placed in a nuclear reactor component, particularly a fuel element, in order to identify the reactor component in event of its failure. Several tag materials consisting of salts which generate a multiplicity of gaseous isotopes in predetermined ratios are used to identify different reactor components.

Abstract: A measuring head suitable for determining the pressure of fission gases released inside non-instrumented bars of nuclear fuel (which have reached high irradiation levels), and for connection to said bars by a method which allows no escape of said active gases and does not cause appreciable disturbance either to the fuel or to the released fission gases.

Abstract: A method and apparatus for testing characteristics of nuclear fuel pellet interaction with nuclear reactor fuel rod cladding whereby the temperature profile within a nuclear fuel rod is more closely modeled in the test device than in the prior art discloses the use of high frequency microwave radiation to heat the fuel pellets within the cladding and using the cladding itself as a waveguide. Sensors monitor various operating parameters and a water jacket cools the test cladding.

Abstract: The present invention is directed to a semi-automatic rod examination gauge for performing a large number of exacting measurements on radioactive fuel rods. The rod examination gauge performs various measurements underwater with remote controlled machinery of high reliability. The rod examination gauge includes instruments and a closed circuit television camera for measuring fuel rod length, free hanging bow measurement, diameter measurement, oxide thickness measurement, cladding defect examination, rod ovality measurement, wear mark depth and volume measurement, as well as visual examination. A control system is provided including a programmable logic controller and a computer for providing a programmed sequence of operations for the rod examination and collection of data.