Abstract: A zirconium alloy nuclear reactor cylindrical cladding has an inner Zr substrate surface, an outer volume of protective material, and an integrated middle volume of zirconium oxide, zirconium and protective material, where the protective material is applied by impaction at a velocity greater than 340 meters/second to provide the integrated middle volume resulting in structural integrity for the cladding.

Abstract: A spacer grid specifically designed for accident tolerant fuel utilizing fuel rods with SiC cladding for implementation in pressurized water reactors. The spacer grid tubular generally square design allows for ease of SiC fuel rod insertion during the fuel assembly fabrication process by providing a smooth contact geometry. The co-planar vertically oriented support allows the fuel rods to be rotated axially more freely at the grid location than a conventional six-point contact geometry used in existing fuel assembly designs. Since the SiC fuel rod has higher stiffness than a metallic fuel rod, the six-point contact geometry, which consists of two spring and four dimples, can potentially damage the fuel rod in the event of fuel rod deflection induced by a seismic event or a bowed fuel assembly. The fuel rod support cells are attached at their corners which are shared between adjacent support cells.

Abstract: An igniter apparatus which generates a high speed buoyancy induced vortex to funnel hydrogen and air from the surrounding onto the “igniter core” where an “igniter core” heats up to the auto ignition temperature by the exothermic catalytic oxidation of hydrogen on its surface. Water (vapor) is formed as the product, which inhibits the oxidation reaction, if not stripped away from the catalyst surface. The high velocity of the vortex ensures the stripping of the boundary layer of steam that is formed by the reaction, thus ensuring more active sites are available for hydrogen oxidation. The vortex is formed by channeling an upward draft into a vortex by guided fins. The upward draft is formed by a plate, which is also coated with a hydrogen recombination catalyst. The plate becomes hot by the same catalytic oxidation reaction in the presence of air containing hydrogen.

Abstract: A detection apparatus is a flow and temperature measuring device in the form of a tube having a channel positioned parallel to a coolant flow stream and contains a drogue that is firmly attached to a mount within the channel. The mount has a load detection apparatus firmly imbedded near the flow inlet to the tube. The drogue has at least neutral buoyancy in the fluid at the minimum fluid temperature of interest. A change in the buoyancy of the drogue as a function of temperature and a corresponding change in the strain detection apparatus output in the fluid is determined by a combination of simple physics and calibration measurements. The relationship between changes in strain detection apparatus signal output and flow-rate-induced forces applied to the drogue surface are also determined using a combination of simple physics and calibration measurements. A system and method are also described.

Abstract: A method whereby signals that are output by replacement SPNDs are converted into equivalent signals that would have been detected by legacy SPNDs for input to the legacy software. The replacement SPNDs have a different geometry than the legacy SPNDs and also have a different neutron sensitivity than the legacy SPNDs. The replacement SPNDs are subjected to a neutron flux in a core of a reactor and responsively output a set of signals. The set of signals and the geometry of the replacement SPNDs are employed to create a characterization of the neutron flux in the form of a curve that represents flux as a function of location along the core of the reactor. The legacy geometry of the legacy SPNDs is then employed to find the values on the curve that correspond with the positions where the legacy SPNDs had been located to create inputs for the legacy software.

Abstract: A device and method that enables a specimen that is to be converted into a radioisotope to be inserted into an extended, retractable thimble of a nuclear reactor moveable in-core detector system and be harvested after irradiation either during reactor operation or a refueling outage without damaging the retractable thimble. The specimen is enclosed within the interior of a forward portion of a tubular member having a closed lead end and structured to travel within the retractable thimble. The tubular member is sized to extend from a position above and proximate the desired core elevation the specimen is to be irradiated at to a location above a seal table that the retractable thimble extends through. The specimen is inserted and withdrawn from the core by inserting or withdrawing the tubular member from above the seal table. Desirably, the forward end of the tubular member is divided into several specimen compartments.

Abstract: A transmitter device includes a neutron detector structured to detect neutron flux, a capacitor electrically connected in parallel with the neutron detector, a gas discharge tube having an input end and an output end, and an antenna electrically connected to the output end. The input end is electrically connected with the capacitor. The antenna is structured to emit a signal corresponding to the neutron flux.

Abstract: A hydraulic apparatus includes a first valve manifold that provides a shutdown capability and a second valve manifold that provides an overspeed control capability. The hydraulic apparatus advantageously further employs a hydraulic appliance that includes a check valve and a bypass apparatus. The hydraulic appliance enables the second valve manifold to additionally provide as an alternative function a redundant shutdown capability, thereby obviating the need to have three separate valve manifolds.

Abstract: A tool is receivable into an interior region of a core shroud of a Boiling Water Reactor. The tool includes an elongated frame, an elevator apparatus situated on the frame, and a manipulator apparatus situated on the elevator apparatus. The tool further includes a reciprocation apparatus that is situated on the manipulator apparatus and that has a mount that is structured to carry a device thereon. The reciprocation apparatus includes an elongated rack of an arcuate profile. The elevator apparatus is operable to move the reciprocation apparatus along the longitudinal extent of the frame. The tool further includes a foot apparatus that is situated at an end of the frame and that is receivable on a core plate to enable the frame to be pivoted about an axis of elongation of the frame with respect to the core plate.

Abstract: A method is described for manufacturing a ceramic composite structure. The method includes wrapping ceramic fibers (22), such as SiC fibers, about the external surface of at least one form. The method further includes heating the wrapped fibers (22) to a temperature no greater than a first temperature, infiltrating voids (24) in the wrapped fibers (22) with the ceramic composite in a first vessel (12) at the first temperature, transferring the infiltrated wrapped fibers (22) from the first vessel (12) to a second vessel (14), distinct from the first vessel (12), and coating the infiltrated wrapped fibers (22) with the ceramic composite in the second vessel (14) at a second temperature, higher than the first temperature.

Abstract: Disclosed herein is a method comprising coating a fissile, uranium-containing ceramic material with a water-resistant layer, the layer being non-reactive with the fissile, uranium-containing ceramic material. The coating is applied to a surface of the fissile, uranium-containing ceramic material. Also disclosed is a fuel for use in a nuclear reactor.

Abstract: A plurality of signal anomalies are identified in a number of tubes in a steam generator. Since the geometry of the steam generator is known, the location of each signal anomaly along each tube is converted into a location within the interior of the steam generator. If a plurality of signal anomalies are at locations within the steam generator that are within a predetermined proximity of one another, such a spatial confluence of signal anomalies is determined to correspond with a loose part situated within the steam generator. Additional methodologies can be employed to confirm the existence of the loose part. Historic tube sheet transition signal data can be retrieved and subtracted from present signals in order to enable the system to ignore the relatively strong eddy current sensor signal of a tube sheet which would mask the relatively weak signal from a loose part at the tube sheet transition.

Abstract: An apparatus for performing an inspection on the beams of the top guide of a BWR includes a housing, an alignment assembly, and an inspection system. The housing is receivable atop the upper edges of a first pair of beams adjacent a receptacle of the top guide. The reception of the housing atop the upper edges of the first pair of beams is facilitated by the alignment assembly which includes a plurality of legs that are simultaneously moved between a retracted position wherein one or more of the legs is disengaged from the beams within the receptacle and an extended position wherein all of the legs are engaged with the beams of the top guide within the receptacle. The inspection system includes a pair of inspection elements that are translated above a second pair of beams that are adjacent the receptacle and that do not have the housing received thereon.

Abstract: An elongate fuel element is described that has a silicon carbide cladding enclosing a fuel, such as UO2, wherein the fuel is dimensioned relative to the cladding to define gaps at each lateral end of the enclosure sufficiently large such that upon swelling in use, the fuel does not increase the strain on the cladding beyond the limits of the claddings strain tolerance. The lateral gaps at the ends of the fuel allow lateral expansion during swelling that reduces the strain on the cladding.

Abstract: A dry cask storage system for spent nuclear fuel includes a detection apparatus having a resonant electrical circuit, with resonant electrical circuit being situated within an interior region of a metallic vessel wherein the SNF is situated. The detection apparatus includes a transmitter that generates an excitation pulse that causes the resonant circuit to resonate and to generate a response pulse. The resonant circuit includes an inductor that is formed with a core whose magnetic permeability varies with temperature such that the frequency of the resonant circuit varies as a function of temperature. The response pulse is then used to determine the temperature within the interior of the vessel where the SNF is situated. Pressure detection is also provided.

Abstract: A passive cooling system for cooling the in-containment refueling water storage tank and the spent fuel pool of nuclear power plants that can extend the number of days the plants can safely be maintained without operator intervention. The cooling system employs a thermosiphon in a closed loop cycle that circulates a refrigerant around the cooling loop between heat exchangers within the spent fuel and in-containment refueling water and the ambient atmosphere outside the containment, by natural circulation.

Abstract: The invention relates to a multi-component cladding for a nuclear fuel rod that includes a combination of ceramic and metal components. More particularly, the invention is directed to a cladding that includes a ceramic composite having a zirconium composition deposited thereon to form a zirconium coated ceramic composite. The ceramic composite includes a ceramic matrix and a plurality of ceramic fibers. The cladding is effective to protect the contents of the cladding structure from exposure to high temperature environments during various load conditions of a nuclear reactor.

Abstract: A method for detecting a leak in a cladding tube in a nuclear reactor is described. The method is well-suited for use in a reactor having a plurality of cladding tubes housed in a plurality of linearly arranged channels for flowing coolant past the cladding tubes. The method includes monitoring the channels for the occurrence of an increase in radiation above a selected base line indicative of the presence of at least one fission product in the coolant in at least one of the plurality of channels, and monitoring the channels for the occurrence of time dependent changes in the strength of radiation in the coolant above the base line along the length of the at least one of the plurality of channels. The leak location is calculated by triangulating the radiation readings from a fixed linear array of detectors positioned adjacent to the channels to determine the location of the strongest radiation reading and the location along the length of the channel where the increase in radiation occurred.

Abstract: A rotation apparatus is usable with a control drum in a nuclear environment. The control drum is situated on a shaft that is rotatable about a horizontal axis of rotation, and the control drum includes an absorber portion and a reflector portion. The rotation apparatus includes a rotation mechanism that is structured to apply to the shaft in an operational position a force that biases the shaft to rotate toward a shutdown position, with the force being resisted by a motor to retain the shaft in the operational position when the motor is powered. The force is not resisted when the motor is unpowered.

Abstract: A device is provided for use in securing a remnant of a tube through a wall of a pressure vessel. The device include an anti-ejection device for attachment to the remnant on an interior side of the pressure vessel and an end cap for attachment to the remnant on an exterior side of the pressure vessel for sealing an open end of the remnant. The anti-ejection device includes an anti-rotation member for constraining the remnant and the anti-ejection device against relative rotation therebetween. A bolt connects the anti-ejection device, the remnant, and the end cap.