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 The specimen is inserted and withdrawn from the core by inserting or withdrawing the tubular member from above the seal table.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 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 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 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.

Abstract: A filtering arrangement for use in a bottom nozzle of a fuel assembly in a nuclear reactor includes a top surface, a bottom surface, a plurality of vertical wall portions arranged in a generally squared grid-like pattern which extend between the bottom surface and the top surface and define a plurality of non-circular passages extending between the bottom surface and the top surface through the arrangement, and a plurality of first debris filters which are each positioned between the top surface and the bottom surface to generally span across a respective one of the plurality of passages.

Abstract: A subcritical reactivity monitor that utilizes one or more primarily gamma sensitive (prompt responding) self-powered detector style radiation measurement devices located within the core of a nuclear reactor to determine the amount that the reactor multiplication factor (Keff) is below the reactivity required to achieve or maintain a self-sustaining nuclear chain reaction. This invention utilizes measured changes in the self-powered detectors' current(s) to allow a reactor operator to measure the value of Keff at essentially any desired interval while the reactor is shutdown with a Keff value less than the critical value of 1.0. This invention will enable integration of the output of the value of Keff directly into the Reactor Protection System, which will enable the elimination of the operational and core design analysis constraint costs associated with the current Boron Dilution Accident prevention methodology and enable automatic control of the Chemical Volume Control System.

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: An apparatus and method are described which enable real time measurements to measure the margin to criticality in a process for manufacturing fissile materials. An exemplary apparatus includes a neutron source capable of being modulated, an optional moderator to reduce the thermal energy of neutrons from the neutron source, a collimator for controlling the direction of any neutrons emanating in use from the target, a plurality of detector arrays positioned in predetermined locations relative to a process vessel for detecting process variables and for sending signals representative of the process variables in real time to a processor for receiving the signals and converting the detected process variables into margin to criticality measurements.

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.