Abstract: A redundant reactivity control system, operating in conjunction with other systems in a nuclear power plant, to mitigate the potential consequences of an anticipated transient without scram event, is described. The invention interfaces to a boiling water nuclear reactor with the reactor's neutron monitoring system, standby liquid control system, control rod drive system, reactor recirculation system, reactor water clean-up feed water control system, and control room and local panels. Two divisionally separated control panels include associated detection and actuation logic and the necessary interface logic to other systems to perform the specific functions in response to an anticipated transient without scram event. Each separate division includes two identical channels. Actuation of any associated reactor system by the invention requires the agreement of the two channels within a division.

Abstract: A method for fabricating a thermocouple unit for service in and about nuclear reactors and other radioactive environments. The method provides a thermocouple encapsulated within a sphere of fissile material.

Abstract: A rhodium self-powered detector, a fission chamber, and appropriate electronic circuitry for combining the output of the self-powered detector and the fission chamber are disclosed in combination wherein the combined output of the self-powered detector and the fission chamber is always proportional to the local reactor power level or neutron flux density in a nuclear reactor.

Abstract: An electronic circuit provides various accurate counts of detected neutrons to enable the assaying of fissile material in a neutron emitting radioactive source. The circuit develops a time correlated window associated with each detected neutron, and delays these windows to develop uncorrelated windows. These windows are used to develop separate detected neutron counts which distinguish between time correlated fission neutron detections and time uncorrelated singular neutron detections. The circuit also develops a count of all detected neutrons.

Abstract: Radiation detectors measuring gamma radiation from radioactive accumulations in an incinerator through low density refractory windows therein for burning combustible, contaminated wastes from nuclear fuel manufacturing activities.

Abstract: There is provided a nuclear fuel element having a zirconium alloy cladding tube with improved corrosion resistance. The cladding tube comprises a metallurgical gradient across the width of the tube wall wherein the tube has a more corrosion-resistant metallurgical condition at the outer circumference and a less corrosion-resistant metallurgical condition at the inner circumference. The metallurgical gradient can be generated by heating an outer circumferential portion of the tube to the high alpha or mixed alpha plus beta range while maintaining the inner surface at a lower temperature, followed by cooling of the tube.

Abstract: A method of replacing a defective circumferential butt joint in a metal pipe is disclosed. An annular metal bridge ring, having a smaller wall thickness than the pipe but the same inside diameter, is positioned coaxial with the pipe in the relatively wide gap created by the removal of the defective joint. The ring becomes an integral part of the weld by being welded in place, thereby partially filling the gap between the edge surfaces of the pipe exposed by the removal of the defective joint. Subsequent layers of fusible material are weld deposited in place on top of the ring until the gap is filled to the exterior pipe surface. Use of the ring in the gap enables replacement of the defective joint with a single weld.

Abstract: An improved method for compression molding of typically brittle ceramic materials comprising uranium dioxide which enhances their compacting and cohering properties in the manufacture of nuclear fuel products. The uranium dioxide is mixed with a fugitive binder comprising a high molecular weight acrylic acid polymer and ammonium bicarbonate. The mixture is then pressed and sintered to expel the binder and to give a fissionable nuclear fuel pellet.

Abstract: In a fuel assembly for a nuclear reactor a fuel element spacer formed of an array of laterally positioned cojoined tubular ferrules each providing a passage for one of the fuel elements, the elements being laterally supported in the ferrules between laterally oriented spring members and oppositely positioned rigid stops, the wall thickness of the ferrules being relatively large and the height of the ferrules being relatively small to reduce hydride concentration in the ferrule material while maintaining relatively low flow resistance.

Abstract: A method and system for quality control of nuclear fuel materials, said system including amplifier/integrator circuitry, signal processors, and drift control feedback circuitry. The invention permits the qualitative and quantitative measurement of paramagnetic additives such as gadolinium for example in a paramagnetic base nuclear fuel material including ferromagnetic impurities. Drift problems relating to temperature and other effects are solved electrically and mechanically. Analysis can be conducted irrespective of the form or composition of the nuclear fuel.

Abstract: In a nuclear fuel assembly spacer providing passages for fuel rods or other elongated elements, a spring component of H-shape including a pair of spaced spring members of hairpin-like configuration connected by a retaining strap wherein an arched side of one of the spring members projects into one of the passages and the arched side of the other of the spring members projects into an adjacent one of the passages for resilient engagement with the fuel rods or other elongated elements extending through the passages.

Abstract: An ultrasonic transducer for use in a high temperature environment and method for fabricating the same. A disk-shaped piezoelectric crystal is weakened in at least one surface in accordance with a predetermined line pattern relative to a first direction in that surface. The crystal is bonded to a thin lens material with a coefficient of thermal expansion dissimilar in this first direction. The predetermined line pattern is adapted to relieve stress in this first direction created by unequal rates of expansion or contraction of the crystal and the lens.

Abstract: Transport apparatus is disclosed for moving a stream of objects along a substantially continuous path between a source and a collection station and past a viewing station. A stream of successive, spatially separated objects is moved into end-to-end abutment to form successive stacks of objects. Each stack is spiraled past the viewing station with minimal vibration to expose the complete surface of each object to inspection. Subsequently each stack is rearranged into spatially separated objects which are rapidly sorted by diverting those objects from the continuous path which do not conform to predetermined criteria upon inspection. The transport apparatus achieves high throughput without compromising the accuracy of the inspection process.

Abstract: Method for precipitating and removing soluble metal compounds from solutions of phosphoric acid. The method is useful in the disposal of metal-containing phosphoric acid waste from electrolytic operations, including such acid solutions contaminated with uranium compounds.

Abstract: A stopper apparatus for use in blocking the unvalved nozzle of a cooling fluid filled nuclear reactor pressure vessel includes a plug, typically in the shape of a frusto-conical member having inflatable gaskets for sealing against a seat of generally unknown surface characteristics and means for positioning and urging the plug into position to seal the nozzle. The plug is typically positioned by suspension cables whereby the apparatus can be temporarily inserted and removed from the pressure vessel. The urging means is generally a two-way hydraulically driven jack controlled by remotely-actuated hydarulic lines. The apparatus is a tool which permits temporary sealing of a submerged outlet in a reactor vessel to permit maintenance on a fluid recirculation loop.

Abstract: Apparatus for remotely controlled examination of the control rod drive penetration stub tubes in the wall of a nuclear reactor pressure vessel including a rotatable carriage on which is mounted a reciprocable shaft to which is attached an inspection instrument for scanning the stub tubes.

Abstract: A method of controlling the bowing action of fuel channels used in nuclear reactor cores is disclosed. Each channel is heat treated and mounted in its control rod module with an orientation dependent on its prior heat treatment. Upon exposure to radiation, the channels will bow in a desired direction away from the control rod.

Abstract: A spacer for use in a fuel assembly of a nuclear reactor having thin, full-height divider members, slender spring members and laterally oriented rigid stops and wherein the total amount of spacer material, the amount of high neutron cross section material, the projected area of the spacer structure and changes in cross section area of the spacer structure are minimized whereby neutron absorption by the spacer and coolant flow resistance through the spacer are minimized.

Abstract: An incinerator is disclosed which includes apparatus for removing ash from an incinerating chamber and which comprises hydraulically operated plows that slide along the floor of the chamber to push the ash towards an ash trough. Ash removal efficiency is improved in accordance with the present invention by the hinged suspension of a brush from the plow face. An auxiliary plow is added to the waste material loading device to clear ash from the highest of several stepped floor levels even in the absence of no new load being entered. The auxiliary plow further includes a clevis assembly which pivots the brush away from the incinerator floor during reverse plow travel.

Abstract: An optical inspection system is disclosed which determines surface and other features of objects by illuminating them with a light beam having substantially uniform light intensity in space and time. The light beam is derived from a light source whose light intensity may vary in space and time. The surface features of each object are inspected by detecting light reflected from the object through a lens system which focuses the reflected light on an array of photosensitive elements. The output signals provided by the array may be used to provide a measure indicative of the conformance of the inspected surface to predetermined criteria. The inspection system is further capable of determining other features of the inspected object, such as the height of the object, by illuminating the object with a second light beam derived from a second light surface.