Abstract: A control rod driveline and grapple is disclosed for placement between a control rod drive and a nuclear reactor control rod containing poison for parasitic neutron absorption required for reactor shutdown. The control rod is provided with an enlarged cylindrical handle which terminates in an upwardly extending rod to provide a grapple point for the driveline. The grapple mechanism includes a tension rod which receives the upwardly extending handle and is provided with a lower annular flange. A plurality of preferably six grapple segments surround and grip the control rod handle. Each grapple rod segment grips the flange on the tension rod at an interior upper annular indentation, bears against the enlarged cylindrical handle at an intermediate annulus and captures the upwardly flaring frustum shaped handle at a lower and complementary female segment. The tension rods and grapple segments are surrounded by and encased within a cylinder.

Abstract: A system for converting heat energy into electricity includes a conversion cell comprising a pair of spaced-apart electrodes having an electrolyte therebetween. The electrolyte is selected to pass negatively-charged hydrogen ions and to inhibit the passage of atomic hydrogen and positive hydrogen ions. Inducing a flow of hydrogen through the cell, a current may be generated between the electrodes as electrons are gained by the hydrogen as it enters the cell and lost by the hydrogen as it leaves the cell. In the preferred embodiment, hydrogen flow is induced by reacting the hydrogen leaving the cell with lithium or sodium to form the metal hydride. The metal hydride is then thermally decomposed to release the hydrogen and the molten metal to be recycled to the cell. In this way, the thermal energy used to decompose the metal hydride is converted into electrical energy by passing the hydrogen through the conversion cell.

Abstract: A monitored nuclear reactor parameter, such as a startup range neutron monitoring signal, is filtered at a filter having a preselected time constant and amplified with the output being passed to one channel of a two channel comparator. The level of the amplification and the filter time constant are chosen to discriminate between normally increasing startup neutron density including the prompt-jump effect and exponentially increasing neutron density due to the occurrence of reactor casualty in view of the design parameters of the reactor. This same startup range neutron monitoring signal is passed unprocessed to the other channel of the two channel comparator. Comparison of the two signals is made with the binary output of the comparator flagging excess of the unprocessed signal over the filtered and amplified signal. Presence of the appropriate reactor flag is typically used to cause rod withdrawal blockage and/or SCRAM.

Abstract: In a modular liquid-metal pool breeder reactor, a radiant vessel auxiliary cooling system is disclosed for removing the residual heat resulting from the shutdown of a reactor by a completely passive heat transfer system. A shell surrounds the reactor and containment vessel, separated from the containment vessel by an air passage. Natural circulation of air is provided by air vents at the lower and upper ends of the shell. Longitudinal, radial and inwardly extending fins extend from the shell into the air passage. The fins are heated by radiation from the containment vessel and convect the heat to the circulating air. Residual heat from the primary reactor vessel is transmitted from the reactor vessel through an inert gas plenum to a guard or containment vessel designed to contain any leaking coolant. The containment vessel is conventional and is surrounded by the shell.

Abstract: In a nuclear reactor fuel assembly, a relatively flexible mounting member for mounting a large coolant conducting tube to the lower tie plate whereby excessive side forces on the fuel rod spacers are avoided in the event of lateral displacement of the fuel assembly such as during a seismic event.

Abstract: Repair apparatus and a method of repair utilized for securing pressure sensing lines to jet pump diffusers in boiling water nuclear reactors is disclosed. Conventional access is made to the reactor with removal of the jet pump inlet mixer to expose the upwardly disposed frustum-shaped diffuser. The diffuser includes a pressure sensing line mounted by a stand off block. It has been found that this pressure sensing line becomes separated from the diffuser due to vibration and accompanying metal fatigue. A repair is effected by introduction of an arcuate beam configured for live support at each end. This pressure sensing line and stand off block is bracketed by the upper end of a beam to register the line to the stand off block. The lower end of the beam brackets the line and stands off from the diffuser at a second introduced stand off block. The line is provided with two points of support to prevent further dislodging vibration.

Abstract: A reproducible method and stable binder composition for preserving the induced plasticity of a particulate ceramic material admixture comprising uranium dioxide and a fugitive binder, and product thereof, for subsequent compaction by compressing molding in the manufacture of nuclear fuel pellets.

Abstract: An apparatus and method for continuously separating and recovering an organic liquid such as a hydrocarbon solvent from immiscible water and/or other impurities mixed therewith. The apparatus and method comprise a system for treating liquids while continuously flowing therethrough, including in series a gravity separation step followed by a distillation separation step.

Abstract: A flow channel-to-nozzle attachment for a nuclear fuel assembly wherein the flow channel and nozzle are formed of material having different thermal coefficients of expansion, the attachment comprising tapered bars secured to the lower inner ends of the channel which bars are fitted into similarly tapered grooves in the adjacent outer surfaces of the nozzle, the angle of taper being selected such that the tapered bars move more or less deeply into the grooves in the nozzle with temperature changes without bending or stressing the lower end of the channel.

Abstract: An improved method for producing nuclear fuel containers of a composite construction having components providing therein a barrier system for resisting destructive action by volatile fission products or impurities and also interdiffusion of metal constituents, and the product thereof. The composite nuclear fuel containers of the method comprise a casing of zirconium or alloy thereof with a layer of copper overlying an oxidized surface portion of the zirconium or alloy thereof.

Abstract: An improved process for producing powdered uranium dioxide from a solution of uranyl nitrate which is suitable for the manufacture of fuel for nuclear reactors. The process is continuous and comprises an incremental precipitation of soluble uranyl nitrate with ammonium hydroxide which is interrupted with an intermediate aging period. The precipitate of ammonium uranate solids is dried and thermally converted to a powdered oxide of uranium.

Abstract: A probe is disclosed for detecting the absence of helical springs from an array of mutually spaced springs, each mounted on a separate shank. The probe includes an elongate arm having a pair of pawls mounted in an aperture at one end of the arm, biased to extend from the aperture. During probing, the helical springs normally prevent the pawls from assuming their extended positions outside the aperture, which is urged by the applied biasing force. If a helical spring is missing from the array, the appropriate pawl pivots outward into its extended position and becomes lodged against the springless shank to lock the probe in position. Its location in the array then indicates where a spring must be replaced.

Abstract: A control apparatus and method for restricting liquid flow in a liquid moving pump, usually of the centrifugal type, to prevent pump cavitation and pump prime mover overloading. The control apparatus includes sensors to detect liquid temperature and pressure at the inlet of the pump. It may further include a device such as a current transformer to develop a signal indicative of power consumed by the prime mover of the pump where the prime mover is an electrical motor. The liquid pressure and temperature indications are used to generate a specific indication of the subcooling of the liquid. The temperature indication is used to derive an indication of the instantaneous required subcooling of the pump. The subcooling indication and the required subcooling indication are introduced to a comparator. Should the subcooling of the liquid fail to exceed the required subcooling, a first control signal is generated.

Abstract: A portable, microprocessor-based test instrument for the calibration, check testing, and checkout of nuclear power reactor systems under simulated operating conditions. The instrument includes a master microprocessor bus having direct communication to interchangeable plug-in printed circuit boards. Applications to which the invention may be put include rod control simulation and analysis, neutron monitoring system analysis, and rod block monitoring system simulation and analysis. The test instrument electronically interconnects at any of a plurality of points within a reactor control and monitoring system. The electrical network from the point of interconnection to the core rods is disabled and the test instrument, receives serial control command signals as would the disabled portion of the network. The test instrument also generates appropriate acknowledgements and response signals. Alternatively, a test instrument can generate faulty response signals to simulate improper command responses.

Abstract: Disclosed is a neutron detector, provided with a sealed chamber having two spaced apart electrodes, hermetically sealed in the chamber with a seal which is located in an environment of at least two decades less neutron flux than that experienced by the detector. An ionizable gas is placed within the space between the electrodes, and pressurized to a pressure above one atmosphere. A layer of a mixture of an active material and a breeding material are positioned within the chamber, the active material and breeding material being respectively U-235 and U-234, which layer has a thickness of at least 0.2 milligrams per square centimeter.

Abstract: An optical transmitter receiver switch incorporating a fiber optic light guide for communicating between electrically isolated circuits. Each switch has a photoemitter and a photosensor in optical communication with each other and with one end of the light guide. The photosensor and photoemitter are enclosed in an opaque housing and communicate with each other and the light guide via a transparent optical cavity. There results an unusually versatile optical isolator which, when in optical communication with a second optical transmitter receiver switch, forms the preferred relay.

Abstract: A reactor fuel assembly (15) configuration which allows cold shutdown margins to be met with minimal penalty to operating efficiency. The assembly comprises a component of fissile material distributed over a substantial axial extent of the fuel assembly and a component of neutron absorbing material having an axial distribution characterized by an enhancement in a relatively short axial zone (65) (the "cold shutdown control zone") corresponding to at least a portion of the axial region of cold shutdown maximum reactivity. The axial distribution of the component of neutron absorbing material typically is characterized by an additional enhancement in an axial zone (62) (the "hot operating control zone"). The component of neutron absorbing material is conveniently incorporated into at least some of the fuel rods (57-G1, G2, G3, G4). The enhancement in the cold shutdown control zone may be provided at least in part by one or more fuel rods (G2, G3) having absorber only in the cold shutdown control zone.

Abstract: A sensor apparatus cooperates with an electrical system capable of delivering power to and receiving signals from the sensor. A cable housing insulated wires is connected to the sensor and disposed in proximity to a fluid possibly containing a corrosive impurity. Corrosion detecting elements are connected to the wires and are immersed in the fluid possibly containing the impurity. Further, the elements are provided with breakable regions fabricated to corrode in the presence of the corrosive impurity. To facilitate fracture, the elements are loaded in tension so the breakable regions will fracture rapidly in the presence of corrosive impurities, to thereby send an electric signal to remote electrical equipment to indicate the presence of at least one impurity.

Abstract: A femtoammeter is disclosed which resists noise induced reversed bias of the ammeter amplifier and avoids long time constant recovery with unusually high measurement accuracy. The amplifier ammeter has a feedback loop which is provided with paired opposingly faced log diodes in parallel across the feedback circuit. Transients of negative or positive bias are accommodated without biasing the amplifier to a reverse polarity and having unacceptably long time constant recovery. Conventional temperature compensation, not possible with the parallel reversed diode configuration, is supplied by heat sinking the ammeter components, providing a log diode temperature sensor for the heat sinked components and controlling the heat sink operating temperature with a thermoelectric cooler. The temperature sensing log diodes output to a computer lookup table. The same temperature sensing log diode outputs to a bridge circuit operating the thermoelectric cooler.