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: An apparatus is provided for the automatic assembly of nuclear fuel rod bundles in a predetermined coordinate array. Each fuel rod is identified during its travel and positioned according to an identifying code carried on its lower end plug which designates the fuel enrichment and additive level of the rod.

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: 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: 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: 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.

Abstract: An improved method for determining the nuclear radiation threshold of a non-metallic material with the aid of a computer is disclosed, in which differently irradiated samples of the material are subjected to thermogravimetric analysis. From the resultant pyrolytic weight-loss, temperature and elapsed time data, the reaction rates are determined for different orders of reaction values and are plotted against inverse temperature values to obtain the activation energy corresponding to each sample. By plotting activation energy against radiation dose for each sample, the radiation threshold of the material is obtained.

Abstract: A velocity limiting device providing greater resistance to motion through a fluid in one direction than in the opposite direction. The device includes a toroidally shaped control member having a smooth generally conical surface on one side for low resistance movement through the fluid in the one direction. On its opposite side the control member is formed with at least one groove providing a concave surface spaced from which is an arrangement of vanes forming a jet for directing a stream of fluid into the groove upon movement in the opposite direction whereby the resultant increase in fluid turbulence increases resistance to rapid movement in this opposite direction.

Abstract: A system for determining the radioactive materials content of the ash or residue from an incinerator of contaminated materials contained in cans. The system includes can handling apparatus, a neutron source for activating the material and neutron and gamma ray detectors for detecting emissions from the materials by which fissile/fertile material content is determined.

Abstract: A system for determining the U-235 and U-238 content in a box of radioactive waste material. The system utilizes a passive arrangement which detects spontaneous gamma ray emission from the material in combination with an active arrangement including a neutron source for activating the material.

Abstract: A method and apparatus are disclosed for monitoring the operation of a boiling water nuclear reactor for the occurrence of a superheated condition. The invention provides redundant monitoring of the level of coolant water in the reactor independently of existing water level gauges. A closed system vapor pressure device, located outside the reactor, probes the temperature of the reactor steam. The temperature of the steam determines the internal vapor pressure developed in the device, the latter being directly compared, externally of the reactor, to the steam pressure in the reactor vessel. The differential between the compared pressures is an indication of a superheated reactor condition and, hence, of a low water level in the vessel.

Abstract: Disclosed is apparatus and method which, in cooperation with an electrical system, analyzes signals generated by detectors placed in a flux field of gamma rays and neutrons. A first detector with a first sensor is coupled to the electrical system. A second detector with a second sensor is coupled to the first sensor and the electrical system. A fissile material is housed in the first detector, and is heatable by gamma ray and neutron capture to in turn heat the first sensor, which generates a first signal which is delivered to the electrical system. A non-fissile material is housed in the second detector, and is heatable by gamma ray capture to in turn heat the second sensor, which generates a second signal. The first and second signals are analyzed in the electrical system to determine the power level, neutron flux, and gamma ray flux within the flux field. Also provided is a microtechnology apparatus and method for measuring neutron flux.

Abstract: A radiation dosimeter includes a plurality of air wall type ionization chambers for radiation detection. Each ionization chamber is connected in series with a selectively actuable switching element under the control of a data processor. The ionization chamber switching element pairs are connected in parallel and the entire group is further connected in series with a load resistor and a source of known potential. A voltage threshold detector is connected across the load resistor and is effective to develop a signal proportional to the peak potential appearing across the load resistor when each of the switching elements is actuated to recharge the various ionization chambers. The voltage peak is proportional to the radiation rate. An A/D converter converts the output of the voltage threshold detector into useful data for a data processor which performs the functions of process control and calculation of radiation rate and cumulative dosage.

Abstract: A method for making a nuclear fuel channel is disclosed having a high degree of dimensional accuracy which uses the thermal expansion of a mandrel to precisely size the channel. An assembly of the mandrel and a channel preform is pulled through a die to die sink the preform into substantial surface-to-surface contact with the mandrel prior to the heating step.

Abstract: The present invention described a signal conditioner. A thermocouple produces a signal that is present at a summing node input of a conditioning amplifier. The conditioning amplifier has a plurality of selectable gain values by which amplifier sensitivity may be varied to complement that of the thermocouple. Provision is made at the summing node input of the summing amplifier for thermocouple cold junction compensation and range offset. The present invention finds application in monitoring thermal conditions in an industrial process, such as a nuclear reactor. The high degree of precision and reliability required in such processes is maintained by including a test circuit which provides a selectable test pulse to the summing node input of the conditioning amplifier. One aspect of the present invention is the provision for testing during actual circuit operation in a process and irrespective of selected conditioning amplifier sensitivity.

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 slender spring members and laterally oriented rigid stops.

Abstract: A stabilizer and aligning support plate arrangement for a vertically and rotatably positionable undervessel platform in a nuclear reactor including a pressure vessel, said arrangement facilitating mobilization of said platform for servicing operation.