General Electric Company

James H Terhune

John P Neissel

David L Richardson

Barry M Gordon

Khosrow Karim-Panahi

Gerald A Deaver

Gerald M Gordon

James C Tung

Frank Ortega

Charles W Dillmann

James Edward Charnley

Balasubramanian S Kowdley

Robert L Cowan, Ii

David L Faulstich

Edward R Dykes

John P Sturtz

Beth Ann McAllister

Roy C May

Brian Charles Duckering

Michael G Smith

George A Romano

Harry H Hendon

Paul J Zimmerman

A clamped support system for a structure comprising a plurality of support piers in a predetermined array, supporting the structure; and at least two rigid reinforcing pads sandwiched about an elastomer layer, the plurality of support piers extending through the reinforcing pads and the elastomer layer.

Elastomeric seismic isolation of structures and components

A method and an apparatus for ultrasonically inspecting the welds which attach the differential pressure and liquid poison nozzles to the bottom head of the reactor pressure vessel in a boiling water reactor. The scanning apparatus is seated on the upper taper of the nozzle outer tube and incorporates a stationary frame having a cutaway section which allows installation from the side. The apparatus has vertical and circumferential positioning mechanisms which are operated remotely to scan an ultrasonic transducer package over the circumferential welds and heat-affected zones thereof. The rotating frame has a transducer carriage mounted thereon which is vertically displaceable relative to the rotating frame. The vertical and angular motion motors can be controlled together to provide the desired path for the ultrasonic transducer around the stub tube. The tool also includes a vessel contour follower which follows the contour of the inclined surfaces of the reactor pressure vessel bottom head. The vessel contour follower is linked to the ultrasonic transducer to ensure that the transducer follows the contour of the weld, in position and angle.

Method and apparatus for remote ultrasonic inspection of nozzles in

A technique for reducing the shadow corrosion effect in zirconium-based alloys caused by .beta.-particles emitted by adjacent components containing one or more elements that emit .beta.-particle flux when activated by neutron capture. The technique entails providing a coating capable of absorbing .beta.-particles, so as to mitigate the adverse effect of .beta.-particle bombardment of a zirconium-based alloy. Preferred coating materials include beryllia, beryllium, tin, zinc, chromium and cadmium. The coatings can be applied to various nuclear reactor structural alloys, such as stainless steel and nickel, platinum, copper, hafnium and yttrium-based alloys containing 0.2 weight percent manganese or more.

Coating for reducing corrosion of zirconium-based alloys induced by      .

A means for damping a low-friction azimuth resolver by use of an array of small magnets acting on a metallic pendulum attached to the resolver shaft. The magnetic field acts on the pendulum motion to induce a motional electromotive force and associated currents, which produce forces opposed to the motion, thereby acting as a non-contact damper on the resolver shaft. When the resolver shaft is at rest, no 'eddy currents' are produced in the static magnetic field and no damping force exists. If the shaft moves, the attached pendulum cuts the magnetic flux lines and produces a drag force proportional to the shaft angular speed. The pendulum is typically made of diamagnetic material, such as lead or copper, thereby assuring that the induced forces arise solely from the motion. The magnetic field is produced by an array of small, but intense, samarium-cobalt magnets contained in a compact package providing for uniform damping throughout 360.degree. of resolver motion. The device is designed and constructed as a modification to standard resolvers and allows for application where tight clearances have previously been a constraint.

Magnetically damped azimuth resolver

A method for stabilizing direct current generated by neutron activation of a plurality of interconnected .beta.-emitter (nuclear decay electron) cells, which are placed in a specific position in the out-of-core region of a light water nuclear reactor. The method entails a synergistic combination of neutron-absorbing isotopes, in specific relationship to each other, the amount of each absorber and their respective locations in the neutron flux field being chosen to render the total current-time characteristic substantially constant over a significant number of reactor full-power-years. The method enhances the current output and lifetime of the current generator by greatly deferring burn-up of the neutron absorbers. If configured as a DC voltage source for powering radiation-hardened, high-temperature integrated circuitry contained in the reactor pressure vessel, voltage regulation circuitry is not necessary. Typically, the useful lifetime is rendered independent of output current and can be extended indefinitely, thereby greatly reducing replacement costs.

Stabilized in-vessel direct current source

A device for generating direct current by neutron activation of a plurality of series-connected beta-emitter (nuclear decay electron) cells, located in the out-of-core region of a light water nuclear reactor. The device can be used as either a current source, or preferably configured as a DC voltage source, capable of powering low-power, radiation-hardened, high-temperature integrated circuitry contained in the reactor vessel. As such, the device acts like a DC battery that is activated by (n, .gamma.) reactions, both thermal and epithermal (by resonance capture). The device is not operable until exposed to a substantial neutron flux, so it has unlimited shelf-life and is not radioactive during manufacture In the preferred embodiment, an isotope of the metallic rare-earth element dysprosium is configured in a 'sandwich' geometry to generate sufficient current that a useful steady voltage can be generated by means of a simple voltage regulation circuit.

Neutron-activated direct current source

A stand-alone low-voltage direct current power supply, for use as a battery, which is energized by the decay of a radioactive isotope in response to neutron capture. During this decay, either .alpha.- or .beta.-particles are emitted. The emitting radioactive isotope should have adequate half-life and no .gamma.-emission. The preferred .beta.-emitting radioisotope is thallium, which decays directly to the ground state of Pb.sup.204 by 763-keV .beta.-decay with no .gamma.-emission. The resulting .beta.-particles are collected to form a current which can be used for various purposes inside a reactor. The preferred .alpha.-emitting radioisotope is americium.

Stand-alone power supply energized by decay of radioactive iostope

A method and an apparatus for electrically suppressing electrochemical potential near highly susceptible components of a boiling water reactor. A small self-powered, electrical device is affixed to the metal area to be protected, which device has the capacity to locally suppress electrochemical potential automatically and continuously without provision for external power supplies, cables, penetrations, or other paraphernalia usually associated with electrical and electronic systems. The result is that components susceptible to intergranular stress corrosion cracking are not as sensitive to the details of the water chemistry flowing over them and do not crack as much, or as rapidly, as presently. The new technique is based on the concept of supplying electrons directly and locally to the sensitized zone(s) of the metal, thereby inhibiting intergranular stress corrosion cracking. The source of the electrons is .beta.-emitting material which is contained in a housing attached to the metal. The electron source is electrically connected to the sensitized zone of the metal. The current of electrons has a magnitude sufficient to compensate for the electrons lost by the metal to electron-accepting fluid in contact with the metal.

Method and apparatus for electro-protection of piping systems and

A method and apparatus for sizing a surface-connected planar crack through a gas- or liquid-filled gap. Ultrasonic energy having a frequency equal to the resonant frequency of the gap is emitted toward the crack edge. A first portion of the energy is back-scattered by the crack edge toward the emitter in a detection mode and a second portion is scattered by the crack edge toward a surface to which the crack is connected, which reflects the second portion toward a detector. The difference between the respective times-of-flight from emission to detection of the first and second portions is measured and used to determine the depth of penetration of the surface-connected crack. The paths traveled by the first and second portions of said emitted ultrasonic energy substantially intersect at the gap. A similar method also applies in sizing buried planar cracks across fluid-filled gaps.

Time-of-flight method for sizing cracks through fluid-filled gaps in

A method and a device for minimizing electrostatically enhanced deposition of charged particulates in the jet pump nozzles of operating BWR plants. The jet pump nozzle has an inner conducting surface which is electrically isolated from the main body of the nozzle. An electrical circuit is electrically coupled to the inner conducting surface of the nozzle. The electrical circuit is designed to electrically minimize charged-particle deposition at the nozzle surface exposed to a free-stream electrical potential, using a DC circuit with active element feedback to adjust the surface potential to minimize the net current to the inner conducting surface, thereby minimizing deposition.

Jet pump electro-nozzle

A non-contact system and method for measuring torsional wave propagation along a rotating shaft as well as static angular deflection due to a constant applied torque. The relative twist angle between two cross-sectional portions of the rotating shaft separated by a predetermined distance is detected over time and then the axial variation of torque along the rotating shaft is determined as a function of relative twist angle. Detection is carried out electro-optically using a pair of photodetectors and bands of reflective marks adhered on the circumferential surfaces of the two cross-sectional portions. Axial variation of torque is determined by determining variations in the phase difference between pulse trains output by the photodetectors.

Rotating shaft vibration monitor

An ultrasonic parametric amplifier incorporates a duct having rigid cylindrical wall with a periodic inner surface that undulates sinusoidally in an axial direction, and an element for heating the external surface of the wall. The sinusoidal undulations of the periodic inner surface have a wavelength which is about half of the wavelength of the waves of ultrasonic energy propagating through a fluid filling the duct. The waves are amplified by synergistic interactions of the ultrasonic waves with the periodic duct walls when heat is added in a predetermined manner, thereby compensating for the exponential decrease in fluid temperature which would otherwise lead to detuning of the amplifier.

Ultrasonic parametric amplifier

A method for ultrasonically inspecting a closely packed regular array of mutually parallel, uniformly sized and spaced rigid rods surrounded by a thin-walled metallic channel and immersed in a compressible medium. The method utilizes the properties of coherently scattered ultrasonic waves to identify rods which are defective, out of position or missing. A plane, monochromatic ultrasonic wave is transmitted toward the array of rods on one side thereof. Then an interference pattern produced on an opposing side of the array is detected. This interference pattern is the result of multiple scattering and diffraction of the plane ultrasonic wave during propagation through the array of rods. When the wavelength is comparable with the rod diameter and the rods are not too close together, scattering results in spatial relationships that produce an unusually large amount of wave penetration through the array in certain directions relative to the incident propagation vector. This is akin to Bragg scattering and is dependent on direction, wavelength, and details of the cylindrical array dimensions.

Method for ultrasonic inspection of a closely packed array of fuel rods

A catalytic recombiner device for reacting two or more molecular species having dilute concentrations in fluids flowing in pipes at elevated temperatures. The species are stable in the bulk fluid, but because of a high electrochemical potential, the species create conditions favorable to stress corrosion cracking in the pipe walls. If the pipe forms a portion of a coolant system, as in a nuclear power plant, the dissolved chemical species are transported and distributed throughout the system with undesirable consequences. To reduce the electrochemical potential, a cartridge having catalytic surfaces is installed in the flow upstream of the component to be protected against stress corrosion cracking. The catalytic surfaces of the cartridge form a small amount of benign reaction product (e.g. water), thereby reducing the concentration of undesirable species. The presence of a compact catalytic recombiner at strategic locations substantially reduces the electrochemical potential and protects both the piping and the vessels and internals connected to the piping from corrosive attack.

Method and apparatus for local protection of piping systems from stress

An ultrasonic method of inspecting repaired stub tubes in a boiling water reactor. The top and bottom ends of each stub tube are respectively welded to the corresponding control rod drive housing and to the bottom head of the reactor pressure vessel. Under certain conditions, a crack can form in the heat-affected zone of the stub tube adjacent to the upper weld, necessitating repair by installing a mechanical seal. A probe inserted in the control rod drive housing has transducers which transmit pulsed ultrasonic energy toward a machined surface-air gap interface disposed to reflect the pulse trains generally axially through the stub tube. The radial and azimuthal dimensions of a radial crack in the stub tube are determined in dependence on which pulsed trains are reflected back to the probe by the crack via the interface.

Growing community of inventors

San Jose, CA, United States of America

James H Terhune