Westinghouse Electric Corporation

Electric Power Research Institute Incorporated

William G Carlson

Tapan K Gupta

Andrew S Sweetana, Jr

Kenneth C Radford

Roswell J Ruka

Douglas M Mattox

Shih M Ho

Gerald B Boyette

Joseph C Osterhout

Philip L Hower

A self-supporting, gas-permeable air electrode tube (16) is made having a sintered structure of calcium-doped LaMnO.sub.3, a density of from 60% to 85% of theoretical density, and a Coefficient of Thermal Expansion of from 10.2.times.10.sup.-6 /.degree.C. to 10.8.times.10.sup.-6 /.degree.C., where one end is open and the other end is sealed with a plug (30).

Thin tubular self-supporting electrode for solid oxide electrolyte

A neutron-absorber body for use in burnable poison rods in a nuclear reactor. The body is composed of a matrix of Al.sub.2 O.sub.3 containing B.sub.4 C, the neutron absorber. Areas of high density polycrystalline Al.sub.2 O.sub.3 particles are predominantly encircled by pores in some of which there are B.sub.4 C particles. This body is produced by initially spray drying a slurry of Al.sub.2 O.sub.3 powder to which a binder has been added. The powder of agglomerated spheres of the Al.sub.2 O.sub.3 with the binder are dry mixed with B.sub.4 C powder. The mixed powder is formed into a green body by isostatic pressure and the green body is sintered. The sintered body is processed to form the neutron-absorber body. In this case the B.sub.4 C particles are separate from the spheres resulting from the spray drying instead of being embedded in the sphere.

Burnable neutron absorbers

A voltage limiting composition, actually a nonlinear resistor, especially suitable for use in a gapless surge arrester is disclosed herein. This composition includes a predetermined amount of zinc oxide as its primary ingredient and one or more specifically selected additives. All of these constituents are combined and sintered so that the composition displays a nonlinear exponent .alpha. at least equal to about 35 over the current range of 1 ma to 5000 amps and such that its energy absorption capability is at least equal to about 50 joules/cm.sup.3.

Voltage limiting composition and method of fabricating the same

A non-linear voltage limiting device displaying a particular stability characteristic and designed to eliminate flashover failure across its circumferential edge is disclosed herein along with a specific method of fabrication. The voltage limiting device is characterized by a rising resistive current with time at predetermined temperature and voltage levels and includes a disc-shaped wafer composed primarily of zinc oxide. In accordance with the method disclosed herein, after this wafer is formed and sintered in accordance with prescribed temperature and time requirements, its circumferential edge is provided with an anti-flashover coating which requires curing. Thereafter, the coated wafer is annealed in a way which cures the coating and, at the same time, reduces and preferably minimizes the resistive current rise characteristic referred to above.

Method of fabricating non-linear voltage limiting device

A sintered nonlinear resistor body, useful in gapless lightning arresters comprises a major amount of ZnO and additional metal oxides including at least Al.sub.2 O.sub.3 and an amount of selected alkali metal oxide of from about 0.003 mole % to about 0.2 mole %.

Voltage stable nonlinear resistor containing minor amounts of aluminum

A sintered nonlinear resistor body, useful in gapless lightning arresters comprises a major amount of ZnO and additional metal oxides including at least Al.sub.2 O.sub.3 and an amount of boron oxide of from about 0.005 mole % to about 0.25 mole %.

A sintered nonlinear resistor body, useful in gapless lightning arresters comprises a major amount of ZnO and additional metal oxides including at least Al.sub.2 O.sub.3 and an amount of boron oxide of from about 0.005 mole % to about 0.6 mole %, in combination with a total amount of at least one selected alkali metal oxide of from about 0.005 mole % to about 0.3 mole %.

Voltage stable nonlinear resistor containing minor amounts of aluminum,

A method for the nondestructive testing of voltage limiting blocks includes the steps of providing several discrete electrical contacts across the block, sequentially applying to each of the contacts a voltage to determine the corresponding current and utilizing the current and voltage values to determine constants related to the microstructure of that particular location. The constants can then be utilized to derive a contour map which will be indicative of a hot spot in such block as determined by a maxima of the contour map.

Growing community of inventors

Murrysville, PA, United States of America

William G Carlson