General Electric Company

Maurice E Indig

Laura L King

Samson Hettiarachchi

Robert James Law

Leonard W Niedrach

William D Miller

Gary L Smith

Jerry F Hanlon

An electrode probe for measuring the electrochemical potential of a surface at a location of interest in a boiling water reactor. The probe has a monolithic sensor configuration built into a single stainless steel mineral insulated (MI) cable. This monolithic sensor can be used as a switch to detect when the appropriate concentration of dissolved hydrogen required to provide IGSCC mitigation is present at any location inside the reactor. Using the sensor switch, it is possible to in situ instantly determine the minimum hydrogen level required to reach the IGSCC protection potential. The sensor configuration consists of a metal/metal oxide/ZrO.sub.2 sensor and a noble metal sensor in a combination wherein the outer sheath of a mineral insulated cable acts as the conductor for the noble metal and the central conductor of the MI cable acts as the conductor for the metal/metal oxide/ZrO.sub.2. The metal/metal oxide/ZrO.sub.2 sensor acts as a reference electrode in the BWR environment (i.e., at constant pH) and the noble metal sensor acts as a hydrogen electrode which responds to the dissolved hydrogen content in the BWR water.

Monolithic sensor switch for detecting presence of stoichiometric H.sub.2

Disclosed is a reference electrode probe for employment in monitoring electrochemical potentials. The inventive electrode probe comprises an elongate alumina tube having a closed distal end and a flanged open proximal end, there being at least one hole, and preferably two holes, penetrating through said tube at its closed distal end. An elongate silver electrode coated with silver chloride is housed atactilely within said alumina tube. Zirconia cloth is disposed in the closed distal end of said alumina tube and covers the hole in said alumina tube, and extended up to and may be spaced-apart from said silver electrode. A silver connector is housed atactilely within said alumina tube to its opening, and has a recess at its distal end into which said coated silver electrode is fitted and a threaded recess at its proximal end at the alumina tube opening. An insulated silver alloy rod having a distal end is threaded into the proximal recess of said silver connector. An annular elastomeric seal is in sealing relationship with the open proximal end of said alumina tube and is retaining in its annulus the distal end of said insulated silver alloy rod at its distal end. An elongate annular alumina insulator having a flanged distal end is abutted against the proximal end of said annular seal and retains said insulated silver alloy rod within its annulus. A retainer which retains said insulated silver alloy rod at the proximal end of said annular alumina insulator. Finally, a threaded two-piece annular fitting that retains said probe within its annulus contacts the flange of said alumina tube and the flange of said alumina insulator with a polymeric washer interposed between said flanges and said fitting. Tightening said fitting brings said annular seal into water-tight sealing relationship with the open proximal end of said alumina tube.

Reference electrode probe for use in aqueous environments of high

An electrode probe suited for employment as an electrical potential reference electrode in an aqueous, high pressure, high temperature, and high radiation field environment such as the core of a nuclear reactor is described. The electrode is a brazed and welded assembly consisting of only ceramic and metal parts including a sapphire base which is brazed to a kovar/stainless steel housing, welded in turn, to a coaxial cable assembly for signal transfer. The base incorporates an integrally formed pedestal through which a conductor wire extends and over which is positioned a selectively coated cylindrically shaped sealing retainer. The device is particularly suited for employment with a silver/silver chloride electrode system.

Electrode probe for use in aqueous environments of high temperature and

The present invention is addressed to an electrode for evaluating electrochemical potentials which has a robust structure particularly suiting it for employment within the rigorous environment of the reactor core of a nuclear power facility. The electrode of the present invention is comprised of five major segments: a metal cap electrode, an elongate annular metal jacket, an alumina retainer (i.e. an insulator), an annular metal transition sleeve, and a positioning and signal transfer assembly. The metal cap electrode has a tip and annulus extending therefrom formed from sidewalls having an interior surface. The elongate annular metal jacket has an annular retainer securing mouth at one end and an outlet at its opposite end. The alumina retainer has a recessed cap securing portion nestably secured to a portion of said cap electrode interior sidewall surface, and an oppositely-disposed recessed jacket securing portion nestably secured to the interior of said annular jacket retainer securing mouth. The retainer further has an access channel penetrating therethrough from said cap to said jacket securing portion. The annular metal transition sleeve has one end placed at the jacket outlet, the opposite end at the positioning and signal transfer assembly. A first insulated electrical conductor in electrical connection with the cap electrode extends through the retainer access channel and through the annular metal jacket to the jacket outlet. Finally, the positioning and signal transfer assembly is associated with the transition sleeve outlet for providing fit-up for said sleeve and for conveying electrical signals from said conductor. The elongated annular metal transition sleeve is interposed between said jacket and said positioning and signal transfer assembly.

The reference electrode probe of the present invention utilizes a metal/metal oxide/ZrO.sub.2 electrode sensor. Metal/metal oxide couples suitable include copper/copper oxide, tin/tin oxide, bismuth/bismuth oxide, and iron/iron oxide. The zirconia tube has a closed end and an open end. The closed end contains the metal/metal oxide powder and is retained therein by mineral insulation packing. A first annular metal sleeve is formed of metal exhibiting a coefficient of thermal expansion compatible with the zirconia tube and has a distal open end in sealing engagement with the open end of said zirconia tube. The first annular metal sleeve also has a proximal open end. An insulated first electrical conductor having a distal end in electrical connection with the metal/metal oxide powder extends through the mineral insulation packing and into the first annular sleeve. The first conductor also has a proximal end that terminates near the proximal end of the first annular sleeve. Advantageously, an annular ceramic tube is nested within said first annular metal sleeve and provides the insulation for the first electrical conductor. A signal transfer assembly is sealingly associated with the proximal end of the first annular sleeve. A second electrical conductor passes through the signal transfer assembly to its electrical connection with the first electrical conductor. The major advantages of the present invention over previous devices are its ability to withstand powerful radiation fields in high temperature, high pressure water; and construction features which avoid any leakage of the radioactive environment, which the sensor contacts, to the ambient.

Disclosed is an electrode probe for employment in monitoring electrochemical potentials and which has a robust structure particularly suiting it for employment within the rigorous environment of the reactor core of a nuclear power facility. The electrode of the present invention is comprised of four major segments: a metal cap electrode, an alumina retainer, an annular metal sleeve, and a positioning and signal transfer assembly. The metal cap electrode has a tip portion and an annulus extending therefrom which defines a cavity having an interior surface. The alumina retainer has a base region with a sleeve attachment surface, an oppositely disposed cap securing portion nestably disposed within said cap electrode cavity and sealingly attached thereto. The retainer further has an axis channel penetrating therethrough from the base region to the cap securing portion. The annular metal sleeve is formed of metal exhibiting a coefficient of thermal expansion compatible with the alumina retainer and has an alumina retainer surface in sealing engagement with said retainer sleeve attachment surface and oppositely disposed outlet. An electrical conductor is in electrical connection with the cap electrode and extends through the retainer access channel and through the annular metal sleeve to the sleeve outlet. Finally, positioning and signal transfer assembly is associated with the sleeve outlet for providing support for the sleeve and for conveying electrical signals from the conductor.

An electrode probe suited for employment as a reference electrode in a high pressure, high temperature, and high radiation field environment such as adjacent the core of a nuclear reactor is described. The electrode is a brazed and welded assembly consisting of only ceramic and metal parts including a sapphire crucible which is brazed to a kovar/stainless steel housing, welded in turn, to a coaxial cable assembly for signal transfer. The crucible incorporates an integrally formed pedestal through which a conductor wire extends and over which is positioned a selectively coated cylindrically shaped sealing retainer. The device is particularly suited for employment with a silver/silver chloride electrode system.

Growing community of inventors

Fremont, CA, United States of America

Maurice E Indig