Abstract: 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.

Abstract: 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.

Abstract: 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.