Liquid-metal Cathode Research Articles

Investigation of the erosion drop fraction for liquid-metal explosive-emission cathodes

The velocity spectrum of drops emitted by a liquid-metal explosive-emission cathode has been investigated. A relation between the sizes of the drops and their maximum velocities has been found for the velocity range 10/sup 3/-8/spl times/10/sup 4/ cm/s. The relation obtained supports the earlier established mechanism for the emission of drops under the action of high pressures developing in explosive emission centers. The possibilities of an additional acceleration of drops due to the explosion of necks formed on breaking the drops off the cathode surface and at the expense of the kinetic energy of the ions of the expanding cathode plasma have been discussed.

Investigation into the erosion of explosive-emission liquid-metal cathodes

The erosion rate has been measured for capillary-type and needle-type liquid-metal cathodes. The erosion drop fraction composition and percentage have been determined. For the needle-type liquid-metal cathodes, the erosion of the core has been discovered and investigated. To describe this erosion, a simple analytical model has been proposed.

Sources of pulsed low-energy electron beams and soft X-rays based on liquid-metal explosive-emission cathodes

This paper describes a pulsed electron beam source with a liquid-metal cathode operating in the explosive-electron-emission mode. The operating voltage range of the source is 10-40 kV. The operating frequency of the cathode is up to 1500 Hz. The device can be used as a point electron source in various electronic tubes and as an element of a multi-emitter electron source producing a large-cross-section electron flow.

Electrohydrodynamic phenomena on the explosive-emission liquid-metal cathode

The paper describes the results of a direct experimental observation of the development of an electrohydrodynamic instability at an explosive-emission liquid-metal cathode along with a theoretical analysis of the growth and destruction of the protrusion formed on the cathode surface. >

Uranium Transport to Solid Electrodes in Pyrochemical Reprocessing of Nuclear Fuel

A unique pyrochemical process is being developed for separation of metallic nuclear fuel from fission products by electrotransport through molten eutectic salt to solid and liquid metal cathodes. The process will allow recovery and reuse of essentially all of the actinides in spent fuel from the integral fast reactor (IFR) and disposal of wastes in satisfactory forms. Electrotransport is used to minimize reagent consumption and, consequently, waste volume. In particular, electrotransport to solid cathodes is used for recovery of an essentially pure uranium product in the presence of other actinides; removal of pure uranium is used to adjust the electrolyte composition in preparation for recovery of a plutonium‐rich mixture with uranium in liquid cadmium cathodes. This paper presents (i) experiments that delineate the behavior of key actinide and rare‐earth elements during electrotransport to a solid electrode over a useful range of ratios in the electrolyte, (ii) a thermodynamic basis for that behavior, and (iii) a comparison of the observed behavior with that calculated from a thermodynamic model. This work clearly establishes that recovery of nearly pure uranium can be a key step in the overall pyrochemical‐fuel‐processing strategy for the IFR.

Simulation op concentrated marangoni convection in electrochemical systems

We investigate the nonlinear closed mathematical model of three-dimensional concentrated Marangoni convection, such as is developed at the boundary separating an electrolyte from a liquid-metal cathode.

Use of a liquid-metal cathode in high-vacuum studies of electric breakdown

Studies of electric breakdown in a high vacuum involving liquid-metal (mercury and gallium) cathodes, whose surfaces are stabilized by centrifugal forces, have shown that an increase in the angular velocity at which the experimental apparatus rotates causes an increase in the breakdown field; the mechanism for the vacuum breakdown is found to be independent of the voltage across the electrodes. According to the Frenkel theory, vacuum breakdown results from a disruption of the steady state on the liquid-cathode surface in an electric field. Drops of liquid metal on the anode degrade the dielectric properties of the vacuum gap. Under these conditions, the breakdown mechanism becomes dependent on the voltage across the electrodes. Oxide films on the cathode surface also degrade the dielectric properties of the vacuum gap. It is suggested that the dielectric may be charged by positive ions emitted from the cathode.