Method and apparatus for regenerating cold traps within liquid-metal systems
AssigneeThe United States of America as represented by the United States Energy Research and Development Administration
InventorJohn M. McKee, Jr.
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Abstract
Oxide and hydride impurities of a liquid metal such as sodium are removed from a cold trap by heating to a temperature at which the metal hydroxide is stable in a molten state. The partial pressure of hydrogen within the system is measured to determine if excess hydride or oxide is present. Excess hydride is removed by venting hydrogen gas while excess oxide can be converted to molten hydroxide through the addition of hydrogen. The resulting, molten hydroxide is drained from the trap which is then returned to service at cold trap temperatures within the liquid-metal system.
Claims12
A method of removing impurities including sodium hydride and sodium oxide from a liquid-metal system including a cold trap wherein said impurities deposit comprising:
- heating said trap to form molten sodium hydroxide from the reaction of sodium hydride and sodium oxide;
- monitoring the hydrogen partial pressure within said cold trap to determine excess sodium hydride;
- and
- removing impurities from said system by draining said molten sodium hydroxide and by adjusting the partial pressure of hydrogen gas to a hydrogen pressure between the hydrogen dissociation pressure of sodium hydride and the hydrogen dissociation pressure of sodium hydroxide at the temperature of the materials within the cold trap.
An improved cold trap apparatus for removing impurities from a liquid-metal system comprising:
- a first tank having an inlet and an outlet interconnected with said liquid-metal system for flow of liquid metal therethrough;
- means for varying the temperature of said first tank from a temperature at which said impurities are solid to a temperature at which said impurities form a melt;
- a second tank interconnected with said first tank for receiving said melt formed of impurities;
- and
- monitoring means for determining whether impurities remain in said trap.
Dependencies are inferred from the claim text.