Liquid‐metal extraction for processing of spent fuel

Abstract

Plutonium and the fission products can be removed from irradiated uranium by liquidmetal extraction by use of another metal immiscible with uranium. Metals studied have been silver, cerium, and lanthanum. Plutonium removal by silver is high, by the rare-earth metals moderate. In a l l cases volatile elements, including cesium, strontium, and barium, are removed. Rare earths are e5ciently removed. Ruthenium and molybdenum are largely unaffected. Experiments with synthetic fuels corresponding to long bum-up periods show improved removal of most elements. Repeated batch extractions indicate that a continuous process separating the fuel into uranium, plutonium, and fission-product fractions could be developed.

Extraction

“…This work, initiated by decontamination problems arising out of the liquid metals fuel reactor program, is of borderline interest in analytical chemistry now but may well be of more direct use to analysts before too long. Rare earths have been extracted from molten bismuthuranium by contact with molten lithium and potassium chloride (14,15,51,124) and the distribution of plutonium between aluminum and bismuth (125) and between uranium and silver (203,208) has been studied. THEORY A helpful organizational pattern for the extraction process, based on three essential aspects common to every metal extraction process, has been proposed (148).…”

Reactions of uranium carbide in a fused KC1-LiCl/zinc system

“…In the latter equilibrations with the KCl-LiCl eutectic salt present, the addition of ZnCl2 was expected to lead to complete oxidation of the carbide at relatively low levels of ZnCl2 in the salt. Considering the reaction to be UC + 3/2'znCl2 -UCI3 + 3/2 Zn(je) + C(9) and with the carbide and zinc both present in nearly pure form or unit activity at equilibrium, the ratiot. _ NUCI3 ^ ^ (NZnCl2)3/2should be a constant in dilute salt solutions where Henry'sLaw is valid.…”

Reactions of uranium carbide in a fused KC1-LiCl/zinc system

“…In the latter equilibrations with the KCl-LiCl eutectic salt present, the addition of ZnCl2 was expected to lead to complete oxidation of the carbide at relatively low levels of ZnCl2 in the salt. Considering the reaction to be UC + 3/2'znCl2 -UCI3 + 3/2 Zn(je) + C (9) and with the carbide and zinc both present in nearly pure form or unit activity at equilibrium, the ratio t. _ NUCI3 ^ ^ (NZnCl2)3/2 should be a constant in dilute salt solutions where Henry's Law is valid. It should be noted that the same ratio applies if the carbide reacting with the zinc is UC2 or UC1.5.…”