DETERMINATION OF URANIUM AND THORIUM IN SOLAR SALTS BY NEUTRON-ACTIVATION ANALYSIS

Uranium and thorium contents of solar salts were measured by neutron a ctivation analysis. In advance of neutron irradiation, U and Th were c oncentrated and separated from some interfering elements by neutraliza tion in which they were precipitated with aluminium hydroxide from sol utions obtained by dissolving the salts in water or dilute nitric acid solution. The uranium and thorium concentrations determined were from several hundred ppt to 10 ppb. It was strongly indicated that uranium tends to remain in the solution (brine from seawater) phase in the pr ocess of solar salt production while thorium tends to transfer to the solid (solar salt) phase.