Determination of Uranium Concentration by Isotope Dilution Method

Abstract

The uranium concentration of the fuel solution in the Water Boiler Type Reactor, which is now in operation at the Japan Atomic Energy Research Institute, was measured by the application of the isotope dilution method using natural uranium as spike isotopes. After mixing completely, the spike solution with the fuel solution, uranium was separated from fission products the extraction method using tetrapropylammonium nitrate-methyl, isobutyl ketone system. The isotopic composition of uranium was then measured by means of a surface ionization type mass spectrometer(CEC21-702B), while the concentration uranium was calculated from the result of the isotopic assay. It has been found that this method can be applied with the satisfying reproducibility to the determination of the uranium concentration in the presence of highly radioactive materials.