This document specifies the measurement method for the determination of total activity concentration of uranium isotopes in non-saline waters by extraction and liquid scintillation counting.

This method covers the measurement of soluble uranium isotopes in water in activity concentrations between approximately 2·10⁻³ Bq/kg and 10 Bq/kg when analysing a 1 l test sample volume with a 60 000 s counting time with a typical alpha LSC instrument.

The ratio ²³⁴U/²³⁸U can also be determined. This method has not been tested for the measurement of other uranium isotopes.