Abstract: By combining a 1030W total carbon analyzer and a 3180 liquid scintillation counter, a method for measuring ¹⁴C in NPP liquid effluents was established. It was achieved by using the totalcarbon analyzer to have the carbon in sample acidized and oxidized to carbon dioxide, which was then absorbed with a sodium hydroxide solution, and succeeded byliquid scintillation measurement. The method can effectively eliminate interference from other radionuclides, and can accurately determine ¹⁴C activity in the sample. The results show that its overall average recovery was 96.91%,detection limit was 2.07 Bq/L, and, the precision (relative standard deviation)and accuracy (relative error) of measurement results was less than ±5% respectively.

Key words: NPP, Liquid effluence, ¹⁴C