Abstract: Tritium is an important radionuclide in gaseous emissions from nuclear facilities. As a low-energy pure β radionuclide, tritium is mostly monitored by cumulative sampling and laboratory analysis. After tritium is sampled in airborne effluent and measured without purification, there may be interference from other radionuclides. The interference of carbon-14 in airborne effluent on tritium measurement is quantitatively analyzed, which provides reference for accurate and quantitative monitoring of tritium in airborne effluent. According to the sampling characteristics of tritium and carbon-14, the interference in the sampling stage is determined, and the mono-nuclear and tritium-carbon double-labeled samples are prepared and measured to determine the interference effect of carbon-14 on tritium measurement stage. In the sampling stage, the influence of carbon-14 on tritium varies with the temperature, and the solubility of CO₂ in tritium capture solution is 0.70 g at 10 ℃. In the measurement stage, the influence of carbon-14 on tritium will vary according to the design and working principle of liquid scintillation spectrometer. For example, if Quantulus1220 ultra-low level liquid scintillation spectrometer is used, the counting contribution of carbon-14 can not be ignored in tritium measurement mode; If LSA2000A liquid scintillation spectrometer is used, the counting contribution of carbon-14 can be ignored in tritium measurement mode.

Key words: tritium, carbon-14, interference, LSC