Monitoring of Kr and Xe isotopes in air using liquid oxygen

A method was developed for determining radioactive Kr and Xe isotopes in air using liquid technical-grade oxygen prepared at air-separation plants. Kr and Xe are less volatile air components than N 2 and O 2 and are therefore accumulated in liquid oxygen in the course of its production. The method allows determination of background volumetric concentrations of Kr and Xe at short distances (∼100 km) from the sources of radioactive noble gas (RNG) injection. The results of 85 Kr and 133,135 Xe monitoring in air of St. Petersburg in 2006–2008 are presented. For some air samples taken in St. Petersburg, back trajectories of the transfer of air masses were calculated, using HYSPLIT dispersion transport model developed by ARL, to determine possible sources of injection of Xe and 85 Kr radionuclides.