Tritium as an indicator of venues for nuclear tests

•A new method to verify underground nuclear testing by using 3H was considered.•The research of local contamination 3H were performed at the Semipalatinsk Test Site.•The 3H distribution in the air in horizontal tunnels was shown.•The 3H distribution in the air at near-mouth parts of vertical boreholes was shown.

Currently, due to the Treaty on the Non-proliferation of Nuclear Weapons there is a highly topical issue of an accurate verification of nuclear explosion venues. This paper proposes to consider new method for verification by using tritium as an indicator. Detailed studies of the tritium content in the air were carried in the locations of underground nuclear tests - “Balapan” and “Degelen” testing sites located in Semipalatinsk Test Site. The paper presents data on the levels and distribution of tritium in the air where tunnels and boreholes are located – explosion epicentres, wellheads and tunnel portals, as well as in estuarine areas of the venues for the underground nuclear explosions (UNE).