Tritium Measurements Along The Sava River

The measurement results of tritium (H-3) concentration in continuously sampled river water in the frame of national monitoring programs follow trends of H-3 contents in liquid releases from Nuclear Power Plant Krsko (NEK) while Pearson coefficient R for those two quantities does not show so clear correlation. Additional study was organized in cooperation among NEK, Slovenian Nuclear Safety Administration and Jozef Stefan Institute. The river water was sampled every 15 minutes on 5 locations downstream of NEK during liquid release from NEK with H-3 activity of 1.94E11 Bq which lasted for three hours. The flow rate of that day was 110 m3 s-1. 90 samples were measured by liquid scintillation technique. Several parameters for the curves of experimental results were calculated for each location with the intention of finding quantities which might help to describe and understand the levels of mixing, estimation of river water contribution to aquifers, its hydrodynamics for the river segment in the vicinity of NEK. All of them show good, but different correlations with the distance from the point of the release (author).