Kinetics of 3H, 90Sr and 137Cs content changes in hydrosphere in the Vltava River system (Czech Republic).

The paper presents results and interpretation of long-term monitoring of occurrence and behaviour of radioisotopes 3H, 90Sr, and 137Cs in the vicinity of the Temelín Nuclear Power Plant. 3H, 90Sr, and 137Cs originate predominantly from residual contamination due to atmospheric nuclear weapons tests and the Chernobyl disaster in the last century. Monitoring of radionuclides comprised surface waters, river sediments, aquatic plants, and fish. This enables an up-to-date appraisal of the Temelín Nuclear Power Plant impact on the hydrosphere in all indicators at standard power plant operation, as well as at critical situations. The time and spatial variability of these radionuclide concentrations were monitored in the hydrosphere at in- and out-flow of the Orlík Water Reservoir. The basic evaluated radioecological characteristics can be used in assessing the long-term kinetics of decline and behaviour of radionuclides and their potential release into the environment. A very slow decline in 3H concentration at unaffected sites was observed. At sites downstream from the power plant the 3H concentrations were significantly higher, an evident impact of the power plant operation. A decline in 90Sr and 137Cs concentrations was observed in all the monitored indicators. Also, the characteristic effective and ecological half-lives were evaluated.

Comparison of balance of tritium activity in waste water from nuclear power plants and at selected monitoring sites in the Vltava River, Elbe River and Jihlava (Dyje) River catchments in the Czech Republic.

During the routine operation, nuclear power plants discharge waste water containing a certain amount of radioactivity, whose main component is the artificial radionuclide tritium. The amounts of tritium released into the environment are kept within the legal requirements, which minimize the noxious effects of radioactivity, but the activity concentration is well measurable in surface water of the recipient. This study compares amount of tritium activity in waste water from nuclear power plants and the tritium activity detected at selected relevant sites of surface water quality monitoring. The situation is assessed in the catchment of the Vltava and Elbe Rivers, affected by the Temelín Nuclear Power Plant as well as in the Jihlava River catchment (the Danube River catchment respectively), where the waste water of the Dukovany Nuclear Power Plant is discharged. The results show a good agreement of the amount of released tritium stated by the power plant operator and the tritium amount detected in the surface water and highlighted the importance of a robust independent monitoring of tritium discharged from a nuclear power plant which could be carried out by water management authorities. The outputs of independent monitoring allow validating the values reported by a polluter and expand opportunities of using tritium as e.g. tracer.

Observed half-lives of 3H, 90Sr and 137Cs in hydrosphere in the Vltava River basin (Bohemia).

A near field study was set up to follow the effects of the Temelin nuclear power plant construction. Reference levels of artificial radionuclides were monitored in the Vltava River upper course and its tributaries in the period 1990-2001. Monitoring continued even after the waste water release startup during the pilot operation in 2002. The assessment of the (90)Sr and (137)Cs concentrations histories in ground water, river bottom sediments and fish showed a decreasing trend. This trend was not influenced by the nuclear power plant pilot operation. In the case of tritium, trend of increasing concentration had been already observed since the pilot operation startup. The monitoring of changes in concentrations of artificial and natural radionuclides in influenced and uninfluenced profiles will be maintained to assess the possible influence of the operation of the Temelin nuclear power plant.