Investigation of radioisotopes in different organisms around Paks NPP

Complete text of publication follows. The Paks Nuclear Power Plant is a pressurised water reactor, therefore, it requires a large amount of cooling water. Cooling water is pumped from the Danube, and used water is also discharged back to the river through the warm-water channel. In the study Danube water and various aquatic organisms (a snail, Viviparus Acerosus, a mussel Unio Tumidus, a predatory fish Stizostedion lucioperca and a non-predatory fish Leuciscus idus) were collected upstream and downstream of the inlet of the channel. After freeze-drying both from the interstitial water and the dry matter of the aquatic organisms collected, tritium measurements were performed by the T-3He method to gain information about the ratio of the tritium concentration of the organically bound and the not-bound hydrogen, as well. The activity of the organically bound tritium reflects the mean activity of the environment of the organism, while the tritium activity of the interstitial water shows the actual activity of the aquatic environment. The activity of gamma emitters in the dry matter was also measured by gamma spectrometry. In case of the mussel and snail samples gamma spectrometry measurements were performed separately from the calciferous skeleton and the tissues. Besides the aquatic organisms, soil and plant samples (Scots Pine Pinus sylvestris, Common Milkweed Asclepias syriaca L., giant goldenrod Solidago gigantea) were collected in the vicinity of the nuclear power plant and in a background site, as well. These samples were analysed by gamma spectrometry and for tritium concentration, and the results were compared with a background site. On the basis of the gamma spectrometry results significant amount of artificial gamma emitter isotopes do not get to the Danube through the warm-water channel. Only 60Co occurred in certain mussel, snail and sludge in a measurable activity concentration, however, it is not of power plant origin, as it was present even in the background samples. The tritium activity concentration of the interstitial water of the aquatic organisms follows that of the surrounding water. Downstream of the inlet of the warm-water channel a slight increase in the tritium activity concentration of the Danube can be observed compared to the background values. The determination of the tritium organically bound in the interstitial water is the aim of our current research. In the soil and plant samples only gamma emitters of natural origin were identified.