Complex water analysis of the observation wells situated around the Puespoekszilagy radioactive waste repository

Complete text of publication follows. The long-term safety of an underground radioactive waste repository strongly depends on the radionuclide transport through the bedrock to the biosphere. The chemical composition of the groundwater has a large influence on the mobility of the radionuclides of interest and the movements of these nuclides are controlled by the groundwater flow. In the frame of a large safety analysis programme of the Puespoekszilagy radioactive waste treatment and disposal facility the observation wells situated around the radioactive waste repository were monitored. 26 water samples were taken during July and September 1999 and a complex water analysis was made. Puespoekszilagy and Nemedi streams flowing through the region of interest were sampled, as well. Classical water analysis methods were used for determination anion concentration (especially PO43-, SO42-, HCO3-, Cl-, CO32-, NO3-, NO2-), ICP (inductive coupled plasma) technique ws used for determination low level metal concentration (Hg, As, Pb, Cd, Co, Cr, Cu, Al, Fe, Ga, Li, Mo, Mn, Ni, Se, Sr, Ti, V, Zn) and AAS (atomic absorption spectrometry) method was applied for determination higher concentration of Ca, Na, K, Mg. Stable isotope ratios (δD, δ18O, δ15N, δ34S, δ13C) were measured by a home-developed mass spectrometer. 14C activity concentration was measured by GPC technique. 90Sr activity concentration was determined by liquid scintillation counting method (TRICARB 3170 TR/SL ultra low level liquid scintillation spectrometer), while 137Cs and 60Co activities were determined by a HPGe detector. Low level tritium concentrations were measured using the 3He-3H method (VG 5400 noble gas mass spectrometer). Water-mixing mechanism were determined, local water flow tendencies and a Puespoekszilagy stream orientated water movement pathway were found, indicating a possible migration route for the water-soluble radioactive waste from the repository. (author)