[en] The studies have been performed for the project for investigation of the radionuclide migration in the cap rock of the Gorleben repository for radio-active waste. The paper reports parameter studies describing the radionuclide migration. The dynamic sorption behaviour of 36 Cl^-, 131 J, 45 Ca²⁺, 85 Sr²⁺, and 134 Cs⁺ have been determined. (DG)

[en] In determining the filter velocity of an undisturbed ground-water flow, summarized, the following information is necessary: 1) Information about the measuring device. a) Shape and position of the measuring probe within the diluting volume: radius and height of the measuring probe height of the diluting volume; b) Type of the measuring probe: resolution resp. dead time; c) Length of the packings bounding the diluting volume. 2) Information about the boring and its construction. a) Borehole radius; b) Well-filter tube: type of filter tube, nominal width and slot width; c) Filtering sand resp. gravel: origin and range of grain sites (resp. about 2 l sample). 3) Information about the ground-water conductor. Stratum inventory and information about the range of grain sites (resp. 10 l sample). 4) Information about the applied tracer type of the gamma tracer (half life) and chemical concentration. (orig./HP)

[en] The once-through column experiments were done in order to determine the sorption parameters of carbon-14 (retardation factor or dynamic distribution coefficient) in porous media (loose rock, fractured solid rock) under defined experimental conditions (packing density of the porous medium, water velocity). The results were to give information for selection of backfilling material for the projected repository sites at Gorleben and in the Konrad mine. (orig./HP)

[en] The task of the project for ''Sorption experiments and hydraulics studies'' was to perform supplementary migration experiments on selected radionuclides in site-specific sediment/water systems of the cap rock of the planned repository at Gorleben, experiments to be carried out as close as possible to natural conditions. The studies reported are: Determination of hydraulic characteristics and sorption parameters of selected radionuclides in cohesive sediments, subject to natural boundary conditions (structure, falling gradient and/or flow velocity). Examination of influence of the flow length on the hydraulic characteristics and dynamic sorption values in sandy sediments. Evaluation of available radionuclide concentration distributions according to a two-phase model (Cameron-Klute model). The established results decribing the migration processes were finally critically analysed for a concluding interpretation. (orig.)

[en] The adsorption behaviour of the hydrologic tracers ₅₁Cr-EDTA, ₈₂Br^-, ₁₃₁I^-, Na⁺, Cl^-, NO^3-, uranin, eosin and pyranin was investigated in four selected sands and gravels. The measurements were performed in column and Batch setups and also in a groundwater flow model. (orig.)

[en] The cohesive and sandy sediments stem from shaft driving at the Gorleben salt done. For the cohesive materials, HTD was used as a tracer substance, while I-131^- was used for the sandy materials. Diffusion coefficients of HTD in cohesive materials in their natural texture are in the range of 2x10^-6 to 5x10^-6 cm²/s, those of I-131^- in the investigated uniform fine and middle sands are approximately 3x10^-6 cm²/s. (DG)

[en] The migration of ¹⁵²Eu in a system of fine sand and water containing humic substances was investigated in a flow column system under realistic conditions. In this system, the trivalent Eu forms colloids with the water. These Eu humates are transported without retardation at recovery rates significantly below 100 per cent. Recovery is more or less a measure of the physical process of filtration of Eu bonded to particulates. In the range of natural filtering rates, the recovery rates decrease with decreasing filtering rate. (orig.)

[en] The third GSF Lysimeter Workshop focused on pollutant migration in underground strata, i.e. the dispersion of water constituents as referred to water transport on the basis of ideal tracer investigations

[en] As a means of assessing contaminated sites as well as in cases of adverse soil alterations the Federal Ordinance on Soil Protection and Contaminated Sites stipulates seepage water forecasts for the soil-to-groundwater path. These forecasts must include a determination of the emission rate of the contaminating material and its speed of transport. This report on the lectures held and posters presented at the Fourth GSF Lysimeter workshop is divided into 7 chapters: seepage water forecasting and lysimeters; determination of emission rates; lysimeter studies on water and material transport; coverings for contaminated materials, diverse studies on seepage water forecasting (degradation, analysis, hydraulics, toxicity); diverse lysimeter studies and lysimeter components

[en] In order to assess the hazard potential of the planned radioactive waste repository in the Gorleben salt dome, laboratory experiments are performed which are designed to provide information about the migration behaviour of emplaced radionuclides after assumed incidents. Complementary to the results obtained so far from investigation programmes, batch and continuous column experiments (I-131, Zr-95, Nb-95, Sr-85, Cs-134, Ca-45, Sn-113, C-14, and Cl-36 used as tracers) were made using natural sediment samples from the mine shafts with natural ground-waters. In this connection, sediment samples which had been taken in a frozen state, stored and inserted in continuous column models were also analysed. These samples in particular, in their geochemical and petrographic states, are considered at present optimum ''undisturbed''. (orig.)