[en] NRC's [U.S. Nuclear Regulatory Commission's] research in the field of hydrogeology addresses the regulatory issues in both the high-level waste (HLW) and low-level waste (LLW) management programs. Contractor research studies and NRC staff efforts examine state-of-the-art methods and theories in analyzing ground water flow and radionuclide transport. This work has been incorporated into international cooperative efforts for studying ground water flow models, HYDROCOIN, and geosphere transport models, INTRAVAL, related to geologic disposal of radioactive waste. With respect to low-level waste management the paper discusses the following topics: regulatory criteria; program objectives; research contractor studies; and regulatory significance

[en] This report is the tenth of a series in which the results of the NRPB environmental radioactivity surveillance programme are presented. Samples of airborne dust, rainwater and milk are collected routinely throughout the UK and in the Channel Islands and the Isle of Man; the concentrations of various radionuclides with particular reference to Cs¹³⁴ and Cs¹³⁷ are measured and the exposure of the population evaluated. (UK)

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[en] The generation and behavior of real colloids and pseudocolloids of the actinides, ²³⁸Pu, ²⁴¹Am and ²⁴⁴Cm, are investigated in four different Gorleben ground waters. Colloids are characterized by ultrafiltration at different pore sizes from 1 nm to 450 nm and various analytical instrumentations. Behavior of pseudocolloids has been analysed by determining their effects on the solubility and the distribution coefficient of actinides between ground water and geomatrix. Sorption of actinide ions on groundwater-colloids (generation of pseudocolloid) are examined and the migration of actinides as pseudocolloids is discussed. 14 references, 6 figures, 2 tables

[en] Experiments concerning the sorption of radionuclides carried out on the site-specific unconsolidated sediments have been in progress in 6 laboratories since 1981 as part of the Gorleben site investigation program for the most relevant radionuclides. Sorption data are being determined for the site-specific conditions, and the influence of parameters, such as pH, Eh, complexing agents and NaCl concentrations is investigated. The data are necessary for the safety assessment of the repository. As the investigations have not yet been terminated, the results represent a preliminary waste. 11 references, 2 figures, 3 tables

[en] The dispersion of ²²²Rn from emitted waste gases at Wairakei geothermal power station, New Zealand, is modelled. It is concluded that resulting concentrations in the nearby township of Taupo will never exceed the maximum permissible in any meteorological situation. The maximum accumulation is calculated to be less than one eighth of the normal background radon concentration. A more realistic set of assumptions predicts long-term mean concentrations about 4% of background levels. A new geothermal power station, Ohaaki, three times further away, is calculated to produce ten times lower concentrations than Wairakei. Measurements using passive solid-state radon detectors show that the natural variation of radon concentrations greatly exceeds any calculated contribution from either geothermal station; hence, much of the radon is probably due to more local minor sources. The measured six-month integrated mean radon concentration at Taupo is a significant fraction of the maximum permissible concentration. It is concluded that these two geothermal power plants are unlikely to produce concentrations of radon hazardous to the population or to plant workers. (author)

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[en] The long-range contamination of the river Weser by the nuclear power station Wuergassen is shown using Co 60 as a tracer. The external radiation exposure of the pathway 'sediment' at the lower part of the river Weser was estimated on the basis of real emission rates and for the hypothetical case of discharging the total activity allowed. From this it followed, that this part of the river Weser has to be considered as a so-called critical impact area for the KWW according to sect. 45 of the German Radiological Protection Ordinance. (orig.)