Tritium and hydrogeology - Investigations and measurements carried out at the Grenoble Nuclear Research Centre

Tritiated water of thermonuclear origin is a new and very interesting parameter of which the hydrogeologist is making increasing use in the study of various problems. The authors present the results of their work in the following fields: Karst hydrology. In the latitudes in which these studies were conducted, the water from precipitation shows an annual maximum of concentration in June. The authors show how this 'signal' can be used to establish correlations between the losses from an aquifer and resurgence about 30 km away, by means of a series of systematic measurements of the precipitation supplying aquifers and springs. These measurements have been valuable in a trial project involving a gamma-emitting tracer; CETA . (Network for the collection of atmospheric tritiated water). This network was set up with the collaboration of the National Meteorological Service. It is concerned with the collection and measurement of monthly samples collected at 26 stations spread fairly evenly across France. Its purpose is two-fold: Primarily to constitute a 'bank' of samples, or sampling data, for use in any subsequent hydrological studies carried out in France; and secondly, to permit study of the spatial distribution of tritium fall-out. Very interesting results in the form of tritium isoconcentration curves, have disclosed a 'sea/continent effect', whereby tritium concentrations increase as one moves inland. The authors hope that these measurements will provide important information on the movements of atmospheric water in France. (author)