Objectif Clay is a candidate host rock for high radioactive waste disposal. The understanding of the behaviour of natural elements in clay formations is an unavoidable step towards the understanding of the fate of such radionuclides. Further laboratory studies are also needed to help forecast, by analogy the behaviour of radioelement released from deep radioactive repositories.The ARCHIMEDE project aims at three major goals1. understanding the mechanisms of acquisition and regulation of formation water chemistry in clay environment, as a result of water rock interactions;2. testing and validating the physico-chemical parameters that describe the clay formation and its properties and that feed geochemical models;3. applying these results to model a real clay environment : Boom Clay formation (Belgium).Rock sample characterization is generally realized in the laboratory after sampling. Sampling techniques usually applied can sometimes significantly disturb the original geochemical and microbial state of the sediment. In this study special attention is paid to prevent such a drawback: the Boom clay formation (solid, fluid and gaseous phases) is sampled from the Underground Research Laboratory facility in Mol (Belgium) under anaerobic and aseptic conditions, and experimental works are designed in order to measure non conservative (pH, Eh) or potentially versatile parameters (interstitial fluids, trapped gases, cation exchange capacity) directly in the formation. Microbiological techniques will be developed for natural sample bacteriological characterization, in conjunction with conventional bacteriological investigations.Seven drill works in the HADES Underground Research Facility (URF) at Mol were completed in 1992, apart from one which encountered technical problems. Solid and fluid sampling: a 20 m long horizontal core was drilled in the URF for solid and fluid sample collection. The work was performed under sterile and anaerobic conditions.Fluid sampling: 2 15 m long horizontal piezometres were drilled on both sides of the previous work in order to collect large amounts of interstitial fluid. As previously they were completed under sterile and anaerobic conditions. One of them is equipped to house and optical fibre dedicated to in situ pH determination.Experimental work: In situ deep freezing and coring (2 cores 2 m long), active geochemistry piezometre setting, and pH/Eh probe setting for in situ measurement have been completed.Work programme:The four main topics of the project are as follows1. fluid and solid sampling, in situ measurements.2. fluid and solid characterization.3. microbial investigations.4. fluid-rock equilibria modelling will integrate the results obtained after the characterization step. Champ scientifique engineering and technologyother engineering and technologiesnuclear engineeringnuclear waste managementnatural sciencesearth and related environmental sciencesgeochemistrynatural scienceschemical sciencesnuclear chemistryradiation chemistrynatural sciencesphysical sciencesopticsfibre optics Programme(s) FP2-RADWASTOM 4C - Specific research and technical development programme (Euratom) in the field of management and storage of radioactive waste, 1990-1994 Thème(s) B.2 - The underground facility HADES in the argillaceous layer under the Mol Site (B) Appel à propositions Data not available Régime de financement Data not available Coordinateur Commissariat à l'Energie Atomique (CEA) Contribution de l’UE Aucune donnée Adresse Route du Panorama Robert Schuman 92266 Fontenay-aux-Roses France Voir sur la carte Coût total Aucune donnée Participants (4) Trier par ordre alphabétique Trier par contribution de l’UE Tout développer Tout réduire Bureau de Recherches Géologiques et Minières (BRGM) France Contribution de l’UE Aucune donnée Adresse Avenue de Concyr 45060 Orléans Voir sur la carte Coût total Aucune donnée Centre d'Etudes de l'Energie Nucleaire-Studiecentrum voor Kernenergie CEN/ SCK Belgique Contribution de l’UE Aucune donnée Adresse Boeretang 200 2400 MOL Voir sur la carte Coût total Aucune donnée Commissariat à l'Energie Atomique (CEA) France Contribution de l’UE Aucune donnée Adresse Centre d'Études de Fontenay-aux-Roses 92265 Fontenay-aux-Roses Voir sur la carte Coût total Aucune donnée Guigues Recherche Appliquee en Microbiologie SA France Contribution de l’UE Aucune donnée Adresse 10 rue Pierre Duhem 13856 AIX-EN-PROVENCE Voir sur la carte Coût total Aucune donnée