Objective THE UNDERSTANDING OF THERMAL EFFECTS DUE TO DECAY HEAT LIKE PORE PRESSURE RISE, CHANGE IN MECHANICAL PROPERTIES AND IN THE HYDRAULIC FIELD UNDER HIGH LITHOSTATIC PRESSURES IS FUNDAMENTAL IN THE EVALUATION OF SAFETY AND IN THE DESIGN OF NUCLEAR WASTE REPOSITORIES IN CLAY. FOR THIS PURPOSE A THERMO-HYDRO-MECHANICAL MODEL HAS BEEN DEVELOPED IN ISMES. ITS SUITABILITY IN REPRODUCING THE THERMO-MECHANICAL RESPONSE OF THE SAMPLES TESTED UNDER DIFFERENT LOADING CONDITIONS HAS BEEN TRIAXIAL CELL OPERATING IN ISMES LABORATORIES ON VARIOUS TYPES OF STIFF CLAYS, EITHER REMOULDED AND UNDISTURBED. FURTHERMORE, THE INTERPRETATION PROCEDURES OF THERMAL TESTS SHOWED THAT FOR SOME OF THE CLAY TESTED THE CAMPANELLA AND MITCHELL PROCEDURE CAN LEAD TO INCONSISTENT RESULTS. IN ORDER TO STUDY POSSIBLE REASONS FOR THIS INCONSISTENCY, FIRST THERMAL EXPANSION COEFFICIENT VALUES WILL BE STUDIED REFFERRING TO THE CONDITIONS OF WATER IN STIFF CLAYS, WHICH ARE SUSPECTED TO AFFECT SIGNIFICANTLY ITS THERMAL BEHAVIOUR. THIS STUDY WILL BE CONDUCTED WITH AECL OF CANADA. THE RESULTS OF THIS RESEARCH COULD AFFECT ALSO THE PREDICTED UNDRAINED RESPONSE OF CLAY IN TERMS OF PORE PRESSURE RISE. IN THE MEANTIME A BETTER UNDERSTANDING OF THERMO-MECHANICAL BOOM CLAY BEHAVIOUR IS FORESEEN IN ORDER TO IMPROVE THE MODEL. THERMO-MECHANICAL EFFECTS ON CLAY DUE TO REALISTIC DISPOSAL GEOMETRIES WILL BE THEN STUDIED WITH THIS MODEL WITH THE COOPERATION OF SCK/CEN. SIMILAR STUDIES ARE PLANNED ALSO FOR SAND/BETONITE MIXTURES, WIDELY ADOPTED FOR BACKFILLING. 1. MICROSTRUCTURAL STUDIES 2. SAMPLING OF THE BOOM CLAY IN THE MOL SITE. 3. EXPERIMENTAL TESTS IN THE HITEP APPARATUS ON NATURAL CLAYEY AND ARTIFICIAL SOILS. 4. IDENTIFICATION OF MATERIAL PARAMETERS ON THE BASIS OF EXPERIMENTS ON BOOM CLAY 5. INTRODUCTION OF THE OPTIONS EXPECTED FROM ACTIVITY 1 IN THE MATHEMATICAL MODEL. 6. CHECK ON THE RSSULTS OF THE LABORATORY TESTS USING THE ABOVE MODEL. 7. DEFINITION OF THE BOUNDARY VALUE PROBLEMS TO BE TREATED ON THE BASIS OF PROSPECTIVE IN-SITU EXPERIMENTS AND/OR TYPICAL DISPOSAL TECHNOLOGY AT MOL SITE. 8. SIMULATION OF CLAY MASS BEHAVIOUR WITH REFERENCE TO THE PROBLEMS ENVISAGED IN ACTIVITY 7 9. EVALUATION OF SIMULATION RESULTS Fields of science engineering and technologyother engineering and technologiesnuclear engineeringnuclear waste managementnatural sciencesmathematicspure mathematicsgeometrynatural sciencesmathematicsapplied mathematicsmathematical model Programme(s) FP1-RADWASTOM 3C - Research and development programme (Euratom) on the management and storage of radioactive waste, 1985-1989 Topic(s) Data not available Call for proposal Data not available Funding Scheme CSC - Cost-sharing contracts Coordinator ENEL.HYDRO SPA EU contribution No data Address Via Pastrengo 9 24068 SERIATE Italy See on map Total cost No data Participants (2) Sort alphabetically Sort by EU Contribution Expand all Collapse all ATOMIC ENERGY OF CANADA LTD Canada EU contribution No data Address MANITOBA See on map Total cost No data CEN-SCK Belgium EU contribution No data Address MOL See on map Total cost No data