European Commission logo
English English
CORDIS - EU research results
CORDIS
Content archived on 2024-04-15

CRUSHED SALT BEHAVIOUR UNDER EFFECT OF A HEAT SOURCE IN BOREHOLES DRILLED IN A SALT MINE.

Objective

THE STUDY CONCERNS THE FINAL STAGE OF A NUCLEAR WASTE DISPOSAL IN DEEP SALT FORMATIONS : THE PARTIAL OR COMPLETE CLOSING OF A SITE. SEALING OF DRIFTS AND SHAFTS MUST BE PERFORMED AS TIGHT AS POSSIBLE TO SET UP A BARRIER AS SIMILAR AS POSSIBLE TO THE NATURAL GEOLOGICAL BARRIER.
AS CRUSHED SALT BACKFILLING CORRESPONDS TO ONE OF THE CONSIDERED CONCEPTS A RESEARCH PROGRAM IS ACTUALLY DEVELOPED ON THE BASIS OF THE FOLLOWING AXIS :
- THERMOMECHANICAL BEHAVIOUR OF CRUSHED SALT DURING THERMAL CLIMAX AND DURING COOLING,
- MECHANICAL INTERACTION BETWEEN CRUSHED SALT AND ROCKSALT,
- EVOLUTION OF FLUIDS, ESPECIALLY TRAPPED AIR IN CRUSHED SALT PORES.
THIS STUDY LED TO PERFORMING AN IN-SITU EXPERIMENT BY HEATING CRUSHED SALT IN SEVERAL BOREHOLES DRILLED IN A SALT LAYER IN A ALSACE POTASH MINE.
ARMINES (ASSOCIATION POUR LA RECHERCHE ET LE DEVELOPPEMENT DES METHODES ET PROCESSUS INDUSTRIELS) IS CONTRACTOR FOR ANDRA TO SUPPORT THE EXPERIMENT WHICH IS CONDUCTED BY LMS (LABORATOIRE DE MECANIQUE DES SOLIDES) AND THE ENGINEERING DEPARTMENT OF MDPA (MINES DE POTASSES D'ALSACE).

1. PREPARATION OF THE TEST SITE
DRILLING OF THE BOREHOLES :
- SIX 240 MM DIAMETER BOREHOLES DESTINED TO BE HEATED,
- SMALL MEASUREMENT BOREHOLES : FOUR AROUND EACH OF THE HEATED ONES.

2. INSTRUMENTATION
2.1. SETTING UP OF THE COMPUTER CONTROLLED SYSTEM DEVELOPED BY LMS FOR DATA ACQUISITION AND DATA TRANSMISSION (FROM THE TEST SITE TO LMS).
2.2. EQUIPMENT OF THE BOREHOLES :
- HEATED HOLES : + INTRODUCTION OF THE FRAMEWORK SUPPORTING THE ELECTRIC WIRES AND SEVERAL TRANSDUCERS (FOR MEASUREMENT OF TEMPERATURE, INTERSTITIAL PRESSURE OF TRAPPED AIR, TOTAL PRESSURE OF CRUSHED SALT, BOREHOLE CLOSSURE),
+ BACKFILLING OF CRUSHED SALT IN FIVE OF THEM, THE SIXTH ONE LEAVING WITHOUT BACKFILL IN ORDER TO CHECK NATURAL CLOSURE OF HEATED SALT AND TO COMPARE ITS BEHAVIOUR TO THE OTHERS,
- SMALL HOLES : INTRODUCTION OF THE TEMPERATURE AND EXTENSOMETRY MEASUREMENT TRANSDUCERS.

3. MODELLING
3.1. PRELIMINARY CALCULATIONS IN ORDER TO DEFINE THE FOLLOWING POINTS :
- THERMAL POWER TO BE SUPPLIED IN EACH BOREHOLE TO REACH A WALL TEMPERATURE OF 110 CELSIUS DEGREES,
- GEOMETRICAL SHAPE AND POSITION OF THE HEATING SOURCES,
- HEATING PROCESS,
- RANGE OF THE TRANSDUCERS.
3.2. INTERPRETATION OF THE IN-SITU RESULTS.

4. LABORATORY EXPERIMENTS :
THE FOLLOWING EXPERIMENTAL STUDY HAS BEEN CONDUCTED IN ORDER TO DETERMINE MECHANICAL AND THERMAL PROPERTIES OF CRUSHED SALT :
- PHYSICO-CHEMICAL ANALYSIS,
- MECHANICAL PROPERTIES AT AMBIENT TEMPERATURE,
- MECHANICAL BEHAVIOUR UNDER TEMPERATURE (UP TO 100 CELSIUS DEGREES,
- THERMAL STUDY.

Topic(s)

Data not available

Call for proposal

Data not available

Coordinator

Commissariat à l'Energie Atomique (CEA)
EU contribution
No data
Address
Route du Panorama Robert Schuman
92266 Fontenay-aux-Roses
France

See on map

Total cost
No data