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DEVELOPMENT AND APPLICATION OF A RETENTION PROPERTIES MEASUREMENT SYSTEM IN A GEOLOGICAL ENVIRONMENT USING RADIOACTIVE TRACERS IN THE DRILL-HOLE (SELF-CONTAINED PROBE FORALAB)

Objective

RADIONUCLIDE FROM A SUBTERRANEOUS WASTE STORAGE PLACE HAVE TO FORCE THEIR WAY THROUGH, AND INTERACT WITH, SEVERAL BARRIERS PRIOR TO REACHING THE GEOLOGICAL MEDIUM ITSELF.
THEY ARE DILUTED BY THE SUBTERRANEOUS WATER WHICH, BY MODIFYING THEIR CHEMICAL STRUCTURE, SETTLE THEM INTO A FINAL BALANCE WITH THE MEDIUM.
THE PURPOSE OF THIS STUDY IN TO DETERMINE THE DELAY TERM OF THE RADIONUCLIDES DURING THEIR MIGRATION THROUGH THE DEEP GEOLOGICAL ENVIRONMENT.
IT BECAME EVIDENT THAT IT WAS PREPOSTEROUS TO ATTEMPT IN-LABORATORY DUPLICATION OF THE PREVAILING PARAMETRIC CONDITIONS OF THE NATURAL MEDIUM, WHETHER PHYSICAL OR BIOLOGICAL.
TO AVOID THE UNCERTAINTIES CONNECTED TO LABORATORY EXPERIMENTS, THE PROBE "FORALAB", WHOSE PERFORMANCES HAD ALREADY BEEN AS CERTAIN DURING THE PRECEDING CONTRACT (WAS 3/7-83-7 P), WAS DEVELOPED TO PERMIT STUDYING THE RADIONUCLIDE SORPTION PHENOMENA IN A GEOLOGICAL ENVIRONMENT IN A CONDITION OF AUQUILIBRIUM WITH UNDISTURBED SUBTERRANEOUS WATES.
THE PROBE NEED NOT SIMULATE THE ENVIRONMENT AS IT IS PLUGED INTO IT.
THE CONTRACT SCOPE IS THE "IN-SITU"QUALIFICATION OF THE PROBE, USING A DUAL TRACING SYSTEM, I.E. TRITIUM AND EU ON THE ONE HAND .PU AND NP ON THE OTHER HAND
THE PROBE WILL THEN BE OPERATED IN 3 GEOLOGICAL SITES, OF SOME INTEREST FOR THE COMMUNITY I.E. AURIAT (GRANITE), MOL (CLAY) AND GORLEBEN (SALT), IN ORDER TO ASSESS THE CONTAINMENT PROPERTIES OF THESE ENVIRONMENTS.
THE PROBE IS ESSENTIALLY COMPOSED OF A PUMP, A SYRINGE, A 20 MM DIA, 200 MM LONG TEST COLUMN AND 40 SAMPLING POTS. ITS DOUBLE INSULATION IS A SAFETY AGAINST DRILL-HOLE POLLUTION.

B.1. PROBE QUALIFICATION
THE PROBE WILL BE CHECKED FOR PERFORMANCE IN THE HOLE DRILLED IN THE GRANITIC SITE OF AURIAT.
THE COLUM, FILLED WITH FONTAINEBLEAU SAND, WILL BE TRACED BY MEANS OFEUROPIUM AND TRITIUM.
THE DRILL-HOLE WASTE WILL BE CIRCULATED IN THE COLUMN FOR ONE DAY BEFORE THE TRACER INJECTION.
B.2. TESTS ON THE REFERENCE SITES
THE TESTS WILL BE PERFORMED IN THE DEEP HOLES AT AURIAT, MOL AND GORLEBEN.
THE COLUMNS WILL BE FILLED WITH A MIXTURE OF FONTAINEBLEAU SAND AND 1 TO 3 % CLAY FROM THE SITE.
THE RADIONUCLIDES USED WILL BE AM, PU AND NP.
EACH COLUMN WILL BE TRITIUM-CALIBRATED FROM EACH INDIVIDUAL TEST.
B.3. FINALLY THE RESULTS FROM EACH INDIVUDUAL TEST WILL BE MATHEMATICALLY PROCESSED TO YIELD THE DELAY TERMS AND THE ABSORPTION ISOTHERMS OF EACH POLLUTANT USED.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Commissariat à l'Energie Atomique (CEA)
Address
Centre D'études De Cadarache Sere-ders
13113 Saint-paul-lez-durance
France