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APPLICATION OF EC-TEST PROCEDURE: REPOSITIRY SYSTEM SIMULATION TEST.

Objective

THE EC TEST PROCEDURE PROVIDES:

- A TEST METHOD WHICH MAY BE USED BY VARIOUS LABORATORIES INTESTED IN EVALUATING WASTE FORM PERFORMANCE IN DIFFERENT HOST ROCK MATERIALS, INCLUDING GRANITE, CLAY AND SALT;

- A VERSATILE TEST APPARATUS WHICH MAY BE USED IN A FLOW TEST OR AS A CLOSED SYSTEM UNDER EXTREMELY DIFFERENT EXPERIMENTAL CONDITIONS INCLUDING PRESSURES UP TO SEVERAL HUNDRED BARS, TEMPERATURES UP TO 200 CELSIUS DEGREES, CORROSIVE SOLUTIONS, ETC... AND WHERE THE WASTE FORM CAN BE TESTED IN THE PRESENCE OF ONE OR SEVERAL ADDITIONAL MATERIALS, E G CANISTER, BACKFILL, OVERPACK AND HOST ROCK MATERIALS;

- EXPERIMENTAL EVIDENCE FOR THE APPROPRIATE FUNCTIONING AND OPERATION EXPERIENCE WITH THE TEST APPARATUS PRIOR TO ITS INCLUSION IN THIS DOCUMENT;

- SPECIFIED EXPERIMENTAL CONDITIONS IN THE DOCUMENT WHICH MAY BE USED AS A REFERENCE IN A ROUND ROBIN TYPE INTERLABORATORY TEST.

THE RESULTS OF THE ROUND ROBIN TEST SHALL BE PUBLISHED AS AN EC REPORT TO PROVIDE A REFERENCE DATA BASE.
The repository system simulation test (RSST) consisted of the investigation of the clay option. Boron and molybdenum, which can be considered as representative of the overall glass dissolution, have a mass loss higher than the other analysed elements. Their behaviour suggests that the glass dissolution rate becomes slower after a fewmonths. It is important to notice that the clay contribution to the ionic concentrations is generally significant, particularly for strontium. On the contrary, molybdenum and caesium amounts in the blanks are less than the detection limits. The test procedure for the clay option had to be completed. The need to work in an argon atmosphere glove box brought in some operational complications.
THE REPOSITORY SYSTEM SIMULATION TEST (RSST) HAS BEEN LAID OUT TO ACCOMODATE A WIDE RANGE OF EXPERIMENTAL CONDITIONS AND MATERIALS IN A MULTI PURPOSE LEACHING CONTAINER. AMONG THE POSSIBLE OPTIONS ARE: ACTIVE TESTS, TEMPERATURES UP TO 200 CELSIUS DEGREES, CHOICE OF STATIC OR DYNAMIC TESTS.

IN ORDER TO VERIFY, THET THE TEST PROCEDURE IS WORKABLE AND THAT REPRESENTATIVE AND REPRODUCIBLE RESULTS CAN BE OBTAINED, THE COMMISSION WILL ORGANIZE AN INTER-LABORATORY TEST CAMPAIGN (ROUND ROBIN) FOR A SINGLE SET OF CONDITIONS, BUT WITH A CHOICE OF 3 GEOLOGIC HOST MATERIALS; SALT, CLAY AND GRANITE. THE TEST CONDITIONS AND MATERIALS SPECIFIED FOR THE ROUND ROBIN TEST THEREFORE ONLY PRESENT A SMALL PART OF THE SCOPE OF THE REPOSITORY SYSTEM SIMULATION TEST.

THE RSST WILL DETERMINE CONCENTRATIONS OF MATRIX CONSTITUENTS AND RADIONUCLIDES RELEASED FROM NUCLEAR WASTE FORMS UNDER SIMULATED GEOLOGICAL REPOSITORY CONDITIONS.

BY CARRYING OUT SOLUTION ANALYSIS AT TIMES BETWEEN 7 DAYS AND ONE YEAR (OR LONGER), MATRIX CORROSION AND NUCLIDE LEACHING RATES CAN BE MEASURED AND, FINALLY, EQUILIBRIUM CONCENTRATIONS IN THE SYSTEM CAN BE DETERMINED. THE RESULTS SHOULD PROVIDE THE INFORMATION TO ESTABLISH AND VALIDATE NEAR-FIELD MODELS FOR RISK ANALYSIS.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Ente per le Nuove Tecnologie l'Energia e l'Ambiente (ENEA)
Address
Via Anguillarese 301
00060 Santa Maria Di Galeria Roma
Italy