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PHYSICO CHEMICAL CHARACTERIZATION OF BITUMINIZED EUROCHEMIC MEDIUM LEVEL WASTE

Objective

THE PRESENT PROGRAMME IS A CONTINUATION OF RESEARCH CARRIED OUT IN THE FRAMEWORK OF THE PREVIOUS CEC R&D PROGRAMME (1981-1984), UNDER ACTION I(CHARACTERIZATION OF LOW AND MEDIUM LEVEL WASTE FORMS), CONVERED BY THE CONTRACT N 302-83-15 WASB.
IN THE PREVIOUS PROGRAMME, A NUMBER OF REAL EUROBITUM SAMPLES HAS BEEN STORED, TO MEASURE AFTER VARIOUS TIMES THE PHYSICO-CHEMICAL PROPERTIES ("AGEING). RESULTS FOR ONE YEAR AGEING WERE OBTAINED. THE CORROSION BEHAVIOUR OF SMALL, REAL EUROBITUM SAMPLE4S IN TWO MEDIA (PURE WATER, CLAY-WATER MIXTURE) WAS INVESTIGATED, AND IMPORTANT DATA ON THE SWELLING LEACHING OF THE WASTE SALTS AND OF THE RADIONUCLIDES WARE GATHERED.
IN THIS PROGRAMME, THE STUDY OF THE AGEING BEHAVIOUR WILL BE CONTINUED.
EXTRAPOLATION OF THE SWELLING DATA ON SMALL SAMPLES TO FULL SIZE CONTAINERS WILL BE ATTEMPTED BY PERFORMING SWELLING TESTS ON INACTIVE SPECIMENS OF INCREASING SIZE. THE STUDY OF THE CORROSION BEHAVIOUR OF REAL, FULL ACTIVE EUROBITUM SAMPLES WILL BE EXTENDED BY PERFORMING TESTS IN CLAY RELATED MEDIA AT REPOSITORY-LIKE PRESSURE (4.0 MPA).
THE EXPERIMENTAL WORK WILL BE ELABORATED IN COLLABORATION WITH BELGOPROCESS (EX-EUROCHEMIC).
The questions addressed concern swelling phenomena during leaching of large samples, the leaching of radio isotopes under clay repository pressure conditions, and the ageing behaviour of real Eurobitum samples.

The swelling behaviour upon leaching was investigated using inactive Eurobitum simulates; the leaching and ageing behaviour were evaluated using real, small Eurobitum samples. The swelling behaviour due to water uptake proceeds almost linear with the leaching duration. The swelling is not controlled by the water diffusion into the bitumen matrix, but rather by the hardness of the bitumen.
B.1. EFFECT OF SIZE
SWELLING EXPERTIMENTS ON INACTIVE EUROBITUM SAMPLES WITH SPECIFIC SURFACE AREA OF 6.25, 2.20, 0.70 AND 0.25 CM TO CONCLUDE ABOUT THE SWRLLING BEHAVIOUR OF FULL SIZE BLOCKS (0.1 CM) THE EXPERIMENTS ARE CONDUCTED IN TWO MEDIA.

B.2. EFFECT OF PRESSURE
CORROSION TESTS ON REAL, SMALL EUROBITUM SAMPLES AT AMBIENT OR THE CLAY REPOSITORY LIKE PRESSURE OF 4.0 MPA, IN INTERSTITIAL CLAY WATER AND WET CLAY. PARTICULAR ATTENTION IS GIVEN TO THE RADIONUCLIDE RELEASE.

B.3. AGEING BEHAVIOUR.
MEASUREMENT OF SOME PHYSICO CHEMICAL PROPERTIES (DENSITY, SOFTENING AND SELF-IGNITION POINT, PENETRATION, THERMAL PROPERTIES,)ON REAL EUROBITUM SAMPLES STORED FOR PERIODS OF 4 AND 6.5 YEARS.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

BELGIAN NUCLEAR RESEARCH CENTRE
Address
200,Herrmann Debrouxlaan 40-42
1160 Bruxelles
Belgium