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IN SITU STUDY OF THE EFFECT OF A PERMANENT ARTIFICIAL IMPERVIOUS SCREEN ON GROUNDWATER FLOW, IN A POROUS MEDIUM, IN ORDER TO IMPROVE THE SAFETY OF A RADIOACTIVE SHALLOW DISPOSAL.

Objective

THIS TECHNIQUE SHOULD ALLOW TO IMPROVE SHALLOW LAND BURIAL QUALITY BY REDUCING VELOCITIES WHILE INCREASING THE GROUNDWATER TRANSFER TIMES WITHOUT INTERRUPTING ITS FLOW.
FLOW VELOCITIES AND DISPERSION COEFFICIENTS ARE MODIFIED BY THE SCREEN.
POLLUTION IS THUS CONFINED DOWNSTREAM IN A ZONE WHERE VELOCITIES HAVE BEEN CONSIDERABLY REDUCED.
THE EXPERIMENTAL DEVICE IS MADE OF:
- 1 INJECTION WELL,
- 18 PIEZOMETERS IN A FAN ARRAY, DOWN FLOW FROM THE INJECTION WELL,
- 5 PUMPING WELLS ABOUT FOURTY METERS FROM THE INJECTION WELL.
THE GROUNDWATER SPEED WILL BE CONTROLLED AND A PARALLEL STREAM FLOW WILL BE MAINTAINED IN ORDER TO STUDY THE TRANSVERSE DISPERSION.
A THEORETICAL STUDY HAS BEEN CARRIED OUT TO DETERMINE THE FLOW AND THE DIMENSIONS OF THE EXPERIMENTAL DEVICE.
THE GROUT DIAPHRAGM WALL OF CEMENT-BENTONIT WAS BEEN REALIZED BY SOLETANCHE.
THE THEORETICAL STUDY, THE "IN SITU" EXPERIMENTS AND THE CALCULATIONS HAVE BEEN EXECUTED BY THE CEA/DERS/SERE OF CEN/CADARACHE (FRANCE).

1. IN SITU STUDY OF THE EFFECT OF A PERMANENT IMPERVIOUS SCREEN ON GROUNDWATER FLOW.
1.1. DIMENSIONS OF THE SCREEN.
1.2. SELECTION OF THE IMPERVIOUS "SETTING SLURRY".
1.3. CHARACTER OF GROUNT.
2. HYDRODISPERSIVE STUDIES OF THE AQUIFER GROUND IN DISTURBED FLOW BY THE IMPERVIOUS SCREEN.
2.1. CHECKING FOR LEAKS OF THE SCREEN AND STUDIES OF THE FLOWS AROUND AND DOWNSTREAM OF THE SCREEN.
2.2. HYDRODISPERSIVE STUDIES PROPERLY SPEAKING.
2.2.1. EXPERIMENTS WITH TRACERS.
2.2.2. CALCULATION OF LONGITUDINAL AND TRANSVERSAL DISPERSION COEFFICIENTS.
2.2.3. DETERMINATION OF THE GEOMETRY OF THE RADIOACTIVE CONFINED AREA DOWNSTREAM OF THE IMPERVIOUS SCREEN.
2.2.4. EVALUATION OF THE VELOCITY DECREASE AND RADIOACTIVE CONCENTRATION DECREASE DOWNSTREAM OF THE SCREEN.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Commissariat à l'Energie Atomique (CEA)
Address
Centre D'études De Fontenay-aux-roses
92265 Fontenay-aux-roses
France