The International Intraval project. Phase 1 case 9: radionuclide migration in a block of crystalline rock

This report presents a summary of the work that was carried out within the international INTRAVAL project on Test Case 9, which is based on laboratory tracer experiments in a single fracture in a large block of granite. A non-sorbing tracer (Uranine) and a sorbing tracer (cesium) were used. Tracer breakthrough curves were monitored at five points, which provides some information on the flow paths within the fracture. The test case was tackled by four Project Teams. Most Teams used variants of the standard dual-porosity model that includes the effects of advection, dispersion, diffusion, sorption and matrix-diffusion. One Project Team also considered a model that represents the dispersion due to flow with a varying velocity in a channel, and another Project Team used a model with an aperture that varied stochastically. The teams were able to calibrate their models successfully, and obtained similar estimates of the parameters. It was considered that the experiment provides some support for the standard model, and considerable support for the concept of channelling. 14 refs., 14 figs., 4 tabs