LARGE SCALE TEST OF THE LONG TERM ENGINEERED CAP AT EL CABRIL LLW DISPOSAL FACILITY IN SPAIN

El Cabril disposal facility was commissioned in 1992 and has 28 concrete vaults for LLW disposal, with an internal volume of 100.000 m 3 . It also has a VLLW disposal facility, commissioned in 2008, with capacity for 130,000 m 3 in four disposal cells of whom only the first cell has been built. One important component of the disposal system is the earthen cap providing long-term protection of the concrete vaults. The design of the cap is based on clay materials and two different designs have been considered. A large scale experimental device has been built with a threefold objective: validating the two basic designs, verifying the thermo-hydraulic model of the system performance and supporting the enhancement of the safety assessment of the facility. The test device includes two test areas, one for each variant, with longitudinal full size cross-sections. A complete set of temperature, humidity, capillary pressure, and heat flow sensors has been installed in different zones of each layer of the cap disposal. The sensor types were selected as a function of the anticipated humidity or capillary pressure: The cables layout allows their disposition through a single layer to a central concrete gallery containing the data collection system, thus preventing the formation of preferential infiltration pathways. The test bed is complete with segregated water collection and volume measurement at each area and layer. Beneath the cap there is a concrete structure simulating a disposal vault, where temperature, humidity and electro-chemical sensors have bee embedded with the intention of improving the thermo-hydraulic model of the disposal system behavior. This paper describes the test bed, the first data reported and their relationship to the modeling effort made in coordination with the experimental work.