Laboratory and in situ determination of the migration processes of actinide complexes and colloids in a fissured granitic environment : El Berrocal project (preliminary activities - Phase 0)
The migration of natural radionuclides in a fractured granitic environment has been studied using samples from the surface and boreholes of the El Berrocal batholith. Approximately 65 % of the total of U in the rock is held as uraninite. The rest is distributed among the essential minerals (5 %), refractory accessory minerals (13 %) and as readily leached U (17 %). In the altered granite, most of the U is held as autunite. Hydrogeochemical data show that CO(2)/H(2)CO(3) is the dominant system, followed by the silica-silicate system. Based on their stability analyses, two zones can be defined: (i) waters north of the dyke and from deep zones where calcite is in equilibrium and albite and gibbsite precipitate; (ii) surface waters, south of the dyke, subsaturated in relation to calcite, producing the alteration of albite and the precipitation of montmorillonite. Colloid characterisation was carried out using water from borehole 2. Column migration tests were performed under static and dynamic conditions, and under oxic and anoxic conditions, using neptunium as radionuclide.
Bibliographic Reference: EUR 15004 EN (1993) 117 pp., FS, ECU 15
ISBN: ISBN 92-826-6180-6
Record Number: 199311397 / Last updated on: 1994-11-28
Original language: en
Available languages: en