CRITERIA FOR COMPILATION OF A SITE-SPECIFIC THERMODYNAMIC DATABASE FOR GEOCHEMICAL SPECIATION CALCULATIONS

A methodology has been developed to establish a site-specific database appropriate to geochemical modelling the critical components and the wide range of near field conditions expected in the low level radioact ive waste disposal site at Drigg in the UK. Several databases availabl e in the public domain have been compared to select a foundation datab ase. The foundation database was 'trimmed-down' and then customised to suit Drigg applications. The species dominant at Drigg have been iden tified and the thermodynamic constants of these species have been crit ically evaluated. The evaluated database has been validated for qualit y by comparing speciation calculations with plutonium and uranium expe rimental solubility results. (C) 1998 Elsevier Science S.A.