Thermochemical Database (TDB) Project
The purpose of the TDB project is to make available a comprehensive, internally consistent, internationally recognised and quality-assured chemical thermodynamic database of selected chemical elements. This database should meet the specialised modelling requirements for safety assessments of radioactive waste disposal systems.
High priority was assigned to the critical review of relevant data for inorganic compounds and complexes containing the actinides uranium, neptunium, plutonium and americium, as well as the fission product technetium. Data on other elements present in radioactive waste (as fission or activation products) such as nickel, selenium, zirconium has also been critically evaluated, as well as data for compounds and complexes of the previously considered elements with selected organic ligands (oxalate, citrate, EDTA and isosaccharinic acid).
Three new reviews of inorganic species and compounds of other elements (Thorium, Tin and Iron) are currently under way.
The data in the TDB database are selected by review teams, consisting of experts from all over the world, through a critical review of the existing primary experimental sources. The process leading to the selection values is documented in the TDB reports.
Objectives
The TDB project aims to produce a database that:
- contains data for all the elements of interest in radioactive waste disposal systems;
- documents why and how the data were selected;
- gives recommendations based on original experimental data, rather than compilations and estimates;
- documents the sources of experimental data used;
- is internally consistent;
- treats all solids and aqueous species of the elements of interest for nuclear waste storage performance assessment calculations.
The unique feature of the TDB database is that it contains data which has been evaluated directly from the original experimental data. TDB reviews are prepared by teams of leading experts drawn from universitites and research institutes around the world. Data from other compilations and estimates are in principle not considered, other than where they contain useful references to original data sources, which will themselves be evaluated.
Please note that only basic formation and reaction thermodynamic data are compiled (Gibbs energies, enthalpies, entropies and heat capacities). No kinetic, diffusion or sorption data are included in the reviews.
A detailed description of the project is set out in the the TDB-0 guideline.
The data selected in the reviews is made available in the TDB review reports, which are the principal output from the project.
Links to other sites which also contain thermodynamic data are also provided.
Current activities
The fourth phase of the Thermochemical Database (TDB) Project began on 1 February 2008 and will continue until 2012. The initial focus during this phase of the project will be to finalise reviews of chemical thermodynamic data for inorganic compounds and complexes of thorium, iron and tin. Overall, the fourth phase of the TDB project will concentrate on:
- performing complementary studies of inorganic species and compounds of iron;
- assessing auxiliary data;
- updating a selected value database developed during the first three phases of the project; and
- reviewing inorganic species and compounds of molybdenum.
Related links
General information
Other thermochemical database sites
E-mail contact: nea.tdb@oecd.org
Last updated: 8 April 2008
