Thermochemical Database (TDB) Project
The purpose of the Thermochemical Database Project is to make available a comprehensive, internally consistent, quality-assured and internationally recognised chemical thermodynamic database of selected chemical elements in order to meet the specialised modelling requirements for safety assessments of radioactive waste disposal systems.
During the first part of the project, a high priority was assigned to the critical evaluation of the data of inorganic compounds and complexes of the actinides uranium, americium, neptunium and plutonium, as well as the inorganic compounds and complexes of technetium.
The second phase of the project provided for further needs of the radioactive waste management programs by updating the existing database and applying the TDB methodology to new elements present in radioactive waste (as fission or activation products): nickel, selenium and zirconium, and also simple organic complexes of the key elements treated in phases I and II.
The third phase started in 2003, with three new reviews on thorium, tin and iron (part 1), and with the constitution of an expert team for the preparation of guidelines for the evaluation of thermodynamic data for solid solutions.
The fourth phase (2008-2013), included in its program of work three reviews concerning molybdenum, iron (part 2) and ancillary data and the initiation of two state-of-the-art reports on cement minerals and high ionic strength solutions. Work is still ongoing with phase IV reviews.
The fifth phase of the TDB project entered into force in 2014.
Current activities
The programme of work for the fifth phase of the Thermochemical Database (TDB) Project consists in the:
- completion of the reviews from the fourth phase;
- preparation of an update of the phase II actinide volumes, including technetium;
- preparation of a state-of-the-art report on the thermodynamic properties of cement minerals;
- preparation of a state-of-the-art report on thermodynamic considerations for actinides in high ionic strength solutions.
The unique feature of the TDB project is that the data are evaluated and selected by teams of leading experts drawn from universities and research institutes around the world, through a critical review of the existing primary experimental sources. The TDB reports documents the process leading to the selected values.
Participating Countries
Belgium, Canada, Czech Republic, Finland, France, Germany, Japan, Spain, Sweden, Switzerland, United Kingdom, United States
Project Period
April 2014 to March 2018
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 database compiles formation data (Gibbs energies, enthalpies, entropies and heat capacities) for each aqueous species and solid phase of interest, as well as chemical reactions and their corresponding thermodynamic data. Non thermodynamic data (diffusion or kinetics) and sorption data are not considered in the TDB project.
A detailed description of the project is set out in the TDB-0 guideline.
The data selected in the reviews are made available in the TDB review reports, which are the principal output from the project.
The project has so far produced 13 authoritative volumes of thermodynamic data for actinide elements and fission or activation products.
Links to other sites that also contain thermodynamic data are provided.
Related links
General information
Other thermochemical database sites
Joint Sorption-TDB symposium download area (requires password | reminder)
Related links
Email contact:
Last updated: 17 July 2019
Publications
TDB publications