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:

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


The TDB project aims to produce a database that:

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

Latest news

General information

Published data reviews

Other thermochemical database sites

Joint Sorption-TDB symposium download area (requires password | reminder)

Related links

Email contact:

Last updated: 10 June 2020


TDB publicationsTDB publications