The Thermodynamics of Advanced Fuels - International Database (TAF-ID) Project aims to use the Calphad method to develop a thermodynamic database as a computational tool for understanding advanced fuel materials. This thermodynamic database allows predicting phase diagrams and thermodynamic properties of the phases.
The TAF-ID Project also provides a forum for information exchange on thermodynamic models, review of experimental data, software evaluation, thermodynamic assessments, etc.
Systems of interest: Fuel and related materials for Generation II, III, IV nuclear reactors
The TAF-ID database is suited to the following applications
Two versions of the TAF-ID database are being developed:
The TAF-ID database is developed in the Thermo-Calc format.
During the first project phase, the project members created the TAF-ID database, starting from the FUELBASE database (CEA), with the addition of pre-existing systems from other project members (for oxide and metallic fuels). The project focused on the database development.
During the second project phase, the TAF-ID database development continued and the current version of the TAF-ID database (V15, January 2023) includes 43 elements, with 237 binaries included and 99 binaries assessed,109 ternaries assessed and 2 quaternaries assessed.
In addition, the project started validating the TAF-ID database with experimental work, including the funding of a post-doc to carry out this work and initiated benchmarking activities. A training course on TAF-ID was successfully organised in February 2021, gathering 70 participants online.
During this second project phase, TAF-ID members published 13 publications related to the TAF-ID project, including a review paper of the TAF-ID project and database.
For this third project phase, the programme of work includes:
Detailed modelling of the fuel-cladding system is of major importance for several studies related to safety improvements, lifetime extension of Generation II and III reactors and the design of advanced Generation IV systems.
The use of thermodynamic data is needed for various analyses involving nuclear fuel: design of the fuel element; modelling of the fuel-cladding system under normal conditions in performance codes; analysis of fuel and cladding behaviour under severe accident conditions (pre-and post-fuel melting); the interaction of corium with the vessel; sacrificial materials (in-vessel); and concrete (ex-vessel).
These analyses may involve different types of fuel and cladding for Generation II, III and Generation IV systems:
One of the ways to obtain thermodynamic data of the chemical properties of interest is by applying the CALPHAD method. This allows for the calculation of phase diagrams (composition and number of phases) over a large composition, temperature and pressure range as well as the thermodynamic properties of these phases (heat capacity, enthalpy, activity, partial pressure, etc.) which come from the mathematical function of the Gibbs energy of the phases that may form.
These functions are based on sub-lattice models derived from the crystalline structure of the different phases (a sub-lattice corresponding to a crystalline site). The free parameters in the model are optimised using a least-square minimisation method between experimental and calculated data. The experimental data consist of phase boundaries (liquidus, solidus, solubility limit, etc.) and/or thermodynamic data (heat capacity, mixing enthalpy, enthalpy of formation, activity, etc.). This approach requires a preliminary critical analysis of all experimental information available on the system before the modelling phase of the chemical species of interest.
TAF-ID Phase 3: Canada, France, Japan, Netherlands, Sweden, United Kingdom, United States, European Commission.
TAF-ID Phase 2: Canada, France, Japan, Netherlands, Republic of Korea, United Kingdom, United States, European Commission.
TAF-ID Phase 1: Canada, France, Japan, Netherlands, Republic of Korea, United States
Phase 3: January 2023 - January 2026
Phase 2: November 2018 - November 2022
Phase 1: March 2013 - March 2017
TAF-ID-3 ≈ EUR 710 K
TAF-ID-2 ≈ EUR 640 K
TAF-ID ≈ EUR 460 K