Image: Microscopic examination of U-bearing particles collected at Fukushima-Daiichi, JAEA

The second phase of the joint project on the Thermodynamic Characterisation of Fuel Debris and Fission Products Based on Scenario Analysis of Severe Accident Progression (TCOFF-II) focuses on generating knowledge and data for analysis of severe accidents sequences going from the early stages of the fuel degradation, through the fuel relocation, the molten pool formation in-vessel, reactor pressure vessel (RPV) failure, and the interaction between the corium and the concrete during ex-vessel phases. The project will also generate knowledge and data on fission products (FPs) behaviour in severe accidents and assess how this may affect source term evaluations.

The TCOFF-II project aims to improve the models describing the materials interactions and the role they play in the various phases of the severe accidents, the ultimate goal being the integration of such models in severe accident simulation codes to increase their accuracy. This improvement is driven in particular by state-of-the-art knowledge of the thermodynamic properties of the material systems relevant to the description of core materials degrading through a severe accident sequence.

The TCOFF-II project is launching a call for R&D proposals open to all NEA countries. It aims to improve thermodynamic database and to validate thermodynamic calculation results of relevance to severe accident scenario analysis based on new experimental work. Priority systems and sub-systems have been identified by the TCOFF-II project members and are listed in the application form.

The overall budget is EUR 330 000 over two years. The maximum financial support that can be granted is EUR 50 000 per proposal. The proposed R&D work should be experimental, and last two years at most.

A second call for R&D proposals will be organised in 2024.

The R&D proposal form should be submitted by email no later than 27 October 2023.

• 6 September 2023: Opening of the call for proposals
• 27 October 2023: End of the submission period
• 20 December 2023: Selection of the R&D proposals by the TCOFF-II project
• 1-2 February 2024: Presentation of the selected R&D proposals during the TCOFF-II project meeting

The selected projects will be expected to present their proposals at the next TCOFF-II project meeting, scheduled in February 2024, and their progress as requested by the TCOFF-II project during TCOFF-II meetings.

At the end of their experimental work, they will write a summary report on their work, including at least the experimental set up, the description of the obtained results and their analysis.