Thermodynamic Characterisation of Fuel Debris and Fission Products Based on Scenario Analysis of Severe Accident Progression at Fukushima-Daiichi Nuclear Power Station (TCOFF)
The TCOFF project will provide a framework for exchange of technical information on topics related to thermodynamic databases available for modelling the fuel/core degradation process,
which include thermodynamic functions/models, experimental data, calculation tools, calculation methods for quasi-equilibrium systems, and prioritization of items for improvement/enlargement, with reference
to the accidental scenario at Fukushima-Daiichi Nuclear Power Station (FDNPS).
The project will aim at:
Improving the quality and/or inventory of thermodynamic databases which are used for severe accident analyses with a reference to the severe accident progression at different units of the FDNPS. Specific technical tasks related to this objective are:
Performing benchmark calculations by various thermodynamic databases under conditions experienced during the accidents in units 1, 2 and 3 at the FDNPS;
Identifying and prioritising material science concerns, in order to define specific needs of improvement and/or enlargement of current thermodynamic databases;
Improving and/or enlarging thermodynamic databases through experimental and analytical knowledge, provided by the Parties as in-kind contribution to the Project.
Conducting joint thermodynamic evaluations of the severe accident progression at in-vessel and ex-vessel phases at units 1, 2 and 3 of the FDNPS, aiming at characterizing: fuel melting; molten core relocation; fission product behaviour; fuel debris chemical and phase composition; and the thermodynamic evaluation of formation of materials which may potentially be detected at the FDNPS.