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Communication Dans Un Congrès Année : 2016

Experimental and thermodynamic calculations results on pwr and srf corium subsystems

Résumé

During a severe accident in a pressurized water reactor (PWR), the nuclear oxide fuel (UO2 or (U,Pu)O2) could react with Zircaloy cladding, Inconel spacer grids, the steel controls rods cladding and the neutronic absorbers (Ag-Cd-In-B4C), leading to the relocation in the lower-head of the reactor vessel of a mixture of liquid and solid phases called in-vessel corium. If the reactor vessel is lost, the molten core can pour onto the containment concrete leading to the formation of the ex-vessel corium. As a first approximation and considering the major components, the system U-Pu-Zr-Fe-Al-Ca-Si-O can be considered as representative of the ex-vessel corium. At the Laboratory of Modelling, Thermodynamics and Thermochemistry, CEA Saclay, a series of experimental results have been achieved using ATTILHA, the novel experimental setup developed at the laboratory. These data are fundamental for the development of a reliable thermodynamic database for corium. Thermodynamic calculations have been performed to better interpret our experimental results. These calculations allow also to study the evolution of corium behavior varying different parameters, as for example the nature of the atmosphere (reducing/oxidizing), to reproduce different scenarios. Using the thermodynamic database of the representative corium developed at the laboratory, it is also possible to estimate the partition of elements in each phase as a function of temperature and composition. It can be shown that at 3000 K, in presence of a miscibility gap in the liquid phase, Pu preferentially segregate in one of the two immiscible liquids, namely in the oxide liquid.
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Dates et versions

hal-02441918 , version 1 (16-01-2020)

Identifiants

  • HAL Id : hal-02441918 , version 1

Citer

A. Quaini, S. Gossé, T. Alpettaz, C. Gueneau, S. Poissonnet, et al.. Experimental and thermodynamic calculations results on pwr and srf corium subsystems. NUMAT 2016, Nov 2016, Monpellier, France. ⟨hal-02441918⟩

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