Izvestiya vuzov. Yadernaya Energetika

The peer-reviewed scientific and technology journal. ISSN: 0204-3327

Model of Molten Lead Concrete Interaction in the CORCONIT Module of the Integral Code EUCLID/V2 and Results of Its Verification

12/10/2025 2025 - #04 Modelling processes at nuclear facilities

Tarasov O.V. Mosunova N.A. Ozrin V.D. Sorokin A.A.

DOI: https://doi.org/10.26583/npe.2025.4.12

UDC: 621.039.58

A model for the molten lead concrete interaction is developed and implemented in the CORCONIT module of the integral EUCLID/V2 code, designed for safety analysis of nuclear power plants equipped with fast-neutron reactors cooled by liquid metal. The approach is based on solving a quasi-two-dimensional thermal problem with a moving boundary due to ablation. Within the CORCONIT module, the ablation front propagation is computed dynamically, resolving the transient behavior of the system. For the concrete domain, the model calculates the temperature distribution, the degree of material degradation (including dehydration and decomposition), and the rate of gas release (H2O, CO2) at each computational node. For the molten lead phase, it assumes uniformity of the melt due to convection and calculates its temperature, heat fluxes at the melt-concrete interface, and chemical reactions with both molten concrete oxides (SiO2, CaO, MgO, etc.) and gaseous decomposition products. The chemical interaction is rigorously modeled through a coupling mechanism between the CORCONIT module and the FPMC (Fission Products – Molten Core) chemistry module. The FPMC module employs Gibbs free energy minimization for gas-melt system to simulate multi-component equilibrium chemistry, calculating the oxidation of lead by concrete constituents and gas bubbles (H2O, CO2). This process generates flammable gases (CO and mainly H2), which are released into the atmosphere of the containment. Verification of the CORCONIT module has been performed using analytical tests covering three different processes: heating of the concrete, gas release from the concrete and ablation of the concrete, establishing confidence in the model’s predictive reliability for severe accident scenarios.

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molten lead concrete interaction CORCONIT FPMC EUCLID/V2

Link for citing the article: Tarasov O.V., Mosunova N.A., Ozrin V.D., Sorokin A.A. Model of Molten Lead Concrete Interaction in the CORCONIT Module of the Integral Code EUCLID/V2 and Results of Its Verification. Izvestiya vuzov. Yadernaya Energetika. 2025, no. 4, pp. 160-174; DOI: https://doi.org/10.26583/npe.2025.4.12 (in Russian).

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