Coupled modeling of neutronics and thermal-hydraulics processes in LFR under SG-leakage condition

The lead cooled reactor BREST-OD-300 is developing as a part of Russian federal project “PRORYV”. Two- circuit scheme used in the for heat removal. An inherent risk two- potential danger water steam ingression core case large leakage generator initiated, example, Steam Generator Tube Rupture (SGTR). Reactor power and temperature response on vapor penetration to studied, but pressurization effects are not purview paper. 3D multi-physics (neutronics + thermal-hydraulics) UNICO-2F code was developed study SGTR accident. calculates unsteady space dependent distributions coolant velocity, pressure temperature, concentration release density fuel pins. Guillotine rupture one tube (SG) considered initial event It shown that even with most conservative assumptions reactivity insertion due ingress causes small increase level result maximum cladding continue stay well below safe operation design limit entire transient. Hypothetical option simultaneous few SG belonging different loops also analyzed. demonstrated leak two transient stays mild after oscillations stabilized at acceptable level. In long term analysis confirmed high self-protection against