Thermal-hydraulic analysis of a VVER-1000 core in MSLB conditions

The objective of this paper is to analyze the ability a VVER-1000 core and its control system cope with hypothetical main steam line break (MSLB) accident in case multiple equipment failures. study involves use advanced 3D calculation models benchmarked validated for reactivity accidents preceding studies. A MSLB boundary condition problem solved on coarse (nodal) mesh coupled COBAYA/CTF neutronic/thermal hydraulic codes. thermal-hydraulic conditions are obtained from full-plant simulation. assessment safety parameters supplemented by fine-mesh (sub-channel) analysis hottest assemblies CTF code using information nodal calculations. Thirteen variants pessimistic scenario considered, each them assuming number failures aggravated eight rods stuck out after scram at different locations overcooled sector. results (within limitations adopted modeling assumptions) show that do not exceed limits simulated accidents.