DETERMINING FRACTURE PARAMETERS TO ASSESS RESISTANCE TO BRITTLE FAILURE OF COMPONENTS OF NPP PRIMARY CIRCUIT EQUIPMENT
DOI:
https://doi.org/10.15407/dopovidi2026.05.022Keywords:
reactor pressure vessel, extended finite element method, brittle fracture resistance, stress intensity factorAbstract
The paper summarizes the results of a comprehensive series of experimental and numerical studies aimed at assessing the resistance of VVER-type reactor vessels to brittle fracture. Engineering methods for determining stress intensity factors are analyzed, including their advantages, limitations, and practical application characteristics, as well as the potential of modern numerical methods to improve the reliability of strength assessments for critical components of the primary circuit in nuclear power plants. The results of applying the extended finite element method (XFEM) for the rapid assessment of brittle fracture resistance are summarized, including the modeling of cracks of various shapes, sizes, and locations without remeshing. The results of numerical simulations of the cylindrical section and the nozzle region of the reactor vessel under typical thermal shock conditions are presented. The effect of crack geometric parameters on the stress intensity factors is also investigated, and the most critical crack locations are identified. The results of numerical modeling of the fracture process in compact specimens of the CT-0.5T, CT-0.16T, and side-grooved CT-0.5T types using the XFEM are summarized. For 15Kh2NMFA reactor steel, the parameters of the fracture criterion, the features of the stress-strain state at the crack tip, the crack propagation kinetics, and the effect of specimen geometry are analyzed. The potential of combining experimental studies and numerical simulation based on the XFEM method to improve computational methods for assessing the strength of critical components of the primary circuit in nuclear power plants has been demonstrated.
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