Numerical investigations of the influence of different factors on the form’s varying  projects of the reactor vessel internals in the conditions of thermal and irradiation fields (Funded by National Scientific Center ‘Kharkiv Institute for Physics and Technics’ National Academy of Sciences of Ukraine, 2023):

The object of research and development is the structural elements of the nuclear reactor vessel internals: the baffle, fuel rods, fastening elements. The purpose of the work is to numerically study the influence of anisotropy and degradation of material properties, load cyclicity on the deformation of the elements of the internal devices of the reactor under the action of thermal and radiation fields. A mathematical formulation of the problems of determining the stress-strain state and the level of hidden damage in the structural elements of the NPP is provided. New approaches have been created, methods for numerical modeling of the processes of long-term deformation of models of structural elements of the NPP nuclear reactor, such as the baffle, fuel rods when in contact with the tube sheet, fastening elements have been improved. A computational analysis of the stress-strain state of a baffle model has been performed taking into account thermoelastic deformation, irradiation creep, irradiation swelling and hydrogen embrittlement. An analysis of swelling anisotropy and creep and damage properties for the deformed state and time to completion of hidden damage accumulation of structural elements with stress concentrators was carried out. The results of solving the elastoplastic problem of contact between fuel rod and tube sheet surfaces were obtained and a method for assessing wear at the contact site was proposed.