Аннотация:The article deals with the problem of the appearance of the grain boundary nanopores in polycrystalline materials of the parquet type. The mechanism of their formation is proposed, as well as appropriate modeling is carried out, which allowed to establish the condition for the appearance of nanopore instead of stress concentrator. These studies are important for understanding the nature of the grain boundary defects in polycrystalline materials for their applications in photovoltaic energy converters.