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Information × Registration Number 0223U004937, 0122U001270 , R & D reports Title Aging of WWER-1000 reactor piping metal during design life and its impact on safety over design life popup.stage_title Head Hozhenko Serhii V., Кандидат технічних наук Registration Date 10-12-2023 Organization National Science Center "Kharkiv Institute of Physics and Technology" popup.description2  The object of the research is the main metal of the pipelines of feedwater and "hot" steam of the power unit of the WWER-1000 reactor after long-term operation. The purpose of the work is to determine the impact of metal aging on the safety of pipeline operation. A general analysis of the operating features of the metal of feedwater and "hot" steam pipelines of power units of VVER-1000 reactors and possible mechanisms of its aging during long-term operation was carried out. The kinetics of changes in the mechanical properties of the metal of feedwater and “hot” steam pipelines during 200,000 hours of operation of power units was studied according to data from monitoring metal cut from pipelines using direct methods and non-destructive (hardness) inspection of pipelines at intermediate stages of operation. A non-monotonic change in the mechanical properties of the metal was revealed during the operation of pipelines during the specified period of time. It is shown that during the operation of feedwater and “hot” steam pipelines during the second 100,000 hours of operation, metal aging is observed, which manifests itself in partial softening of the metal. An increased rate of aging of pipeline metal is observed in areas where the metal was subjected to the greatest plastic deformation during the pipe manufacturing process (compressed and stretched sides of bends). In the examined stretched sections of feedwater pipeline bends, the strength and yield limits of the metal (steel 20) decreased by 3.8% and 4.8%, respectively. In the examined stretched sections of the bends of "hot" steam pipelines, the strength and yield limits of the metal (steels 15GS, 16GS) decreased by 3.1% and 5.5%, respectively. If the rate of change in the mechanical properties of the metal is maintained during the second 100,000 hours of operation until one of the standard characteristics of the critical level is reached, the minimum service life of the surveyed pipelines is ~400,000 hours. Product Description popup.authors Gozhenko Sergiy V. Krainіuk Yevhen O. Rudenko Oleksii G. Tolstolutska Halina D. popup.nrat_date 2023-12-10 Close