Pakhalovych M. Improving normative documents on the safe operation of the elements of pipeline systems of nuclear power plants beyond design term

The object of study is the process of ensuring operational safety of pipelines reactor units; The aim is to improve regulations on safety and operational life extension pipe reactor nuclear power through the development of scientific and reasonable mathematical model and algorithm of technical diagnostics. Novelty is based on such scientific research: First developed a mathematical model for calculating the brittleness of the metal pipes by taking into account the time and geometry of the crack after prolonged operation depending on the load, allowing to assess technical condition and forecasting the service life of pipelines and improve the safety of pipeline systems, mathematical model determining the accumulation of fatigue damage in hard mode symmetric load; The mathematical model determining fatigue damage accumulation in soft symmetric mode load; The mathematical model determining the accumulation of fatigue damage in hard mode asymmetric loading; The mathematical model determining fatigue damage accumulation in the soft asymmetric mode load; For the first time dependences of stress concentration in the metal pipe from the time of operation and the geometry of the crack by solving nonlinear differential equation of cracks in the metal that allows to predict the remaining life of the pipeline. Further developed the method and model forecasting technical condition of pipeline systems through the development of an automated system of calculation of stress-strain state, allowing us to determine the technical parameters of the pipelines outside the project life. Methods: Theoretical based on the theory of modern standardization fundamental provisions in dynamics and strength, system analysis. In calculating transient processes used finite-difference components. Empirical studies based on the use of modern technology, process measurement results and implemented using proven engineering methods.