Pyrohov T. Substantiation of safe operation of emergency cooling heat exchangers WWER-1000 nuclear installations taking into account non-stationary loads

The thesis is devoted to the solution of an actual scientific and technical task: enhancing the safety of NPP operation by improving the existing methods of calculating the justification for the safe operation of emergency cooling heat exchangers (ECHE) of NI WWER-1000, namely, taking into account non-stationary loads corresponding to the operation of these heat exchangers during planned and emergency cooling of the core. The performed analysis and generalization of existing methods and approaches to the calculation substantiation of the safe operation of ECHE heat exchangers made it possible to highlight their main disadvantages and determine the tasks for carrying out scientific research. Analysis of design calculations of the strength of ECHE heat exchangers, as the main design and plant document for justifying the safe operation of these heat exchangers, showed that this document contains examples of deviations from the requirements of the current regulatory documents of Ukraine in the area of nuclear energy.