Reliability analysis of selected systems of nuclear power unit

The reliability analysis is discussed of selected facilities of the 440 MW nuclear power unit using the failure tree method. The first part of the paper deals with the primary circuit and analyses the possibility of a dangerous failure arising of the system of accident alarm of the first order of the WWER 440 nuclear reactor during the event of the ''outage of four and more circulating pumps''. The second part of the paper is related to the secondary circuit. It studies the causes and probabilities of the failures of functions of condensate flow pumping and control with regard to the event the ''turbogenerator failure''. (author)