Use of bayesian method for NPP equipment components reliability parameters estimation

This articles is representing the development of modified method of NPP components reliability parameters Bayesian estimation. The necessity of such a development consists in questionable accuracy of Bayesian estimation used in Zaporizhzha unit 5 ISA. An old approach to Bayesian analysis converts the continuous probability distribution into a truncated discrete probability distribution (this is called the 'DPD approach'). In contrast, using the modified method based on numerical integration methods one can obtain specified accuracy. The correspondent software has been developed for on-line calculation of reliability parameters via Internet. The results, obtained by modified Bayesian estimation, have been compared with ZISA reliability parameters calculation results. The considerable difference in some significant failure rates has been obtained. Such a difference can lead to significant change of PRA final result: core damage frequency