One-dimensional transient model for the analysis of boron dilution in the primary system of the nuclear power plant with WWER

One-dimensional transient model for calculating the change of boron acid concentration in cold loop of the primary coolant circuit in the case of its dilution by pure water in front of reactor core inlet is presented. Such a model is the first step when developing an algorithm for calculating transients in complete three-dimensional statement. It is shown that one-dimensional model can predict nonuniformity in boron concentration time variations, but it is not able to take into account spatial heterogeneity at reactor core inlet. The conclusion is made that the model discussed adequately reflects peculiarities of boron concentration change in cold loop of the primary coolant circuit during main circulating pumps start-up. It is especially useful when conducting multi-variant calculations