Modernization of Diagnostics Methods for Local Boiling of Coolant in a VVER Core

A method is proposed for modernizing the method currently used in power-generating units with VVER-1000 to perform diagnostics of the local boiling of the coolant in a reactor core. The method is based on analysis of the neutron flux noise recorded by neutron flux sensors. A new diagnostics parameter, related with the axial profile of the neutron flux beam at the level of the top sensors, is proposed. The results of an analysis of the efficacy of the modernized method are presented.