Assessment of the Core Flow Pattern and Pressure Tube Creep at Cernavoda Unit#l

Abstract

In time, the Cernavoda NPP Unit #1 has experienced a core flow redistribution: central core channels increased flows and outer core channels decreased flows. NUCIRC simulations have been performed to investigate the possible causes of the core flow redistribution. Both, commissioning and in-service data sets have been used for this investigation. This lecture will present the results obtained based on these simulations. Also the lecture intend to point out the correlation between core flow redistribution and possible occurrence of pressure tube strain due to creep, mainly in the high power channels.