Uncertainty evaluation of RBMK NPP DGH blockage calculation by CIAU Methodology

Abstract

CIAU (Code with capability of internal Assessment of Uncertainty) methodology has been proposed having as basis, or ‘engine’, the UMAE (Uncertainty Method based on Accuracy Extrapolation). The resources needed for the development of the error database of CIAU constitute an issue for the application of the method. An applicable version of the CIAU has been utilized for the code calculation of the RBMK accident scenario caused by the DGH (Distribution Group Header) blockage which causes flow stagnation in several channels and lack of cooling