Numerical simulation of the detection of crack in reinforced concrete structures of NPP due to expansion of reinforcing corrosive products using impact-echo method

Abstract

Nuclear energy boom is starting nowadays. But also current nuclear power plants (NPP) are duty to certify their security for regular renewal of their operating licenses. NPP security can be significantly affected by defects of large amount of ageing reinforced concrete structures. Advanced Impact-Echo method seams to be very hopeful to cooperate at performing in-service inspections such structures. Just these in-service inspections are included in the first priority group of specific technical issues according to the recommendations of OECD-Nuclear Energy Agency, Commission on Safety of Nuclear Installation in the field of ageing management. This paper continues of extensive project dealing with Impact-Echo method application. It will present a method description and main results of numerical modeling of detection and localization of crack caused by corrosive product expansion. Steel reinforcing rods are subjected to corrosion due to diffusion of corrosive agents from structure surface. Corrosive products have up to 7-times larger volume than pure steel. Raised strain can cad lead up to concrete failure and crack development. We investigate whether it is possible to detect these growing cracks by Impact-Echo method in time. Experimental verification of our numerical predictions is prepared on Civil Faculty in Brno.