Numerical Investigation of the Leakage Behaviour of Reinforced Concrete Walls

For the verification of nuclear power plant safety, the leakage behaviour of the containment walls is of decisive importance. In order to improve the knowledge of the leakage behaviour through cracks during a severe accident an experimental setup was developed at IfMB and several tests with different parameters were performed. To improve the understanding of the behaviour of the wall elements during the tests numerical simulations of the performed leakage experiments are necessary. Reliable numerical tools provide a basis for the transfer of the leakage behaviour from the tested specimens to the behaviour of whole containment structures. To address the task of developing tools for the numerical simulation of the leakage behaviour of reinforced containment structures, EDF and IfMB decided to cooperate. During this cooperation two different numerical approaches had been made basing on existing tools and models of EDF and IfMB. In the following sections a short overview about the two different models will be given. For the numerical investigation of the leakage phenomena IfMB used the commercial Finite-Element-Program ADINA with its capability to solve coupled fluid-structure-interaction (FSI) problems. EDF used two of their self-developed tools for the numerical simulation in a chained calculation: CODE ASTER® for the mechanical calculation of the specimen and ECREVISSE for the air/steam/water leakage flow calculation. The calculated leakage rates and temperature profiles of both models will be compared to the experimentally determined leakage rates and the results will be discussed.