Modelling of dynamic containment loads due to H2 deflagrations

A computational strategy for predicting dynamic loads on LWR containments due to hydrogen deflagrations under severe accident scenario conditions is presented. The method is based on state-of-the-art thermohydraulic codes for computing global and local phenomena. A lumped-parameter code is employed to model the complete containment building providing hydrogen distribution and thus identifying initial conditions for deflagrations. Detailed modelling is achieved in parts of the containment exposed to turbulent H2 deflagration by employing a multi-dimensional Navier-Stokes solver. The resulting thermohydraulic loads on the entire containment building can then be computed by feeding local information back to the global model. It is shown that such an integration of available modeling procedures provides the necessary information reliably and most economically. (author)