The physically based isothermal model of a monolith NOxstorage catalyst (NSC), proposed in Schmeißer et al. (Top Catal 42--43:77, 2007), has been further developed and adjusted to experimental results from Schmeißer et al. (Top Catal 42--43:15, 2007). It now describes all relevant reactions basically known from a three way catalyst, including several inhibition effects, over a wide concentration and temperature range. The different dynamics of NOxstorage and regeneration can be very well modeled by the build-up and break-open of a diffusion hindering nitrate shell around the (nano-size) Ba storage particles. The NSC-behavior under periodic lean-/rich-operation is well represented, even starting with the initially completely regenerated catalyst, moving towards cyclic steady state. Furthermore, the model gives insight into the periodic change of the nitrate distribution along the catalyst length. It turned out, however, that not all of the reaction rates determined under steady state conditions could be used for the simulation of the periodic storage/regeneration behavior. In particular it was necessary to increase the rate of the NO-oxidation during periodically lean conditions by a factor of 3.6. This can be explained by the build-up of a deactivating oxidation layer during steady state operation under lean conditions.