[en] For prognostic dose estimates the evolution of the state of the retention barriers inside the nuclear facility, of the source term and of the atmospheric dispersion conditions have to be taken into account. The diagnostic dose estimates have to be based on the actual release and weather conditions as well as on the measurements in the region of interest. In Germany the operating nuclear power stations are monitored by computer-based KFU systems. Although the KFUs have been primarily conceived for other purposes, they already offer some features of a decision supporting instrument for off-site emergency management. The implementation of additional (software) modules in the KFU could enlarge its original purpose from a purely monitoring to a decision making support system. (author)