[en] Research and development work on nuclear fusion is still at a relatively early stage. The physical and technological problems are not yet all solved. Detailed construction plans for a fusion reactor and the hypotheses concerning its radioactive stock and its release are still very make-shift. Working from the knowledge gained so far it is possible to predict how many experimental stages still have to be completed before the first fusion reactor will yield electricity. By taking into account the time required for planning, constructing and operating the subsequent pilot plants one can estimate that nuclear fusion could start to contribute to the energy supply in the middle of the next century at the earliest. Nevertheless, it can already be shown today that fusion reactors have a high inherent safety potential and that their impact on the environment and our climate is very small both during normal operation and in the event of accidents. (orig./DG)