[en] The experts of the TUeV working group on nuclear engineering, Western section, on behalf of the North-Rhine Westphalian Ministry for Labour, Health and Social Affairs, have been participating in the investigations of the history of the water intrusion event in the AVR reactor. The investigations are concluded by now and are summarized in the report in hand. In the wake of the event under review, the failure analysis of the case of water gas formation has been re-examined, taking into account the new information gained from the fuel element investigations made after the event. A modified computer program for calculating water gas formation has been added, and the reactor system has been equipped with a continuous hydrogen measuring device. This ensures that already the initial formation of hydrogen during normal operation is taken into account in the failure analysis, and that even small leaks entailing intrusion of water into the reactor will be recorded in the failure analysis. The supervisory authority demanded additional monitoring equipment to be installed in the reactor system, such as continuous-line recorders indicating the cooling-gas moisture, and a process computer system for recording safety system data in excess of the limit values. The hot gas temperature monitoring system has been checked, and statistically derived failure limits have been defined. The operating instructions have been thoroughly revised and modified to comply with the latest codes and regulations, so that the AVR GmbH met the obligations set by the supervisory authority. (orig./GL).