[en] The nuclear power reactor AVR constructed by Arbeitsgemeinschaft Versuchs-Reaktor GmbH is an independent part of the Julich Nuclear Research Center. In 1960s, the AVR was built to demonstrate the feasibility and the reliability of a high temperature reactor using spherical fuel elements. The electrical power output is 15 MW, and the thermal output is 46 MW, which is produced by 92,000 fuel elements of 60 mm diameter, and helium is used as the cooling gas. The power generation began in December, 1967, and since then, about 1.5 billion kWh has been generated. One of the most important events during the operation of nearly 20 years was the raise of the exit temperature of cooling gas from 850 deg C to 950 deg C in February, 1974. Kernforschungsanlage Julich planned to modify the high temperature reactor AVR so as to be usable as a process heat source. The theoretical consideration based on the irradiation behavior of actual nuclear graphite cannot completely avoid the damage caused by irradiation-induced stress. Therefore, visual inspection was performed for the top and side reflectors in May, 1984. The construction of the core, the irradiation test of ARS/AMT graphite, the estimation of stress in the reflector components, the visual inspection and the cameras used and so on are reported. As the result, cracking and corrosion were not found at all. (Kako, I.)