Operating experience with inspection techniques for SNR 300

Following normal pratice for other reactor types, the coolant enclosures of the SNR 300 reactor are to be subjected to inservice inspections to ensure their integrity. Some of the tests are visual examinations using optical methods. High local radiation (up to 120 Gy/h) and temperatures (up to 473 K) necessitate the use of remotely-controlled manipulators which transport the test instruments to the positions to be examined. In addition to the above ambient conditions, complex geometrical boundary conditions impose special requirements on this equipment. It was therefore impossible to use equipment which was readily available on the market for either the visual testing instruments or the manipulators. Consequently all equipment had to be newly developed within the scope of R + D programs and tested on 1 : 1 models until it was suitable for use in the SNR 300. This paper describes commissioning experience with the visual inspection equipment for the outside wall test and for testing of the inside of the reactor vessel above the sodium level