Development and performance of in-service inspection equipment in Fugen

'Fugen' consists of a pressure pipe assembly for the reactor core, inlet feeder tubing and outlet riser tubing of small diameters and a steam drum, which are characteristics of an ATR. It has been obligatory to carry out in-service inspection (ISI) of these reactor members. In the Fugen Nuclear Power Station, special ISI apparatus for the ATR have been developed on the basis of existing ISI techniques for light water reactors, and have been used for the periodical inspection. Structures, performance and achievements of these ISI apparatus are outlined in this report. The apparatus are roughly categorized into three groups: automatic ISI apparatus, remote automatic apparatus and semi-automatic apparatus. When attached to a reactor member for inspection by an inspector, an automatic apparatus automatically reads, processes and evaluates required data. The inspector will remove the apparatus after the inspection. A remote automatic apparatus can perform such inspection procedures through a remote control system. A semi-automatic apparatus can automatically carry out easily mechanized procedures such as measurement and recording of ultrasonic flaw detection points and beam path lengths while probe scanning is performed by an inspector. (Nogami, K.)