Sodium observing device

Purpose: To enable macro- or micro-observation in reactor cores by scanning the tops of fuel assemblies for a wide range utilizing a rotary plug for fuel exchange and movable arms. Constitution: The control rod of a rotary housing rotatably supports pantagraph arms, by the free ends of which a transducer holder is rotatably supported. The upper end of the control rod is connected to the driving section of the device. The vertical movement of the control rod caused by the driving section rotates each of the pantagraph arms which, in turn, moves the transducer holder horizontally. The transducer holder can scan the upper surface of the reactor core for a wide range by the horizontal movement of the arms and the rotational movement of the rotary housing. Closer observation for the narrow range through finer scanning is also possible by the vertical movement of the control rod. (Kawakami, Y.)