The development and deployment of an ultrasonic under-sodium viewing system in the fast breeder test reactor

A personal-computer (PC-) controlled under-sodium viewing (USV) system developed and deployed in a fast breeder test reactor (FBTR) is reported. The system is used as a sweep-arm to scan the space below the core cover plate mechanism (CCPM) of the reactor to find any obstacle, and is also used to image the CCPM to demonstrate its horizontal (side) viewing capability. The 6-m long and 900-mm diameter viewer uses an indigenously developed sodium-immersible ultrasonic transducer mounted horizontally at its bottom end whose full movements of complete rotation and 350-mm long vertical travel are controlled by two stepper motors in the drive assembly connected to its top. During the deployment of the under-sodium viewer at 180°C in the FBTR reactor vessel, an Apple-II PC compatible run by a BASIC program is used. It controlled the stepper motors´ rotations through one of its parallel ports, monitored an echo detector output through its single-bit game input port, and displayed the CCPM image online on a monochrome monitor. Reprocessing of the data yields pseudo-three-dimensional color images. The quality of the images obtained is discussed