Linear-array ultrasonic waveguide transducer for under sodium viewing.

Abstract

In this report, we first present the basic design of a low--noise waveguide and its performance followed by a review of the array transducer technology. The report then presents the concept and basic designs of arrayed waveguide transducers that can apply to under--sodium viewing for in--service inspection of fast reactors. Depending on applications, the basic waveguide arrays consist of designs for sideway and downward viewing. For each viewing application, two array geometries, linear and circular, are included in design analysis. Methods to scan a 2--D target using a linear array waveguide transducer are discussed. Future plan to develop a laboratory array waveguide prototype is also presented.

Ultrasonic Imaging in Hot Liquid Sodium Using a Plate-Type Ultrasonic Waveguide Sensor

“…Therefore, immersion sensors may have a limited lifetime in such a hostile liquid-sodium environment (Recently, electromagnetic acoustic transducer phased arrays have been developed to overcome such drawbacks of classical piezoelectric sensors in sodium environment [10]). On the other hand, waveguide sensor technology [11][12][13] uses an ultrasonic transducer in a relatively cold region, i.e., outside the reactor vessel (above the reactor head), and transmits ultrasonic waves to the target using a long waveguide, part of which is submerged in hot liquid sodium. In this configuration, the transducer can perform with better sustainability and it has been possible to inspect the space between the bottom of the upper internal structure (UIS) and the top of the core during the refueling process without thermal and radiation damage.…”