ICONE19-43187 Development of real time sensor for under sodium viewer

Abstract

For the commercialization of the sodium cooled FBR system, it is desirable to develop a plant concept that has economic competitiveness compatible with the LWR system and excels in safety. Since it is difficult to perform inspection and maintenance of the core internals at FBR, such as the reactor vessel inner wall and the core support structure, measures have been taken to ensure safety and reliability by allowing a sufficiently large margin in the design reducing the burden of inspection and maintenance. To date due to problems such as the effect of radiation penetrating from the reactor core, the opacity and high chemical activity of sodium, and the fact that the inspection of reactor vessel of the FBR is performed at a high temperature, approximately 200 degree C, to avoid freezing of sodium, no method of inspecting structures inside the reactor vessel has been developed. In this study, aims to experimentally produce a real-time sensor which is used for the underwater and under-sodium test to demonstrate their applicability to the FBR system. The real-time sensor would be a piezoelectric element type sensor with a resolution of approximately 2.0mm, a resolution of sufficient quality to allow for the identification of deformation, the failure or dropping of components, and an image processing time per one image of approximately 0.5 second. Concerning the backing material, aluminum titanate (alumatite), wollastonite and hexagonal boron nitride were selected for the first screening. Based on the test result, alumatite that has an excellent damping property was finally selected for the trial production of the sensor element. We have designed and made 256 channel matrix-arrayed sensor and high speed processing system. It was shown that the real-time sensor was achieved about 2.0mm resolution and about 0.5 seconds/frame signal processing time, and succeeded taking the first under-sodium movie of the world.