Titles & Positions: Dr. Eng., Associate Professor

Affiliation: Laboratory for Zero-Carbon Energy, Institute of Innovative Research Tokyo Institute of Technology Tokyo, JAPAN.

Email: kikura.h.aa@m.titech.ac.jp

Biographical Sketch

Dr. Hiroshige Kikura is currently an Associate Professor of the Laboratory for Zero-Carbon Energy at Tokyo Institute of Technology in Japan. Prior to joining at Tokyo Institute of Technology in 1999, he worked at LSTM, University Erlangen-Nuremberg, Germany, and Paul Scherrer Institute (PSI), Switzerland, from 1993 – 1999. His research includes nuclear safety, thermal hydrodynamics, process instrumentation, transportation of radioactive materials, vitrified waste storage, deep geological repository, solar energy systems, solar power system, robotic measurement, revitalizics. He has authored or co-authored more than 900 publications (124 technical journals, 4 books, 370 international conferences, 410 national conferences), and has 20 patents. He is a member or a chair in several committees at the Japan Society of Mechanical Engineers (JSME), Atomic Energy Society of Japan (AESJ), the Visualization Society of Japan (VSJ), the Japan Society for Multiphase Flow (JSMF), and so on. In addition, he is engaged as an editor board member of several journals.

Title: Remote Measurement by Robot Arm Equipped with Ultrasonic Velocity Profiler (UVP) and Laser-Induced Breakdown Spectroscopy (LIBS)

Authors：Hiroshige Kikura, Weichen Zhang, Yuan Chen

Abstract

A prototype system for remotely detecting leaks and determining sediment shape and elements in the primary containment vessels (PCVs) of the decommissioned Fukushima Daiichi Nuclear Power Station is presented in this speech. The accident broke the PCVs, leaking cooling water injected to cool the fuel debris and large sediments in the leakage field. The investigation has focused on the vessel’s internal structure, leakage position, and reactor nuclear fuel debris distribution.

Ultrasound Velocity Profile (UVP) and Laser-Induced Breakdown Spectroscopy (LIBS) were used to identify sediment elements above the water surface. Radioactivity also created an arm robot that could carry UVP and LIBS. This study found that the visualization flow field map estimated leakage location and sediment characteristics and identified sediment above water, improving detection efficiency. It was found that the UVP technique accurately captured the velocity distribution and leakage location in the simple flow field, while the LIBS technique accurately determined the above-water elemental composition. The arm robot measured remotely without radiation exposure. This study shows UVP and LIBS with an arm robot can be used to investigate leak locations and sediment properties in Fukushima Daiichi Nuclear Power Station PCVs, aiding for decommissioning and nuclear power plant safety and environmental protection.