Abstract
In the process of decommissioning the Fukushima Daiichi Nuclear Power Plant (FDNPP). It is crucial the investigation of the internal conditions of the reactor. Nuclear fuel debris was formed in the reactor and need to be taken out first. Up to now, the main investigation is on the investigation of the vessel’s internal structure, and nuclear fuel debris distribution inside the reactor. However, to cut and store nuclear fuel debris, it is equally important to analyze the elemental composition of them.
In this research, Laser-Induced Breakdown Spectroscopy (LIBS) and Ultrasound Solid-liquid Level Measurement technology are noted. LIBS is chosen because it can realize remote real-time element analysis with Optical fibers. And it can perform in-site analysis which could save a lot of time. Ultrasound solid-liquid level measurement is chosen because it can obtain shape and position information as well as distance information to help LIBS focus.
Therefore, this research hopes to combine ultrasound solid-liquid level measurement and remote LIBS elemental analysis to get the shape, position, and element information of nuclear fuel debris. Developing an in-site elemental mapping system.
In this research, a remote LIBS system and an ultrasound solid-liquid level measurement system were constructed and verified. Then, the two systems are integrated. Finally, the integration system is verified by experiments. The result of the integrated experiment showed the efficiency of the system both in element analysis and shape reconstruction and the experiment results roughly realize the element mapping in one direction.
