Development of ROV system to explore fuel debris in the Fukushima Daiichi Nuclear Power Plant

Instruments and Methods were developed to explore fuel debris at the bottom of the Primary Containment Vessel in the Fukushima Daiichi Nuclear Power Plant. A Remotely Operated Vehicle was designed to explore fuel debris and to investigate the distribution and surface profile of fuel debris at the bottom of the primary containment vessel using a sonar and a compact radiation detector. Several tests were carried out using various facilities to determined the capabilities of the sonar and gamma-ray detector to determine the feasibility of the device