Abstract
Stopping contaminated water leaking is required for reactor decommissioning of Fukushima 1 nuclear power plant. Using Ultrasonic velocity profile measurement (UVP) is proposed to find leak points. However hard environment prevents us from getting in and finding leak points. Therefore it is expected that robot with UVP system gets in and measures flow field there. As a basic research of making robot with UVP system, making two dimensional vector map of the flow field which was made by measuring four different points of flow fields in the tank which water came out from an outlet with fan shaped array transducers. Hence, vector of the map shows the place of outlet.
