With the increasing power and better quality of laser oscillators, laser processing, which has not been applied to thick concrete, has been increasingly used in recent years. In this report, we describe laser cutting of thick concrete columns (with a maximum thickness of 1200 mm) by using high-power fiber laser of over 20 kW and an ultra-long focus optical system, aiming at establishing a remote demolition technology for nuclear plant buildings that are high radiation areas. This report also describes a new beam laser damper system using water that was developed as a technology for receiving the high-power laser beam passing through a cutting object, which has been an issue in high-power laser processing.
