Laser Technologies for The Nuclear Power Plant Maintenance

Abstract

The recent improvement of laser technologies will contribute to the maintenance of nuclear power plants. The Japan Atomic Energy Agency developed a specially designed probing system was developed to inspect and repair the cracks of the welded beads of the heat exchanger tubes of nuclear power plants. Eddy current testing detected inner wall cracks in heat exchanger tubes. The tube thickness was 4.5 mm and the inner diameter was 23 mm. The minimum detectable depth of the cracks was 10% of the tube thickness. Endoscope observation confi rmed the cracks along the welded beads. Laser welding by a 300 W compact fi ber laser successfully repaired them. The probing system will operate in new nuclear power plants with various laser monitoring technologies for coolant pipes.