As the need for technologies to cut and dismantle reactors and internal structures increases due to the end of the operational lifespan of nuclear power plants, an innovative laser cutting technology for nuclear dismantlement has been developed. This cutting-edge technology ensures safety in underwater conditions while minimising contamination. Furthermore, a water tank that simulates laser cutting in an underwater environment for nuclear dismantlement has been developed and patented for the first time globally.
The research team, led by Dr. In-Deok Park, Principal Researcher at the department of Industrial Laser Technology of the Busan Machinery Research Center under the Korea Institute of Machinery and Materials (President Seog-Hyeon Ryu, hereinafter referred to as KIMM), affiliated with the Ministry of Science and ICT, successfully developed an underwater laser cutting technology. This technology is capable of cutting stainless steel specimens with a thickness of over 100mm in a simulated 10-metre water depth environment.
During nuclear power plant dismantlement, structural cutting methods include mechanical and thermal cutting. The technology developed by KIMM falls under the thermal cutting category, employing high-power lasers to perform underwater cutting that is both safer and generates minimal contamination. The research team achieved a breakthrough by successfully cutting a 100mm-thick stainless steel specimen, the primary material used in nuclear pressure vessels, at an actual water depth of 10 metres.
The team optimised the kerf width (cutting gap) to approximately 2mm, and reduced the flow rate of cutting gas used in the laser process to 600ℓ/min. A cutting speed of up to 50mm/min was also achieved, demonstrating the efficiency of the technology.
In preparation for full-scale nuclear dismantlement, the team developed and patented the world’s first 30-meter-grade underwater laser cutting pressurized tank, replicating actual field conditions. They also designed a compact multi-nozzle system optimised for high-pressure underwater environments, for which a patent application is currently underway. Additionally, they independently developed an anti-collision device to prevent accidents during the underwater laser cutting process caused by collisions between the specimen and the nozzle.
Principal Researcher In-Deok Park of KIMM stated: “The underwater laser cutting technology developed is significant as it directly simulates the nuclear dismantlement environment, greatly minimising secondary contamination during the dismantling process. With the number of nuclear facilities expected to permanently shut down continuing to rise until 2050, we plan to further advance and conduct demonstration research based on this technology.”
