Gicheon Yeon, Secures Underwater Laser Cutting Technology for Nuclear Power Plant Decommissioning

Underwater laser cutting technology for nuclear power plant dismantling has been developed domestically.

The Korea Institute of Machinery and Materials (KIMM) announced on the 30th that the research team led by Principal Researcher Park In-duk at the Laser Technology Commercialization Laboratory of the Busan Machinery Technology Research Center has developed underwater laser cutting technology capable of cutting stainless steel specimens over 100 mm thick at once, simulating an environment at a depth of 10 meters.

The research team led by Principal Researcher In-duk Park (first on the right) is preparing to conduct laser processing experiments in a simulated environment with a water depth of over 10 meters. Photo by Korea Institute of Machinery and Materials

When dismantling nuclear power plants, mechanical cutting and thermal cutting methods are mainly used to cut structures. Among these, the technology developed by KIMM is classified as a type of thermal cutting technology. It is characterized by using a high-power laser to safely operate underwater while minimizing contaminants.

Stainless steel is the main material used for nuclear pressure vessels. The research team succeeded in cutting a 100 mm thick stainless steel specimen at a depth of 10 meters, which is a condition required in actual field operations, using the underwater laser cutting technology.

In this process, the team reduced the kerf width of the cut to 2 mm, which is narrower than other thermal cutting methods, and decreased the cutting gas flow rate used in laser cutting technology to 600 ℓ/min. The cutting speed achieved was 50 mm/min.

Separately, in preparation for full-scale nuclear power plant dismantling, the research team developed and patented the world’s first pressurized water tank for underwater laser cutting capable of operating at a depth of 30 meters under conditions similar to the field.

Currently, to find the optimal conditions for underwater laser cutting, the team has completed the fabrication of miniaturized multi-nozzles for high-pressure underwater environments and is in the process of filing a patent application. To prevent accidents caused by collisions between the specimen being cut and the nozzle during the underwater laser cutting process, a collision prevention mechanism was also independently designed.

This research was conducted as part of KIMM’s basic project, “Development of Laser Decontamination and Underwater Laser Cutting Technology for Safe Nuclear Power Plant Dismantling.” Busan National University and Korea Maritime and Ocean University participated jointly, and demonstration tests were carried out through the Ministry of Trade, Industry and Energy’s “Laser Cutting and Dismantling Technology Advancement and Demonstration (Nuclear Power Plant Dismantling Competitiveness Enhancement Technology Development Project).”

Park In-duk, principal researcher at KIMM, said, “The underwater laser cutting technology developed by KIMM is significant in that it simulates the nuclear power plant dismantling site exactly and minimizes secondary contaminants generated during the dismantling process.” He added, “Considering the continuous increase in permanently closed nuclear facilities, the research team plans to continuously advance and conduct demonstration research on underwater laser cutting technology.”

This content was produced with the assistance of AI translation services.