Kori Unit 1 produced enough electricity over the past 40 years to power all of Busan for about eight years. Starting this year, the facilities you see now will be dismantled in sequence.
On the 3rd floor of the turbine building at Kori Nuclear Power Plant Unit 1 in Gijang County, Busan, on the 18th. Where a site official from Korea Hydro & Nuclear Power Co. (KHNP) pointed by hand, three massive turbines, a generator, a condenser, piping, and pumps were stacked floor by floor. A turbine is a device that rotates using the power of steam to drive a generator, and a condenser cools the steam that has passed through the turbine back into water. These facilities, which used steam from the reactor to generate electricity, were once the heart of the plant, but now they were waiting their turn to be dismantled.
Kori Unit 1 is the country's first commercial nuclear power plant. It reached initial criticality in 1977, began commercial operation in 1978, received a continued operation license in 2007, and was permanently shut down in June 2017. It subsequently applied for decommissioning approval in May 2021, and after a regulatory review, received final approval of the decommissioning plan in June last year.
However, nearly nine months after receiving decommissioning approval does not mean the site will be torn down immediately. That is because preparatory work to safely begin dismantling comes first, rather than cutting up turbines or generators right after approval. Inside the turbine building, temporary scaffolding and other provisional structures used in industrial settings had been erected, and preparations were underway to remove external insulation from piping and equipment.
Kwon Ha-uk, KHNP Director General for construction management, said, "Because Kori Unit 1 was built in the 1970s, there is a possibility the insulation used at the time contains asbestos, so we are dismantling it sequentially after component analysis," and added, "We must first remove asbestos, a substance harmful to the human body, to proceed in earnest with dismantling piping and equipment."
Dismantling begins in non-radiation areas. As the name suggests, non-radiation areas are spaces where radiation control is not required, including the turbine building and some yard facilities on the plant's perimeter. KHNP plans to finish insulation removal and work preparations in the first half of this year and, in the second half, begin dismantling relatively small non-radiation facilities such as the condensate demineralizer room (equipment that removes impurities from water returning from the condenser) and some perimeter tanks and facilities. From the end of the year, dismantling of turbines and generators will also ramp up. The dismantled turbines and generators will be recycled through steel companies.
Areas requiring radiation control, such as inside the reactor building, cannot be torn out right now. That is because Kori Unit 1's spent nuclear fuel is currently stored in a pool. Spent nuclear fuel continues to generate heat and radiation even after use in power generation, requiring separate cooling and storage. The interior of the reactor building cannot be dismantled in earnest until this fuel is moved out.
KHNP explained that it aims to complete a dry storage facility in the parking lot site in front of Kori Power Plant No. 3 in the second half of 2031 and, after moving the spent nuclear fuel there, will begin dismantling in the radiation-controlled areas.
Once dismantling of radiation-controlled areas begins, large equipment inside the reactor building—such as steam generators, reactor coolant pumps, and pressurizers—will be removed first, followed by sequential dismantling of internal reactor structures and the reactor pressure vessel. In this process, equipment will be used as much as possible instead of people. Steam generators will be dismantled by remote control to reduce worker exposure, internal reactor structures will be cut using specialized underwater equipment, and the reactor pressure vessel will be cut using cutting tools mounted on robotic arms and wire saws.
After that, the process proceeds in the order of demolishing remaining structures in non-radiation areas and ground and underground structures of the turbine building, measuring residual radioactivity, conducting safety reviews, and restoring the site. KHNP presented a plan to begin site restoration in 2035 and complete overall decommissioning in 2037. The total project period is about 12 years.
Handling the waste generated during dismantling is also a key task. Director General Kwon said a separate support facility will be built to handle it, where metal waste decontamination (reducing or removing radioactive contaminants), cutting, and packaging will be carried out. Metal with low contamination will be decontaminated to reduce the volume of waste, and radioactive waste will be managed separately according to relevant standards.
A look around the site also revealed that dismantling Kori Unit 1 is a task with many variables. Although a partition wall dividing Units 1 and 2 had been erected inside the turbine building, the mechanical sound of Kori Unit 2, which is being readied for restart, continued to be heard through the idle Unit 1 equipment. Because the two reactors are that close to each other, there were concerns that, in such an environment, vibrations, dust, and scatterable materials could affect Unit 2's equipment when the dismantling of Unit 1 gets into full swing.
In response, KHNP said, "Dismantling work will proceed within a range that does not affect Unit 2's equipment," and explained, "We plan to combine partition wall installation, process adjustments, and separate safety management."
Jeong Ji-yun, project manager for decommissioning and SF regulation at the Korea Institute of Nuclear Safety (KINS), said that after decommissioning approval, the regulator receives reports from the operator on the dismantling status every six months and, through on-site inspections, confirms that preparations are being made in accordance with the decommissioning plan and laws. She added that during the first inspection early this year, it was still before full-scale demolition, so there were no major issues, but once actual dismantling gets into full swing, more meticulous inspections may be needed than now.
She went on to say, "Decommissioning of reactors like Kori Unit 1 has been carried out several times in the United States, and we visited sites to directly check inspection methods and decommissioning progress," adding, "As this is Korea's first nuclear decommissioning case, we are preparing thoroughly and providing oversight to minimize trial and error."