The now-retired Kori-1 nuclear reactor located in the southeastern port city of Busan is seen in this Oct. 29, 2019 file photo provided by Korea Hydro & Nuclear Power. Yonhap

Korea began a decontamination process Tuesday to dismantle the country's now-defunct first commercial Kori-1 nuclear reactor, the state-run energy firm said.

After some 40 years of service from April 1978, the unit 1 reactor of the Kori nuclear power plant in the southeastern city of Busan was permanently closed in June 2017.

Korea Hydro & Nuclear Power (KHNP) said it began the chemical decontamination process to remove radioactive materials from the reactor, which is deemed a crucial first step of its decommissioning procedures, though the KHNP is required to win approval by the Nuclear Safety and Security Commission for its dismantlement.

The company employs indigenous technologies and equipment for the decontamination process, which is expected to allow Korea to make inroads into the global nuclear decommissioning services market.

"The successful dismantlement of a power plant carries significance in the industry ecosystem. The Kori-1 reactor project is expected to serve as a chance to boost the competitiveness of the industry," a KHNP official said.

It generally takes seven to eight years for the completion of a decommissioning process. But it is not yet clear how long it will take for the Kori-1 reactor dismantlement due to some issues regarding the construction of spent nuclear fuel storage facilities, according to officials. (Yonhap)