South Korea started construction work on two nuclear reactors on Friday in what President Lee Myung-bak described as a "big milestone" in the country's atomic industry, Yonhap news agency reported.
South Korea currently has 21 reactors, with 12 more scheduled to come into operation by 2022.
President Lee attended the ceremony at the Uljin power plant, 315 km southeast of Seoul, for the two 1,400-megawatt reactors, which will be built using solely domestically-made components.
Seoul is realising its dream of building nuclear reactors without using foreign technology, Lee said.
"The reactors mark a turning point for South Korea's commercial nuclear energy programme because no foreign-made parts are used in the most important areas," the Ministry of Knowledge Economy said in a statement.
About 7 trillion won (about $6 billion) has been earmarked to build the reactors, the ministry said.
It said it had "learned lessons" from Japan's Fukushima nuclear disaster last year and that "special safety measures" would be incorporated into the reactors' design.
Safety concerns about nuclear power have risen in South Korea following the failure of an older power plant in February.
Work on the first reactor at Uljin is scheduled to be completed by April 2017, and on the second by February 2018, the ministry said.