The Shin-Hanul No. 1 and 2 nuclear reactors at Uljin, 330 kilometers southeast of Seoul, are seen in this undated file photo provided by North Gyeongsang Province. (Yonhap)
President Moon Jae-in has championed breaking away from nuclear energy since his inauguration in 2017 by retiring old plants and refraining from building new ones.
But Yoon, as presidential candidate of the main opposition People Power Party, slammed the policy and pledged to use nuclear power generation to reduce carbon emissions and the country's foreign dependence for energy.
As the first step, the new government is widely expected to resume the now-suspended construction of two nuclear reactors -- Shin-Hanul No. 3 and No. 4 -- in the coastal county of Uljin, 330 kilometers southeast of Seoul, according to Yoon's promise.
The project to build the two 1,400-megawatt reactors has been put on hold since 2017, though they were supposed to be completed by next year.
Yoon also pledged to continue to operate current nuclear reactors as long as their safety can be ensured, through which the country will keep the proportion of the country's nuclear energy at the current level of around 30 percent.
South Korea now has a total of 24 nuclear reactors, and the current government has sought to decrease the number of plants in operation to 17 by 2034 in a move to reduce nuclear energy to account for 23.9 percent of the country's total power generation by 2030.
In 2017, the government shut down the country's oldest reactor, the Kori-1, in the southern port city of Busan, 39 years after its opening, and closed the Wolsong No.1 reactor the following year.
Yoon has also called for an active push for securing advanced nuclear power technologies, such as small modular reactor technology, and their exports.
He vowed to win orders for more than 10 nuclear power plants from overseas by 2030 so as to create 100,000 high-quality jobs.
To better support exporters, Yoon pledged to set up a pan-government entity in charge of backing overseas sales of nuclear power plants and to devise measures for the participation of civilian entities in nuclear reactor construction and operation.
"I will recover the ecosystem of nuclear power generation and advance safe nuclear technologies so that they can become a core engine to drive the country," Yoon wrote on his Facebook page last month.
On Thursday, the prosecutor-turned-opposition candidate won a remarkably close presidential election to replace Moon of the liberal bloc whose single five-year term ends in May.