South Korea’s nuclear-first power mix to be reviewed under new president

South Korea's new President Lee Jae-myung, who won the country's June 3 election on a platform of giving renewable generation greater priority in the country's electricity mix, is expected to reduce South Korea's heavy reliance on nuclear energy.

On the campaign trail, Lee, the leader of the left-leaning opposition Democratic Party, expressed concerns about nuclear safety and disposal of nuclear waste, describing nuclear power as "inherently dangerous and unsustainable."

Instead, Lee has pledged to boost the role of renewable energy by building more wind turbines and solar panels to help meet the country's growing power demand. Lee and his Democratic Party is strongly backed by anti-nuclear civic groups and environmentalists.

Lee, who took office June 4, is set to review his predecessors' nuclear-focused energy policy, which emphasized achievement of higher capacity factors at existing units and construction of new reactors.

The June 3 election came with the ouster of impeached President Yoon Suk-yeol in the aftermath of his unlawful imposition of martial law in December, a move largely aimed at cracking down on the labor-friendly opposition.

Since taking office in May 2022, Yoon, from the conservative, business-friendly People Power Party, had carried out a nuclear-focused power mix policy, reversing his predecessor's nuclear phaseout policy.

Under Yoon's nuclear power drive, the utilization rate of reactors climbed to 81.8% in 2023 and 83.8% in 2024, compared with 74.5% in 2021, 70.6% in 2019 and 65.9% in 2018, according to state-owned nuclear power operator Korea Hydro & Nuclear Power.

Nuclear power emerged as the largest source for the country's power production for the first time ever last year, replacing coal and LNG, according to the Ministry of Trade, Industry and Energy.

Nuclear power accounted for 32% of the country's total power production in 2024, up from 26% in 2019, while the portion of coal in the power mix dropped to 28% in 2024, compared with 40% in 2019. The role of LNG in the power mix slightly increased to 28% in 2024, from 26% in 2019.

Yoon had stepped up his drive to build and operate more reactors. In December 2022, KHNP started commercial operation of Shin Hanul-1, with a capacity of 1.4 GW, the first time a new South Korean reactor had entered commercial service since the Shin Kori-4 APR1400 in August 2019.

In April 2024, the 1.4-GW Shin Hanul-2 started commercial power production. This will be followed by the start of commercial operation in February 2026 of the 1.4-GW Saeul-3 and 1.4-GW Saeul-4 in November 2026.

KHNP started construction of Shin Hanul-3 and Shin Hanul-4, the country's fourth pair of APR1400s, in September last year, with an aim to start operations by 2033. South Korea currently operates 26 reactors with a combined capacity of 26.05 GW.

In February, Yoon unveiled a plan to build two additional reactors, a new APR1400 pair, by 2038. Under Yoon's blueprint, the country is to launch its first 700-MW small modular nuclear reactor plant, potentially comprising four units, by 2035.

Slowing nuclear expansion

However, Lee could now delay or scrap the project to build two additional APR1400s.

"President Lee is unlikely to suspend nuclear reactors already under construction or shut down existing reactors, but he is expected to seek to reduce nuclear power and refrain from building new reactors," South Korea's major law firm and energy consultancy, Yulchon, said in a report on the new president issued June 4.

Lee has said that he supports extending the life of existing reactors, but opposes building new units, citing land constraints and worries over safety and nuclear waste.

Lee has vowed not to pursue a nuclear phaseout policy similar to that adopted by former president Moon Jae-in from the Democratic Party. Lee has said that he will instead push for a more balanced power mix, including the use of renewables, nuclear power and LNG.

"There could be some adjustments of the nuclear-focused power mix policy, but President Lee is unlikely to return to nuclear phaseout due to mounting power demand, particularly with the rise of the AI era," Chung Dong-wook, energy system professor at Chung-Ang University in Seoul, said in an interview June 5.