"In the lead up to the presidential election, I promised to make a safe Republic of Korea", the president said in a ceremony in Busan, marking the permanent shutdown of the country's first nuclear reactor, the Kori-1.
Our Kim In-kyung has more. A subsequent relicensing process could have taken Kori 1 to 2027, but Korea Hydro & Nuclear Power (KHNP) announced in August 2015 that it had withdrawn its application to extend the unit's operating licence. The president stressed that the government's energy policies in the future should focus on boosting public safety, environmental protection and sustainable growth. Nuclear safety reemerged as a major issue for the public after the nuclear disaster in Fukushima, Japan in 2011, and the 5.8-magnitude quake that struck the Korean city of Gyeongju past year - an area not far from a number of nuclear plants.
"I will scrap all preparations to build new reactors now underway and will not extend the lifespan of current reactors", he said.
Moon on Monday also vowed to decommission "as soon as possible" another aged atomic plant in the southeast, whose original 30-year lifespan had been extended by another decade to 2022.
The shutdown of Kori-1 is estimated to cost $567 million, South Korean newspaper Segye Ilbo reported Monday.
Moon said he will soon reach a consensus on the Shin Kori No.5 and Shin Kori No.6 reactors after fully considering their construction costs, safety and the potential costs of paying compensation.More news: Deputy AG Rosenstein set for budget hearing Tuesday
He pledged to abandon the nuclear-centric electric power policy and open a post-nuclear era. On being elected, he immediately shut down eight old coal-fired plants and said no new such plants would be constructed. He said the seismic resistance of the country's nuclear power plants - which had been reinforced since the March 2011 Fukushima Daiichi accident in Japan - would be re-examined.
The new government plans to increase the use of renewable energy to 20% of the country's total power generation by 2030.
Numerous reactors are located near residential areas along the country's southeast coast.
Stressing that Korea is not safe from a major natural disaster, Moon said the country would face calamity if a nuclear accident took place, however low the likelihood of one is.
Korea presently operates 25 reactors, including Kori-1, and these provide 23GW of energy, or about a third of the country's electricity demand. South Korea is also searching for answers on how and where to store spent nuclear fuels permanently.