But South Korean industries are anxious, since nuclear and coal power cuts are certain to raise energy costs and could squeeze the country's electricity supply.
South Korea's nuclear power could dwindle rapidly in the years ahead if steps are taken to implement recently elected President Moon Jae-in's call to dismantle older nuclear reactors. President Moon attended a ceremony Monday morning to proclaim the reactor's retirement at the Kori Nuclear Power Plant in Busan.
"So far, South Korea's energy policy pursued cheap prices and efficiency". The country has 59 coal plants supplying nearly 40% of the country's electricity. But it's time for a change.
"We will end the nuclear-oriented power generation plan and pave the way for a nuclear-free era", Moon said.
"The Fukushima nuclear accident has clearly proved that nuclear reactors are neither safe, economical nor environmentally friendly", Yonhap news agency quoted Moon as saying.
It was built in 1977, and 40 years later (KOREAN) "As of 12 AM on June 19th, 2017, Korea has permanently shut down its first nuclear reactor, Kori-1".
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"While Western advanced countries are rapidly ending nuclear power generation, we are increasing it, and Korea has become the country with the most concentrated nuclear power plants", he said. "We will obtain a social consensus as soon as possible, taking into account the safety, construction progress rate, costs and spending as well as reserve power rate", Moon said. Its nuclear power production from 25 nuclear plants in 2016 was the fifth-largest in the world, according to the World Nuclear Association.
But South Koreans' enthusiasm for nuclear energy quickly waned following the 2011 Fukushima meltdowns in its neighbour Japan.
The former president Lee Myung-bak saw nuclear as an important source of clean energy, while Park wanted to increase the number of reactors to 36 by 2029.
The country was the fifth-largest producer of nuclear energy past year, according to the World Nuclear Association, with its 25 reactors generating about a third of its electricity.
Anti-nuclear campaigners have long warned of the potentially disastrous consequences of a meltdown at a nuclear plant in South Korea, where many reactors are close to densely populated areas.
"South Korea is not safe from the risk of natural disaster, and a nuclear accident caused by a quake can have such a devastating impact", he said. He said that the Kori-1 reactor has been the symbol of Korea's industrialization and enabled the nation to meet its increasing energy demands. The decommissioning will take at least 15 years and cost 643.7 billion won ($569 million), the energy ministry said.