South Korea’s leading presidential candidates are offering diverging visions on the future of nuclear power, though both agree that the nation must soften its plans to phase out the power source to meet climate targets.

The front-runner Lee Jae-myung from the ruling Democratic Party doesn’t want any new atomic plants, but is open to operating reactors that are currently under construction. Lee’s top contender Yoon Seok-yeol from the opposition People Power Party, on the other hand, wants nuclear to account for 30% of total energy generation, reversing President Moon Jae-in’s plans to gradually ditch reactors.

The candidates are reassessing policies on nuclear power at a time when nations from China to France are moving forward with new plants in the quest for more reliable and less-polluting forms of energy. Since Moon took the reins in 2017, South Korea has adopted a phase-out policy on nuclear energy because of concerns over safety in the wake of Japan’s Fukushima disaster in 2011.