Citing the introduction of new regulations in July, the Nuclear Regulation Authority said Wednesday it will not accept applications from utilities seeking permission to run their reactors beyond 30 years under existing procedures.

To address concerns about aging reactors, nuclear plant operators have been asked to conduct safety assessments of reactors that are set to operate beyond 30 years and compile a 10-year maintenance plan in seeking an extension.

But the NRA, which debuted just last September, is in the process of overhauling the country's nuclear regulations in light of the Fukushima No. 1 plant meltdown catastrophe that started in 2011. It plans to require existing reactors to clear the new safety standards once the rules come into force.