If the draft assessment by the Nuclear Regulation Authority receives final approval it will mean reactors 3 and 4 at the Kansai Electric Power Co.'s Oi plant in Fukui Prefecture can remain online through September, Kyodo News reported Thursday.
At that time they would be taken offline for mandatory routine safety checks, authorities said.
New industry regulations are set to take effect in July, but the NRA decided to conduct a special assessment of the safety of the Oi plant's reactors 3 and 4 before then because they are the only currently operating reactors in Japan out of a total of 50.
"As of the end of June, we think ... the situation will not create serious safety problems immediately," the NRA said in the report on the Oi plant.
The new regulations, in the wake of the 2011 Fukushima No. 1 nuclear power plant disaster, will require utilities to put plans in place to protect their facilities from tsunami and to prevent and minimize the consequences of severe crises, such as meltdowns.