OSAKA, Japan - The No. 1 and No. 2 reactors at Takahama nuclear power plant in Fukui prefecture, western Japan, gained initial approval for their safety measures on Wednesday from Japan's nuclear watchdog Nuclear Regulation Authority (NRA).

The decision will be finalized after soliciting technical comments from the public, which will make the two reactors the first ones over 40 years old to clear screening in Japan.

The No. 1 reactor of the Takahama complex marked 40 years of operation in November 2014, and the No. 2 reactor last November.

To resume operation, the two reactors will still have to go through a separate screening for operating beyond 40 years by July 7.

Under tighter safety standards imposed after the 2011 Fukushima nuclear disaster in Japan, reactors are not allowed to operate more than 40 years in principle unless with safety clearances from the NRA. In that case, they can be allowed to continue operating for up to 20 more years.

Among Japan's 48 commercial reactors, seven are around 40 years old. Japan's power company Kansai Electrics has also applied for extension of operation for the No. 3 reactor at Mihama nuclear power plant, which will turn 40 years old this year.

So far a total of five reactors at three plants have obtained final approval for restarts under the stricter safety rules. Three of them have resumed operation, including two reactors at Kyushu Electric Power Co.'s Sendai plant in Kagoshima Prefecture and the No. 3 reactor at the Takahama plant.