Japan plans to reinvestigate the 2011 Fukushima nuclear disaster that forced 160,000 people to flee.
The Nuclear Regulation Authority (NRA) will look into how radiation leaked from damaged reactor containment vessels and other factors.
It will also look at cooling systems set up to keep the melted fuel in the reactors from overheating.
Authorities said radiation levels gradually fall enough in reactor buildings to allow closer examination.
In 2011, three reactors of the power plant melted after it was struck by an earthquake and tsunami.
The disaster, which was termed as the world's worst nuclear disaster since Chernobyl in 1986, led to the eventual shutdown of all Japan's reactors.

Israeli strikes kill two in Gaza, destroy medicine storage warehouses
All 10 climbers confirmed killed in Pakistan avalanche
Russia pounds Kyiv with missiles, killing at least ten
Trump says deal reached to disarm Hamas, Israeli support for plan remains uncertain
