A team of U.N. nuclear inspectors began a four-day assessment on Monday of a nuclear power plant that was severely damaged by an earthquake last month.
The magnitude-6.8 quake in Niigata prefecture (state) on July 16 killed 11 people and injured more than 1,000. It also caused numerous malfunctions and leaks at the plant - the world's largest in terms of capacity - and raised concerns about safety at Japan's nuclear power stations.
The International Atomic Energy Agency team, led by Philippe Jamet, director of its Nuclear Installation Safety Division, started examining the plant Monday morning.
The team will return to Tokyo on Friday for talks with Japanese nuclear safety officials, Japan's Nuclear and Industrial Safety Agency said in a statement.
Jamet said he would like to inspect the facilities first hand and would seek explanations of all the problems that occurred in the quake.
"Our aim today is to draw lessons from the earthquake that happened here and share (them) with the international community," he told reporters Monday.
Jamet told reporters after his arrival Sunday that his team will conduct an independent examination and then write a report.
Japanese officials, already at the plant for investigations, will cooperate with the six-member IAEA team, but the U.N. agency's probe will be independent, agency officials said.
Plant operator Tokyo Electric Power Co. has come under fire in the wake of the quake.
The company has revealed hundreds of problems and damages in the quake's aftermath, including a leak of radioactive water into the sea, although the amount of radioactivity released was minimal.
Plant officials said they had not foreseen such a powerful quake hitting the facility, and repeatedly underreported its impact afterward.