The IAEA experts will work with experts from about a dozen countries during their 10-day trip to look at the situation at Fukushima, one of the world's worst nuclear disasters, Kyodo News reported.
The efforts to stabilize the Fukushima plant since March 11 have been constantly hampered by a host of problems, including hydrogen explosions, radiation leaks, inadequate cooling of the pools holding spent nuclear fuel rods resulting in their partial melting, and flooding of the reactors by contaminated water.
The investigators will present their findings at a ministerial meeting on nuclear safety to be hosted by the IAEA next month in Vienna.
Tokyo Electric Power Co., the plant's operator, said a nuclear waste disposal facility at the site will be filled up in the next several days with radioactive floodwater diverted from No. 2 and 3 reactors.
Currently, utility workers have been working inside No. 1 and 2 reactors to restore their cooling systems, which currently are being cooled by pumping massive quantities of seawater. But this in turn has led to the flooding problems.
Japanese Prime Minister Naoto Kan denied in parliament about issuing any instruction to Tokyo Electric to stop injecting seawater into the No. 1 reactor, which would have worsened the situation at the reactors, Kyodo News reported.