The operator of Japan's stricken nuclear plant said Sunday it will send two remote-controlled robots into a reactor building damaged by a hydrogen explosion to gauge radiation and temperature levels.
Emergency workers battling to stabilize the plant after a massive earthquake and tsunami knocked out cooling systems on March 11 have not been able to enter any of the reactor buildings since the disaster.
The explosion, one of several caused when a build-up of hydrogen reacted with oxygen in the atmosphere in the days immediately after the quake, blew the roof off the outer structure housing reactor three.
A spokesman for the Tokyo Electric Power Co. (TEPCO) said the two American-made robots would enter the reactor three building on Sunday to check radiation, temperature, humidity and oxygen levels.
Radiation from the overheating reactors has made its way into the air, land and sea, leading the government to impose exclusion zones around the plant in Fukushima prefecture and damaging local fishing and farming industries.
The news came as Yukio Edano, the right-hand man of Japan's prime minister, made his first visit to Fukushima, where he met local officials and emergency workers.
Edano, who is also Japan's top government spokesman, said the safety of people in the area was Tokyo's main priority, as new data indicated highly radioactive water may still be leaking into the sea from a nuclear plant.
"The government will place the highest priority on the safety of local residents," he told reporters in Fukushima city.
Edano also said TEPCO was "in the final stage" of coming up with a detailed strategy for solving the world's worst nuclear crisis since Chernobyl, adding it would be made public soon.
Japan's Prime Minister has said bringing the situation at the plant under control was his "top priority" and pledged to "maintain transparency" over the crisis.
"We continue to make the utmost efforts to address the issue of outflow of radioactive water from the plant into the ocean," Naoto Kan added in an article published in the International Herald Tribune newspaper Saturday.
His comments came as TEPCO said levels of radioactive iodine-131 in the sea near reactor number 2 had risen to 6,500 times the legal limit on Friday, up from 1,100 times on Thursday.
TEPCO said earlier it had managed to plug a leak of radioactive water from a cracked pit into the ocean and was checking for any more water runoffs from the plant.
The company has also been forced to empty containers with lower-level radioactive water into the ocean, sparking protests from local fishermen and concern in neighbouring countries.