Robot detects high radiation in Japan reactors

Readings on Monday from a robot that entered two crippled buildings at Japan’s tsunami-flooded nuclear plant for the first time in more than a month displayed a harsh environment still too radioactive for workers to enter.

Nuclear officials said the radiation data for Unit 1 and Unit 3 at the tsunami-flooded Fukushima Daiichi plant—collected by a US-made robot that looks like a drafting lamp on treads—do not alter plans for stabilising the complex by year’s end under a “road map” released by the plant operator on Sunday.

With the public growing increasingly frustrated at the slow response to the earthquake, tsunami and nuclear crises, parliament grilled Prime Minister Naoto Kan and officials from plant operator Tokyo Electric Power Co.

“You should be bowing your head in apology. You clearly have no leadership at all,” Masashi Waki, a lawmaker from the opposition Liberal Democratic Party, shouted at Kan.

“I am sincerely apologising for what has happened,” Kan said, stressing that the government was doing all it could to handle the unprecedented disasters.

TEPCO’s president Masataka Shimizu looked visibly ill at ease as lawmakers heckled and taunted him.

Workers have not gone inside the two reactor buildings since the first days after the plant’s cooling systems were wrecked by the March 11 earthquake and tsunami.

Hydrogen explosions in both buildings in the first few days destroyed their roofs and littered them with radioactive debris.

The robot, called a Packbot, haltingly entered the two buildings on Sunday and took readings for temperature, pressure and radioactivity. More data must be collected and radioactivity must be further reduced before workers are allowed inside, said Hidehiko Nishiyama of Japan’s Nuclear and Industrial Safety Agency.

Officials said the radiation findings should not hamper the goal of achieving a cold shutdown of the plant within six to nine months as laid out in a timetable that TEPCO announced on Sunday. Rather, the new information would help the company in figuring out how to push ahead with the plan. The robots being used inside the plant are made by Bedford, Massachusetts company iRobot. Travelling on miniature tank-like treads, the devices opened closed doors and explored the insides of the reactor buildings, coming back with radioactivity readings of up to 49 millisieverts per hour inside Unit 1 and up to 57 millisieverts per hour inside Unit 3.

The legal limit for nuclear workers was more than doubled since the crisis began to 250 millisieverts. The US Environmental Protection Agency recommends an evacuation after an incident releases 10 millisieverts of radiation, and workers in the US nuclear industry are allowed an upper limit of 50 millisieverts per year.