Radiation error 'unacceptable'

Japan's top government spokesman has blasted the operator of the stricken Fukushima Daiichi nuclear plant for giving an erroneous radiation reading, calling it "unacceptable".

Tokyo Electric Power Co said radiation in puddles in the turbine building of reactor two at the plant was 10 million times higher than normal, before later correcting the information to say it was 100,000 times higher.

Top government spokesman Yukio Edano said: "Considering the fact that the monitoring of radioactivity is a major condition to ensure safety, this kind of mistake is absolutely unacceptable.

"(The government) has ordered TEPCO not to repeat this again," he said.

However he added that he understood workers at the site were probably exhausted from their round-the-clock efforts to avert a nuclear disaster at the stricken plant.

The radiation level in the water puddle at reactor two soared to more than 1000 millisieverts per hour, forcing the evacuation of workers toiling to restore its cooling systems.

Meanwhile, the operator of the plant has detected radioactive iodine 1150 times the legal limit in water 30 metres from reactors 5 and 6, the nuclear safety agency said.

Those two reactors were under maintenance when a huge 9.0-magnitude earthquake hit, triggering a devastating 14-metre tsunami that tore into the northeast coast and crippled cooling functions at the Fukushima Daiichi plant.

Previously Tokyo Electric Power, the operator, said that reactor five's external, non-emergency power connection had been restored and cooling of its spent fuel pool had resumed.

At reactor six, the emergency power generator and cooling functions had been restored, TEPCO had said.

Levels of radioactive iodine some 1850 times the legal limit were reported a few hundred metres offshore, up from 1250 times the limit, but officials ruled out an immediate threat to marine life or to seafood safety.