The Japanese government has expressed regret for not disclosing some important results of the radiation monitoring conducted near the Fukushima Daiichi nuclear plant soon after the accident.
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A reading on March 12th, one day after the massive earthquake and tsunami hit the plant, shows that radioactive tellurium was detected 7 kilometers away. Tellurium is produced during the melting of nuclear fuel. Three hours before the data was collected, the government expanded the radius of the evacuation area around the plant from 3 kilometers to 10 kilometers. But the government's Nuclear and Industrial Safety Agency reported at a news conference several hours later that the nuclear fuel was intact.
The government also failed to disclose the high radiation levels in weeds 30 to 50 kilometers from the plant. On March 15th, 123 million becquerels of radioactive iodine-131 per kilogram were detected 38 kilometers northeast of the plant. The nuclear safety agency says it deeply regrets not releasing the data.
http://www3.nhk.or.jp/daily/english/04_20.html