Japan more than doubles estimate of radiation leaked at nuclear plant in days after quake

Japan on Monday more than doubled its initial estimate of radiation released from the crippled Fukushima Daiichi nuclear plant in the week after the tsunami, just before an official investigation into the accident was set to begin on Tuesday, according to AFP.

The nation's Nuclear and Industrial Safety Agency now says that it believes 770,000 terabecquerels escaped into the atmosphere in the first week after the March 11 earthquake, compared with its earlier estimate of 370,000 terabecquerels released in the first month, the New York Times said. At the time of the first estimate in April, Japan’s Nuclear Safety Commission, an independent government panel, had called the reading too low; its estimate was 630,000 terabecquerels in the first month.

The Japanese nuclear regulatory agency also said that it believes that reactor cores at some of the units at the Fukushima plant melted much faster than the plant operator had previously suggested, the Wall Street Journal said. The regulatory agency added that the reactor pressure vessel at one of the Fukushima reactors appeared to have been compromised as early as five hours after the earthquake, the New York Times said.

The findings were released on the eve of the first meeting, set for Tuesday, of an independent 10-member academic and expert panel that will look into the causes of the worst nuclear accident since Chernobyl in 1986, AFP said.

The revision, almost three months after the earthquake, is likely to fuel criticism of the way information about the accident was disseminated by the government and the plant operator, Tokyo Electric Power Company, AFP said.

Japanese government safety officials played down suggestions of a greater impact on human health or food safety in the affected area as a result of the revision, the Wall Street Journal reported. It also said the new report wouldn't change the timeline for bringing the nuclear reactors to a safe shutdown.