April 12, 2011
Japan Raises Nuclear Threat Level To Seven
Japanese authorities have raised the nuclear crisis rating to the highest level of seven.
The new decision reflects the amount of radiation leaked at the damaged Fukushima Daiichi power plant.
The last time level seven was applied was during the 1986 Chernobyl disaster, where 10 times as much radiation was emitted.
Japanese Prime Minster Naoto Kan said radiation leaks at the plant were starting to decline.
Kan said in a news conference that The Tokyo Electric Power Co. (TEPCO) will provide a schedule for getting it under control.
"Step by step, the reactors in the Fukushima Daiichi power plant are moving toward stability," he said according to BBC News.
There have been no fatalities resulting from the leaks at Fukushima, and risk to human health is still thought to be low.
The Nuclear Safety Commission of Japan announced in a statement that the crisis level at the Fukushima Daiichi plant was being raised, adding that it was a preliminary assessment that required further technical evaluation by specialists.
Officials said that the level seven signifies a "major accident" with "wider consequences" than the previous level.
"We have upgraded the severity level to seven as the impact of radiation leaks has been widespread from the air, vegetables, tap water and the ocean," Minoru Oogoda of Japan's Nuclear and Industrial Safety Agency (NISA), the government's nuclear watchdog, said in a statement.
The IAEA said previous level five ratings have been provided separately for accidents at Reactors 1, 2 and 3 but had now been combined as a single event.
Reuters reported that one official from TEPCO said that radiation leaks had not stopped completely and could eventually exceed those at Chernobyl.
However, a nuclear safety agency spokesman told reporters the leaks were still small compared to those at the plant in Ukraine.
"In terms of volume of radioactive materials released, our estimate shows it is about 10% of what was released by Chernobyl," he said.
The decision to raise the threat level was made after radiation of a total of 630,000 terabequerels had been estimated.
That classifies the crisis at level seven on the International Nuclear and Radiological Event Scale.
Reports said the level has subsequently dropped to less than one terabequerel an hour.
The Japanese government said the release from Chernobyl was 5.2 million terabequerels.
These measurements do not have any bearing on the likely medical effect on humans, which is measured in sieverts.
The severity level of Japan's nuclear crisis had previously been set at five, which is the same as that of the accident at Three Mile Island in the U.S. in 1979.
The cooling systems at the Fukushima Daiichi nuclear plant were damaged in last month's disaster and workers have been struggling to prevent reactors from overheating.
Officials have warned it will be several months before the situation at the nuclear facility is brought under control.
On the Net:
- Tokyo Electric Power Co. (TEPCO)
- Nuclear Safety Commission, Japan
- Nuclear and Industrial Safety Agency (NISA)
- International Nuclear and Radiological Event Scale