Raising the Fukushima nuclear disaster to a level 7, the highest possible rating on the International Nuclear Event Scale, one month after the accident, comes far too late, says nuclear expert David Albright. Albright, a former nuclear inspector, and president and founder of the Institute for Science and International Security (ISIS), says the scale is for alerting the public of the hazard—it is not an official rating to be decided after the fact.
Failure to provide accurate assessment of the severity right after the accident “undermined the purpose of the scale, which is to warn the public what to do,” says Albright.
According to the International Atomic Energy Agency (IAEA) that created the scale,
INES is “a tool for promptly communicating to the public in consistent terms the safety significance” of reported nuclear incidents. The scale goes from 0 to 7. Chernobyl was rated a 7, and Three Mile Island was a 5.
“If they declared it a level 6 right away, other countries would have insisted on helping,” says Albright, who said Japan was too slow to accept help from the United States and other countries with managing the situation at the Fukushima plant.
Originally, Japan’s Nuclear and Industrial Safety Agency assigned INES ratings to individual reactors, rating the explosions at reactors no. 1, 2, and 3 as INES level 5 and reactor no. 4 as level 3. Based on data obtained before March 18, they gave the event an overall rating of level 5.
But Albright says the radioactivity coming out of the different reactors is “a collective hazard to public health.” He says the accident should be assessed comprehensively.
On April 12, the Japanese government announced that “considering information obtained after March 18,” it had recalculated the likely release of radioactive material into the air and the situations of the reactors, and based on that, it was elevating the event to a level 7, the same rating as Chernobyl.
Although the amount of radioactive material released is only 10 percent of what was released at Chernobyl, Fukushima still meets the criteria to be rated a level 7. First, the amount of contamination is significant enough to have a widespread effect on health and the environment. Second, the accident also released a significant amount of radiation within the facility. The third factor of the INES rating is the failure of preventive measures to avert an accident.
The Japanese government now estimates the release of radioactive material at 630,000 terabecquerels, whereas Chernobyl was 5,200,000 terabecquerels. A becquerel measures how radioactive a substance is. One becquerel is equal to the breakdown of one atomic nucleus per second. A terabecquerel is a trillion becquerels.
The earlier assessment of the severity of the accident was based on data obtained before March 18, in the six days following the initial explosion on March 12. But the data available from that period may have been very limited.
In the ISIS report, “Fukushima Crisis: Unmonitored Releases,” Albright and co-authors write that seven of the eight monitoring posts around the perimeter of the Fukushima Daiichi nuclear plant were not operating because of the loss of electricity following the earthquake and tsunami. One may have been operational. At that point, radiation measurements were being collected by mobile monitoring in a car.
They also write that “radiation monitoring equipment at the reactor buildings was also damaged and unable to provide basic information about the amount and type of radioactive material” released during the accidents.
“We don’t really know what got out, we don’t really know where it went,” said Albright, who analyzed the radiation data taken right after the explosions at the plant. He says it took almost a week before the monitoring posts were back online.
When queried, the IAEA said it could not confirm if the monitoring posts were inoperative immediately after the March 11 earthquake and tsunami.
“You have to be careful not to buy into what the Japanese and U.S. governments are saying,” said Albright by phone.
He says government generalizations about the safety of the situation are misleading. The actual dose of radiation people in the area are getting has not been thoroughly assessed.
“People shouldn’t be saying there is no risk,” he says, because there are people who get high doses and people who get low doses. Although existing data is insufficient, it suggests that some sectors northwest and southwest of the reactors may have gotten significant doses of radiation.
Albright says many assumed that prevailing winds blew the plume of radioactive gases that vented out of the reactors out to sea and away from Japan. But he says the data that TEPCO was able to collect shows ground winds going inland during that time. For that time when the reactors were venting during the first week, we don’t have enough data to know what was released and where it went.
He says laborious calculations must be done to assess the dose people received, especially those living in the vicinity of the plant. He says it may turn out there is a substantial sub-population that got a high dose of radiation.
Nevertheless, in Albright’s estimation, the Fukushima accident probably should be rated an “upper 6” on the scale. It shouldn’t been seen as same level as Chernobyl, he said.
He recommends that now the Japanese government should form an independent commission to investigate the disaster, one with people who do not have ties to the energy industry.
On Monday, Japanese cabinet minister Yukio Edano announced the evacuation zone would be expanded beyond the current radius of 20 km (12.4 miles) around the plant, but that people did not need to rush. He explained there was no new radiation threat, but people should avoid long-term exposure to the radiation already in the area.