The crisis management center was not informed about SPEEDI data predicting how radioactive substances would spread from the damaged Fukushima No.1 power plant, Chief Cabinet Secretary Yukio Edano said Friday.
Edano said the prime minister’s office received a fax containing computer projections of how radioactive materials probably dispersed in the early hours of March 12 — a day after the earthquake and tsunami triggered the nuclear crisis -but that this data was not passed on to Prime Minister Naoto Kan nor himself.
This would indicate that when Kan inspected the stricken plant by air that morning, he was unaware of the estimates, which were made using the Nuclear Safety Technology Center’s system for prediction of environmental emergency dose information, or SPEEDI.
Edano said the data could have been meaningful in issuing evacuation orders to residents near the plant during the nuclear emergency.
The government eventually directed people within 20 km of the plant to evacuate and those within 20 to 30 km to stay indoors or voluntarily leave on March 11 through 12. But the SPEEDI projections were only being sent to the United Nations. It was disclosed to the Japanese public much later.
“We will thoroughly check the circumstances regarding why the data was not reported, and also want this to be reviewed by an independent panel probing the nuclear accident,” Edano said.
No-go zone too small?
A decision by the Nuclear Safety Commission to leave the size of “emergency planning zones” in its disaster guidelines unchanged in 2006 resulted in a much smaller initial evacuation than Fukushima Prefecture needed in March, minutes of the discussion show.
The NSC’s guidelines call for any danger zone set up around a nuclear disaster to have a roughly 8- to 10-km radius, much smaller than the 20- to 30-km radius now in place at Fukushima. This casts doubt on whether the NSC fully grasped the dangers nuclear disasters pose to their surroundings.
After the Fukushima No. 1 power plant was stricken by the quake and tsunami on March 11, the government formally designated an area with a 20-km radius around it as a no-go zone and told most residents within 30 km of the plant to evacuate.
Many municipalities across the country have based their emergency planning on the commission’s guidelines. Now they are raising questions and calling for a review as the Fukushima crisis drags on.
“The subject of reviewing the scope of the zone hasn’t been a topic for a long time,” an official at the NSC’s secretariat said.
Noting that it should have been reconsidered earlier, the official said the commission plans to review it in the future.
The NSC’s panel discussed the matter in 2006 — after the International Atomic Energy Agency urged that a roughly 5- to 30-km radius be used as the criteria for setting up an emergency planning zone that requires preparations be made in advance.
During its five sessions, however, the NSC’s secretariat said the emergency planning zone referred to in the Japanese guidelines had a “sufficient leeway,” noting that the IAEA also allows each country to use its own discretion, according to the minutes.
The panel didn’t suggest the scope of the zone be reconsidered, concluding that “pains should not have to be taken to include additional measures” in the guidelines, the minutes show.
The guidelines say that even in extremely severe disasters, “no protective measures are needed outside (the emergency planning zone), such as staying indoors or evacuation.”
For the Fukushima crisis, the government initially told people within 20 km of the plant to evacuate and those between 20 and 30 km to stay indoors or voluntarily leave. The U.S. was more cautious and urged citizens within 80 km of the plant to leave. Japan has since expanded the area beyond the 20-km zone.