Japanese officials have failed to justify why it took them over a month to disclose large-scale releases of radioactive material in mid-March at the crippled Fukushima Daiichi nuclear power plant.

A special government tool had been producing critical maps, and other data, hourly since the first hours after the catastrophic earthquake and tsunami, some of the maps clearly showed a plume of nuclear contamination extending to the northwest of the plant, beyond the areas that were initially evacuated.

Japan’s nuclear safety agency and the science ministry had data on the spread of radioactive materials that could have prevented unnecessary radiation exposure, but decided to sit on it instead of reporting it to the crisis management center at the prime minister’s office.

Accurate or Not?

The ministry has argued that the data was only predictions and releasing it could have caused unnecessary public disorder, and since the tsunami had knocked out sensors at the plant: without measurements of how much radiation was actually being released by the plant, it was impossible to measure how far the radioactive plume was stretching.

“Without knowing the strength of the releases, there was no way we could take responsibility if evacuations were ordered,” said Keiji Miyamoto of the Education Ministry’s nuclear safety division.

However as it turned out later its predictions were fairly accurate, yet SPEEDI data was never used in mapping out the evacuation routes for Fukushima Prefecture residents.

A new report from Japan’s science ministry casts serious doubt on the officials that the readings were inaccurate, and exposes that central government confirmed that the SPEEDI radiation fallout simulations were accurate, and reliable, but still refused to release the data for more than one month after the nuclear accident in Fukushima.

The science ministry’s report reveals that not only were ministry officials worried about the simulations, they also double checked the physical levels.

The Education, Science, Culture, Sports and Technology Ministry operates and maintains SPEEDI and WSPEEDI (World Edition), these systems estimate where radioactive material will spread based on data, including figures provided by the Nuclear and Industrial Safety Agency (NISA) on the amount of radioactive material released.

To use the model, scientists enter radiation measurements from various distances from a nuclear accident. The model produces an estimate of the radioactive material escaping at the source of the accident.

The ministry inexplicably decided such data would be unavailable due to the loss of power at the plant following the massive March 11th earthquake.

That evening, it began projecting how much radioactive material would leak every hour, on the assumption that one becquerel was released per hour, which was not indicative of the actual release taking place at the crippled plant, rather in line with Nuclear Safety Commission guidelines.

In essence, the SPEEDI predictions will not reveal the exact radioactivity levels in a given area, or identify every type of radioactive isotope that may be present, but merely provides a map of sorts, to identify which areas are more likely to be affected than others.

Data from the costly high-tech system designed to predict the dispersal of radioactive materials could have served as a reference for evacuation because, although the amount of radiation was not accurately predicted, it still provided a clear picture of areas with relatively higher or lower radiation levels.

NISA submitted some of SPEEDI’s results to the Prime Minister’s Office after 1:30 a.m. on March 12, but not all of the information was relayed.

Furthermore, as the results that were conveyed were accompanied by documents suggesting the data “were not very reliable,” they were not passed to then Prime Minister Naoto Kan.

SPEEDI data around Namie alarmed experts

On March 15th, the ministry had made projections for what would happen if all radioactive material was discharged from the nuclear plant. These figures were not released for fear of panicking the public.

After being increasingly alarmed by the SPEEDI documents forecasting the spread of radioactive materials that were produced, the ministry decided dispatched officials to Namie Town, Fukushima to perform manual measurements.

Measurements showed that the town located 20 kilometers from the nuclear plant did in fact have dangerously high levels of radiation, over 330 microsieverts per hour, yet still the public was never warned.

Itaru Watanabe, an official at the Ministry of Education, Culture, Sports, Science and Technology, has admitted that data produced by SPEEDI, was provided to the U.S. before the Japanese public.

The data was disclosed to get the assistance of the U.S military for the relief effort on March 14th, Watanabe said.

This data was shared with NISA, the commission and the Fukushima prefectural government. However, none of these entities knew how to make maximum use of this information.

The data release for the public “was delayed while it was being considered at the government’s disaster response headquarters,” Watanabe added.

Media outlets had asked the ministry to provide SPEEDI data immediately after the accident began on March 11th. The ministry, NISA and the commission discussed what data should be made public, and concluded information that was not highly accurate should not be released.

The ministry received a request to disclose more information on March 24th, and public criticism of the lack of available information became louder. The organizations eventually relented and released more of their SPEEDI data by May 3.

Municipalities around the crippled nuclear plant have realized that some of their residents evacuated from their homes immediately after the crisis began to places with higher radiation levels, unaware of the danger due to lack of information.

As a direct result of the delay in the communication of critical data, people who fled the coast of Fukushima Prefecture and went northwest ended up in places where the danger was higher because spring winds at the time were blowing in that direction, carrying radioactive fallout to areas well beyond the 20-km radius evacuation zone.

Given no official guidance from the central government, Namie town officials led the residents north, believing that winter winds would be blowing south and carrying away any radioactive emissions.

Evacuees said that, believing they were safe in Tsushima, they took few precautions. They did not know that SPEEDI’s projections predicted the radioactive material would spread and accumulate over these areas.

For three nights, while hydrogen explosions at four of the reactors spewed radiation into the air, they stayed in a district called Tsushima where the children played outside and some parents used water from a mountain stream to prepare rice.

Yoko Nozawa, 70, said that because of the lack of toilets, they resorted to pits in the ground, where doses of radiation were most likely higher.

“We were in the worst place, but didn’t know it,” Ms. Nozawa said. “Children were playing outside.”

While the evacuees were waiting to return home, government computer system models were showing that winds were blowing directly over the town where the evacuees had escaped to, but the town officials wouldn’t be informed for two months, long after any protection could be offered to the residents.

“From the 12th to the 15th we were in a location with one of the highest levels of radiation,” said Tamotsu Baba, the mayor of Namie.

Mr. Baba said that if the SPEEDI data had been made available sooner, townspeople would have naturally chosen to flee to safer areas.

“But we didn’t have the information,” he said. The withholding of information, he said, was akin to “murder.”

Mayor Tamotsu Baba has since said the Namie town government in Fukushima Prefecture is considering filing a criminal complaint over delays in the disclosure of radioactive material diffusion estimates under Japan’s SPEEDI system.

A report by an official Japanese government panel investigating the Fukushima disaster did admit, “[Residents] had no option but to follow instructions issued by their mayors, who were unaware” of the potential danger, but no remedy has been proposed to ensure the same situation would not occur again.

Embattled Japanese officials at the heart of the SPEEDI scandal have continued to maintain that the actions were justified because the data was “merely a hypothetical calculation result”, that releasing the data “would cause unnecessary panic”, and firmly insist that they did not knowingly imperil the public, but critics inside and outside Japan argue that some of the exposure could have been prevented if officials had released the data sooner.

In other interviews, officials at the ministry and the agency each pointed fingers, saying that the other agency was responsible for SPEEDI.

Economy, Trade and Industry Minister Yukio Edano admitted in a public hearing that the delay in releasing information from the System for Prediction of Environmental Emergency Dose Information (SPEEDI) was a major reason the government lost the public’s trust.

On July 4, 2011, the Atomic Energy Society of Japan, a group of nuclear scholars and industry executives, said, “It is extremely regrettable that this sort of important information was not released to the public until three months after the fact, and only then in materials for a conference overseas.”

In a 2011 interview, Goshi Hosono, the minister in charge of the nuclear crisis acknowledged that certain information, including the SPEEDI data, had been withheld for fear of “creating a panic.”

Toshiso Kosako, a top Japanese expert on radiation measurement explained the SPEEDI maps would have been extremely useful in the hands of someone who knew how to sort through the system’s reams of data.

Kosako also revealed that the SPEEDI readings were so complex, and some of the predictions of the spread of radiation contamination so alarming, that three separate government agencies — the Education Ministry and the two nuclear regulators, the Nuclear and Industrial Safety Agency and Nuclear Safety Commission — passed the data to one another like a hot potato, with none of them wanting to accept responsibility for its results.

Seiji Shiroya, a commissioner of Japan’s Nuclear Safety Commission, an independent government panel that oversees the country’s nuclear industry, said that the government had delayed issuing data on the extent of the radiation releases because of concern that the margins of error had been large in initial computer models.

But he also suggested a there may have been a public policy reason for having kept quiet.

“Some foreigners fled the country even when there appeared to be little risk,” he admitted. “If we immediately decided to label the situation as Level 7, we could have triggered a panicked reaction.”

For months after the disaster, the government flip-flopped on the level of radiation permissible on school grounds, causing continuing confusion and anguish about the safety of schoolchildren in Fukushima.

After the nuclear disaster, the government raised the legal exposure limit to radiation from one to 20 millisieverts a year for people, including children — effectively allowing them to continue living in communities from which they would have been barred under the old standard.

The limit was later scaled back to one millisievert per year, but applied only to children while they were inside school buildings.

About 45 percent of 1,080 children in three Fukushima communities surveyed in late March 2011 tested positive for thyroid exposure to radiation, according to an announcement by the government, which added that the levels were too low to warrant further examination.

Seiki Soramoto, a lawmaker and former nuclear engineer to whom Prime Minister Naoto Kan turned for advice during the crisis, blamed the government for withholding forecasts from the computer system, known as the System for Prediction of Environmental Emergency Dose Information, or Speedi.

“In the end, it was the prime minister’s office that hid the Speedi data,” he said. “Because they didn’t have the knowledge to know what the data meant, and thus they did not know what to say to the public, they thought only of their own safety, and decided it was easier just not to announce it.”

Sources: JiJi Press, NHK, CNN, The Japan Times, The New York Times, The Yomiuri

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