Right after the start of the nuclear accident on March 11, 2011, the Japanese national government, then under the Democratic Party of Japan headed by Naoto Kan, initially said they didn't know about SPEEDI. What was SPEEDI? Then they said SPEEDI failed to work. Then on March 23, 2011, Nuclear Safety Commission reluctantly made several SPEEDI simulation maps available to the public. Full disclosure didn't come until early May, 2011. (WSPEEDI disclosure was even later, in mid May 2011.)
By that time, it was too late for the residents in Fukushima Prefecture and areas in Miyagi Prefecture and northern Kanto, and it was apparently too late for Dr. Shunichi Yamashita, thyroid expert and special advisor to Fukushima Prefecture at that time.
According to Asahi Shinbun's still on-going "Trap of Prometheus", Dr. Yamashita was caught off guard when the SPEEDI simulation maps were finally made public. He had confidently persuaded the officials of Fukushima Medical University in the preceding days that there was absolutely no need to distribute potassium iodide pills because the spread of radioactive materials from the accident, compared to the Chernobyl accident, would be so miniscule.
But the SPEEDI simulation maps showed the areas with 100 millisieverts or more equivalent dose at thyroid (effective dose for the whole body is 100x0.04=4 millisieverts) extended far beyond the 30-kilometer radius evacuation zone.
I guess Dr. Yamashita was basing his assertion on his hope. Or he truly believed there was no SPEEDI simulation. Or he was a medical doctor not nuclear scientist. Or all of the above.
From "Trap of Prometheus" on November 7, 2013, on Dr. Yamashita prevailing on potassium iodide pills and speaking about the "fate" of Japan as an earthquake-prone country with many nuclear power plants:
Yamashita arrived in Fukushima in the afternoon of [March] 18, via Osaka Airport. He appeared in the lecture for the staff at Fukushima Medical University on the same day at 6PM. He was accompanied by the fellow professors [at Nagasaki University], Naoki Matsuda (age 56) and Noboru Takamura (age 45).
There were 300 people who attended the lecture held in the large conference room. Many were wearing masks to block radioactive materials.
Yamashita spoke last.
The talk was about whether potassium iodide pills were necessary. Citing the Chernobyl accident, Yamashita said there was no need:
(1) Many believe that potassium iodide pills will prevent thyroid cancer, but it is nothing but "iodine religion". For the Japanese, the intake of radioactive iodine would be 15 to 25%, unlike 40 to 50% for people in Belarus.
(2) The amount of radiation exposure west of the twenty, thirty kilometer radius [from the plant] will probably be less than 1 millisievert. [Not clear whether he meant effective dose for the whole body or thyroid equivalent dose.] Compared to Chernobyl, the amount of radiation exposure will be so small that the Japanese government will not issue instruction to take potassium iodide pills.
(3) The dosing manual has many defects. I hope it won't be used.
In conclusion, Yamashita tried to raise the morale of the staff:
"I beg that you do not escape [desert your post]. Radiation exposure due to a nuclear accident is a fate of the quake-prone Japan that has nonetheless been promoting nuclear power plants."
Well, his last remark is, sadly, spot on. People in Japan had failed to see it, or refused to see it, until the Fukushima I Nuclear Power Plant accident.
From "Trap of Prometheus" on November 8, 2013, on "Oops...":
After discussion, they [Fukushima Medical University staff] decided to adopt the plan they had been fleshing out, which was to use the neighborhood pharmacies. (1) People receive potassium iodide at the neighborhood pharmacies; (2) pills for adults, power for small children; (3) for small children, powder was to be dissolved in juice, since the powder was bitter.
If Yamashita OKed, this plan was to be suggested to the prefectural government. The Fukushima prefectural government had ample stock [of potassium iodide] and had the authority to instruct people to take it. This was an opportunity to distribute potassium iodide pills to the residents.
However, Yamashita rejected the plan, for the following reasons:
(1) The procedure was not in the manual by the Nuclear Safety Commission; (2) There was a danger that people would take a wrong dosage, and it would be hard to respond to the side effect; (3) there was no knowing if it was effective if mixed with drink.
As the president of Japan Thyroid Association, Yamashita's opinion carried weight. The plan to distribute potassium iodide that had been discussed at Fukushima Medical University since March 12 tapered off.
Yamashita reveals he was surprised by the fact that was beyond his imagination. The following is from our interview with Yamashita in June this year.
What surprised Yamashita was the SPEEDI simulation maps that the national government disclosed on March 23, 2011. At that time, the standard for taking potassium iodide pills was when the equivalent dose at thyroid was expected to reach 100 millisieverts. In the simulation maps, the areas where the equivalent dose would exceed 100 millisieverts extended far outside the 30-kilometer radius from the plant.
"I thought, 'Oops...'"
Radiation contamination far exceeded Yamashita's expectation.
"I had thought a nuclear power plant in Japan was properly equipped with filter or something to remove iodine and other nuclides. I never imagined such wide areas were contaminated."
This particular segment of "Trap of Prometheus" reads like a hit piece to put all blame on Dr. Yamashita regarding the debacle over potassium iodide pills that were never distributed.
Distributing potassium iodide pills on March 19, 2011 may have helped somewhat to protect the residents in Fukushima (at least) from the fresh release of radioactive materials from Fukushima I Nuclear Power Plant from March 20 to 23, 2011. But what would have mattered much, much more is if the residents were able to take potassium iodide before the reactors exploded and dry vents were carried out, with the latter apparently releasing much more radioactive materials than the explosions.
And that was all before March 15, 2011, and Dr. Yamashita didn't even arrive in Fukushima until March 18.
Who was responsible for ordering the distribution of the pills? The national government, and the Fukushima prefectural government. Instead of distributing the pills, what did they do? They accused the town of Miharu that distributed the pills and ordered the residents to take them of acting on its own without the government order. They also used the media to educate the viewers on the "danger" of potassium iodide pills, instead of danger of radioactive iodine uptake. (They continue to do this even today, and enough people are so convinced of the danger of potassium iodide pills that they furiously try to refute anyone who touts the benefit of taking them in a nuclear accident.)
Unlike Dr. Yamashita who didn't see the SPEEDI maps until March 23, 2011 like the rest of us, the ministers of the Kan administration, bureaucrats at METI and Ministry of Education, the governor of Fukushima Prefecture and officials at the Fukushima prefectural government, and even the municipal government heads in Futaba, Okuma, and Tomioka in Fukushima had either SPEEDI simulation maps or TEPCO's simulation maps or both from the beginning of the accident. They all sat on the data. Or worse. In case of the Fukushima prefectural government, they deliberately deleted the emails that contained SPEEDI simulation maps.
There is one good thing I would say about Dr. Yamashita. He is honest. As Asahi reports, he readily admitted he had made a potentially grave mistake when he saw the SPEEDI simulation maps. No self-conscious and politically savvy scientist would say things like "Oops..." in an interview for a national paper. When he gave lectures to the residents in Fukushima Prefecture in the populous middle-third Nakadori region starting March 21, 2011, telling them the effect of radiation won't come to people who are smiling, his face and mannerism as he delivered the speech revealed he was at least uncomfortable, probably very worried.
That lecture series started right when there was something happening in Reactor 3 causing the release of a significant amount of radioactive materials, and spikes in radiation were observed in wide areas in Tohoku and Kanto (March 20 - 23, 2013). Dr. Yamashita continued telling the Fukushima residents there was nothing to worry about, after he saw the SPEEDI maps and realized his assumption was very wrong.
Dr. Yamashita has since returned to Nagasaki University, though he still is the special advisor on radiation risk management for Fukushima Prefecture.