Tuesday, July 5, 2011

More on the NSC Disclosure of Radiation Survey on Fukushima Children in Late March

(The original post is here.)

Tokyo Brown Tabby found a one-page document (no detailed data) that Japan's Nuclear Safety Commission created on May 12 and last modified on May 13 that simply says:

"Yes, we tested 1,080 children aged 0 to 15, and no one exceeded the threshold of dose equivalent of 100 millisieverts."

According to Tabby, the NSC person said:

"It's not that we withheld this information, but nobody asked us about this already-uploaded-data until a reporter from Tokyo Shinbun did at the press conference on July 4. "

So, I decided to look up three additional documents: the transcript of the press conference on July 4, and the NSC minutes of the meeting on May 12 and the transcript of the press conference on May 12.

First, the transcript of the July 4 press conference. It's in Japanese only, but I can assure you (and you can verify it if you read the language) that there is NO TOKYO SHINBUN reporter asking the question of thyroid radiation of Fukushima children. The NSC person that Tabby talked to did say there was a reporter from Tokyo Shinbun who asked that question.

Conclusion: the NSC edited out the reference from the transcript.

Second, the NSC minutes of May 12 meeting, to see how this information was handled by the Commissioners in the meeting.

The segment where the Commissioners discussed the radiation exposure survey for children in Fukushima reads as if the the survey was done as an exercise to see if SPEEDI simulations had been accurate and if they had indeed predicted the radioactive fallout as would be revealed by the survey. And since no child exceeded 100 millisievert dose equivalent, nothing needed to be done further:

班目委員長: どうもありがとうございました。他に。そうしたらもう1件、SPEEDIを活用したというか、この結果を活用した例といった方がよろしいのかもしれません。資料第4-3号がございます。これは、事務局の丸山安全調査管理官から、ご説明をよろしくお願いいたします。

Madarame: Thank you very much. Is there anything else [to add]? [Seeing there was none] In that case, here's another example of using SPEEDI, or I should say using the [simulation] results of SPEEDI, as the Reference No. 4-3 [that's the one-page document]. Mr. Maruyama will explain.

○説明者(丸山安全調査管理官) 資料第4-3号に基づきご説明を申し上げます。「福島県における小児甲状腺被ばく調査結果について」ということでございます。平成23年3月23日のSPEEDIの試算を踏まえ、原子力安全委員会緊急技術助言組織より、特に、感受性の高い小児への健康影響をより正確に把握するため、屋内退避区域あるいはSPEEDIを用いた試算(3月23日公表分)で甲状腺の評価線量が高いと評価された地域の小児の甲状腺線量の実測を原子力災害対策本部事務局あてに依頼した。その結果、原子力災害現地対策本部において、いわき市、川俣町、飯舘村において、小児甲状腺被ばく調査を実施した。

Maruyama: Allow me to explain the data, the Reference No.4-3 titled "The survey result of the thyroid gland radiation in children in Fukushima Prefecture". Based on the SPEEDI simulation on March 23, 2011, the NSC advised the Headquarters for the Nuclear Disaster Countermeasures [which was set up by the national government] to conduct the actual survey of children in the areas which the SPEEDI simulation showed potentially high levels of dose equivalent radiation on thyroid gland and in "stay indoors" areas. The Headquarters for the Nuclear Disaster Countermeasures did the survey accordingly in Iwaki City, Kawamata-machi, and Iitate-mura.


No.1, the subjects. 134 children were surveyed on March 26 and 27 in Iwaki City, 647 children on March 28 to 30 in Kawamata-machi, 299 children on March 30 in Iitate-mura. Total of 1,080 children were tested. It's in the footnote but the survey done in Kawamata-machi on March 24 was excluded because of the high background radiation.

2)測定方法、でございます。「緊急被ばく医療ポケットブック」(平成17年3月 財団法人原子力安全研究協会)の「頸部甲状腺に沈着した放射線ヨウ素の測定」に基づき、NaIシンチレーション式サーベイメータを用いて実施したということでございます。

No.2, method of measurement. It was done using the NaI scintillation survey meter based on the manual issued by the Nuclear Safety Research Association [which was set up as a government association in 1964] in 2006.


No.3, the result. The subjects were aged zero to 15. Among 1,080 children tested for thyroid gland radiation, there was no one who exceeded the screening level of 0.2 microsievert/hour (dose equivalent of 100 millisieverts at thyroid gland for 1 year old). That's all.

○班目委員長 どうもありがとうございました。それではこれにつきまして、何かご質問、ご意見はございますでしょうか。よろしゅうございますか。これは実は、こういう形で、紙で出すのは初めてかもしれませんけれども、実際には4月の時点で既にこのような調査が行われ、特に問題のある結果は出ていない、ということは公表済みだということでございます。改めて、こういうきちんとした形で発表しておきたいということで、今日の日付になっているというものでございます。よろしゅうございますでしょうか。それでは大変ありがとうございました

Madarame: Thank you very much. Is there any question on this issue? No? About this survey, this may be the first time it was published on paper, but I've been told that it was announced in April that there was such a survey, and there was no problem. But we wanted to publish in a more formal way, so it was published with today's date. Is there any comment or questions? Thank you very much.

So they tested children in Kawamata-machi on March 24, one day after the SPEEDI simulation showed high radiation levels. If they were high levels, they weren't reported as such on March 25. Asahi Shinbun that day said 0.24 microsievert/hour was detected from one boy in Kawamata-machi, and the number was much lower than 2 microsieverts/hour (?), so it was safe, no problem. I have no idea where Asahi came up with the "2 microsieverts/hour" number as the threshold number.

If I remember right, Kawamata-machi had been receiving the evacuees from the areas closer to the plant since March 12. So had Iitate-mura.

Also, Maruyama or Madarame didn't mention 45% of children had the radiation exposure at thyroid gland in the May 12 meeting. That information clearly didn't come out until the Tokyo Shinbun reporter asked on July 4.

Third, the transcript of the May 12 press conference. This one's easy. IT DOES NOT EXIST. The NSC started to publish the transcript of the press conference from May 19. Prior to May 19, there was no transcript, there was no recording of the press conference. How convenient. We would never know whether the Commissioners even mentioned anything about the survey in the press conference, or whether there was any reporter who did ask.


Fall out man! said...

>>>"It's in the footnote but the survey done in Kawamata-machi on March 24 was excluded because of the high background radiation."

Does that mean that if the radiation figures are higher than they would like to report, then they simply exclude that data?

Anonymous said...

"Does that mean that if the radiation figures are higher than they would like to report, then they simply exclude that data?"

That means exactly that, see robot sample analysis of building 3 withheld.


Anonymous said...

if the dose goes down i.e. no further release like in March , then the dose may be low enough to be safe. After March, who knows without measurement. Why no zinc for kids in March, though?

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