#Radiation in Japan: Decontamination Work in 70 - 130 Microsieverts/Hr Location in Fukushima

What is the point here?

Contract workers pile up plastic bags containing highly contaminated soil on the ground in one of the most contaminated area in the entire Fukushima Prefecture. (Photo from Yomiuri)

This particular location, Ottozawa District of Okuma-machi (where Fukushima I Nuclear Power Plant is located), regularly measures well over 100 microsieverts/hour in air radiation 1 meter off the ground.

Just 6 days ago (2/3/2012 in Japan), the air radiation was 130 microsieverts/hour in Ottozawa District, according to Fukushima Minyu. The newspaper says the levels of radiation haven't changed much.

At 130 microsieverts/hour, if one stands there 24/7 for a year, it will be 1138.8 millisieverts, or 1.138 sievert, per year. (Only Professor Wade Allison may say it is safe.)

To say Ottozawa District is "inside the 20 kilometer radius no entry zone", as Yomiuri in the article below does, is a severe understatement. Ottozawa is within 3 kilometers from Fukushima I Nuclear Power Plant. Some of the public facilities of Ottozawa District are right up against the plant compound.

From Yomiuri Shinbun (2/10/2012):

政府は９日、東京電力福島第一原発から半径２０キロ・メートル圏の警戒区域にある福島県大熊町夫沢(おっとざわ)地区で、除染モデル事業で出た廃棄物を仮置き場に搬入する様子を報道関係者に初めて公開した。

On February 9, the national government invited the press for the first time to the temporary storage site of the waste from the government's decontamination model project. The storage site is located in Ottozawa District in Okuma-machi in Fukushima Prefecture, inside the 20-kilometer radius "no entry zone".

　公開されたのは第一原発から約３キロ・メートルにある町営野球場グラウンドの２か所。この日の夫沢地区の放射線量は高い所で毎時７０マイクロ・シーベルトを超えていた。国の調査地点の中では最高値だ。

Two locations on the town's baseball ground, 3 kilometers from the plant, were shown to the press. The radiation levels in Ottozawa District on February 9 exceeded 70 microsieverts/hour in some locations. The radiation levels [in Ottozawa District] are the highest among the locations regularly monitored by the government.

　作業員は防護服にマスク姿の重厚ないでたちで、汚染された土や草などが入った約１トンの袋を次々と積み上げていた。作業員の１人は「防護マスクは息苦しいし、ゴム手袋だから手がかじかんで重労働」と話した。

The workers in protective clothing and face masks were piling up 1-tonne bags of contaminated soil and vegetation. One of the workers said, "The protective mask is suffocating, and my hands are freezing because of the rubber gloves. It's a hard work."

　袋を置く地面には遮水シートなどが４層にも敷いてあった。袋を積み上げた後はさらに３層のシートなどで覆い、最後には土をかぶせる予定だ。事業を受託する日本原子力研究開発機構の担当者は、「放射線は９８％遮蔽できる」と説明した。

Four protective layers, including water-shielding sheet, were laid on the ground where the bags were being put. After the bags are piled up, they will be covered with 3 layers of sheet, which they will be covered with dirt. The Japan Atomic Energy Agency who contracted the decontamination work explains, "98% of radiation [coming from the bags] can be shielded."

Well, there is no information in the article what's the radiation coming from the bags that contain extremely contaminated soil right near the nuke plant. The workers, as far as Yomiuri reports, are not concerned about radiation but inconvenience of having to work in the protective gear which does not shield radiation.

There is no information on whether the workers are JAEA employees or the contract workers, but judging from the remark by one of the workers in the article, it is likely to be the latter. I hope they were fully informed of the risks and paid accordingly, but hope is a dirty word.

My uneducated guess is that the radiation coming off the bags can be measured in millisieverts, not in microsieverts.

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