Japan earthquake - contamination & consequences outside Fukushima NPP

westfield

Yes, if someone like google had geiger counters on their streetview cars it might reveal some interesting data.

tsutsuji

http://www.fnn-news.com/news/headlin...N00210584.html & http://www.yomiuri.co.jp/national/ne...OYT1T00553.htm At the Setagaya Hachiman'yama district supermarket, the excavation work will start on 1 November. A ward official said the "excavation work, etc. " should be completed in one or two weeks' time. On 31 October afternoon, protective sheets are laid out for dust release prevention. According to ward officials, there are only two radiation sources: the 170 μSv/hour pavement and the other location where 110 μSv/hour was found. The nature of the radioactive substances is still unknown.

zapperzero

Aum Shinrikyo had a center in Setagaya for a long time. They were stockpiling deadly bacteria and chemicals... why not some radioactive materials for a dirty bomb too? It would make sense to keep the stuff in many small stashes, no?

http://www.japantimes.co.jp/text/nn20020619b6.html

tsutsuji

Tokyo:
http://mainichi.jp/select/jiken/news...40132000c.html[Setagaya] Until the supermarket was started in 1999, there was a parking lot. As written on the commemorative stone, in 1955 ~ 1973 there was a junior college training students into agricultural managers. Until 1986 there was a facility belonging to an organization involved in the training of foreigners into agricultural managers. A 66 year old graduate says "it was not supposed to have anything to do with radioactivity". An employee of the organization said "we did not use radioactive substances".

http://www.tamapre.jp/news/2011/10/2...t-in-tama.html A 0.44 μSv/h (5 cm above ground), 0.17 μSv/h (50 cm above ground) 0.12 μSv/h (1 m above ground) μSv/h hotspot was found, made no-entry, on 27 October in a school in Tama city.

Kanagawa:
http://news.kanaloco.jp/localnews/article/1110310014/ Sagamihara city announced on 31 October that 13 spots higher than 0.23 μSv/h, the highest one being 0.63 μSv/h (5 cm above ground), were found and cleaned in 7 schools.

Fukushima:
http://www.yomiuri.co.jp/kyoiku/news...OYT8T00810.htm As a result of the lifting of the evacuation-prepared zone, the 229 students of Minamisoma's agricultural high school are leaving their temporary school buildings in Soma, and going back to their old school in Minamisoma. As a result of the cleaning work which has been performed since August, radiations inside classrooms were brought to 0.12 ~ 0.18 μSv/h. Measurements will be performed twice a day in places such as classrooms and schoolyards. Outdoor club activities will be practised with long sleeves, trousers and masks. Agriculture practice will be restricted to practice inside greenhouses or vinyl houses. During the parent-teacher conference, parents asked "What are the countermeasures against aftershocks or tsunamis?" or "are you going to ask the students to remove grass or fallen leaves, on which radioactive substances can easily adhere ?", but there was no voice against the move.

tsutsuji

Tokyo:
http://www.asahi.com/national/update...111010480.html [Setagaya] The ministry of education and science said there was a high probability that the source is radium 226. The characteristic radiation of radium was detected.

http://mainichi.jp/select/science/ne...40026000c.html An open bottle with a 40 mSv/h radiation was found at a 40 cm depth below the 110 μSv/h Setagaya hotspot.

Fukushima:
http://www3.nhk.or.jp/news/genpatsu-...101/index.html The ministry of education and science released tellurium and silver maps. Where the concentration is the highest, tellurium accounts for 0.03% of Cs-137 and silver for 0.16% of Cs-137.

http://radioactivity.mext.go.jp/ja/d...600_103120.pdf Tellurium and silver maps

http://www.yomiuri.co.jp/national/ne...OYT1T01107.htm Fukushima City released the results for 3 of the 6 private homes where decontamination efforts were carried out starting on 18 October in the Onami district (radiation before and after cleaning in μSv/h at 1 cm above ground) :

Gravel yard: 　3 to 0.7 (-76.7%)
In front of house entrance: 2.7 to 0.7 (-74.1%)
Tilled roof: 1.4 to 1.1 (-21.4%)
Asphalt yard: 1.8 to 1.4 (-22.2% "only")

Bodge

Where has the Silver come from?

Neutron capture by silver-109 from the reactors?

Is silver in the control rods?

Bodge

The science ministry is saying that the 40 millisievert source is buried radium-226.

Why would someone keep burying this around Setagaya?

I imagine it is expensive stuff?

Astronuc

Silver is a fission product. Silver is used in PWR control rods in Silver (Ag) - Indium (In) - Cadmium (Cd) or AIC control rod. BWRs typical use B4C and possibly Hf, depending on the control blade design, and the neutron absorbers are cladding in high purity (and low Co) 304 stainless steel.

Marita

Just a guess but during WW2 there was a lot of "Cottage Industry" in Japan , maybe there were some Radium Dial painting going on in those areas and the "Vials" were just lost at the end of the war and wound up buried where they are found today. But I think if they were leftovers from the war they would have pretty much decayed to lower levels by now.

I don't think the war remains is very likely but I also don't think there is some deranged Radium Vial planter going about hiding them in random locations either. It would be nice to see some information on the history of the locations where there were found. Japan has enough to contend with without these "hot spots" popping up randomly.

Shinjukusam

Well, the half-life of R226 is 1601 years; the war wasn't that long ago.

zapperzero

Setagaya-ku is where Aum Shinrikyo was based for some years. I can't think of anything else.

Shinjukusam

Well, it's also the most populated (1st or 2nd) of the 23 wards of Tokyo, so there is a whole lot that took place there. I don't think it would be related to Aum, they tended to go for much quicker acting methods...

joewein

Its use really declined from the 1950s. That turned an asset into a liability.

Parts of Setagaya still had a more rural character then. Even now the Tokyo University of Agriculture has a major campus here, with fields and greenhouses.

Setagaya is relatively affluent, so there may be more than a few families that owned industrial companies that might have used radium in the past. Also, higher incomes may lead to a higher rate of possession of dosimeters, hence a better chance of detection of such hotspots than elsewhere.

tsutsuji

Tokyo:
http://sankei.jp.msn.com/affairs/new...8280015-n1.htm [Setagaya] Inside the bottle there is a brown color solid believed to be radium 226. Because the radiation was 2 mSv/h after removing the bottle, it is feared that the earth is polluted by things such as scattered glass. Removal work will be continued on 3 November. As a result of a new survey performed today, 8 μSv/h was found in the supermarket's selling space. It is believed that there are multiple radiation sources. Until now only the 110 μSv/h spot near shop entrance was dug. The 170 μSv/h spot near the concrete block wall will be dug in turn.

http://mainichi.jp/select/jiken/news...40041000c.html The bottle is broken. Some earth was removed together with the bottle. Radioactive substances and glass are remaining. Radiations will be further lowered by removing more earth. An 8 μSv/h spot and a 12 μSv/h spot were found close to the digging place. A 2 μSv/h one was also found on the street on the western side of the supermarket premises.

http://news.tv-asahi.co.jp/ann/news/...211102021.html video of the digging.

Martin Peters

Is the level of radiation of the soil, glass shards, and other debris left in the hole after the bottle and it's brown contents were removed really 2 MILLI Sv/HR? This is not an inadvertent slip of the wrong "m"?

rowmag

No obvious typo.
It was 110 micro-Sv/h measured on the surface before they started digging down.
The bottle (which had no cap) was 40 mSv/h.
2 mSv/h was what remained in the dirt after removing the bottle.

tsutsuji

http://www.asahi.com/national/update...111020803.html After removing the bottle, the 40 mSv/h (one mili is ten micro) dropped to 2 mSv/h. After removing earth and scattered glass from the surroundings, it further dropped to 25 μSv/h. The bottle has an about 10 cm diameter and an about 30 cm height. It is broken and was put together with the adhering earth in a special sealed container. It does not bear any label, but looks rather old.

http://www3.nhk.or.jp/news/html/2011...695301000.html (with video) in a 50 m range around the supermarket, 15 new hotspots were found. The highest one is a 12 μSv/h on the parking lot. The radiation at 1 m above these 15 spots is not much higher than normal, but the ministry of education and science put sandbags on some of them as a radiation shielding countermeasure. A detailed investigation of the 15 new spots is currently being discussed.