Japan earthquake - contamination & consequences outside Fukushima NPP

[tsutsuji]

http://sankei.jp.msn.com/region/news/111011/szk11101118100003-n1.htm Dried shiitake mushrooms with 599 Bq/kg (above the 500 Bq/kg limit) have been found in Izu (Shizuoka prefecture). As a consequence all Izu shiitake sales are stopped. Some people propose to resume sales with a test on every box (20 kg), but nothing has been decided yet.

 

[tsutsuji]

http://mainichi.jp/select/today/news/20111012k0000e040065000c.html As the results of the final tests in Nihonmatsu and Miharu became known on 12 October, all the rice grown in Fukushima prefecture has been found to be below the 500 Bq/kg limit and is allowed for distribution. Rice growing had been forbidden in the three zones (the restricted zone, the planned evacuation zone and the evacuation prepared zone) .

http://new-fukushima.jp/result.php?kind_detail%5B%5D=%E7%B1%B3%28%E6%9C%AC%E8%AA%BF%E6%9F%BB%29&kind_detail%5B%5D=%E7%B1%B3%28%E4%BA%88%E5%82%99%E8%AA%BF%E6%9F%BB%29&start_year=2011&start_month=8&end_year=2011&end_month=10&search_area=&hyoji=all&x=28&y=24 The detailed rice tests results.

http://mainichi.jp/select/weathernews/news/20111012dde041040016000c.html The Yokohama City municipality is carrying out strontium tests in 3 locations in Kohoku ward. From March to May strontium had been found in Fukushima prefecture: 250 Bq/kg in Namie (29 km away from the plant), 120 Bq/kg in Iitate (36 km away), and 7.7 Bq/kg in Fukushima City (62 km away).

 

[joewein]

Near an elementary school in Tsurumaki, Setagaya-ku, Tokyo as much as 3.35 uSv/h have been measured, according to http://www3.nhk.or.jp/news/html/20111013/t10013231511000.html" for a report.

It was also observed that the reading was higher off the ground than at ground level, which is kind of consistent with the failure of the steam cleaning to significantly reduce radiation. A test by experts then showed that the radiation comes off the side of adjacent properties, such as fences and walls (if my Japanese is good enough), with an even higher reading of 3.35 uSv. Both the original reading and the latest reading are higher than at the village headquarter at Iitate mura in Fukushima prefecture.

I also live in Setagaya, about 2.5 km from that location.

 

[joewein]

The news from Tsurumaki, Setagaya took a surreal twist when the city announced that the unusually high radioactivity measured out in the street was emanating from a bottle kept inside a cardboard box in a house at that street.

No explanation was given for why that bottle was there, what exactly it contained and how come it was kept in that home, except that the radiation was not related to the Fukushima accident.

See: http://www3.nhk.or.jp/news/html/20111013/t10013243881000.html"

 

[swl]

Some good news about the triple meltdown. Had there been no accident in Fukushima, that radiation source in Setagaya might have gone undetected for years or decades.

 

[joewein]

There was a playground across the street from that house and a kindergarden and a pre-school for toddlers (hoikuen) nearby, as well as an elementary school.

It's the house at the corner of the intersection, surrounded by trees, in the middle of this map:

http://g.co/maps/fx9uc

The bottle was in a cardboard box inside a wooden box under the floor of the house, which was uninhabited.

 

[tsutsuji]

http://mainichi.jp/select/wadai/news/20111014k0000m040083000c.html The dimensions of one glass bottle is diameter 5 cm x height 7 cm, and there are 3 or 4 thin and high glass bottles. The 30 μSv/h upper limit of the measuring instrument was exceeded. The owner says "it is the first time I see those [bottles]". The radiation in the area dropped to 0.1 to 0.3 μSv [per hour, I guess] after the ministry of education and science employees put the bottles in a lead containment.

http://mainichi.jp/select/wadai/news/20111014k0000m040083000c2.html The Funabashi City municipality (Chiba prefecture) announced on 13 October that 0.91 μSv/h was found in a location in a park where a citizen group had found 5.82 μSv/h on 12 October. At a ceramic-made grass burning equipment it was 1.40 μSv/h. The spots have been designated as no entry zones and surface removal has been undertaken. 1.40 μSv/h is the highest record so far in that city. The municipality "does not want to treat lightly" the measurement difference with the citizen group, which is higher than the normal variation that is observed in one day's time.

http://radioactivity.mext.go.jp/ja/1910/2011/10/17485.pdf Niigata and Akita helicopter survey results.
http://radioactivity.mext.go.jp/ja/5000/2011/10/5000_1013.pdf Aichi helicopter survey plan.

TBS video news about Setagaya, made before discovering the bottles. About the helicopter surveys, it is explained that helicopters display mean values, and are not able to detect small hot spots. Then there is a report about a junior high school in Ota ward, where 1.01 μSv/h was found. 13 among 37 schools in Ota ward were found with "high levels" of radiations. Then there is a report about the 1.40 μSv/h spot in Funabashi. Then it is about the schools and kindergartens in Karuizawa, Nagano prefecture, where a survey found results between 0.05 and 1.7 μSv/h. Then the video goes back to Setagaya with a university professor detecting radium-226 with a 90% probability with his measuring instrument, and suspecting the radiation is not Fukushima-related.

 

[Bodge]

"in Funabashi, city workers cordoned off an area near a children’s theme park when a citizens’ group detected a level there of 5.82 microsieverts per hour"

http://www.washingtonpost.com/world...around-tokyo/2011/10/13/gIQA6XqHhL_story.html

Maybe there are radioactive bottles buried everywhere

 

[tsutsuji]

http://new-fukushima.jp/result.php?kind_detail%5B%5D=%E3%82%B7%E3%83%AD%E3%83%A1%E3%83%90%E3%83%AB&start_year=2011&start_month=8&end_year=2011&end_month=10&search_area=&hyoji=all&x=25&y=15 In Iwaki, Fukushima prefecture, shiromebaru fish (Sebastes cheni) caught on on 8 September was found with 1200 Bq/kg of Cs-137 and the one caught on 5 October had 420 Bq/kg.

http://www.asahi.com/national/update/1014/TKY201110130770.html Picture of the Setagaya bottles. The picture caption reads "tens of bottles where radioactive radium 226 was found. Some of them are filled with powder".

Another TBS video saying that radium was detected from the Setagaya bottles and that the ministry of education and science believes for this reason that this event is not related to Fukushima Daiichi. The video contains no precise explanation about the contents of the blue box that is carried from the house to the car.

http://mainichi.jp/area/tokyo/news/20111012ddlk13040260000c.html 208 measurements were made from 6 to 11 October 5 cm above ground below rain gutters near flowerbeds in 25 primary schools, 12 junior high schools, 5 kindergartens and 1 nursery in Ota ward, Tokyo. 30 measurements at 13 of these schools are above the 0.25 μSv/h limit.

 

[zapperzero]

http://new-fukushima.jp/result.php?kind_detail%5B%5D=%E3%82%B7%E3%83%AD%E3%83%A1%E3%83%90%E3%83%AB&start_year=2011&start_month=8&end_year=2011&end_month=10&search_area=&hyoji=all&x=25&y=15 In Iwaki, Fukushima prefecture, shiromebaru fish (Sebastes cheni) caught on on 8 September was found with 1200 Bq/kg of Cs-137 and the one caught on 5 October had 420 Bq/kg.

That's... a lot. Are these fish bottom-feeders?

 

[tsutsuji]

http://www.yomiuri.co.jp/national/news/20111013-OYT1T01038.htm The radiation on the top of the Setagaya bottles was 600 μSv/h. At the bottom of a tree, 8.40 μSv/h. On the wall of the building, 18.6 μSv/h.

That's... a lot. Are these fish bottom-feeders?

http://ja.wikipedia.org/wiki/メバル Unlike kasago (Sebastiscus marmoratus) it does not stay on the bottom but also swims in shoals around reef. Sometimes they are also treading water and hovering along vertical rock walls.

 

[joewein]

"in Funabashi, city workers cordoned off an area near a children’s theme park when a citizens’ group detected a level there of 5.82 microsieverts per hour"

http://www.washingtonpost.com/world...around-tokyo/2011/10/13/gIQA6XqHhL_story.html

Maybe there are radioactive bottles buried everywhere

Maybe not:

False alarm in Funabashi

Staff report

Measurements by a citizens' group of high radiation at a park in Funabashi, Chiba Prefecture, proved to be incorrect, the city said Thursday.

The group reported readings of 5.82, 2.1 and 1.79 microsieverts per hour at three locations in Anderson Park, but the city measured 0.91, 1.40 and 0.79 microsierverts per hour at the same spots Thursday. (http://search.japantimes.co.jp/cgi-bin/nn20111014a1.html" )

 

[tsutsuji]

I think the Japan Times article is biased. 1.4 μSv/h is still high compared to the 0.25 μSv/h standard for schools. And as mentioned in the Mainichi article I mentioned above, the action of the citizen group was followed by the municipality cleaning the hot spots, so it was useful. Also, the Mainichi article gives me the impression that the municipality is trying to have a trusting relationship with the citizen group, so I don't believe that the municipality attacked the citizen group by saying that the citizen group's measurement is "incorrect" or "false". [sorry if this belongs to the "more political thread"].

 

[joewein]

1.4 μSv/h is still high compared to the 0.25 μSv/h standard for schools.

It is indeed, but also not entirely surprising if it was an incinerator for grass, since grass already tends to collect fallout and incinerating organic matter would concentrate the dose.

On the 5.82 vs. 0.91 microsieverts per hour, it's a large difference and it's to their credit that the city is not just brushing it off as a measuring error on behalf of its citizens.

BTW, I ordered a Ukrainian-made dosimeter on eBay yesterday to start collecting radiation data around where I live. While Setagaya and most of Tokyo generally has fairly low levels, I have also been hiking in the remote mountains of Okutama recently, which according to the helicopter maps are the more highly affected parts of the Tokyo Metropolitan area, along with the eastern parts bordering on Northern Chiba.

 

[Jim Lagerfeld]

http://ja.wikipedia.org/wiki/メバル Unlike kasago (Sebastiscus marmoratus) it does not stay on the bottom but also swims in shoals around reef. Sometimes they are also treading water and hovering along vertical rock walls.

Interesting. So far, the worst contamination in fish has mostly been from sandlance, skate and flounder. All bottom dwelling, and eating filter feeders like small shrimp, crab, worm. Mebaru are but are much more predatory.

BTW, I ordered a Ukrainian-made dos...ted to hear how you get on with your counter!

 

[Bodge]

I just got some results from some soil I collected. Total cesium soil from open areas ranged from a couple of hundred bq/kg in my garden in Nakano to a couple of thousand in a Nagareyama playground.

I also collected some material from nearby drains, which ranged from about a thousand bq/kg in Nakano to over ten thousand bq/kg in Nagareyama.

I'd be interested to hear how you get on with your counter!

Where any other isotopes tested for?

"where's there's cesium there's strontium" AFAIK

 

[tsutsuji]

http://www.tokyo-np.co.jp/article/tokyo/20111014/CK2011101402000023.html Every Tokyo ward is responding to the insecurity feeling aroused by the Setagaya events. Suginami ward, which answered to 65 enquiries until 4 PM, is planning to perform additional measurements in children centers and parks, beyond the more than 500 locations already tested. Toshima ward answered to 14 enquiries, and will go on with the weekly testing at the same locations as before in primary and nursery schools. The maximum so far was 0.21 μSv/h. Chiyoda ward has started planning a survey of the paths used by children on their way to school. Koto ward received a few enquiries, but not as many as when highly contaminated Earth was found in Kameido in May. Ota ward has set at 0.25 μSv/h the value above which the ward would start its own survey. Locations such as flowerbeds close to rainspouts with high radiations have been marked as no entry zones in 13 Ota ward schools. In Kita ward, 1.01 μSv/h was found behind a sport warehouse and the surroundings were made a no-entry zone, while Earth removal is under study. 5 additional measurements will be made outside the schoolyards of schools, nursery schools and kindergartens. Citizen groups in Katsushika ward will explain their findings, including 8 locations above 3 μSv/h and 56 locations above 1 μSv/h, to ward officials on 18 October. Theses measurements were made mostly at private facilities which have not been surveyed by the ward so far.

 

[swl]

I just got some results from some soil I collected. Total cesium soil from open areas ranged from a couple of hundred bq/kg in my garden in Nakano to a couple of thousand in a Nagareyama playground.*

I also collected some material from nearby drains, which ranged from about a thousand bq/kg in Nakano to over ten thousand bq/kg in Nagareyama.

*I would be very interested in knowing how you tested your soil samples to determine Bq/kg along with the specific isotopes.

I have found shrubs at Soka Koen measuring as high as 0.8 uSv/h and a roof at our local bunka center that has dirt pooled in a low spot that measures 0.75 uSv/h.*
The soil in our garden (in Soka,
Saitama) dropped from 0.2 to 0.15 uSv/h after tilling, but we still have piles of grass and leaves that are as high as 0.4 uSv/h. I'm particularly interested in knowing the isotopes and Bq/kg of the park and bunka center contamination as I'm reluctant to report it to them just to have them laugh at my Ukranian GM counter.*

 

[tsutsuji]

TBS video of the 1.01 μSv/h find in Kita ward.

http://mainichi.jp/select/jiken/news/20111014ddm041040124000c.html picture of hotspot cleaning in Funabashi

TBS video showing the Setagaya bottles being carried out of the house in yellow drums.

 

[Bodge]

Great article from the NYT on contamination in Tokyo and the Japanese media's complicity in this debacle.

http://www.nytimes.com/2011/10/15/world/asia/radioactive-hot-spots-in-tokyo-point-to-wider-problems.html?_r=1

[pg2]

"Some of the results were shocking: the sample that Mr. Hayashida collected under shrubs near his neighborhood baseball field in the Edogawa ward measured nearly 138,000 becquerels per square meter of radioactive cesium 137, which can damage cells and lead to an increased risk of cancer."

Dusty game, baseball:

 

[Jim Lagerfeld]

*I would be very interested in knowing how you tested your soil samples to determine Bq/kg along with the specific isotopes.

I posted the soil samples by regular post to the US where they were counted by a volunteer using a HPGe detector properly calibrated with a prepared cesium 137 source.

Where any other isotopes tested for?

The test focused on cesium 134 and 137 only, and as far as I know detecting strontium accurately requires a different setup completely.

As far as the cesium isotopes go, the ratio of 137 to 134 was very similar to the other results reported so far, the highest sample tested about 6500 bq/kg 137 + 5700 bq/kg 134. I suspect the strontium is everywhere, between 1:300 and 1:500 with the cesium is what we've seen so far *reported in the media recently* in Yokohama.

If you live in Japan and would like to look at the specifics, perhaps send me a private message.

 

[Astronuc]

Where any other isotopes tested for?

"where's there's cesium there's strontium" AFAIK

Not necessarily. In the case of Chernobyl, perhaps, where there was atmospheric dispersion of particulates as well as gases and volatiles.

Strontium is a alkine Earth or group 2 element. Sr-90 precursor Rb-90 has a short half-life and a low yield, so it is more likely to bound in the fuel, or dissolved in the reactor water. The precursors for Cs, Xe and I are more abundant and bit longer lasting.

We are now at 217 days or 7 months from shutdown. About 75% of fission products have decayed through their respective chains to inert non-radioactive isotopes.

The main Cs isotopes are Cs-134 and 137, although there is Cs-135, produced from Xe-135, but Cs-135 has a half-life of 2.3 million years, so the specific activity (Bq/kg) is very low. Iodine-129 is another longer-lived radionuclide with a half-life of 15.6 million years, so it's specific activity is relatively low. After slightly more than 27 half-lives, I-131 activity should have decreased by a factor of 6.8E-9.

There is a nice little app, courtesy of energyfromthorium, which shows the radionuclides as a function of time after shutdown.
http://energyfromthorium.com/2006/07/14/new-visualization-tool-for-decay-chains/

http://www.energyfromthorium.com/javaws/DecayChain.jnlp

Update: I discovered that the default fission product distribution is for U-233. For U-235 and Pu-239 fast and thermal fission yields, one needs to 'right-click' with the mouse. A popup menu then gives some options on the display. Scroll to 'Select Fission Yield', and pick the desired set. Fast fissions from U-238 are represented as yellow lines over the bars of the other sets.

Sliding the cursor along time line will show which radionuclides are present in measurable quantities at that time. It is approximate however, but a reasonable estimate.

The vertical bars are the cumulative yield for the isotopes of that mass. The dots represent the particular isotopes. Moving the mouse cursor over plot will reveals each nuclide by Z,A with information on its half-life.

It would be nice to have the isotopes reported with the activities measured.


Update: I have attached the plots for U-235 and Pu-239 fission product distributions (from thermal fissions) for 7 months after shutdown.

 

[nikkkom]

Where any other isotopes tested for?

"where's there's cesium there's strontium" AFAIK

Wrong. Find Chernobyl contamination maps. They show very graphically that Sr deposition area is significantly smaller than Cs.

So, the opposite is true: Where's there's strontium there's cesium. Lots more cesium than strontium.

Therefore, mapping contamination is actually very easy: map Cs (easy - it's gamma active), determine evacuation zones based in Cs data alone, and all other nasty stuff is inside the Cs-contaminated area.

I'm not saying that strontium should be ignored.

But some seem to think that it is some kind of sneaky invisible death which can just appear hundreds of kilometers away from source, without accompanying cesium. It can't.

 

[Bodge]

Thanks for explaining the properties of Strontium.

If it is more likely to be dissolved in water, than dispersed by air, does that mean that the majority of Strontium produced has ended up in the sea/ground/basement water?

 

[Astronuc]

Thanks for explaining the properties of Strontium.

If it is more likely to be dissolved in water, than dispersed by air, does that mean that the majority of Strontium produced has ended up in the sea/ground/basement water?

The strontium would more likely be found in the water at the plant or in the sea, or deposited wherever the water took it. Some will still be in the fuel.

The exact state of the fuel is not known, i.e., how much melted, how much is still intact, and how much reacted with the cooling water and seawater.

Strontium has a melting point of 777 °C and boiling point of 1382 °C, and it tends to form oxides, SrO or in water, hydroxides. It is less volatile than Cs, which has a melting point of 28.44 °C and a boiling point of 671 °C. [data taken from www.webelements.com]

The addition of saltwater would have allowed elements like Cs and Sr to form chlorides, and those would be soluble in water.

 

[tsutsuji]

Great article from the NYT on contamination in Tokyo and the Japanese media's complicity in this debacle.

http://www.nytimes.com/2011/10/15/world/asia/radioactive-hot-spots-in-tokyo-point-to-wider-problems.html?_r=1

I don't think it is the greatest of articles. The use of "false alarm" language concerning the Setagaya bottles is strange. It is not a secret that Edogawa ward was more highly contaminated than other parts of Tokyo. It is shown on radiation maps including the most recent helicopter survey : http://radioactivity.mext.go.jp/ja/1910/2011/10/1910_100601.pdf I think the New York Times should have interviewed Edogawa ward officials or whichever administration or private institution is owning the baseball field. Has there been no measurement of radiations in that baseball field since March, apart from the measurement made by the citizen group ? The radiation measured at the baseball field of Rinkai Ballpark No1　- probably a different one: it is difficult to say as the New York Times does not provide the name of the baseball field - on 26-27 June was 0.15 μSv/h 1 m above ground and 0.15 μSv/h again at 5 cm above ground, according to the ward website at http://www.city.edogawa.tokyo.jp/shinsai/housyasen/kunai_sokutei_kekka/index.html . Has the "patch of dirt just yards from" the unidentified baseball field contamination been reported to ward officials ? How did they react ? Has the place been marked as a no-entry zone ? Why didn't the New York Times journalists go to the place with a dosimeter and take pictures ?

http://www.asahi.com/national/update/1015/TKY201110150155.html One of the Setagaya bottles was marked with "Japan Nocturnal Luminescence". There was a factory with that name, which made luminescent paint for ship and airplane instruments, but it was completely destroyed in the 25 May 1945 bombing of Tokyo.

http://sankei.jp.msn.com/affairs/news/111015/crm11101522430023-n1.htm It is possible that the bottles had been there since the construction of the house in the 1950s.

http://mainichi.jp/area/tochigi/news/20111015ddlk09040168000c.html One fourth of the area of Tochigi prefecture is concerned by the national standard that aims to bring radiation below 1 mSV/year. It is the area above 0.23 μSv/h on the helicopter map. The ministry of environment has yet to prepare detailed maps, but it is expected that Nasu, Nasushiobara, Otawara, Yaita, Shioya, Nikko and Kanuma are included. In Nasu the town has set as a priority to clean schools and the streets used by children going to school by the end of this year, with the goal of cleaning each hot spot higher than 0.5 μSv/h. In one place the radiation could not be brought lower than 0.3 μSv/h after surface removal. Then next year public facilities will be cleaned. "We want to build a 2-3 year middle term plan" a town official said.

 

[tsutsuji]

Fukushima prefecture:

(NHK) and http://www3.nhk.or.jp/news/genpatsu-fukushima/20111017/0700_suiteisagyo.html The first part of a health survey concerning 28000 people of Fukushima prefecture is late (the video shows the form people must fill indicating if they were indoors or outdoors or travelling, hour after hour, each day on 11 March and following days). The results - estimates of each person's radiation exposure - should have been sent to the people in mid-September, but entering the data into computers takes more time than expected. Sometimes people have forgotten to fill data such as the address of the place where they were evacuated to, and checking those missing data takes time. The survey will ultimately concern the whole Fukushima prefecture population.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20111017/2000_hinankuiki.html According to the last update of the roadmap, the revision of the planned evacuation zone, which depends on the completion of step 2, should be done this year, instead of in January as was originally planned. Tepco estimated the radiation released by the Daiichi plant to be 100,000,000 Bq/hour, which is one half of what it was one month ago, and amounts to an increase of 0.2 mSv/year or below at the border of the plant premises.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20111018/0455_zyosen.html Fukushima City is starting on 18 October its plan to bring in two years' time the radiation in the everyday life space to 1 μSv/h or below. It plans to clean public facilities and all 110,000 households. On 18 October, 360 households in the more highly contaminated Onami district will receive cleaning service from companies commissioned by the City: high pressure cleaning of roofs and gutters, Earth removal from gardens will be performed. The streets used by children going to school and the woods and hills near people's homes will also be cleaned. The city is commissioning companies to do the work in the more highly contaminated areas and when the work is more dangerous such as on roofs. In other cases the City expects the collaboration of the inhabitants and of volunteer groups. Finding the workforce is one problem. Another problem is finding how to dispose of the generated waste.

[Fukushima City] municipal government is considering removal of the leaf soil (soil made up of decaying leaves) within 75 meters of local properties, pending the consent of land owners -- significantly more than the forestry ministry's 20-meter guideline.
http://mdn.mainichi.jp/mdnnews/news/20111011p2a00m0na020000c.html "Residents near Fukushima mountains face nuclear recontamination every rainfall"

Tokyo:

http://sankei.jp.msn.com/affairs/news/111015/crm11101522400022-n1.htm Interview of a Tokyo housewife who joined a 5-6 member radiation checking citizen group: "I sacrificed the time I should spend with my family, but as this is for children, I must do it. Two months ago I measured 0.7 μSv/h near my home, and asked the administration to clean as quickly as possible, but I can't have this being done. One feels a difference of degree of commitment".

Yokohama:

http://www.asahi.com/national/update/1014/TKY201110140533.html On 14 October, Yokohama city confirmed the presence of strontium in two samples. The sample from Go-Chome area, Okurayama district - deposits in a street side ditch - was measured with 129 Bq/kg of Strontium 89 and Strontium 90 added together and 39,012 Bq/kg of cesium [137 or 134 or both added together is unclear]. The sample from San-Chome area, Shinyokohama district - deposits in a turned off fountain - was measured with 59 Bq/kg of Sr and 31,570 Bq/kg of Cs.

http://www.yomiuri.co.jp/national/news/20111014-OYT1T01201.htm The results from the third sample, taken on the same apartment building rooftop where a private laboratory had previously detected strontium, have not been publicly released because the agreement of the apartment building inhabitants could not be obtained.

In light of the latest discoveries, the municipal government plans to ask the central government to conduct checks in Yokohama for radioactive strontium. Checks for radioactive material are currently being conducted within a 100-kilometer radius of the nuclear plant.
http://mdn.mainichi.jp/mdnnews/news/20111017p2a00m0na019000c.html

Kawasaki (August - September):

Kawasaki City announced it measured 0.90 microsievert/hour at the side of the swimming pool in Hirama Park in Kamihirama, Nakahara-ku (special ward), exceeding the target level of 0.19 microsievert/hour set by the Ministry of Education and Science
(...) The citizen volunteer group "Peace and Smile Project Kawasaki" measured the near-surface radiation in this area on August 14, which measured 0.50 microsievert/hour at 5 centimeters off the ground. The group alerted the city.
http://ex-skf.blogspot.com/2011/08/high-radiation-right-next-to-childrens.html translating http://news.kanaloco.jp/localnews/article/1108180048/ (18 August)

http://news.kanaloco.jp/localnews/article/1108230025/ (23 August) Kawasaki city checked the accumulations of leaves in 35 parks in response to the discovery of high levels of radiations in Hirama park. 0.20 μSv/h (above the 0.19 μSv/h national target value) was found in Nakamaruko Ryokudo. All other locations were below the target value. The 0.20 μSv/h measurement was made 5 cm above the leaf accumulation, close to the center. At the border between the leaves and the path where people walk, it was 0.12 μSv/h.

http://news.kanaloco.jp/localnews/article/1108310014/ (31 August) 34 locations in parks were checked again. The measurement at the location where 0.20 μSv/h had previously been found, was 0.16 μSv/h.

http://headlines.yahoo.co.jp/hl?a=20110908-00000028-kana-l14 (8 September) 0.41 μSv/h (above the 0.19 μSv/h national target value) was found 5 cm above accumulated fallen leaves in Sakuragawa park, Kawasaki city announced. The 4 m² area was covered with a sheet and marked as a no entry zone. It is planned to repeat the measurement in the future.

 

[Sorai]

Fukushima prefecture:
Tepco estimated the radiation released by the Daiichi plant to be 100,000,000 Bq/hour, which is one half of what it was one month ago

Is this measured in I-131 equivalents or just directly cesium releases without any conversion?

Sorry if this has been asked before.

 

[Astronuc]

Is this measured in I-131 equivalents or just directly cesium releases without any conversion?

Sorry if this has been asked before.

100,000,000 Bq/hour is a measure of decay rate, regardless of the isotope. It should be Ʃλ_iN_i/V, where λ_i is the decay constant of radionuclide i, N_i/V is the concentration of radionuclide i in whatever volume is released - whether air/steam or water.

There should be little I-131 (~8-day half-life) left to release, since this should have decayed away. The longer-lived I-129 would be present, but with low activity. It's possible that Kr-85 would be in steam or air released. In the water would be Cs-134, Cs-137 and Sr-89, Sr-90, along with Ru-103, Ru-106, and perhaps radioisotopes of Se, Sn, Sb are likely in the effluents. Most other remaining isotopes (of Y, Zr, Nb, Ce, Pm, Sm, Eu) should be bound as oxides in the fuel, although some may have leached out. It's also possible that the coolant contains activitated corrosion products from core structural materials. And there may be some transuranics.

It would help if they itemized the nuclides they believe are responsible for the activity.

 

[clancy688]

100,000,000 Bq/hour is a measure of decay rate, regardless of the isotope. It should be Ʃλ_iN_i/V, where λ_i is the decay constant of radionuclide i, N_i/V is the concentration of radionuclide i in whatever volume is released - whether air/steam or water.

I believe that he wanted know whether this number is the converted I131 activity as used for determining INES classifications or just the actual escaping activity with no conversion whatsoever.

 

[Shinjukusam]

I believe that he wanted know whether this number is the converted I131 activity as used for determining INES classifications or just the actual escaping activity with no conversion whatsoever.

Heh, I remember the day the media learned you could do that. Suddenly they got a whole new bunch of big numbers to throw around.

 

[tsutsuji]

Tokyo:

http://www3.nhk.or.jp/news/html/20111018/t10013350041000.html 3.99 μSv/h was found in an Adachi ward survey on 17 October, 5 cm above ground near a swimming pool equipment room in Higashifuchie primary school. On 18 October afternoon the top 10 cm layer of Earth was removed and the radiation dropped to 0.15 μSv/h at 5 cm above ground and 0.12 μSv/h at both 50 cm and 100 cm above ground, which is below the 0.25 μSv/h standard decided by this ward, and the no-entry regulation was lifted in the night. The completion of a survey of the school's side ditches, roofs and places where rainwater gathers is planned for 19 October. In the future, the ward will check the side ditches and draining trenches in 800 locations such as schools and parks one after the other.

http://www.yomiuri.co.jp/e-japan/tokyo23/news/20111018-OYT8T00085.htm Map of the location of the Higashifuchie primary school hot spot (black circle on the map). The 17 October survey was performed in a hurry by the ward after some citizens who had measured 20 locations reported that five of them, including the Higashifuchie school hot spot, were above the 1 μSv/h national standard. While it was confirmed that 1 μSv/h was exceeded at 5 cm above ground at the Higashifuchie school hot spot, at 50 cm and 100 cm above ground the measurements were respectively 0.41 and 0.24 μSv/h. In the other four spots, the ward found radiations between 0.43 and 0.95 μSv/h at 5 cm above ground. Until then the ward had made measurements at 1500 locations where children spend their everyday lives (schoolyards, parks, etc.) and had performed cleaning each time the ward's own standard - set at 0.25 μSv/h - had been exceeded. In the future, the ward will check locations that children don't enter on a daily basis inside schools, kindergartens, nursery schools etc, but where there is a probability of presence of hot spots such as below rainspouts.

http://www.yomiuri.co.jp/politics/news/20111018-OYT1T00963.htm In response to the recent hotspot discoveries in Funabashi (Chiba prefecture) or Adachi ward (Tokyo), the minister of education and science, Masaharu Nakagawa announced in a press conference after the 18 October cabinet meeting that the government will issue a guideline addressing hotspot measurement method and cleaning.

 

[Astronuc]

I believe that he wanted know whether this number is the converted I131 activity as used for determining INES classifications or just the actual escaping activity with no conversion whatsoever.

Perhaps, but normally, the iodine may be calculated as does equivalent iodine (DEI) in which case one needs to know the activity of specific isotopes and weight the dose appropriately.

Total activity is simply not enough information.

 

[Sorai]

I believe that he wanted know whether this number is the converted I131 activity as used for determining INES classifications or just the actual escaping activity with no conversion whatsoever.

Yes, that was my question. But it seems they are just reporting total releases without conversion. Cs-134 and Cs-137, according to the new version of the roadmap: http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/111017e3.pdf [page 14]

 

[tsutsuji]

http://www.yomiuri.co.jp/national/news/20111019-OYT1T00946.htm The nashi pear growers of Tottori prefecture (Western Japan) are requesting a compensation because the nashi pear prices dropped by 30% after nashi pears from Fukushima prefecture were distributed in Kansai and other areas.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20111019/index.html Helicopter monitoring, originally planned in 22 prefectures from Aomori to Aichi, will eventually be performed in the whole country.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20111019/1545_mujinheri.html Tamura town (former evacuation prepared area) will use a 2.70 m long unmanned helicopter to monitor radiations in field and forest areas.

Hagashimurayama, Tokyo:

http://mainichi.jp/select/jiken/news/20111020k0000m040090000c.html 2.153 μSv/h have been found in a ditch behind the lunchroom in a primary school in Hagashimurayama, Tokyo metropolis. The city surveyed 22 schools on 18 October and found radiations of 0.19 μSv/h and higher at 8 schools and removed the contaminated mud. The mud was then temporarily buried inside school premises. The city mayor announced that the scope of the radiation surveys "will be extended with maximum efforts".

http://sankei.jp.msn.com/region/news/111019/tky11101922200016-n1.htm Hagashimurayama city found radiations higher than 0.19 μSv/h at 13 locations in 6 primary schools and 2 junior high schools. A survey of ditches and rainspouts will be performed in kindergartens and nursery schools in the future.

http://www3.nhk.or.jp/news/html/20111019/t10013368281000.html Video of the cleaning of the 2.153 μSv/h hotspot. The radiation dropped to 0.102 μSv/h after Earth and sand removal. The second highest hotspot in the 8 schools, after the 2.153 μSv/h one, was a 0.5 μSv/h one.

Adachi ward, Tokyo:

http://www3.nhk.or.jp/news/html/20111018/t10013350041000.html 3.99 μSv/h was found in an Adachi ward survey on 17 October, 5 cm above ground near a swimming pool equipment room in Higashifuchie primary school.

http://www.yomiuri.co.jp/dy/national/T111019004399.htm (English) "Soil to a depth of 10 centimeters in a one-square-meter area around the drainpipe [where 3.99 μSv/h had been found on 17 October] was removed, put in a bag and buried in a hole 1.2 meters deep at a different location at the school."

http://www.city.adachi.tokyo.jp/010/d00400047.html (and http://www.city.adachi.tokyo.jp/010/pdf/futie_tihyo_1019.pdf Map of measurement points). 6 additional locations were checked on 19 October at Higashifuchie school. 3.61 μSv/h was found 5 cm above ground at a rainwater gully near the entrance of the gymnasium (see circled number 24 on the map). After high pressure washing of the gully and installation of a concrete cover, the radiation dropped to below 0.25 μSv/h at 50 cm above ground. A temporary enclosure was set up to prevent people from approaching. The Earth clogged inside the gully will be removed tomorrow or later. More details are provided about the other finds and countermeasures.

http://www.yomiuri.co.jp/kyoiku/news/20111019-OYT8T00666.htm The number of locations in the Adachi ward where high levels of radiation might be found and which the ward has began to survey and clean is 800. According to a ward official, completing this work "will take a considerable amount of time".　At Sano district learning center, which is one of the five locations checked on 17 October, the radiation was still high with 0.31 μSv/h after cleaning, and the ward is considering asphalt removal.