Japan earthquake - contamination & consequences outside Fukushima NPP

[tsutsuji]

http://www.yomiuri.co.jp/dy/national/T120210006056.htm (English) Waste site open to journalists in Okuma

http://www.yomiuri.co.jp/feature/20110316-866921/news/20120213-OYT1T00936.htm 58,000 Bq/kg from Earth from discarded vinyl greenhouses from Togane, Chiba, being recycled in a plastic factory in Chiba prefecture. The factory has recalled all the Earth (140 tons) produced after the nuclear accident.

http://www.yomiuri.co.jp/feature/20110316-866921/news/20120213-OYT1T00881.htm A study group of the ministry of education and science held a meeting on 13 February about sea radiation surveys. They decided to launch another survey of river mouths and seas in Tokyo Bay and on the Pacific coast, with Fukushima prefecture as the main focus, starting in April. The frequency of testing in coastal waters and in far waters will be reduced to once every 2 or 3 months instead of once a month.

http://www.yomiuri.co.jp/feature/20110316-866921/news/20120212-OYT1T00538.htm 3000 Bq/kg in dried daikon radish grown in Fukushima city. 102 bags (50 g each) have already been sold.

http://www.okinawatimes.co.jp/article/2012-02-08_29578/ 468 Bq/kg in Fukushima wood in an Okinawa restaurant. 3 Other restaurants have already used their Fukushima wood so it cannot be tested, but 39,960 Bq/kg was found in ashes. 15.7 tons of Fukushima wood were distributed in Okinawa by a Gifu prefecture based company. 8.4 tons were sold to restaurants, and 7.3 tons are remaining in a container near Naha port.

http://www.chibanippo.co.jp/c/news/national/69198 Chiba prefecture tested 46 locations in a park and found 3 locations above the 1 microsievert/hour standard. The highest is 3.42 microsievert/hour at 50 cm above ground near a parking lot storm-water inlet.

http://www.tokyo-np.co.jp/article/national/news/CK2012020402000037.html 6.85 microsievert/hour at 1 cm above ground (above the 0.59 microsievert/hour at 1 cm above ground standard) near an unused drainage channel near a school in Yokohama. 62,900 Bq/kg in Earth samples taken in a close location.

http://www.minyu-net.com/news/news/0204/news6.html Second announcement of results of the whole body counter examinations of Minamisoma citizens. The first results were announced in October. Among 579 primary and middle school children, 218 were above the detection level for Cs-137 and 361 were below detection level. 4 had 20 Bq/kg or above. The highest one had between 30 and 35 Bq/kg. Among 4745 senior high school students, 1943 were above detection level. Among these, 1774 had 20 Bq/kg or below. 16 had 50 Bq/kg or above. The highest had 110.7 Bq/kg. According to the City, only one person had an accumulated dose higher than 1 milisievert over 50 years, with 1.069 milisievert/50 years.

http://mainichi.jp/select/weathernews/20110311/radioactive/news/20120219k0000e040102000c.html There is a problem with the new food safety levels. There are two sorts of radiation measurement tools. The Germanium semiconductor detector, and the sodium iodide scintillator detector. As a rule, one should have a detection level of about 10% of the safety standard. As the safety standard for general food is brought down to 100 Bq/kg, one should have a detection level of 10 Bq/kg. This is possible with a Germanium (Ge) detector, but sodium iodide (NaI) detectors can't do this. At present the national government and the prefectures own 116 Ge detectors and 227 NaI detectors. The person in charge at Ibaraki prefecture government says "we don't have the budget to buy new detectors. We have to do with the detectors we have". Ibaraki prefecture owns one Ge detector, which performs between 15 and 20 tap water tests per week, and 5 NaI detectors, that perform beef tests on 500 to 600 cows per week. When the 100% beef control was started in August, they had only one Ge detector, and for two months they had to perform tests on a 24 hour/day basis, and the employees could hardly sleep. They are afraid that the same situation is going to occur again as the new safety levels are implemented. The health ministry issued a proposal to set the NaI detector detection level at 25 Bq/kg, but according to the maker, Hitachi Aloka Medical, the test must last for 60 to 70 minutes instead of the present 10 to 15 minutes. To reduce that time, and increase the measurement tool's sensitivity, the sample holding container would need to be improved. Miyagi prefecture has decided to perform such improvements, but it will cost 13 million yens. "Can the national government help with the improvement cost?" the Miyagi prefecture person in charge is asking.

 

[Neredera]

A year [actually 11 months, but it seems it will go on] on, only brief home visits for Japan nuclear evacuees
http://news.yahoo.com/only-brief-home-visits-japan-nuclear-evacuees-081517728.html

This article links a picture that shows a 11.3mSv/h reading.

http://news.yahoo.com/photos/world-events-slideshow/radiation-gauge-shows-reading-11-3-millisieverts-per-photo-081517930.html

That has to be a mistake and should be 11.3 uSv/h, or not?

 

[tsutsuji]

This article links a picture that shows a 11.3mSv/h reading.

http://news.yahoo.com/photos/world-events-slideshow/radiation-gauge-shows-reading-11-3-millisieverts-per-photo-081517930.html

That has to be a mistake and should be 11.3 uSv/h, or not?

Yes it should be 11.3 μSv, as you can see on the larger version of the photograph at http://www.novosti.rs/upload/images/2012//02/13/japan.jpg

 

[zapperzero]

http://www3.nhk.or.jp/daily/english/20120220_26.html

partial results of an ongoing survey in Fukushima:

40% of residents from 3 affected municipalities got more than 1 mSv in the first four months after the accident.

Highest dose received was 23 mSv.

 

[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120221/1915_sokutei.html The ministry of education and science is releasing a new online map with real time radiation measurements in 2700 places such as schools and parks in Fukushima prefecture. A trend graph is provided for each sensor.

http://radioactivity.mext.go.jp/ja/important_imformation/5100_2012022114.pdf presentation of the new real time map.

http://radiomap.mext.go.jp/ja/ The new real time map.

[It is a bit disappointing that they don't say the height of each sensor. All they say is "either 50 cm or 1 m". Another problem is the 3 microsievert/hour upper limit of the trend graph. With about 9 microsievert/hour, the trend graph of Namie's prefectural high school is not available as it is higher than 3 microsievert/hour]

 

[Astronuc]

The Health Physics Society (HPS) is concerned about radiation exposures associated with these reactor problems and desires to keep our members and the concerned public advised on current events associated with the Japanese nuclear plants.

http://hps.org/fukushima/

The Health Physics Society has a lot of relevant information on the health and environmental effects of radiation.

 

[tsutsuji]

http://www3.nhk.or.jp/daily/english/20120220_26.html

partial results of an ongoing survey in Fukushima:

40% of residents from 3 affected municipalities got more than 1 mSv in the first four months after the accident.

Highest dose received was 23 mSv.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120220/2100_hibakuryou.html Results of the external radiation estimates for 14,680 people of Iitate, Namie and Kawamata, for the 4 month period after the accident. Among the 9747 people who are not nuclear workers, 4111 are above 1 mSv, 71 are above 10 mSv. The highest is a woman with 23 mSv. She evacuated once, but came back and lived for 3 months in the planned evacuation zone.

http://radioactivity.mext.go.jp/ja/important_imformation/5100_2012022114.pdf presentation of the new real time map.

http://radiomap.mext.go.jp/ja/ The new real time map.

[It is a bit disappointing that they don't say the height of each sensor. All they say is "either 50 cm or 1 m".

http://ajw.asahi.com/article/0311disaster/fukushima/AJ201202220028 "It measures air radiation levels of gamma rays at a height of 50 centimeters above the ground in kindergartens, day care centers and elementary schools and at a height of 1 meter above the ground at junior high and senior high schools and at other public facilities."

http://www.bbc.co.uk/news/science-environment-17124909 "research cruise in June last year led by the Woods Hole Oceanographic Institution (WHOI).The initial findings were presented to the biennial Ocean Sciences Meeting. "

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120225/1430_100m.html The ministry of environment is releasing an interim report with a 100 metre mesh radiation map. It was started in November and displays the measurements in 7963 locations. Some of the areas in the central part of Iitate village that were marked as above 20 mSv/year in the helicopter maps were found below 20 mSv/year. The highest location is in the Yamada district of Futaba with 89.9 microsievert/hour (472.5 milisievert/year). The final report will be released next month. It will be used by local governments to plan decontamination, and by the national government to revise the boundaries of the evacuation zones.

http://www.env.go.jp/press/press.php?serial=14870 Detailed monitoring pursuant of decontamination special law (interim report)

 

[zapperzero]

Xenon-133 and caesium-137 releases into the atmosphere from the
Fukushima Dai-ichi nuclear power plant: determination of the
source term, atmospheric dispersion, and deposition
http://www.atmos-chem-phys.net/12/2313/2012/acp-12-2313-2012.pdf

Regarding 137Cs, the inversion results indicate a total
emission of 36.6 (20.1–53.1) PBq, or about 43% of the estimated
Chernobyl emission. This means that nearly 2% of
the available inventory of the reactor cores in units 1–3 and
the spent-fuel pool in unit 4 was discharged into the atmosphere.
The inversion strongly increased the emissions early
on 12 March, around the time when the first explosion occurred
in unit 1. These early emissions were estimated lower
by the Japanese authorities, but are in accordance with the
first estimates published by Central Institute for Meteorology
and Geodynamics (2011). The highest release rates occurred
on 14 March, when hydrogen explosions occurred in reactor
units 3 and 4 and, presumably, unit 2. We also find unexpectedly
high 137Cs emissions from 16–19 March, which
suddenly dropped by orders of magnitude when spraying of
water on the spent-fuel pool of unit 4 started. Thus, we believe
that these high emissions are related to the degraded
fuel in the spent-fuel pool of unit 4, and this result would
also confirm that the spraying was an effective countermeasure
at least in this case.

Exactly
during and following the period of the highest 137Cs emission
rates on 14 and 15 March, the FD-NPP plume was advected
towards Japan and affected large areas in the east of
Honshu Island. The advection towards Japan was triggered
by a developing cyclone, which produced precipitation on 15
March, leading to the deposition of large fractions of the airborne
137Cs over Japanese land. However, the situation could
have been even much worse, as fortunately no rain occurred
at the time

During a second episode from 20–22 March, even larger
areas of Honshu were covered by the FD-NPP radioactive
cloud, from Shizuoka prefecture in the south to areas
north of FD-NPP. Strong frontal precipitation nearly completely
cleansed the atmosphere of 137Cs and again produced
strong deposition of this radionuclide over Honshu, including
Tokyo. This episode again followed a period of high (though
fortunately not as high as on 14–15 March) 137Cs emission
fluxes on 19 March, which were transported to Japan on 20
March.

 

[tsutsuji]

http://sciences.blogs.liberation.fr/home/2012/02/fukushima-contamination-chronique-et-p%C3%A9renne-irsn.html The French IRSN will publish a report on the Fukushima accident on the first anniversary of the accident [that must be on 11 March 2012].

Releases into the air:

radioactive noble gasses : 6550 PBq (petabecquerels =10^15 Bq) (≈ Chernobyl), mostly xenon 133 (133Xe, period of 5,3 years)

Radioactive iodines : 408 PBq (about one tenth of Chernobyl), including 197 PBq of iodine 131 (131I, period of 8 days) and 168 PBq of iodine 132 (132I, period de 2,3 hours)

Radioactive telluriums : 145 PBq including 108 PBq of tellurium 132 (132Te, period of 3,2 days) and 12 PBq of tellurium 129m (129mTe, period of 33,6 days)

Radioactive cesiums : 58 PBq (about three times less than Chernobyl), including 21 PBq of cesium 137 (137Cs, period of 30 years), 28 PBq of cesium 134 (134Cs, period of 2,1 years) and 9,8 PBq of cesium 136 (136Cs, period of 13,2 days)

http://sciences.blogs.liberation.fr/files/irsn-bilan-des-cons%C3%A9quences-environnementales-de-laccident-de-fukushima-28fev2012.pdf IRSN press release of 28 February 2012, page 3

 

[nikkkom]

http://sciences.blogs.liberation.fr/home/2012/02/fukushima-contamination-chronique-et-p%C3%A9renne-irsn.html The French IRSN will publish a report on the Fukushima accident on the first anniversary of the accident [that must be on 11 March 2012].

"radioactive noble gasses : 6550 PBq (petabecquerels =10^15 Bq) (≈ Chernobyl), mostly xenon 133 (133Xe, period of 5,3 years)"

Xe-133 period is 5.2 days, not years.

 

[tsutsuji]

Xe-133 period is 5.2 days, not years.

oops. sorry for the mistake.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120124/index.html As a countermeasure decided after finding that contaminated stones were delivered from a contaminated stone pit in Namie, the government is goint to check construction materials from the restricted zone. The namie stones were used in the concrete which was used to build a new appartment building in Nihonmatsu and high radiation levels were measured inside the appartments. A report will be issued within this month. Concerning the preparation of national safety level for construction materials, the nuclear disaster response headquarters said "it will take time to study it".

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120228/index.html A ministry of Economy and Industry study group is proposing a 100 Bq/kg safety limit for crushed stones.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120304/1040_ochiba.html The Forestry agency made a study of fallen leaves in 400 locations in Fukushima Prefecture. In a location 10 km west of the plant and in a location 25 km north-west of the plant the radiations were both 4,440,000 Bq/kg.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120305/index.html An NHK survey found that there is a strong suspicion that at least 5 people left isolated in the evacuated zone died of starvation. The body of a man in his seventies was found at the end of March on the second floor of a house located 5 km away from the plant. The first floor had been damaged by the tsunami. A woman in her sixties was found dead in her house in April. She had a chronic disease affecting her legs. Her house did not suffer large tsunami damage. All five bodies were thin as a consequence of losing weight. The police and the doctors who examined the bodies say that there is a high probability that they weren't able to evacuate by themselves or to call for help. The NHK found that the detailed causes of the bodies found on tsunami sites were not researched using autopsies and were counted as "drowned". The doctors say that it is possible that among the people counted as "drowned", some of them might have survived for some time and died later from a different cause. Several evacuation zone firemen testify that before the rescue operations were halted, they had heard voices of survivors trapped in the tsunami debris, calling for help. Yoshihisa Takano, a Namie fireman, recalls that after hearing voices and rattling in the debris, he went back to the town hall to call for help, but there weren't people or equipment available, and another tsunami warning came. Finally it was decided to resume rescue operations the next morning. But the next morning, the evacuated zone was extended to the 10 km range, and evacuating the 10 km range became the priority. "I am still regretting today that we did not go to rescue this/those person(s), although I had told him/them "we will come tomorrow for for help, please wait"".

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120305/1850_gashi.html According to an NHK survey, the number of patients from evacuated hospitals who died during the long hours of evacuation or after their health deteriorated shortly after evacuation is at least 68. Asked about the 5 people strongly suspected of having died of starvation, isolated at home or near their homes, the NISA said it is studying a revision of the guidelines so that cities and villages have to specify in their evacuation plans the method by which they will respond to the citizens who need help to evacuate, and the method by which they check that no citizen is left behind.

 

[tsutsuji]

http://www.yomiuri.co.jp/feature/20110316-866921/news/20120306-OYT1T01065.htm According to the Japan Agency for Marine-Earth Science and Technology, the quantity of Cesium that flowed into the ocean is 6 times as much as the Tepco estimate. It was announced at a research reporting conference at JAEA on 6 March. This research is based on seawater samples in 500 locations and a simulation of cesium migration until 7 May 2011. The contaminated water that flowed into the ocean was estimated between 4200 and 5600 TBq of cesium. The cesium released into the atmophere that sunk into the ocean (with the rain, etc.) is estimated between 1200 and 1500 TBq.

 

[etudiant]

http://www.yomiuri.co.jp/feature/20110316-866921/news/20120306-OYT1T01065.htm According to the Japan Agency for Marine-Earth Science and Technology, the quantity of Cesium that flowed into the ocean is 6 times as much as the Tepco estimate. It was announced at a research reporting conference at JAEA on 6 March. This research is based on seawater samples in 500 locations and a simulation of cesium migration until 7 May 2011. The contaminated water that flowed into the ocean was estimated between 4200 and 5600 TBq of cesium. The cesium released into the atmophere that sunk into the ocean (with the rain, etc.) is estimated between 1200 and 1500 TBq.

These estimates don't square with the IRSN estimates of about 58,000 Terabequerels of cesium. We are out by almost a factor of 10.
Also, the IRSN mentions very large early releases of tellurium, which presumably decay to iodine in short order. These were not mentioned afaik in the various TEPCO releases. Were they summarized with the iodine levels?

 

[clancy688]

These estimates don't square with the IRSN estimates of about 58,000 Terabequerels of cesium. We are out by almost a factor of 10.

I think they do. You compare the wrong levels.

First of all, IRSN claimed that 58 PBq of Cesium were released via the atmosphere, not water. Moreover, those 58 PBq are all kinds of Cesium - 137 (21 PBq), 136 (9.8 PBq) and 134 (28 PBq).

But there's another estimate for release into the ocean. They claim that 27 PBq of Cesium-137 was released into the sea.
TEPCOs initial estimate was 4.2 to 5.6 PBq C-137 released. Six times that estimate would be 25.2 to 33.6 PBq. Which puts it right into the vicinity of the IRSN estimate.

 

[etudiant]

I think they do. You compare the wrong levels.

First of all, IRSN claimed that 58 PBq of Cesium were released via the atmosphere, not water. Moreover, those 58 PBq are all kinds of Cesium - 137 (21 PBq), 136 (9.8 PBq) and 134 (28 PBq).

But there's another estimate for release into the ocean. They claim that 27 PBq of Cesium-137 was released into the sea.
TEPCOs initial estimate was 4.2 to 5.6 PBq C-137 released. Six times that estimate would be 25.2 to 33.6 PBq. Which puts it right into the vicinity of the IRSN estimate.

Thanks for the clarification.
I'm still confused. If 58 PBq of cesium is near correct, even after removing the ocean water release of 33 PBq, there are 25 PBq of airborne release to be accounted for.
Does that mean that TEPCO's initial estimate of 1.2 to 1.5 PBq was off by a factor of 15?

 

[clancy688]

I'm still confused. If 58 PBq of cesium is near correct, even after removing the ocean water release of 33 PBq, there are 25 PBq of airborne release to be accounted for.

There's only 21 PBq of C137 aerial releases in that estimate, and as far as I understand, it doesn't include the water release. For IRSN, it's 21 PBq C137 air + 27 PBq C137 sea, which gives us a total release of 48 PBq C137 (~60% of the Chernobyl C137 air release).
The water release number of 27 PBq can't include aerial deposition since it was calculated with water samples taken 500 m away from the plant.

Does that mean that TEPCO's initial estimate of 1.2 to 1.5 PBq was off by a factor of 15?

I don't know where those 1.2 to 1.5 PBq come from, but I'm sure it's not TEPCO. Afaik TEPCO never gave us an estimate for atmospheric releases. It's probably a NISA or NSC number.
The first total atmospheric release estimates coming from NISA and NSC when they announced INES 7 was 6.1 and 12 PBq C137. Since then they upgraded their estimates to 15 and 11 PBq. But that's still way off the real numbers.

IRSN estimates, as mentioned above, 21 PBq. There's a recent paper created by atmospheric scientists which goes even further - they estimate that 20.1-53.1 (36.6 would be the middle value) PBq C137 was released into the atmosphere. Of which 80% was deposited over the Pacific.
So you get 27 PBq + 0.8 * 36.6 PBq as the total value of C137 which ended up in the Pacific.

 

[tsutsuji]

For IRSN, it's 21 PBq C137 air + 27 PBq C137 sea, which gives us a total release of 48 PBq C137

I don't know the details of the IRSN estimate, but one possibility is that the 27PBq include some cesium that was carried by air, and later sunk into the sea with the rain.

Where have the IRSN's 21 PBq of airborne cesium fallen ? onto the land (on Japan, on the Asian continent ? on the American continent ? etc.) or into the sea (into the Pacific Ocean ? into the Indian Ocean ? etc. ) ?

The amount of "between 1200 and 1500 TBq" from the JAMSTEC study mentioned in the Yomiuri article is perhaps not a quantity over the Pacific Ocean as a whole, but only over the part of the sea where the 500 sea water samples were taken ?

The Yomiuri article quotes Yasumasa Miyazawa, who published the following :

http://www.terrapub.co.jp/journals/GJ/pdf/2012e/460100e1.pdf Dispersion of artificial caesium-134 and -137 in the western North Pacific one month after the Fukushima accident, Geochemical Journal, 46, e1-e9 (Online published January 16, 2012)) [English]

The above paper relies on

http://www.sciencedirect.com/science/article/pii/S0265931X11002463 Daisuke Tsumune, "Distribution of oceanic 137Cs from the Fukushima Dai-ichi Nuclear Power Plant simulated numerically by a regional ocean model", Journal of Environmental Radioactivity, Available online 8 November 2011

We then used a regional ocean model to simulate the 137Cs concentrations resulting from the direct release to the ocean off Fukushima and found that from March 26 to the end of May the total amount of 137Cs directly released was 3.5 ± 0.7 PBq ((3.5 ± 0.7) × 1015 Bq).

 

[zapperzero]

Where have the IRSN's 21 PBq of airborne cesium fallen ? onto the land (on Japan, on the Asian continent ? on the American continent ? etc.) or into the sea (into the Pacific Ocean ? into the Indian Ocean ? etc. ) ?

iirc it was something like almost 80% Pacific, 20% over Japan and some insignificant bit for the rest of the world.

 

[clancy688]

I don't know the details of the IRSN estimate, but one possibility is that the 27PBq include some cesium that was carried by air, and later sunk into the sea with the rain.

I don't think so. The 27 PBq estimate was calculated with water samples taken 500 metres away from the plant. So aerial deposition is most likely not included, since it happened over a surface of millions of square kilometres.

 

[zapperzero]

I don't think so. The 27 PBq estimate was calculated with water samples taken 500 metres away from the plant. So aerial deposition is most likely not included, since it happened over a surface of millions of square kilometres.

I wouldn't be so sure about that. All it takes is some rain, or an atmospheric inversion day.

 

[tsutsuji]

I don't think so. The 27 PBq estimate was calculated with water samples taken 500 metres away from the plant. So aerial deposition is most likely not included, since it happened over a surface of millions of square kilometres.

That's right. The IRSN's 27 PBq are not including aerial deposition.

http://www.irsn.fr/FR/Actualites_pr...ident_Fukushima_sur_milieu_marin_26102011.pdf page 7-8 : " [airborne] Cs 137 deposited on the sea over an 80 km range [from the plant] is 76 E12 Bq (...) [or] 0.3% of the Cs 137 radioactivity in the sea".

See also http://www.irsn.fr/FR/Actualites_pr...ident_Fukushima_sur_milieu_marin_26102011.pdf page 6 and 7 where they say that their new (October) estimate is twice their own July estimate, and 20 times the Tepco estimate. What they revised between July and October was their assumptions about the vertical distribution.

TEPCOs initial estimate was 4.2 to 5.6 PBq C-137 released. Six times that estimate would be 25.2 to 33.6 PBq. Which puts it right into the vicinity of the IRSN estimate.

http://www.irsn.fr/FR/Actualites_pr...ident_Fukushima_sur_milieu_marin_11072011.pdf page 3 quotes the Japanese government's report to IAEA in June, where 4.7 PBq is the total of Cs137, Cs134 and I131 directly poured into the sea. According to that report, Cs137 alone is 0.95 PBq.

So I think that what the Yomiuri means by "six times as much as the Tepco estimate" is that 0.95 * 6 = 5.7 PBq which nearly equals the upper limit of the "between 4200 and 5600 TBq" mentioned in the latest JAMSTEC study.

 

[tsutsuji]

As for Fukushima, nobody died, that's right.

As mentioned by the NHK articles I mentioned above in https://www.physicsforums.com/showpost.php?p=3799632&postcount=501 , the evacuation of the population surrounding Fukushima Daiichi is suspected to be a contributing factor to the death of at least 68 + 5 = 73 people, among other factors such as a poor health, or having one's houses' first floor destroyed by a tsunami.

 

[r-j]

The new paper shows that minute quantities of plutonium from Fukushima have spread far from the plant. In samples taken to the northwest and in the J-Village, where workers live, the authors found trace amounts of plutonium in the surface soil (see map). Looking at the ratio of plutonium-241 to plutonium-239, they were able to conclude that the plutonium came from Fukushima rather than other sources, such as old nuclear-weapon tests.
...
Nevertheless, the measurements are interesting. The distances at which the team finds the material imply that plutonium was ejected during the hydrogen explosions in the first days of the crisis. And the relatively low levels (around 10,000 times lower than Chernobyl) suggest that the heavily shielded concrete casings around the reactors did offer some protection from the worst of the fallout.

http://blogs.nature.com/news/2012/03/plutonium-spotted-far-from-fukushima.html

 

[tsutsuji]

As seen above in this thread ( https://www.physicsforums.com/showpost.php?p=3802228&postcount=511 and above), there seems to be a large range of contradicting estimates as regards how much radioactive substances were released into the sea :

* The Tepco estimate
* 6 times the Tepco estimate (JAMSTEC)
* 20 times the Tepco estimate (IRSN)

This variation seems to be further confirmed by the following :

http://edition.cnn.com/2012/03/10/opinion/buesseler-fukushima-ocean/?hpt=hp_t3 Ken Buesseler is a Senior Scientist at the Woods Hole Oceanographic Institution : "There is also little agreement on exactly how much radioactivity was released or even whether the fires and explosions at the power plant resulted in more radioactive fallout to the ocean than did direct releases of radioactivity caused by dumping water on the reactors to keep them cool."

 

[mheslep]

WSJ article yesterday summarizing radiation impacts. Authors Hayaskhi, Dvorak, Hotz

Experts cited:
o Kathryn Higley, Oregon State, specialized in tracking radiation in the environment.
o Toshiso Kosako, Tokyo U., radiation protection (resigned in April as adviser to PM Kan)
o Shunichi Yamagarbagea, Fukushima Medical U, radition impact on human health
o US EPA
o TEPCO
o Timothy Mousseau, U South Carolina, radio ecologist.
o Tatsuo Aono, Japan's National Institute of Radiological Sciences

Lead sentence:

A year after the Fukushima nuclear accident, the emerging consensus among scientists is that its effects on physical health and the environment have so far been minimal. There have been no reported radiation-related deaths or illnesses from the accident, even among workers who faced very high exposure.

Dose details (US annual background 3msv, nuclear worker safety limit 100 msv):
o Survey 10k people in three high risk towns:
<1msv 58%
<5msv 95%
>15 msv 23 people

o Fukushima Plant, 20k workers:
>100msv, 167 workers
>250msv, 6 workers, highest dose 679 msv

Other details:
o Bird populations around Fukushima as of last July dropped by a third, without causal link yet.

o Thyroid problems, including cancer, future long term predictions (by Kosako, Tokyo U): 300 to 500 people.

 

[tsutsuji]

Dose details (US annual background 3msv, nuclear worker safety limit 100 msv):
o Survey 10k people in three high risk towns:
<1msv 58%
<5msv 95%
>15 msv 23 people

This is a survey based on asking people where they were (indoors/outdoors, in which village etc. ) each day of March 2011. Even if those accounts by the people saying where they were are accurate, the survey maker needs to make various assumptions about how much radiation those people encountered in each location. I am not sure if it is possible to make reliable assumptions concerning cloudshine or Iodine levels.

Still, reports on population exposure are as much guesswork as science. Experts from Hirosaki University did their own thyroid tests on evacuees and found exposure levels higher than the government figures.
http://online.wsj.com/article/SB10001424052970203961204577271152728725214.html
My bolding/underlining

December 2011:

http://www3.nhk.or.jp/news/genpatsu-fukushima/20111130/0430_hanmei.html A study by Nagasaki university found that among 170 Nagasaki prefecture citizens, such as medical professionals, who went to Fukushima prefecture after the accident, 55 people, or 32% were detected as having iodine internal contamination in whole body counter tests performed during the first month after the accident. The highest thyroid equivalent dose was 15 mSv. A trend emerges of higher doses being detected among the people who were in Fukushima prefecture during the first week of the accident. As iodine was never detected in the tests performed in June or later among Fukushima citizens, this Nagasaki university study is deemed a valuable document that might be helpful to accurately estimate the doses received by Fukushima prefecture citizens.

March 10, 2012:

Findings by the research team, led by professor Shinji Tokonami from Hirosaki University, showed that 50 of 65 people checked from April 11 to 17 last year had radioactive iodine-131 in their thyroids, with 26 absorbing radiation doses over 10 millisieverts, and five with doses over 50 millisieverts -- the upper limit set by the International Atomic Energy Agency (IAEA).
http://mdn.mainichi.jp/mdnnews/news/20120310p2a00m0na005000c.html

 

[tsutsuji]

http://sciences.blogs.liberation.fr/home/2012/02/fukushima-contamination-chronique-et-p%C3%A9renne-irsn.html The French IRSN will publish a report on the Fukushima accident on the first anniversary of the accident [that must be on 11 March 2012].

http://www.irsn.fr/FR/expertise/rap.../IRSN_Rapport_Fukushima-1-an-apres_032012.pdf IRSN "Fukushima, one year after: First analysis of the accident and its consequences", 12 March 2012. 189 pages, in French.

Table 6-XI page 113/189 compares their own estimate ("Bally du Bois et al.") of direct sea releases and airborne deposits into the sea with the other available estimates (PBq of Cs-137) :

publication direct release (PBq)      airb. deposit (PBq)        airb. deposit surface (km x km)
a)                            0.94        
b)                            4                         5                     1700 x 1700
c)                            3.5 ± 0.7    less than direct release
d)                          27 (12-41)               0.0076                 50 x  100
e)                                                       0.18                 1500 x 1500
f)                                                        1                       600 x  600
g)                                                       1                     1700 x 1700

a) NERH 2011 (TEPCO) calculation of the leak's flow rate

b) Kawamura et al. (2011) Comparison of modelling (SEAGEARN)/measurements at sea

c) Tsumune et al. (2011) Comparison of modelling (ROMS)/measurements at sea

d) Bailly du Bois et al.(2011) (IRSN) Quantities deducted from measurements at sea and dilution + pX simulation

e) Honda et al. (2011) Comparison of modelling (JCOPE2)/measurements in Japan

f) Morino et al. (2011) Comparison of modelling (CMAQ)/measurements in Japan

g) Yasunari et al. (2011) Comparison of modelling (FLEXPART)/measurements in Japan

 

[tsutsuji]

http://mdn.mainichi.jp/mdnnews/news/20120326p2a00m0na011000c.html "Some 24.4 percent of people who were hospitalized in Fukushima with psychiatric disorders in the wake of the outbreak of the crisis at the crippled Fukushima No. 1 Nuclear Power Plant had done so possibly because of fears of radiation exposure" (survey at 30 hospitals in Fukushima Prefecture for two months from March 12, 2011, and 27 of them responded to the survey)

 

[tsutsuji]

http://www.nikkei.com/news/topic/side/article/g=96958A9C93819490E2E4E2E3818DE2E4E2E1E0E2E3E0E2E2E2E2E2E2;q=9694E2E6E3E3E0E2E3E3E7E3E5E3;p=9694E2E1E2E4E0E2E3E3E4E6E5E5;n=9694E2E1E2E4E0E2E3E3E4E6E5E6;o=9694E2E1E2E4E0E2E3E3E4E6E5E7 Fuji Film Fine Chemical Plant is located in Hirono, 21 km south of Fukushima Daiichi. In the past, they were awarded the Prime Minister prize for environment, but they had to remove all the lawns and trees for decontamination. Outdoor areas were decontaminated by removing 3 cm thick layers of asphalt, and 5 cm thick layers of soil. At the end of January, when a decontamination phase was ended, they had brought outdoor radiation to 0.1 ~ 0.2 microsievert/hour and indoor radiation to 0.1 microsievert/hour or lower. It is a sharp contrast with the areas outside the plant premises where radiations above 0.5 microsievert/hour can be found. Normal production with three shift work resumed in October. They want to appeal to customers by providing data about their decontamination efforts, but the plant is not running at full capacity. "There is no standard saying how much [decontamination must be done] so that it is safe, so we must make efforts on our own". Mr Akita, the manager in charge of decontamination at the Fuji Film Fine Chemical plant is also a member of the Hirono fire brigade. The fact that the town hall administration came back on 1 March 2012 is a good thing, but when one thinks that not only one chemical plant but the whole town must be decontaminated so that the people can feel safe, thinking about the cost and how hard the efforts have to be, "one feels overwhelmed".

 

[Yamanote]

The fact that the town hall administration came back on 1 March 2012 is a good thing, but when one thinks that not only one chemical plant but the whole town must be decontaminated so that the people can feel safe, thinking about the cost and how hard the efforts have to be, "one feels overwhelmed".

Me too. And what to do with the huge amount of radioactive rubble after this so called "decontamination"?

In some cases it might be better to abandon this places and let the decay do the work.

 

[tsutsuji]

The detailed JAEA/MEXT helicopter map, previously only available as an online zoom and drag map application (at http://ramap.jaea.go.jp/map/ ) is now available in downloadable pdf format at http://ramap.jaea.go.jp/map/mapdf/index.html

 

[MadderDoc]

Stohl et al.:
"Xenon-133 and caesium-137 releases into the atmosphere from the
Fukushima Dai-ichi nuclear power plant: determination of the
source term, atmospheric dispersion, and deposition"

"Regarding 133 Xe, we find a total release of 15.3 (uncertainty range 12.2–18.3) EBq, which is more than twice as high
as the total release from Chernobyl and likely the largest radioactive noble gas release in history.
<..>For 137 Cs, the inversion results give a total emission of 36.6 (20.1–53.1) PBq, or about 43 % of the estimated Chernobyl emission."
http://www.atmos-chem-phys.net/12/2313/2012/acp-12-2313-2012.pdf

 

[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120407/0830_anzenkiizyun.html A ministry of labour and health study group has prepared a standard for workers working in contaminated areas, such as repairing roads and water pipes. In areas above 5 mSv/year, workers must carry a dosimeter, and their exposure is limited to 50 mSv/year and 100 mSv/5 years. When working on debris higher than 10,000 Bq/kg whole body counter tests must be performed.

http://www.pnas.org/content/early/2012/03/26/1120794109.abstract Buesseler et al. "Fukushima-derived radionuclides in the ocean and biota off Japan" Proceedings of the National Academy of Sciences of the United States of America. 2012 Apr 2. approved February 24, 2012 (received for review December 19, 2011)

 

[nikkkom]

"Regarding 133 Xe, we find a total release of 15.3 (uncertainty range 12.2–18.3) EBq, which is more than twice as high
as the total release from Chernobyl and likely the largest radioactive noble gas release in history."

Has it any practical long-term significance? Xe-133 decays to stable Cs-133 with half-life of 5 days.

 

[clancy688]

There's something interesting in this recent TEPCO publication:

http://www.tepco.co.jp/cc/press/betu12_j/images/120405j0301.pdf

On page 19 you can see a chart depicting water contamination values:

Cs-134: 9.4E1
Cs-137: 1.1E2
?β: 5.0E5

Where're those samples taken from? And what does the last row imply? All other beta emitters? Only 0.04% of all decay processes in that water are caused by Cs?