Update #58: August 29 & 30, 2011
Yesterday, SKF reported this story on soil contamination results. There is a map at the SKF link.
Monday, August 29, 2011
Soil Contamination in 34 Locations in Fukushima Exceeds Chernobyl Confiscation/Closed Zone Level
"In one location, the contamination level is more than 10 times the Chernobyl level.
What a surprise. Now that PM Kan is out, the government dribbles out the information that it withheld as it de-emphasized and even attacked the reports of high soil contamination as measured by private entities including citizens' groups.
The most contaminated location found so far is Okuma-machi, where Fukushima I Nuke Plant is located: 29,460,000 becquerels per square meter with cesium-134 and cesium-137 combined. 15,450,000 becquerels per square meter if only cesium-137 is counted.
The confiscated/closed zone after the Chernobyl accident is set in locations whose cesium-137 level in soil exceeds 1,480,000 becquerels per square meter.
The level of cesium-137 in the location in Okuma-machi is 10 times that of the Chernobyl confiscated/closed zone….
Below is the NHK story on this. Note their article uses the IAEA limit of 10 million Bq/square meter and thus report only lists 3 locations that exceed that limit.
Then it throws in the Chernobyl limit of 555 thousand Bq/square meter evacuation limit which is at odds with the SKF article quote of 1.48 million Bq/square meter evacuation limit. Very confusing.
I searched around and finally found the explanation in an article from May on EnergyNews which explains that 1.48 million Bq is the compulsory migration limit and the 555 thousand Bq is the lower end of the temporary migration limit:
"According to Kawata, soil in a 600 square kilometer area mostly to the northwest of the Fukushima plant is likely to have absorbed radioactive cesium of over 1.48 million becquerels per square meter, the yardstick for compulsory migration orders in the 1986 Chernobyl catastrophe.
Kawata also said soil in a 700 square km area is likely to have absorbed 555,000-1.48 million becquerels per square meter, which was a criteria for temporary migration during the Chernobyl disaster."
High radiation levels on land near Fukushima plant
"The education and science ministry has identified land near the damaged Fukushima Daiichi nuclear plant where radiation levels are higher than IAEA-designated emergency levels.
The ministry released a map on Monday showing the contaminated land. It conducted a survey for radioactive cesium at some 2,200 locations mainly in Fukushima Prefecture in June and July.
The map shows 29.46 million bequerels of cesium on one-square-meter land in a location in Okuma Town, several hundreds meters from the nuclear plant…." Monday, August 29, 2011 21:43 +0900 (JST)
The other important story at SKF yesterday regards the estimates on the dispersion of Plutonium.
On June 6, NISA reported an estimate of 32 BILLION Bqs. According to the press conference yesterday the estimate is now 76 TRILLION Bqs.
Monday, August 29, 2011
NISA Mentions "Neptunium-239" in August 29 Press Conference
"Now this is very curious.
The Nuclear and Industrial Safety Agency (NISA)'s daily press conference is ongoing (August 29). The NISA spokesman Moriyama mentions neptunium-239's conversion ratio to plutonium-239 as 1 to 1.
According to the June 6 estimate by the NISA:
Plutonium-239: 3.2×10^9
Neptunium-239: 7.6×10^13
So, now it is:
Plutonium-239: 7.6 x 10^13, or 76,000,000,000,000 or 76 terabecquerels
The amount of plutonium-239 has increased 23,000-fold.
On August 15 I wrote about neptunium-239, half life of about 2 days, having been detected in large quantity in Iitate-mura, 35 kilometers from Fukushima I Nuclear Power Plant. I had to take down the second post on the subject, but the information was correct.
Now, NISA is suddenly mentioning neptunium-239. Admission of wide dispersion of this nuclide and resultant plutonium-239 may be finally forthcoming, after more than 5 months."
Today SKf reports on the death of a worker at Fukushima. Note that TEPCO has disavowed this had anything to do with his work at Fukushima despite his clean bill of health (no unusual white blood count prior to beginning work there). I note that, Radiation Exposure is the best documented risk factor for Acute Leukemia in adults. EnergyNews also reports this story. Since there is to be no follow-up, we will never know the truth on this one.
Monday, August 29, 2011: Worker Died of Acute Leukemia, TEPCO Said in Aug 30 Press Conference
"But the doctor assured the company that the death had nothing to do with having worked at Fukushima I Nuclear Power Plant.
The unnamed worker died in early August, after having worked at Fukushima I for about a week. TEPCO's Matsumoto says the company does not know where the worker had worked before he came to Fukushima I. He's from one of TEPCO's 1st-tier subcontractors.
Since the death has nothing to do with having worked in Fukushima I Nuke Plant, TEPCO is not going to track the worker's past work history or conduct further investigation. TEPCO will not release personal information about the worker, either.
The radiation exposure of the worker was 0.5 millisievert external radiation, and zero internal radiation for the duration of his work at Fukushima I.
Additional information from Mainichi (8/30/2011):
The worker was in his 40s. At Fukushima I, his work included manning the rest area and radiation control of the workers. There was no abnormal reading of white blood cells before he started to work at Fukushima I. He worked for about a week in August, and fell ill. He was diagnosed with acute leukemia, and died at the hospital. His company reported his death to TEPCO on August 16.
TEPCO's Matsumoto emphasized that the death was a private matter, and TEPCO had no intention of investigating it further now that the doctor denied any relationship between the death and the work at Fukushima I.
While NHK doesn't mention the worker death story it does carry this story on the future reduction of worker radiation levels to the previous international stand of 100 mSv/year. This is based on "reduced" exposure limits according to the health ministry. One wonders about those hotspots on the site and the fact workers are entering the reactor buildings which have very high levels of radioactivity.
Radiation limit to be lowered for Fukushima staff
"Japan's health ministry will restore the cumulative radiation exposure limit for emergency workers at the Fukushima Daiichi nuclear plant to the original 100 millisieverts this autumn. The current limit is 250 milisieverts.
The ministry raised the exposure limit soon after the nuclear accident in March to secure enough time for workers at the plant to bring the situation under control.
At a news conference on Tuesday, Health Minister Ritsuo Hosokawa said he wants to return the legal limit to the previous level by autumn.
The ministry says 103 workers who started at the plant just after the accident have been exposed to cumulative radiation of more than 100 millisieverts.
But it says all staff who began work from April on have been exposed to less than 100 millisieverts.
Based on the reduced exposure, the ministry has concluded that there is no longer a need to maintain the higher provisional radiation limit." Tuesday, August 30, 2011 13:52 +0900 (JST)
Also at NHK yesterday and today are two stories on contaminated farm land.
Map of radiation levels on farmland released
"Japan's agriculture ministry has unveiled a map of radiation levels in agricultural areas. It shows levels of radioactive cesium are higher than the government-regulated standard in some areas.
The ministry drew up the map based on analysis of soil samples taken at 580 locations in 6 prefectures including Fukushima where the tsunami-damaged nuclear power plant is located.
The map released on Monday shows radioactive cesium exceeding the regulated level of 5,000 bequerels per kilogram in 9 locations. Vegetables and fruit are grown in the farmland.
The government has banned rice planting on farmland contaminated with radioactive cesium higher than 5,000 bequerels per kilogram, following the accident at the Fukushima Daiichi nuclear plant.
The map shows contamination of 8,571 bequerels on a field in Date City and 6,882 bequerels in Iwaki City, both in Fukushima Prefecture.
In areas where rice planting has been prohibited, including Namie Town and Iitate Village in Fukushima, the map shows radioactive cesium of over 20,000 bequerels per kilogram.
The agriculture ministry plans to increase monitoring around the highly contaminated farmland." Monday, August 29, 2011 20:26 +0900 (JST)
This related story today concerns a decontamination experiment on a contaminated rice paddy in Iitate Village.
Paddy decontamination method tested
Japanese researchers have begun testing a method for removing radioactive substances from paddies in an evacuation zone near the Fukushima Daiichi nuclear power plant.
The National Agriculture and Food Research organization is conducting the test in Iitate Village, more than 30 kilometers northwest of the troubled plant, at the request of the government.
On Tuesday, the researchers used a power shovel at a paddy to break up about 3 centimeters of surface soil that had been hardened with a solidifier. The soil was then collected using a vacuum hose…." Tuesday, August 30, 2011 18:22 +0900 (JST)
Also of import is this article from the Japan Times yesterday. Note this is not just about contaminated incineration ash from burning radioactive debris, but also about contaminated dust. Dust means soil contamination at the incinerators (and where ever the ash has been temporarily stored). Read the full story at the link.
Cesium in incinerator dust across east Japan
Monday, Aug. 29, 2011, Kyodo
"High levels of cesium isotopes are cropping up in dust at 42 incineration plants in seven prefectures, including Chiba and Iwate, an Environment Ministry survey of the Kanto and Tohoku regions shows.
…The 16-prefecture survey covered 469 incinerator operators in Tohoku and Kanto from late June, and was reported to a panel of experts at the ministry that is discussing how to safely bury incinerator ash and dust with cesium levels above 8,000 becquerels per kilogram…."
Decommissioning Fukushima?
Here is the complete article on the decommissioning process that appeared in Sunday's Mainichi Daily News. It has a lot of basic details, so readers can understand the enormity and complexity of the process facing TEPCO. They have no basis for comparison as nothing like this has ever occurred before.
Note this quote:
"Katsuta predicts that it will probably take at least 10 years just to determine whether it is possible to remove the fuel.
He adds that it could very well take 50 years before the task of dismantling the reactor and other facilities is completed."
Then consider that Japan announced today that it will apply to hold the 2020 Olympics just 9 years from now!
Experts split on how to decommission Fukushima nuclear plant
August 28,2011
Regardless, what we face is a great unknown to all of mankind.
As Japan struggles with the reality of the contamination on the ground, The rest of the world (except it seems Canada) comes to grips with enormity of this nuclear accident. This is an excellent article as it summarizes the history and current status of the unfolding disaster.
Why the Fukushima disaster is worse than Chernobyl
"Japan has been slow to admit the scale of the meltdown. But now the truth is coming out…."
David McNeill reports from Soma City