Radioactive cesium may have reached Hokkaido (NHK, Nov 15, 2011)
A team of researchers says radioactive cesium discharged from the damaged Fukushima Daiichi nuclear plant may have contaminated soil in Hokkaido and areas of western Japan more than 500 kilometers from the plant.
The international team, including researchers from Nagoya University, simulated the spread of radioactive materials. They combined global atmospheric patterns with nationwide radioactive measurements taken over one month from March 20th, 8 days after a hydrogen explosion at the Fukushima plant.
The researchers say the results suggested that some cesium-137 had reached the northernmost island of Hokkaido, and the Chugoku and Shikoku regions of western Japan.
They say the radioactive material may have accumulated in the soil due to rain.
Cesium-137 has a half-life of 30 years.
But the research team says the pollution is not high enough to require decontamination.
The radiation density per kilogram reached 250 becquerels in eastern Hokkaido, and 25 becquerels in mountainous areas of western Japan.
Nagoya University professor Tetsuzo Yasunari says the simulation suggested cesium had dispersed across a wide area. He called for a nationwide testing of soil, and warnings of hot spots where radiation levels are high.
If you have food safety and shopping concerns, watch this really useful video clip on food safety to watch is Food safety in Japan: Random sampling results and a trip to the supermarket (by William)
Contaminated water still a headache for TEPCO (Japan Times, Nov 15 )
Tokyo Electric Power Co. has fought an eight-month battle to decontaminate the massive amounts of radioactive water in the reactor basements of the Fukushima No. 1 plant, and the struggle is far from over.
Though it continues to process contaminated water currently flooding the basements of the reactor and turbine buildings for recycling to cool the reactors, the utility has yet to come up with a way to drain all the water from the buildings. With the trouble unlikely to be resolved anytime soon, the threat of further soil, groundwater and sea contamination near the power plant continues.
Tepco originally planned to process 200,000 tons of contaminated water and remove it all by the end of this year, but some 200 to 500 tons of groundwater flows into the buildings every day, rendering this option impossible.
The massive inflow of groundwater indicates the basement walls may be cracked, and thus there is a risk that the contamination can spread to the outside environment. Tepco does not know exactly where the groundwater is coming in from.
The amount of groundwater changes depending on the weather, and increases when it rains, Tepco spokesman Junichi Matsumoto said Friday.
Groundwater around the Fukushima plant flows from mountains in the west toward the Pacific.
Tepco takes groundwater samples every day and has so far said the contamination has not spread below the water table or, during the current cleanup operations, to the sea, at least to any significant extent.
Matsumoto stressed the importance of keeping the current water levels both inside and outside the reactor and turbine buildings constant.
The water level inside the reactor and turbine buildings is about 3 meters above mean sea level, and lower than the groundwater, which is 5 to 6 meters above sea level.
As long as these water levels are kept in balance, the contaminated water will not leak into the ground, he said.
“We will maintain the current balance for a while,” said Matsumoto, adding that the utility is not sure how long it will have to do so.
This means the water from inside the buildings will not leak out and contaminate the groundwater. But because groundwater continues to flow into the buildings, Tepco’s water removal efforts are endless and until the problem is resolved, the plant won’t be brought under control.
The reactor basements contained 77,000 tons of radioactive water as of Nov. 8. Until most is cleared out, it won’t be possible to spot cracks or holes in the containment vessels.
In addition, the amount of radioactive waste, particularly sludge, created through processing tainted water keeps increasing. The amount of sludge was 581 cu. meters as of Nov. 8. Reactors 1, 2 and 3, which suffered meltdowns, are currently being cooled by circulating the contaminated water, which is being processed before it is pumped in.
To keep the radioactive water from draining into the sea, Tepco started constructing an underground wall between the shore and the reactor buildings late last month.
The wall, about 800 meters long and 22 to 23 meters deep, will take two years to complete.
Experts say, however, that building the containment wall just on the east side will not be effective.
“The groundwater keeps flowing in the direction of the sea. Even if the wall blocks a certain amount of it, the water will accumulate behind it, eventually build up and flow around the wall into the ocean,” said Yoshikazu Suzuki, who heads Chiba-based Kimitsu System Co., which specializes in soil and water decontamination.
It would be more effective to build a wall around the west, north and south sides to keep the groundwater from reaching the reactor and turbine buildings rather than building a wall by the sea, said Suzuki, who surmises the contaminated water is already flowing into the groundwater and sea. He said Tepco should then dig wells at the plant complex to pump the contaminated water out of the ground.
Tepco considered the full enclosure option but decided against it for now because it entails further risk and would upset the current water level balance, posing the danger of the contaminated water inside the buildings escaping into the ground.
Taking thyroid tests to the children in Fukushima (NHK, Nov 14, 2011)
Doctors in Fukushima Prefecture are hitting the road to improve children’s’ access to thyroid tests in an effort to spot possible health problems associated with the nuclear accident in the prefecture.
Medical personnel visited a health center and a nursery school in Kawamata Town on Monday and conducted ultrasound scans on about 240 children. The town is about 47 kilometers from the Fukushima Daiichi nuclear plant.
The tests, which began last month, were initially available only at a medical university in Fukushima City.
People not living in the city found it hard to bring their children to the university for the tests.
The tests cover about 360,000 children in the prefecture who were 18 years old or younger as of April 1st, about 20 days after the accident.
Radioactive iodine released from the nuclear plant could accumulate in the thyroid glands of children and raise their risk of developing cancer.
The results of the tests will be mailed out in about a month.
The Fukushima children will undergo thyroid checks every two years until they turn 20, and once every five years after that.
“In just one hour, had the bus not moved, the 1,000 microsieverts an hour — the highest encountered on the media tour — would have exposed everybody to a dose in excess of the annual legal limit for ordinary citizens.
Still, the route was chosen carefully to keep radiation exposure as low as possible for the journalists, who were not allowed inside any structures except one quake-resistant headquarters building.
In August, Tepco found that the bottom of an exhaust pipe between reactors 1 and 2 was still emitting radiation greater than 10 sieverts (or 10 million microsieverts) an hour, the highest level detected so far. One-time exposure to 10 sieverts is lethal.
But Masao Yoshida, the plant’s general manager, who has led the effort by thousands of workers to contain the crisis since March, stressed to the reporters that the plant has been safely stabilized and the likelihood of a large-scale leak of radioactive materials is low.
At the same time he admitted the plant is still a very dangerous place for the workers.
The facility “has been stabilized sufficiently enough to ease the worries of local people (outside the no-entry zone). But some conditions are still very tough for working,” Yoshida said at the plant’s control center.
Indeed, although the temperature at the bottom of the reactor pressure vessels has been kept below 100 degrees for weeks, preventing coolant water from boiling off and spewing large amounts of radioactive materials into the atmosphere, reporters still saw many buildings left half-destroyed, their windows shattered.
In spite of mobilizing about 3,000 workers a day, Tepco has only been able to focus on fixing and maintaining the critical ad hoc water-circulation system to cool the melted fuel in the cores of three reactors. …
Although nuclear fission ceased when the reactors were automatically shut down shortly after the monster earthquake shook the plant, melted fuel will continue to emit decay heat for years to come. Even this relatively weak product of radioactive decay is powerful enough to melt the fuel fragments again if the injection of coolant water is disrupted long enough.
A worst-case scenario was released by Tepco on Oct. 1, along with a plan for dealing with it.
According to a computer simulation run by the utility, if the cooling system is disrupted for any reason, the temperature of the fuel fragments would reach 2,200 degrees in 38 hours.
At that point, the fuel fragments would melt again, releasing large amounts of radioactive materials into the environment, according to the scenario.
Tepco, however, has already set up multiple backup pumps and water lines as well as placing firetrucks on standby to inject water into the reactors as a last resort.
Even if multiple accidents occur, Tepco claims it would be able to resume injecting water within three hours, saying the probability of another meltdown is extremely small.
Some backup systems have been set up nearby, on land 35 meters above sea level to survive monster tsunami.
Kenji Sumita, a professor emeritus of nuclear engineering and a former deputy chief of the Nuclear Safety Commission, basically agrees with Tepco’s views on the safety of the reactor and cooling system.
“I don’t think any large leakage of radioactive materials is likely any more unless (Tepco) makes a very big blunder” in dealing with an emergency, he said.
Still, concerns that a big temblor could wreak havoc can’t be dismissed as Tepco spends at least the next 10 years cooling the reactors, waiting for the decay heat to fall off far enough for the melted fuel to be removed. …” Read the rest of the article here.
In other related news:
Power plant chief details Fukushima nuclear disaster (Mainichi, Nov 14)
Gov’t to reinforce protection of nuclear plants from terrorists (Kyodo, Nov 15)
Youtube clip on the massive anti-nuclear demonstration in Fukuoka Nov. 12, 2011
In earlier news:
Japanese food retailer promises radiation-free food (Blog by Wakao Hanaoka | November 9, 2011)
Reactor accident Fukushima – New international study on emissions of radioactive substances into the atmosphere Excerpts from the [Press Release Oct. 21 joint press release by ZAMG and BOKU]:
“A new study by an international team of researchers estimates the emissions of the radioactive noble gas Xenon‐133 and the aerosol‐bound nuclide Caesium‐137 from the Japanese NPP Fukushima Daiichi.”
“The main result of the investigation is that the emissions from the power plant started earlier, lasted longer and are therefore higher than assumed in most studies conducted before.”
“Regarding the radioactive noble gas Xenon‐133, the results indicate an emission of 16700 Peta‐Becquerel (1 Becquerel is one radioactive decay per second, 1 Peta‐Becquerel equals 1015 Bq). This is the largest civilian noble gas release in history, exceeding the Chernobyl noble gas release by a factor of 2.5. There is strong evidence that emissions started already on 11 March 2011 at 6:00 UTC, which is immediately after the big earthquake. Xenon‐133 is neither ingested nor retained in the inhalation process and therefore of less health concern, but it is important for understanding the accident events.”
“Regarding Cesium‐137, which is of high relevance for human health due to its physical properties and the long half‐life time of 30 years, the new estimate shows that emissions started earlier and ended later than assumed in most studies so far. The total release amounts to 36 PBq, which equals 40% of the Chernobyl emissions. About 20% of the caesium was deposited on Japanese territory, while about 80% was deposited in the water.”
“The study was conducted by a team of researchers from the Norwegian Institute for Air Research (NILU) in Kjeller, Norway, the Institute for Meteorology of the University of Natural Resources and Life Sciences (BOKU‐Met) in Vienna, the Austrian Central Institute for Meteorology and Geodynamics (ZAMG) in Vienna, the Institute of Energy Technologies from the Technical University of Catalonia in Barcelona (INTE), Spain, and by the Universities Space Research Association, Columbia, MD, USA.”
‘Harmless Xenon cloud is known to cause dramatic increase in lung cancer‘ Captured on a Youtube video and speaking on the 11th March — 15th March release of Xenon gas this week, is Dr. Helen Caldicott seen chatting with Arnold Gundersen, a nuclear energy consultant with Fairewinds Associates [Dr Helen Caldicott had in March earlier declared “Why I am leaving Vancouver BC Canada, Thanks Fukushima, Japan“]:
- The xenon cloud bombards people with external gamma rays which are really powerful x-rays… as they decay, they turn into iodine, cesium.
- Dramatic increase, a measurable statistically meaningful increase in lung cancer in people that were in that cloud [during Three Mile Island]. That shows up about 3-5 years after the accident.
Most, if not all, reports on this subject did not mention that xenon posed a health risk. In fact, it was the opposite:
- “Xenon 133 has a half life of 5.2 days and is relatively harmless, Tetsuo Ito, the head of Kinki University’s Atomic Energy Research Institute, said by phone.” –Bloomberg
- “Xenon itself is harmless as it’s not absorbed by organisms or by the environment, and is dispersed in the atmosphere.” –Nature.com
186,000 Becquerels/Kg Radioactive Cesium in Aizu Wakamatsu City in Fukushima(Sankei Shinbun (Aug 16, 2011) … found from the sludge in the drain. Aizu Wakamatsu City is 100 kilometers west of Fukushima I Nuclear power Plant.
The Fukushima District Court Aizu Wakamatsu Branch (in Aizu Wakamatsu City, Fukushima Prefecture) announced on August 16 that 186,000 becquerels/kg of radioactive cesium was found in the sludge in the drain in the court compound. The Aizu Wakamatsu Branch of the Fukushima District Court is located 100 kilometers west of Fukushima I Nuclear Power Plant. The radioactive sludge will be removed under the guidance from Fukushima Prefecture and Aizu Wakamatsu City. (Source)
“China sent a survey ship and taking seawater samples off the coast of Fukushima back in June and July. The State Oceanic Administration now says the contamination of the Pacific Ocean may extend as far as 800 kilometers (497 miles) off the coast of Fukushima, as reported by the Science and Technology Daily (ST Daily) in China, according to Asahi Shinbun.
An independent radiation test in Toronto Canada has revealed startling levels of radiation just days after famed nuclear expert Arnie Gundersen claimed that radioactive rain would continue to hit the west coast for upwards of a year.
The radiation test was conducted with what looks to be a quality Geiger counter by a knowledgeable citizen.
A similar independent test taken last week in Oklahoma City also revealed dangerous levels of radiation in the rain.
Oklahoma health officials confirmed that they had indeed viewed the “alarming” video which showed the test and were currently looking into it further.
A private individual has posted a Youtube video on radioactive rainfall in St Louis at 270+ times greater than background radiation- 2.7 mR/hr (Oct 17)
Aug 6 Oklahoma City: First Rain Since Drought Started … Is Radioactive – “Rain stopped long enough to go outside and see what came down in the rain. Got rain sample from top of plastic trash bin. Started raining again toward the end of the video. I had to stop and get out of it. You can come to your own conclusion of what is going on in this video.” Read more.
Universal Detection Technology (www.udetection.com), a developer of early-warning monitoring technologies that protect against biological, chemical, and radiological threats, commented today on a recent study funded by the US Departments of Energy and Homeland Security that linked elevated radiation in US rain water and food to the nuclear accident in Japan. The study found that following the nuclear accident at the Fukushima Daiichi power plant in Japan, elevated levels of radiation were detected in US rain water as well as vegetables and milk. “The first sample that showed elevated radioactivity was collected on March 18 and levels peaked on March 24 before returning to normal,” said the study led by Professor Eric Norman in the department of nuclear engineering at the University of California at Berkeley. The study also noted that “similar gamma ray counting measurements were performed on samples of weeds collected in Oakland and on vegetables and milk sold commercially in the San Francisco Bay area.”
On October 19-21, 2011, UNDT will be presenting at the RISCON Safety and Trade Expo in Tokyo, which will feature over 283 exhibitors specializing in the security and safety fields and is sponsored by the Tokyo Metropolitan Government, the National Police Agency and the Fire and Disaster Management Agency. UNDT plans to display the full array of its Radiation Detection Devices. These include dosimeter systems used for measurement of cumulative radiation exposures and advanced survey meters and surface monitors used in detection on contamination on surfaces and in particular food and water.
In earlier related news:
Radiation in Our Food (Jun 30, Fox News)
Radiation tests conducted since the nuclear disaster in Japan have detected radioactive iodine and cesium in milk and vegetables produced in California. According to tests conducted by scientists at the UC Berkeley Department of Nuclear Engineering, milk from grass fed cows in Sonoma County was contaminated with cesium 137 and cesium 134. Milk sold in Arizona, Arkansas, Hawaii, Vermont and Washington has also tested positive for radiation since the accident.
Additionally, drinking water tested in some U.S. municipalities also shows radioactive contamination.
Fukushima in Our Food: Low Levels of Radiation from Japan’s Nuclear Meltdown Detected in Milk, Fruit and Vegetable Samples Tested from California Farms (June 1, 2011 Independent Tests Indicate Radiation Is Entering the U.S. Food Chain)
Authorities in the U.S. insist that there is no danger to public health or the environment from the Fukushima nuclear crisis, and that levels of radiation that have been detected in water, air, soil and food in North America since the accident are in such minuscule quantities as to present little to no danger. EPA discontinued its Fukushima radiation monitoring efforts, and FDA says there is no danger to our food or seafood and therefore testing is not necessary. There have been no calls since the accident for heightened nuclear safety inspections or to upgrade or decommission aging nuclear power plants in the U.S.
Yet, in limited testing conducted by states and independent labs since the accident, radioactive iodine and cesium—both toxic to human health—have appeared at elevated levels in milk and vegetables produced in California. Radiation has also been detected in milk sold in Arizona, Arkansas, Hawaii, Vermont and Washington since the accident.
Elevated levels of radioactivity have also been detected in drinking water in numerous municipalities from Los Angeles to Philadelphia, and in soil samples tested in California.