Friday, September 30, 2011

Ministry of Education Admits to Plutonium in Iitate-mura in Fukushima

35 kilometers northwest of Fukushima I Nuclear Power Plant.

Jiji Tsushin (5:42PM JST 9/30/2011):

文部科学省は30日、福島県双葉町と浪江町、飯舘村の土壌から、福島第1原発事故によるとみられるプルトニウムが検出されたことを明らかにした。同原発の敷地以外で、検出されたのは初めてという。

Ministry of Education and Science disclosed on September 30 that plutonium has been detected from the soil in Futaba-machi, Namie-machi and Iitate-mura in Fukushima Prefecture, which derived from the Fukushima I Nuclear Power Plant accident. According to the Ministry, it is the first detection of plutonium outside the plant.

Readers of this blog have been alerted to the existence of neptunium-239 (which decays into plutonium-239) in the soil of Iitate-mura, so it should be no surprise. It is no surprise at all either that it has taken more than 6 months for the Ministry of (Re-)Education to admit.

Neptunium-239 has reportedly been detected in Date City also. That's even further away from the plant (60 kilometers).

Thursday, September 29, 2011

WSJ: Potassium Iodide That Never Came

for the residents near Fukushima I Nuclear Power Plant, because of "miscommunication" between the government agencies in the post-accident confusion.

(And after more than 6 months WSJ still tries to give two versions of the same story - one for the Japanese, one for everyone else, withholding information in the Japanese version. See the bottom of the post for more.)

But if you read the article carefully, "miscommunication" alone does not explain the actions taken by both the national government and the Fukushima prefectural government.

But here's the Wall Street Journal article by Yuka Hayashi (9/29/2011) to form your own opinion (emphasis is mine). The WSJ article has a map of Fukushima that shows the affected municipalities:

TOKYO—Government officials failed to distribute to thousands of people pills that could have minimized radiation risks from the March nuclear accident, government documents show.

The disclosure is the latest evidence of government neglect of emergency procedures in the chaotic days after the disaster, in which an earthquake and tsunami damaged the Fukushima Daiichi nuclear plant.

The Fukushima area and some municipalities surrounding the stricken plant had ample stocks of potassium iodide, like most local communities near nuclear reactors around the world. That is a relatively safe compound that can prevent thyroid cancer, the most common serious outcome of a major nuclear accident.

Government disaster manuals require those communities to wait for the central government to give the order before distributing the pills. Though Japan's nuclear-safety experts recommended dispensing pills immediately, Tokyo didn't order pills be given out until five days after the March 11 accident, the documents show.

By then, most of the nearly 100,000 residents evacuated had gone to safer areas and the release of radiation from the plant had subsided from its earlier peaks.

Potassium iodide, which blocks radioactive iodine from entering the thyroid gland, is most effective when taken just before exposure, or within two hours after. It has little effect when administered days after the release of radiation.

In interviews with The Wall Street Journal, several national and local government officials and advisers blamed the delay on a communications breakdown among different government agencies with responsibilities over various aspects of the disaster.

They also cited an abrupt move by the government shortly after the accident, when local officials raised sharply the level of radiation exposure that would qualify an individual for iodine pills and other safety measures, such as thorough decontamination.

"Most of our residents had no idea we were supposed to take medication like that," said Juichi Ide, general-affairs chief of Kawauchi Village, located about 20 miles from the plant. "By the time the pills were delivered to our office on the 16th, everyone in the village was gone."

Mr. Ide said the boxes containing pills, also known as KI, for Kawauchi's 3,000 residents still sit in its now-empty village hall.

The towns closest to the plant had pills in stock, and two of them—Futaba and Tomioka—did distribute them to residents without awaiting word from Tokyo. Two communities farther away from the plant, Iwaki and Miharu, handed out KI pills to their residents based on their own decisions. While Iwaki residents were told to hold off until the government gave instructions, those in Miharu took the pills, leading late to a reprimand from prefectural officials.

Japanese radiation experts say results of subsequent tests among Fukushima residents suggest few had been exposed to dosages large enough to raise the risk significantly of developing thyroid disease, even without the medication. [This statement is simply not true. Actually, the expert at Nuclear Safety Commission the article cites later said in August that at least 40% of the evacuees must have reached the level where they should have taken the KI pills.]

Still, officials from two government bodies—the Nuclear Safety Commission and the Nuclear and Industrial Safety Agency—are asking why the residents weren't given the pills known to be highly effective, particularly among young children.

A NISA official said the agency is investigating the case.

"It was very clear to us experts what we needed to worry about the most was to provide protection against the risk of thyroid cancer among children," said Gen Suzuki, a physician specializing in radiation research who was summoned to the Nuclear Safety Commission following the March 11 accident as a member of its emergency advisory team. "I had simply assumed local residents had been given potassium iodide."

When he learned recently [in August, as clearly stated in the Japanese version of the article] that wasn't the case, Mr. Suzuki said he was "flabbergasted."

The NSC, a national government-policy advisory body, recently posted on its website a hand-written note dated March 13 as proof that it recommended distribution and ingestion of the pills.

NISA, the main nuclear-regulatory body charged with administering the government's nuclear-disaster headquarters, says the note never came.

Kenji Matsuoka, director of the Nuclear Emergency Preparedness Division at NISA, said the agency was still investigating the case of the lost memo. "We are sorry if the message was lost because of the chaos at the disaster headquarters," he said. "Our priority at that time was getting people out as quickly as possible."

Officials in Fukushima prefecture in charge of distributing potassium iodide to local communities say they waited in vain for an instructions from the government's disaster headquarters, headed by then-Prime Minister Naoto Kan.

The failure to disburse the preventive pills follows other examples of how the Japanese government failed to implement available measures aimed at protecting local residents from the harms of radiation.

Some local officials have accused the government of failing to share the data from its radiation-projection systems, which, they said, resulted in their evacuating residents into highly contaminated areas.

Others blame the authorities for taking weeks before asking some residents outside the initial evacuation zones to evacuate, despite signs of radioactive dangers. The government was widely criticized for declaring food, including beef, to have been safely tested, only to find later that contaminated meat had been sold in grocery stores.

Potassium iodide is an inexpensive and readily available substance that governments and local communities with nuclear reactors typically have on hand. Following the Chernobyl accident in 1986, Poland gave 10.5 million children at least one dose of KI soon after the accident, with very few reports of resulting side effects. In the U.S., Congress passed a law in 2002 promoting distribution of the pills to communities near nuclear plants, but the law hasn't been implemented.

Japan's NSC recently posted on its website a document dated March 13 stating Fukushima residents aged 40 or younger should be given potassium iodide, if radiation screening confirmed they received certain levels of exposure. The commission says the document was sent to NISA, the coordinator of disaster response, at 10:46 a.m. that day, two days before the worst day of the accident on March 15, when explosions of two reactors sent thick radioactive plumes across many towns of Fukushima prefecture.

As with most of the correspondence between government officials following the accident, the statement was sent to disaster headquarters in Tokyo by fax, rather than via e-mail. An NSC representative stationed in that office then handed a copy to a NISA official, according to Hideaki Tsuzuku, director of the radiation-protection and accident-management division at the NSC. "It's not for us to know what kind of judgment was made and action was taken after that," he said in an interview.

NISA's Mr. Matsuoka says the agency can't confirm whether a NISA official received the memo, adding that an investigation into the case continues.

NISA issued an instruction March 16 for residents of towns within 20 kilometers of the plant to take KI pills, nearly four days after the government issued an evacuation order for those same towns.

People close to the situation say the delay may have been caused in part by an abrupt change in the standard used in determining what level of radiation exposure would trigger distribution of the pills. According to official disaster manuals written before the accident, anyone who showed radiation readings of 13,000 counts per minute—a measure for external exposure, as opposed to the more commonly used benchmark of sieverts, which measures health effects—was to be given KI pills, as well as a thorough decontamination, including showering and a change of clothes.

On March 14, Fukushima prefecture raised that cutoff to 100,000 cpm. Once the level was raised, people registering between 13,000 and 100,000 were given wet wipes to clean off the top layer of their clothing. They were not given pills.

During March, roughly 1,000 residents registered readings of 13,000 cpm or higher—102 had readings above 100,000 cpm.

"When they told us they wanted to raise the screening level, we instantly knew we had a serious level of contamination," said Mr. Suzuki, the NSC adviser. "They were implicitly telling us they had more people than they could handle logistically, amid the shortage of water, clothing and manpower."

Naoki Matsuda, a professor of radiation biology at Nagasaki University and an adviser to the Fukushima prefecture government, recalled a meeting with prefectural staff after a day of screening local residents on March 14. They reported gauges on radiation monitors set for 13,000 cpm going off repeatedly. "It was very clear the previous level of 13,000 cpm wouldn't work," Mr. Matsuda wrote in an essay posted on the university's website. "We discussed how the staff should turn off alarm sounds and refrain from wearing protective suits and face masks in order not to fan worries among residents."

The NSC was initially cautious about allowing the higher screening benchmark. On March 14, it issued a statement advising Fukushima to stick to the current level of 13,000 cpm, noting that level is equivalent to a thyroid-gland exposure level at which the International Atomic Energy Agency recommends disbursing KI. The World Health Organization advocates one-tenth of that level for giving the medication to children.

The NSC relented on March 20, after the prefecture used the new benchmark for days. In a statement, the commission noted 100,000 cpm was permissible according to the IAEA's screening standard in the initial stage of a nuclear emergency.

Before the government's March 16 order to disburse the iodine pills, two towns located near the plants, Futaba and Tomioka, with a combined population of 22,500, independently ordered some of their residents to take the pills that were in their stock, according to town officials.

Those in other nearby towns never did so, including Namie, where contamination was later confirmed to be worst among Fukushima communities.

In all, after the government's March 16 order, the prefecture delivered to all communities located within 50 kilometers of the plant enough KI pills and powder to be given to 900,000 people. Most were untouched.

It doesn't make sense to me. The article says there were enough potassium iodide pills to give to the residents but the prefecture waited for the national government to give orders to do so. Then what was the move by the Fukushima prefectural government to raise the standard from 13,000 cpm to 100,000 cpm?

It could be interpreted in two ways:

  • They waited for the orders, and they were unwilling to do anything on their own. So they raised the standard so that they wouldn't need to administer KI pills and violate the pre-determined government protocol of waiting for the national government to give orders; or

  • Contrary to what the article says, they did not have enough KI pills to give to the residents. If they were worried about 1000 people exceeding 13,000 cpm, that would mean they didn't even have 1,000 doses.

Either way, to cover this ineptitude, the national government and its experts went on PR blitz, telling everyone inside and outside Japan that everything was under control, that potassium iodide side effects would be more dangerous than a remote threat of thyroid cancer, that the level of radiation was not enough to warrant the distribution of the pills.

Now the new administration is just the same or worse than the old one, and it is determined to extend and pretend. "Cold shutdown" (of the reactor vessels, nothing more), "decontamination" of forests and mountains by picking up dead leaves and cutting off some branches, and this minor nuclear accident will be over. The government will continue to ask local governments like Tokyo to burn the radioactive debris and sludge to share the pain of Fukushima.

----------------------

Oh wait a minute.... I just noticed the part that this WSJ English article mentions but is completely missing in the WSJ Japanese article on the exact same topic. It's this part in red:

The NSC was initially cautious about allowing the higher screening benchmark. On March 14, it issued a statement advising Fukushima to stick to the current level of 13,000 cpm, noting that level is equivalent to a thyroid-gland exposure level at which the International Atomic Energy Agency recommends disbursing KI. The World Health Organization advocates one-tenth of that level for giving the medication to children.

I don't know who the editor is at Wall Street Journal Japan, but the paper sure behaves just as good as the Japanese counterparts. Omit the very inconvenient part that the Japanese authorities may not want the citizens to know from its Japanese version, but state it clearly in the English article to calm their journalistic conscience.

#Radiation Map by Ministry of Education: Chiba and Saitama, and Closing in on Tokyo...

Light-blue areas of elevated air radiation in western part of Saitama Prefecture and western part of Chiba Prefecture look set to come in to Tokyo.

From the Ministry of Education's aerial radiation monitoring (using helicopters) maps released on September 29:

Air radiation (microsievert/hour, 1 meter off the ground):


Cesium-134 and -137 deposition (becquerels/square meter):


And again, for reference, Professor Hayakawa's map (version 4), which by the way does not show much contamination in the western part of Saitama:


Wednesday, September 28, 2011

#Fukushima I Nuke Plant Reactor 2 Achieves "Cold Shutdown"

and Yomiuri Shinbun has this extremely hopeful diagram that they came up with to celebrate the occasion. It shows part of the melted fuel inside the shroud of the Reactor Pressure Vessel and part of it at the bottom of the RPV, both cooled below 100 degrees Celsius inside the RPV, supposedly.

Yomiuri says:

東京電力は28日、福島第一原子力発電所2号機の原子炉底部の温度が、同日午後5時時点で99・4度と、3月11日の事故後、初めて100度を下回ったと発表した。

TEPCO announced on September 28 that the temperature at the bottom of the reactor of Reactor 2 at Fukushima I Nuclear Power Plant was 99.4 degrees Celsius as of 5PM on September 28. It was the first time since the March 11 accident that the temperature there dropped below 100 degrees Celsius.

これで1~3号機すべてで、原子炉を安定して冷却する「冷温停止状態」の2条件の一つである「100度以下」を達成した。

Now one of the two conditions for the stable "cold shutdown", "temperature below 100 degrees Celsius", has been achieved.

The other condition is to suppress the release of radioactive materials. Then the national government will make a declaration that the Fukushima accident is over, residents will return home, and we can all forget about the accident ever happened.

The red dot on the bottom right of the RPV indicates the location where TEPCO has been measuring the temperature.

Never mind that the basement of Reactor 2 is flooded with highly contaminated water. Needless to say, the RPV leaks, and the Containment Vessel (drywell) leaks. And we know that the suppression chamber leaks after it exploded in March 15.

Tokyo Metropolitan Government Will Accept and Burn Disaster Debris from Tohoku, Renews Efforts to Invite Olympic Games to Tokyo

If I thought Yokohama City was so slow in responding to citizens' concern on radiation contamination, I certainly didn't know what the Tokyo Metropolitan government could do.

It doesn't even tell the citizens.

First, the Tokyo government didn't tell anyone that they started dumping the radioactive ashes in the landfill in the Tokyo Bay in May. And now, without bothering asking the citizens, again, it will start bringing the disaster debris from Tohoku that are likely to be radioactive and burn in Tokyo.

NHK News (9/29/2011):

東京都は、東日本大震災で出た岩手県内のがれきを都内に運び込んで焼却処理することを決め、30日、岩手県との間で協定を結ぶことになりました。

The Tokyo Metropolitan government has decided to bring in the disaster debris from Iwate prefecture to Tokyo and burn them, and will sign an agreement with the Iwate prefectural government on September 30.

東日本大震災の被災地では、建物などが津波によって壊されたり、流されたりして出た大量のがれきの処理が問題になっていて、被災地だけでは処理しきれない状況になっています。国が被災地以外の自治体にがれきの処理を求めた結果、東京都は、被災地のうち、岩手県で処理しきれずに残っているがれきを、平成26年3月までの2年半にわたって受け入れることを決め、30日、岩手県との間で協定を結ぶことになりました。

In the disaster-affected areas in Tohoku, the amount of debris from tsunami is simply too huge for the affected municipalities to process by themselves. The national government has requested the prefectures and municipalities not affected by the disaster to take the debris and process. Responding to the request, the Tokyo Metropolitan government has decided to accept the debris from Iwate Prefecture for 2 and a half years till March 2014, and will sign an agreement with the Iwate prefectural government on September 30.

都では、今後、がれきを焼却処理などする業者を公募で決めたうえで、来月から岩手県宮古市のがれきをコンテナに入れて鉄道で都内に運ぶことにしています。がれきを運び出したり、焼却したりする際には放射性物質の濃度が測定され、処理されたものは、最終的に江東区青海の先にある処分場に埋め立てられる計画です。

The Tokyo Metropolitan government will conduct public bidding to decide which contractors will get to process (incinerate) the disaster debris before starting to accept debris from Miyako City in Iwate Prefecture starting next month. The debris will arrive in Tokyo in containers by rail. Radioactive materials will be measured when the debris are shipped, and when they are burned. After incineration, the ashes will be buried in the landfill beyond Aomi in Koto-ku.

東京都によりますと、事前に宮古市にあるがれきや焼却したあとの灰について、放射性物質の濃度を測ったところ、埋め立てが可能となる国の目安をいずれも下回っていたということです。被災地のがれきを東北以外の地域が受け入れるのは東京都が初めてで、都は最終的に東北の被災地からおよそ50万トンのがれきを受け入れる予定だということです。東京都環境局は「被災地の復旧や復興の支援につなげていきたい」と話しています。

According to the government, the density of radioactive materials measured on the debris and in the ashes from burning the debris in Miyako City was lower than the national standard to allow burying. Outside Tohoku, Tokyo will be the first to accept the disaster debris from Tohoku. The Tokyo government plans to accept the total of about 500,000 tonnes of debris. The Metropolitan bureau of environment says "We want to contribute to the recovery and rebuilding of the disaster-affected areas".

The landfill beyond Aomi, Koto-ku is the same one in the Tokyo Bay that the Tokyo Metropolitan government has been dumping the radioactive ashes since May. (See my 9/13/2011 post.)

As to the "safe" level of burying the radioactive ashes and debris, that's totally meaningless now that the Ministry of Environment has allowed the burial of just about anything, even the ashes that measures over 100,000 becquerels/kg of cesium, as long as there are measures in place at the processing facilities that will prevent the leakage. Uh huh.

Apparently, when the Tokyo Metropolitan government answered questions from the Tokyo Metropolitan Assembly on September 28, it was already a done deal. Assemblyman Hirofumi Yanagase, who has been active in alerting the citizens about dangerous radiation levels at sludge plants and waste incinerators in his district in Tokyo, fumes (link is in Japanese):

"The government said during the question and answer session in the Assembly on September 28 that the details were still being worked out. But then less than half a day later they announced a concrete plan of accepting 1,000 tonnes of debris from Iwate Prefecture by the middle of November."

Yanagase also wonders if his colleagues in the Assembly are even aware of radiation and radiation contamination in Tokyo at all. Probably not, Mr. Yanagase, from what I read and hear.

NHK also reports that the Tokyo will launch the campaign to invite the 2020 Summer Olympics to Tokyo but with the reduced budget, after the lavish and unsuccessful campaign by Governor Ishihara the last time (for 2016) was heavily criticized. Now Isihara says he will only use 7 billion yen (US$91.5 million) of taxpayers' money instead of 14 billion yen he spent the last time.

Oh and the national government now wants Tokyo and 7 other Prefectures in Kanto and Tohoku (Fukushima, Miyagi, Iwate, Ibaraki, Tochigi, Gunma, Chiba) to build intermediate storage facilities of highly contaminated soil in their own prefectures, according to Yomiuri Shinbun (9/28/2011). Half of Tohoku and most of Kanto are to have a nuclear waste dump, and Tokyo wants to invite Olympics.

Tokyo looks set to become the most radioactive capital in the world. I bet the governor of Tokyo likes that: "Ichiban (Number One)!" I doubt that it will win the Olympics bid, ever again.

#Radioactive IODINE from Milk from Miyagi Prefecture

(UPDATE: Now, Niigata Prefecture's site says it is radioactive CESIUM, not iodine.)

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Niigata Prefecture announced the result of the test for radioactive materials in milk and milk products on September 29.

Iodine-131 was detected from the milk from Miyagi Prefecture.

According to the Niigata prefectural government site:

Date tested: September 28
Item: Milk
Place produced: Miyagi Prefecture
Radioactive cesium: ND
Radioactive iodine: 19.1 becquerels/kg

Remember those detections in wide areas of Japan in mid August to early September of iodine-131 in sewer sludge, and mostly dismissed as a patient or two in each city being treated for thyroid-related illnesses?

I wish Niigata Prefecture say where in Miyagi, but these milk cows did eat or drink something that was freshly contaminated with radioactive iodine, and I don't think that something was the radioactive sewer sludge.

Fuku I Hydrogen Gas Update: It Was 63% Concentration

and no need to worry, TEPCO will take care of it.

TEPCO also says since there is no oxygen in the pipe that leads to the Reactor 1 Containment Vessel, there is NO DANGER of explosion.

(Uh huh. "There is no danger of explosion" was what they said to the fire department and the Self Defense Force right before Reactor 1 blew up, and then before Reactor 3 blew up.)

From Yomiuri Shinbun (9/28/2011):

 東京電力福島第一原子力発電所1号機の格納容器に通じる配管から高い濃度の水素が検出された問題で、東電は28日、濃度は63%に上ると発表した。

TEPCO announced on September 28 that the concentration of hydrogen gas in the pipe that leads to the Containment Vessel of Reactor 1 at Fukushima I Nuclear Power Plant was 63%.

 配管内で酸素が検出されなかったことから爆発の恐れはないとしているが、東電は29日に配管内に窒素を注入し、水素を排出する。

TEPCO says there is no danger of explosion because no oxygen was detected in the pipe. The company will inject nitrogen in the pipe on September 29 to expel hydrogen.

 高濃度の水素は、格納容器から放射性物質の漏出を抑えるための排気装置で使用する配管から見つかった。2、3号機でも同様の配管の水素濃度を調べる。

The high concentration of hydrogen was found in the pipe that was to be used as part of the filtering system to suppress the leak of radioactive materials in the Containment Vessel. TEPCO will measure the levels of hydrogen gas in the similar pipes in Reactors 2 and 3.

 水素は、事故直後に核燃料が高温になり燃料を覆う金属と水が反応して発生したものとみられる。空気中に4%以上の水素と5%以上の酸素が同時にあると爆発の危険性が高まる。東電では、格納容器の上部やほかの配管にも水素がたまっている可能性があることから、今後の作業では水素がある可能性を前提にして安全対策を行うとしている。

It is considered that hydrogen gas was generated when the nuclear fuel was heated to high temperature right after the accident and the cladding and water reacted. If there are more than 4% hydrogen and more than 5% oxygen in the atmosphere, the chance of explosion increases. It is possible that there is hydrogen gas in the upper part of the Containment Vessel and in other pipes. The company says it will take measures to address hydrogen gas before proceeding on any work from now on.

Looking at TEPCO's handout for the press on September 28 (Japanese only for now), all they will do is to try to expel hydrogen in the pipe alone by injecting nitrogen from the far end of the pipe. They must be operating on the assumption that all the hydrogen in the pipe is from the initial zirconium cladding and water interaction, not the recent or on-going radiolysis, and once the hydrogen currently in the pipe is expelled, that will be the end of the story.

The idea seems to be that as long as the "MO11" valve is closed off, they can just purge hydrogen from the pipe and not worry about any "fresh supply" if any from the Containment Vessel, and they are free to cut the pipe for their gas management system.

There's a word for that in Japanese, "ba-atari-teki", and it can be translated as "ad hoc". The word seems to describe how TEPCO has been dealing with the crisis very well. (Remember the bath salt as tracer?)

Tuesday, September 27, 2011

#Radiation Map by Ministry of Education: Gunma Looks Worse Than Expected

On September 27 the Ministry of Education and Science announced the result of their latest aerial survey of radiation contamination they did over Gunma Prefecture, and many people are dismayed that the contamination in the prefecture looks worse than feared.

So far, the Ministry has done the aerial surveys and mapped air radiation and soil contamination in: Fukushima, Miyagi, Yamagata, Ibaraki, Tochigi, and Gunma.

From 9/27/2011 map, on air radiation (microsievert/hour, 1 meter off the ground):


Cesium-134 and -137 deposition (becquerels/square meter):

Professor Hayakawa's map that he's been updating since April (current version is 4.0):


Monday, September 26, 2011

Japanese Researcher: 2,600 Bq/Kg of Cesium-137 from Rice Grown on Soil Taken from Iitate-Mura

Kazue Tazaki is a professor emeritus at Kanazawa University in Ishikawa Prefecture. She took the contaminated soil from Iitate-mura in Fukushima Prefecture where the villagers were required to evacuate, and grew rice using that soil.

Rice planting and growing was banned in Iitate-mura this year.

Professor Tazaki just harvested the rice, and measured the concentration of cesium-137. The result?

  • From the rice grains: 2,600 becquerels/kg

  • From the straw: 2,200 becquerels/kg

  • From the roots: 1,500 becquerels/kg

  • Soil contamination: 50,000 becquerels/kg

Roughly an equal amount of cesium-134 is to be expected. The transfer rate of cesium-137 in this case was about 0.05.

From Toyama Shinbun, local paper in Ishikawa Prefecture (9/27/2011):

田崎和江金大名誉教授は26日までに、高い放射線量が観測された福島県飯舘村の土を使って稲を栽培する実験を行い、収穫したコメから国の暫定基準値(1キロ当たり500ベクレル)の5倍以上となる2600ベクレルの放射性セシウムが検出されたとする結果をまとめた。同村は福島第1原発事故でコメの作付けが禁止されており、データは土壌の放射線量が農作物に与える影響を裏付ける重要な資料となる。

Kazue Tazaki, professor emeritus at Kanazawa University has compiled the result of her experiment of growing rice using the soil from Iitate-mura in Fukushima Prefecture where high radiation levels have been recorded. 2,600 becquerels/kg of radioactive cesium was detected from the harvested rice, more than 5 times the provisional safety limit (500 becquerels/kg) set by the national government. It was prohibited to plant rice in Iitate-mura because of the Fukushima I Nuclear Power Plant accident. The professor's data will be extremely valuable in studying the effect of radiation in the soil on the agricultural crops.

 田崎名誉教授は6月下旬に福島を訪れた際、高い放射線量を記録した飯舘村長泥地区の水田で土壌を採取。金沢市内の自宅で、この土壌に同市俵町で発芽させたコシヒカリの苗を植えた。

Professor Tazaki collected the soil from the rice paddies in Nagadoro District of Iitate-mura, area with very high radiation, when she visited Fukushima Prefecture in late June. At her home in Kanazawa City, she planted the seedlings of "Koshihikari" which were germinated in Tawara-machi in Kanazawa City on the soil from Iitate-mura.

 今月中旬に稲を刈り取り、北陸環境科学研究所(福井市)で各部分のセシウム137を分析し、1キロ当たりの線量を割り出した。その結果、籾米(もみごめ)からは、最も高い2600ベクレルが検出された。わらは2200ベクレル、根は1500ベクレルで、土壌の線量は5万ベクレルだった。

She harvested the rice in mid September, had it analyzed at a laboratory in Fukui Prefecture for cesium-137 in various parts of the rice and calculated the radiation levels per kilogram. The highest cesium-137 concentration of 2,600 becquerels/kg was found in (unprocessed) rice, 2,200 becquerels/kg from the straw, and 1,500 becquerels/kg from the roots. 50,000 becquerels/kg was detected from the soil itself.

 比較のため、俵町の水田に植えたコシヒカリも分析したところ、放射性物質はまったく検出されなかった。

To compare, "Koshihikari" rice planted in the rice paddies in Tawara-machi was also analyzed but no radioactive materials were detected at all.

 田崎名誉教授は「可食部の放射線量が最も高くなり、私自身も衝撃を受けた。土壌の除染を急ぐ必要があるとあらためて感じる」と話した。27日には福島県南相馬市で農家に能登の珪藻土(けいそうど)を使った除染方法などを指導する。

Professor Tazaki says, "I myself was very shocked to find that the edible part of the rice had the most radiation. The decontamination of the soil should be carried out as soon as possible". She will teach farmers in Minami Soma City in Fukushima on a decontamination method using diatomite unique to Ishikawa Prefecture.

Professor Tazaki found a bacterium that absorbs radioactive materials like uranium and thorium in Tanzania earlier this year, where she taught geology after she retired from Kanazawa University in 2009.

Her result makes me very suspicious of the results announced by Fukushima Prefecture. Iitate-mura does have high soil contamination but it is by no means the highest. Judging by the rice hay contamination there are many other locations within Fukushima that may have radiation levels just as high and still grow rice because they lie outside the 30 kilometer radius from the plant. And yet the prefectural government says it's found 500 becquerels/kg of radioactive cesium at most from one location, and the rest is below 200 becquerels/kg.

It is also possible that the professor scraped the top soil only, whereas farmers in Fukushima tilled deeper and thus mixing the highly contaminated soil in the top 5 centimeters with the uncontaminated soil below, lowering the overall radiation.

Well, despite the official ban with the threat of fines, the rice grew in Iitate-mura after all as at least one farmer spread the seed rice directly in the rice paddies. And as this Iitate-mura villager tweets, the rice has grown better than ever with far less work and resources. Why not test that too for radiation, instead of cutting it down?

Japan's National Tax Agency To Test Wines and Sake for Radiation

Now it's National Tax Agency joining other government ministries testing radiation independent of each other. Why National Tax Agency? Because the Agency taxes alcoholic beverages.

The Agency will test wines, sake, and beer. Water and the resulting liquors will be tested but not the ingredients - grapes, white rice, hop, wheat, etc.

Hmmm. That's like Shizuoka Prefecture insisting that the only thing people need to worry about is the radioactive materials in a brewed cup of tea, not the tea leaves...

From Asahi Shinbun (9/27/2011):

日本酒やワインの製造が本格化する時期を迎え、国税庁は26日、出荷前の酒類の放射性物質検査を10月から実施すると発表した。

Now it is a season for Japanese sake and wine making, and the National Tax Agency announced on September 26 that it will conduct the test for radioactive materials in liquors before they are sold in the market, starting October.

 対象となるのは、東京電力福島第一原発から150キロ以内の地域(福島、宮城、山形、新潟、栃木、茨城の6県の一部)の全ての製造場。その他の地域では無作為に選んだ約2~4割の製造場が対象となる。酒や醸造用の水に含まれる放射性物質が食品衛生法で定めた飲料水の暫定基準値(1キロあたり放射性セシウム200ベクレルなど)以下かどうかを調べる。

All the brewers within the 150-kilometer radius from Fukushima I Nuclear Power Plant (part of Fukushima, Miyagi, Yamagata, Niitaga, Tochigi and Ibaraki) will be tested. Outside this area, randomly selected brewers, about 20 to 40% of the brewers, will be tested. The agency will test the liquors and the water that is used for brewing to see if radioactive materials are below the provisional safety limit for drinking water (including 200 becquerels/kilogram of radioactive cesium).

 製造時期にあわせて検査時期も変える。10月はワインなどの果実酒、11月から来年1月は日本酒、2月にビールなどとなっている。

The test will be done according to the time of brewing. In October, fruit liquors including wines will be tested; from November to January next year will be sake, and beer in February.

Rice for sake brewing is different from rice for eating, and each prefecture seems to have its specialty brand or two. Hyogo Prefecture's Nada district is the most famous place for sake brewing in Japan. In east Japan, Niigata Prefecture is famous, and unfortunately the prefecture has also been affected by the radioactive fallout from the plant accident.

Grapes were flowering in April and May. Radioactive cesium has been constantly detected from summer wheat, though not exceeding the provisional safety limit. I haven't seen the test on hops.

Fuku I Hydrogen Gas Update: TEPCO Was Going to Cut the Pipe Without Testing

In case you're wondering what happened to the precise measurement of the hydrogen gas inside the pipe that leads to the Reactor 1 Containment Vessel, the worker who tweets from Fukushima I Nuke Plant says (in Japanese) it will be a few more days till TEPCO can even get the instrument for measurement.

"I'm so glad that we didn't cut the pipe. It may sound incredible but there was no measurement [of flammable gas] scheduled in the initial work plan. But they decided to measure one day before they were going to cut the pipe. Close call. There is no instrument that can measure hydrogen alone, at Fuku I. It will come on September 28, so the measurement may be done on either September 28 or 29. The result seems obvious, but..."

You have to give TEPCO some praise for their dare. They were going to cut the pipe without measuring what could be inside the pipe. But don't breathe a sigh of relief just yet, because the worker also says TEPCO currently plans to cut the pipe anyway while purging the hydrogen gas inside the pipe with nitrogen gas. There seems to be no plan to deal with anything else than this particular pipe, although the regulatory agency NISA has asked TEPCO to conduct similar tests in Reactors 2 and 3.

TEPCO sort of knows how to operate a nuclear power plant. They have zero expertise in how to fix an utterly broken nuclear power plant, but they continue to be allowed to attempt, to the horror and dismay of the northern hemisphere.

Sunday, September 25, 2011

#Radiation in Japan: DoCoMo to Introduce Smartphone with Radiation Detection Jacket

Japan's DoCoMo is set to introduce a smartphone jacket with radiation detection sensor in the "CEATEC Japan 2011", an annual high-tech trade show in Japan, at Makuhari Messe in Chiba which will start on October 4, according to Sankei Biz (9/26/2011).

(Just when the government has launched a sort of smear campaign on small, personal survey meters as "inaccurate"...)

Apple's iPhone and iPod already have an attachment and an application that detects radiation.

According to the Sankei Biz article, DoCoMo's radiation sensor jacket, that will be attached to the back of a smartphone, will allow not only the radiation detection but also data collection over time and sharing, and mapping.

DoCoMo's press release says it will detect gamma radiation. It can detect radiation from 0.01 microsievert/hour to 100 millisieverts/hour, according to Asahi Shinbun. No information about the pricing.

In the photo, the plastic case next to the phone contains radium pellets.

#Radiation in Japan: Evacuation-Ready Zone to Be Abolished on September 30

The Japanese government says it will abolish the "evacuation-ready" zone in 5 municipalities that lie between 20 to 30-kilometer radius from Fukushima I Nuclear Power Plant on September 30, all at once. It may be construed as a declaration by the national government that it is now "safe" to return after slightly over 6 months after one of the worst nuclear accidents in history (which many thing is "the" worst).

Yomiuri Shinbun (9/26/2011):

東京電力福島第一原子力発電所事故で同原発から半径20~30キロ圏を中心に設定された緊急時避難準備区域について、政府は30日に一括して解除する。

The Japanese government will abolish the "evacuation-ready" zone on September 30. The "evacuation-ready" zone was set between 20 to 30-kilometer radius from Fukushima I Nuclear Power Plant after the accident [where the residents are required to be ready to evacuate on a moment's notice and where no pregnant women and small children are supposed to be living].

 松下忠洋経済産業副大臣が26日午前、同区域に設定された福島県川内村の遠藤雄幸村長らに方針を伝えた。

Tadahiro Matsushita, Vice Minister of Economy, Trade and Industry, informed the heads of the municipalities in the zone in the morning of September 26.

 同区域は、緊急時に屋内退避や圏外への避難ができるよう準備しておくことが求められている。南相馬市、田村市、楢葉町、広野町、川内村の5市町村の全部または一部が該当し、原発事故前の人口約5万8000人のうち、約3万人が域外へ避難している。

In the "evacuation-ready" zone, residents are required to be ready to take refuge indoors or evacuate outside the zone in case of a nuclear emergency. The zone includes part or all of 5 municipalities - Minami Soma City, Tamura City, Naraha-machi, Hirono-machi, Kawauchi-mura. Currently, about 30,000 residents out of pre-accident area population of 58,000 have evacuated outside the area.

 今後、各自治体は復旧計画に基づいて学校や住宅などの除染を進めながら、域外に避難している住民らに帰宅を呼びかける。

Each municipality will carry out decontamination of schools and homes based on the "recovery plan" [that it has submitted to the national government], and ask the residents who have evacuated to come back.

Fukushima Prefecture will build new homes for the returning residents, Yomiuri also reports:

東京電力福島第一原発周辺で指定している緊急時避難準備区域を政府が今月中に解除する方針を示したことを受け、福島県は区域内の5市町村に仮設住宅を建設する方針を固め、用地の選定作業を始めた。

On the national government's notice that it will abolish the "evacuation-ready" zone by the end of this month, Fukushima Prefecture is finalizing the plan to build temporary houses in the 5 municipalities whose designation as "evacuation-ready" zone will be lifted. The prefectural government has started the selection process for the locations.

 津波や地震で自宅が壊れた人たちに、より近い場所で暮らしてもらうための措置。

The houses are for people who lost their homes in the earthquake and tsunami, so that they can live closer to their old homes [i.e. come back from their temporary shelters outside the area].

 5市町村は、南相馬市と田村市、広野町、楢葉町、川内村。県は、各市町村が希望する戸数などを聞き取り、建設に着手する。南相馬市からは既に400戸程度の要望を受けている。

The 5 municipalities are Minami Soma City, Tamura City, Hirono-machi, Naraha-machi, Kawauchi-mura. The prefectural government will ask the municipalities how many houses they want built. Minami Soma City has already asked the prefectural government for 400 houses.

Japanese have always been good at construction projects. I mean, good at "dango" profit sharing of all scales and sizes between the contractors and subcontractors, and between them and the government officials.

And "decontamination"? Good luck to them if the data from Watari District in Fukushima City is any indication. Professor Tomoya Yamauchi of Kobe University compared the radiation levels before and after the district's "decontamination" effort, and found that it hardly made a dent. In a place where the removal of contaminated dirt didn't happen, the radiation level doubled in a month, possibly with new deposits of radioactive cesium migrating from the surrounding area. Scrubbing the roofs and walkways with power washer lowered the radiation by 30% at most. (Professor Yamauchi's report is here, in Japanese.)

But the "decontamination" projects, which are usually undertaken by the neighborhood associations with minimal support from the municipal government's cleaning contractors, seem to have an effect of making the residents feel the radiation may have gotten lower because of their own effort, and that it will be OK to continue to be living there.

A cheap, almost ideal solution for the politicians in the national government and the prefecture - decontamination by the residents, no need to pay for evacuation costs, a building boom for temporary houses creating jobs for the locals.

#Radioactive Train in Tokyo Metropolitan Area? Over 10 Microsievert/Hour Inside the Train

See for yourself. An expat from California measured the radiation level inside the train to Narita, and found it was extremely high right where he was sitting.



No, it was not his suitcase. It seems it was that particular seat where he was sitting.

Yes, his personal survey meter could be broken, as he repeatedly wonders in the video, and people just ignore the gaijin telling them the radiation level inside the train is the Fukushima level, while a woman sitting next to him praises his Japanese as native level. Surreal.

This line, Sobu-Yokosuka Line, belongs to JR East, which covers the entire Tohoku, Kanto and about half of Chubu.

Saturday, September 24, 2011

#Fukushima I Nuke Plant: Steam Rising from Reactors 2 and 3

The latest videos of Reactors 2 and 3 at Fukushima I Nuclear Power Plant show steam rising from the locations where the reactors are located.

The video of Reactor 3 was taken on August 24, and the video of Reactor 2 was taken on September 17 when the company sampled the air using the remote-control crane; a video camera was attached to the boom.

You can download the zip files from TEPCO's Photos for Press page for your record (Reactor 3, Reactor 2), or you can view them here, courtesy of the Mainichi Shinbun video page.

Reactor 3, August 24, 2011 (see this document for the view angle):



Reactor 2, September 17, 2011, from the opening on the east side of the reactor building (see this document for the view angle):


According to Asahi Shinbun (9/24/2011), TEPCO thinks:

東電は「湯気の下には原子炉がある。原子炉から漏れた水蒸気が立ち上っているのか、雨が入り込んで原子炉のふたの熱で蒸発しているのではないか」と話している。

"Under the steam are the reactors. It could be either the steam is escaping from the reactor, or the rainwater is evaporating on the lid of the reactor which is hot."

Looking at the videos, they do not look like rainwater being evaporated, as the steam comes out unevenly and sporadically. If it's rainwater I would imagine a steady rise of steam.

TEPCO: It May Be 100% Hydrogen Gas Inside the Pipe Connecting to Reactor I Containment Vessel

First it was reported that "over 10,000 ppm" or over 1% of hydrogen gas was detected at 2 locations in the pipe that connects to the Containment Vessel of Reactor 1 at Fukushima I Nuclear Power Plant. Then it was allegedly "over 40,000 ppm" or 4%.

According to Jiji Tsushin, TEPCO thinks the hydrogen gas concentration in the pipe may be 100%. 1,000,000 ppm.

Still, TEPCO says possibility of explosion is not necessarily high because there is no source nearby that could cause sparks. (Never mind that they were going to use blow torches to cut the pipes...)

Jiji Tsushin (12:28PM JST 6/24/2011): 

福島第1原発1号機の格納容器につながる配管から1%を超える濃度の水素が検出された問題で、東京電力は24日、配管内部の気体はほとんどが水素である可能性が高いと発表した。東電の松本純一原子力・立地本部長代理は同日の記者会見で、「着火源がないので、直ちに爆発のリスクが高いとは言えない」と述べた。

Concerning the detection of hydrogen gas in more than 1% concentration inside the pipe that connects to the Containment Vessel of Reactor 1 at Fukushia I Nuclear Power Plant, TEPCO announced on September 24 that it is highly probable that almost all the gas inside the pipe is hydrogen gas. TEPCO's Matsumoto said in the press conference, "Since there is no source for sparks, it cannot be said that there is a high risk of explosion immediately".

 東電によると、23日午後に配管の出口部分の気体を複数回測定したところ、いずれも「水素を含む可燃性ガスが100%以上」との数字が出た。今後、水素だけを計れる測定器を用意し、正確な濃度を測定する方針。

According to TEPCO, they measured the gas at the pipe exit several times in the afternoon of September 23. Each time, the result showed "flammable gas including hydrogen gas, over 100% ". The company plans to use the instrument that only measures hydrogen, in order to accurately measure the concentration of hydrogen.

It's so TEPCO. First they used the device that could only measure up to 10,000 ppm, and that maxed out. Then they apparently used the device that could only measure up to 40,000 ppm, and that maxed out. So they brought in a bit more powerful instrument, but it measures all flammable gases including hydrogen.

I suppose they were hoping that one of these devices would suffice. But now, even they have admitted that the air inside the pipe may be 100% hydrogen.

(H/T WaveCepter311)

Friday, September 23, 2011

105,600 Bq/Kg of Radioactive Cesium from Apartment Bldg Rooftop in Yokohama City

The apartment building is located in the same Kohoku-ku in Yokohama City where 63,000 becquerels/kg of radioactive cesium was found also from the rooftop of another apartment building, and 42,000 becquerels/kg was found from the dirt around the side drain on the road.

It looks like this person had the dirt on the rooftop tested on his own, and posted the test result sheet on his blog.

Cesium-134: 49,900 becquerels/kg
Cesium-137: 55,700 becquerels/kg
Total radioactive cesium: 105,600 becquerels/kg

Meanwhile, this is how the Yokohama City workers (or the contract workers) "cleaned" the highly contaminated (42,000 becquerels/kg cesium) dirt from the side of the road. No protection, no masks, no rubber boots.


Yokohama City Assembly recently voted down the citizens' petition asking the city not to accept radiation-contaminated disaster debris from Tohoku by the majority vote by the DPJ and LDP and Komei Party.

The city temporarily halted the dumping of radioactive sludge ashes into the ocean as the citizens' protests were fast and furious once they knew about the scheme, but the mayor in the press conference took pains to emphasize that only thing that had gone amiss was that the city officials under her clearly didn't "explain" well enough to the Yokohama residents living in the area around the final dumping site in Minami Honmoku Pier in advance. "We should have explained better to soothe the fear and anxiety of the residents", she said.

The mayor, who fed 80,000 elementary school children in the city with radioactive beef, then went to an APEC's women's meeting in San Francisco and appealed Yokohama. (As what?) And she wants her official residence renovated by city's taxpayers' money.

Something seems to me to be really out of whack in Yokohama City. I've heard Mayor Hayashi speak in the press conference. She speaks well, very dry, businesslike. Maybe that's all she does well - to speak well. Understanding what the issues are or what's at stake is for someone else to do for her.

It Is More Than 40,000 ppm Hydrogen Gas, not 10,000 ppm Inside Reactor 1 CV Pipe

(UPDATE 9/24/2011: It may not be even 40,000 ppm or 4%. TEPCO now says it may be 100%, or 1 million ppm, hydrogen gas. See my post.)

-------------------------------------------------

Just last night I reported on the hydrogen gas detected inside the pipe leading to the Reactor 1 Containment Vessel. TEPCO, according to the report and by their own press conference, said the density was "over 10,000 ppm".

Well. It was an understatement if the worker who tweets from Fukushima I Nuke Plant is correct. He says they went back to test the locations again with the meter that can measure up to 40,000 ppm. The meter maxed out.

It is over 40,000 ppm, or over 4%.

The media and TEPCO reported the number as "over 10,000 ppm", which is technically correct. "Over 40,000 ppm" is definitely over 10,000 ppm.

The worker tweeted:

そして今日は4%まで計れる測定器を準備して測定したら4%Maxだったから、またまた作業中止で発表になったんだ。オイラは化学の事詳しくないからわからなかったけど、水素が4%を越えると爆発する可能性があるみたいなんだ。

And today [September 23; they knew about "over 10,000 ppm" the day before] we went to measure using the meter that can measure up to 4%. It was 4% max. So the work [to cut the pipe] was canceled, and TEPCO made an announcement. I didn't know, as I'm not very knowledgeable about chemistry, but it seems there's a chance of explosion if hydrogen gas is more than 4%.

He is wondering if zirconium cladding is still melting and reacting, producing hydrogen.

But as one reader of this blog points out after putting two posts from yesterday together (the one about Reactor 4 SFP water radiolysis and the one about the hydrogen detection in the Reactor 1 CV pipe), it may be possible that the water radiolysis is happening somewhere deep inside the reactor building where boiling water is getting irradiated and generating hydrogen gas.

First Instance of #Radioactive Rice with 500 Bq/Kg of Radioactive Cesium from Nihonmatsu City in Fukushima

Now the government scientists have some explaining to do, because the soil at that location contained only 3,000 becquerels/kg of radioactive cesium. The government has used the transfer rate of cesium from soil to rice at 0.1, but in this particular instance, if we believe the number for the soil contamination the transfer rate is more like 0.17.

Nihonmatsu City where the 500bq/kg rice was found is located at about 55 kilometers west from Fukushima I Nuclear Power Plant.

Yomiuri Shinbun linked below says it was from Iwashiro District that the radioactive rice was found. But according to the Fukushima prefectural data, the district is not Iwashiro District but Obama District.

From the surveys that have been done so far on rice in locations in Tohoku and Kanto, the transfer rate has been between 0.001 to 0.01, which is what the agricultural scientists have been saying from the beginning.

Now what?

From Yomiuri Shinbun (1:06AM JST 9/24/2011):

福島県は23日、一般米の放射性物質の予備検査で、二本松市の1検体から国の暫定規制値と同じ1キロ・グラム当たり500ベクレルの放射性セシウムが検出されたと発表した。

On September 23 Fukushima Prefecture announced the result of the preliminary survey of regular rice, and said one sample from Nihonmatsu City was found with 500 becquerels/kg of radioactive cesium. The level is the same as the national provisional safety limit.

 国が定めた重点調査区域を指定する基準の1キロ・グラム当たり200ベクレルを超えたため、同市全体が重点調査区域になり、計画していた38地点から約300地点に増やして本検査が行われる。重点調査区域の指定は初めて。

Since the level exceeded 200 becquerels/kg, which is a standard used to determine whether more rigorous survey is necessary, the entire city of Nihonmatsu is designated as "special survey area", and 300 locations in the city will be tested instead of the planned 38 locations when the real survey starts. It is the first time a "special survey area" is designated.

 基準を超える放射性セシウムが検出されたのは、12日採取した同市岩代地区のコメ。この水田の土壌の放射性物質濃度は、1キロ・グラム当たり3000ベクレルだった。ほかの同市産のコメ18検体は、いずれも基準を下回った。

Radioactive cesium exceeding the standard (of 200 becquerels/kg for "special survey area") was found from the rice sample taken on September 12 from a location in Iwashiro District in Nihonmatsu City. The density of radioactive materials [cesium] in the soil in the rice paddy where the rice was harvested was 3,000 becquerels/kg. 18 other samples from the same city all tested below the standard.

 予備検査ですべての検体が基準を下回った市町村は、本検査で、旧市町村ごとに2検体を調べ、基準を下回れば出荷が認められる。重点調査区域では、約15ヘクタールごとに2検体を調査する。すべてが国の暫定規制値以下であれば、出荷が認められるが、上回ると旧市町村ごとに出荷停止になる。

Old municipalities [now incorporated into a bigger city, as in the case of Iwashiro District] whose samples all test below the standard [200 becquerels/kg] in the preliminary survey will only need to test 2 samples per district, and if the 2 samples test below the standard the shipment of rice from the entire district will be allowed. In a "special survey area", 2 samples from every 15 hectares will be tested. If all samples test below the national provisional safety limit, then the shipment of rice from the district will be allowed. If one sample exceed the provisional safety limit, the shipment is banned for the entire district.

In Japanese, this type of testing is called "ざる" - pronounced "za-ru" - sieve. It still caught 500 becquerels/kg cesium rice, to the dismay of Fukushima producers and the prefectural government.

Well well. The Fukushima prefectural government sat on the data for 8 days. This particular sample was taken on September 12 along with other samples in Nihonmatsu City, and the other results were published on September 15, which showed the level of radioactive cesium between ND and 61 becquerels/kg.

More than 10,000 ppm Hydrogen Detected Inside the Pipe That Leads to Containment Vessel of Reactor 1

Speaking of hydrogen, TEPCO just announced it detected hydrogen at 2 locations inside the pipe that leads to the Containment Vessel of Reactor 1.

TEPCO's handout for the press on September 23 says (not their exact words):

  • TEPCO was planning to cut the pipe for the spray system to install a gas management system for the Reactor 1 Containment Vessel;
  • Before cutting, they measured hydrogen inside the pipe to be safe. More than 10,000 ppm hydrogen was detected;
  • They won't cut the pipe until the safety is assured.

10,000 ppm is equivalent to 1%. As we know from the previous post, if the hydrogen density is more than 4% in the air, a hydrogen explosion could happen.

The company assures us, according to Yomiuri Shinbun, that the existence of hydrogen in the pipe had been expected, although the density was higher than expected, and that there would be no danger of an explosion.

So if TEPCO says "more than 10,000 ppm", it either means they didn't bring the instrument that could measure higher than 10,000 ppm, or they don't want you to know how high.

I wouldn't be surprised at either. We haven't heard anything more about the location near the exhaust stack for Reactors 1 and 2 that measured "more than 10 sieverts/hour". Was it 11 sieverts? 20 sieverts? 50 sieverts?

It could be the same here in the pipe. "More than 10,000 ppm" could be 11,000 ppm, 20,000 ppm, or 40,000 ppm.

Yomiuri also mentions the reassuring word from TEPCO:

東電は、4月から格納容器への窒素を注入しており爆発に不可欠な酸素がほとんどないと思われることから、直ちに爆発の心配はないとしている。

TEPCO has been injecting nitrogen into the Containment Vessel since April, and it is considered there is hardly any oxygen that would be required for an explosion, according to the company. TEPCO says there is no immediate danger of explosion.

Here we go again, "no immediate" danger. (Calling Mr. Edano...) That word makes me nervous.

Besides, the very fact that the water being injected into the Reactor Pressure Vessel somehow ends up in the basement means the Containment Vessel is leaking badly. Nitrogen that's been injected since April is leaking, as the pressure doesn't go up at all. How would they know that there is hardly any hydrogen left? It could easily leak in from outside, couldn't it?