Saturday, April 30, 2011

#Fukushima I Nuke Plant: Ishikawa of JNTI Talks about Reactor Core Conditions

More on 77-year-old Michio Ishikawa of the Japan Nuclear Technology Institute on the situation at Fukushima I Nuke Plant, as he appeared on Asahi TV on April 29.

As I watched the video, I started to like Mr. Ishikawa, who continues to believe in the safety of nuclear power generation. He didn't mince his words, and said what they are doing at Fukushima I Nuke Plant is not working. That surprised some, including the host of the show, as Ishikawa is known as a strong proponent for the nuclear power generation and the nuclear industry.

I watched the segment (video No.2 out of 11) where he discussed the situation at Fukushima I Nuke Plant, particularly about the condition of the reactor core.

Here's what I'd add to the snippets on my previous post. (My summary translation of what Mr. Ishikawa said, not literal; my comment in square bracket):

About TEPCO's "roadmap:

"I believe what they are trying to achieve after 9 months is to cool the reactor cores and solidify them so that no radioactive materials can escape. But they are just doing peripheral tricks like water entombment and nitrogen gas injection. Nitrogen gas, it's dangerous, by the way.

"What they must do is to cool the reactor cores, and there's no way around it. It has to be done somehow."

About the condition of the reactor cores:



"Volatile gas has almost all escaped from the reactor by now.



[He's an old-timer so he's used to curie instead of becquerel as a unit. 1 curie equals 3.7 x 10^10 becquerels (37,000,000,000 becquerels or 37 gigabecquerels).
10 million curies equals 370,000 terabecquerels, and 1 million curies equals 37,000 terabecquerels. I used this conversion table. Tell me I'm wrong! Cobalt-60 alone would make a Level 7 disaster...]



[As Ishikawa explains, a notable opponent of nuclear power, Tetsunari Iida (executive director of the Institute of Sustainable Energy Policy and Kyoto University graduate majoring in nuclear science) nods in deep agreement.]

About "war" at Fukushima I Nuke Plant:




The show's host says "But wait a minute, Mr. Ishikawa, you are a proponent of nuclear power and we expected to hear from you that everything is going well at Fukushima..."

Mr. Ishikawa answers, "Well, if I'm allowed to tell a lie..."

Now, Mr. Tetsunari Iida speaks, agreeing to Mr. Ishikawa's "war" analogy:

"I totally agree with Mr. Ishikawa's assessment of the plant, and that this is a war. The government simply orders TEPCO to "do it". But it is like the Imperial General Headquarters (大本営) on the eve of the Sea of Japan Naval Battle during the Russo-Japanese War [in 1905] ordering merchant ship TEPCO to attack [the imperial Russian navy].

"The government should appoint a commander. TEPCO has a limit as a private business. No one knows what to do. We have to seek the advice from the best and the brightest in the world."

Mr. Hasegawa of Chunichi Shinbun jumps in, and says "We took the numbers from the government like 30% core melt as true, and went from there. But then Mr. Ishikawa says it's a total melt."

Then, Kohei Otsuka, the Vice Minister of Health and Welfare and politician from the ruling party (DPJ), sitting right next to Mr. Ishikawa, butts in, and warns everyone:

"Since none of us knows for sure the condition of the reactor cores, we shouldn't speculate on a national TV."

Mr. Hasegawa overrides the politician, and says "The real problem is that what no one knows is presented to us every day as if it is a fact, like 30% core melt in the chart."


I wish Mr. Ishikawa had punched the light-weight politician in the face. At least he should have laughed at him.

Again, the video (2 of 11) for those of you who understand Japanese:

#Fukushima I Nuke Plant: Japan Nuclear Technology Institute Senior Advisor Says "Reactors 1, 2, 3 All Had Complete Meltdown"

(UPDATED with the video in question at the end. He says not only the fuels have melted down completely but some of them may already be outside the Pressure Vessels.

(He also talks about potentially extremely high concentration of radioactive materials ("like we've never seen before") in the water inside the Pressure Vessel, as the result of core meltdown and continuous water injection.

(For more on his very frank assessment of the reactor core and the situation at Fukushima I Nuke Plant, PLEASE DO GO TO my latest post.)


Michio Ishikawa, the former head of the Japan Nuclear Technology Institute and the current "most senior" advisor to the Institute, appeared on an Asahi TV program on April 29 and shared his candid assessment of Fukushima I Nuke Plant accident.

He is known as one of the most ardent proponents of nuclear power generation. The Japan Nuclear Technology Institute was set up in 2005 by Ishikawa in order to represent the interest of the nuclear industry in Japan and promote nuclear energy.

People who watched this Asahi TV program were surprised to hear him contradict the official government "narrative" (I hate that word, but in this case it is exactly what it is, a "narrative" as opposed to reality) about the plant accident, even as he continues to insist nuclear power plants are safe and 100 milli-sieverts cumulative radiation is perfectly safe not just for the plant workers but for everyone.

Here are some of the comments he made during the program, jotted down by a viewer as he watched the program, and supplemented later with tweets by others. He weaves his own narratives like "no one anticipated such an accident" (oh yes many people did). Original in Japanese, my English translation, [my comment in italic in square bracket]:

"It's an accident that no one in the world anticipated."

[Uh huh. "Who could have known?" That's what every crook in a government anywhere says.]

"If an Act of God happens all the time, it's no longer an Act of God."

[Literal translation of the Japanese word 天災 is "calamity from heaven", a calamity that mere mortals have no control over. The government, the industry, TEPCO are therefore guiltless.]

"The Fukushima accident never would have happened without tsunami."

[Nice try, Mr. Ishikawa. But it was a power failure caused by the earthquake that triggered the accident, and the only transmission tower TEPCO owned that fell during the earthquake was the one that supplied power to the plant. More later.]

"If the power was restored within 8 hours, we wouldn't have the situation we have today."

[Yeah? How could the power have been restored in 8 hours?]

"The accident didn't happen because of the earthquake or the aging plant."

[Yes it did.]

"A nuclear power plant lasts not just for 30 years, but for 60, 100 years."

[And uranium and plutonium will last for "eternity" in human scale.]

"At Fukushima I Nuke Plant, they've been applying minor countermeasures as if it is a normal situation. They need the emergency response."

[Thus the bath salt as tracer - the only comical relief in the whole sorry saga.]

Right now, it's the war with radiation. TEPCO's response is horrendous.

[And where is the government? The response from your own industry, other than trying to win a contract for cleanup jobs? And what do you expect from a utility company?]

Fukushima I Nuke Plant is at war, it's a war zone.

[That I agree. But the US NRC has now joined the Japanese government and says it's under control. Hahaha.]

The government announcement is wrong. I think all the fuel rods have been melted down.

Don't bother with water entombment. Focus on cooling the core as soon as possible.

(Responding to the idea of introducing trailer houses in the earthquake/tsunami affected area, with a smirk on this face) Another tsunami will come.

[So he's expecting another big earthquake that will cause big tsunami?]

It's wrong to evacuate people at mere 20 milli-sieverts. It's safe up to 100 milli-sieverts, so let them go home.

[There we go. Speaking like a true proponent of safe nuclear power. It's safe up to 100 milli-sieverts for civilians! Maybe he should go up there and cheer up the residents.]

Nuclear plant workers are safe up to 250 milli-sieverts.

[Mr. Ishikawa, why don't you take TEPCO's top management with you to the plant, and scoop out the contaminated water with a bucket and help the workers? No need for protection. It's safe.]

(Responding to the question whether it is TEPCO or the Japanese government who has promoted nuclear power) Not TEPCO. It's the government.

No need to stop Hamaoka Nuke Plant [the one on the earthquake faults and in the supposed center of Tokai quake]. It is built strong. Fukushima survived a Magnitude 9 earthquake. [Well, not really.] So, no need to worry about Hamaoka. As long as electricity is available, no need to fear tsunami. [Rrrriiiggghhht. Haven't you heard the news yet, that the nuke plants in Japan do not have adequate backup power supplies to keep cooling the reactors? ]

Among my colleagues, there are those who embarked on the career in nuclear power generation as a revenge against the nuclear bombs [dropped on Japan].

[Well, that revenge has turned out to be the revenge against their own people. How sad.]

For those who understand Japanese, here's the video (part 2 of 11) where he discusses the melted core:

#Fukushima I Nuke Plant: 2 Workers Exceeded 200 Milli-Sieverts

The number is the total of external and internal exposures, as of the end of March. The reason why TEPCO is now announcing? Well TEPCO didn't know, because they couldn't use the whole-body counters that measure the internal radiation at Fukushima I Nuke Power Plant.

Why couldn't the whole-body counters be used? (There are 4 of them at Fukushima I.)

Another Mainichi article (in Japanese, 4/30/2011) explains that there was no power at the plant until the end of March so the counters couldn't be used. By the time the power was finally restored, the air radiation level at the plant had gotton so high that the measurement was rendered irrelevant; even when the radiation was detected by the whole-body counter, they couldn't distinguish between the internal radiation exposure level and the environmental radiation level. TEPCO finally moved the workers who exceeded 100 milli-sieverts to its Iwaki-City facility and measured the internal radiation there, with the help of Japan Atomic Energy Agency.

If TEPCO was so disorganized and rattled with the on-going crisis at Fukushima I and wasn't paying enough attention for the radiation safety for the workers, wasn't it the government's responsibility to ensure the safety of the workers by arranging for the whole-body counters and doing the testing, much, much sooner?

(Oh I forgot. This is the government who said it was basically TEPCO's problem to find enough food, water and blanket for the workers, while it stood by, saying it regretted the situation.)

So it suddenly occurred to the government and TEPCO after 6 weeks that they could take the workers off-site and have them tested?

Just criminal.

Mainichi Shinbun reports the news, but no other major newspapers like Yomiuri or Asahi do. Or maybe they do but I can't readily find the news as they are busy with the British royal wedding.

From Mainichi Shinbun (4/30/2011; my translation, emphasis is mine):

　東京電力は３０日、福島第１原発事故の復旧作業に当たっていた作業員２人が国の規制の限度に迫る２００ミリシーベルトを超える被ばくをしたと公表 した。３月末時点の外部被ばくと内部被ばくを合計した。東電は「福島第１原発の計測機器（ホールボディーカウンター）が使えなかった」として内部被ばくの 測定が遅れたという。２００ミリシーベルトを超える作業員の確認は初めて。

On April 30, TEPCO disclosed that two workers at Fukushima I Nuclear Power Plant have suffered the radiation exposure exceeding 200 milli-sieverts, approaching the [emergency] limit set by the national government [250 milli-sieverts/year]. The number is the total of both external and internal radiation exposure as of the end of March. According to TEPCO, "The whole-body counters at Fukushima I Nuke Plant could not be used", and they couldn't measure the internal radiation exposure. It is the first time that any worker has been found to have been exposed above 200 milli-sieverts.

　３月末までに１００ミリシーベルトを超える外部被ばくをした２１人について、優先的に内部被ばくを測定した。２００ミリシーベルトを超えた作業員 は、３月２４日に３号機のタービン建屋で電源復旧作業中に被ばくし、病院に搬送された３人の協力会社社員のうちの２人。最も被ばく線量が高かった作業員 は、外部被ばく２０１．８ミリシーベルト、内部被ばく３９ミリシーベルトで、計２４０．８ミリシーベルトだった。現在、残る１人の作業員と共に同原発での 作業はしていない。

TEPCO measured the internal radiation exposure of the 21 workers whose external radiation exposure exceeded 100 milli-sieverts by the end of March. The two workers whose total radiation exposure exceeded 200 milli-sieverts are two of the three workers from TEPCO's affiliate companies who were irradiated in the Reactor 3 turbine building [in the highly radioactive water] on March 24 as they were performing the electrical work to restore the power and were sent to hospital. One of them suffered 201.8 milli-sieverts external exposure, and 39 milli-sierverts internal exposure, the total 240.8 milli-sieverts. The two workers no longer work at Fukushima I Nuke Plant.


Of 21 workers [who exceeded 100 milli-sieverts], 8 had 150 to 200 milli-sieverts, 11 had 100 to 150 milli-sieverts. [And 2 exceeded 200 milli-sieverts.]

　作業員（放射線業務従事者）の被ばく線量は、原子炉等規制法に基づく告示などで、５年間で１００ミリシーベルト、１年間では５０ミリシーベルトと 規定。緊急時には別途１００ミリシーベルトを上限に被ばくが許容されるが、国は特例で福島第１原発の復旧に限り、２５０ミリシーベルトに引き上げている。 【奥山智己、八田浩輔】

By law that governs the nuclear materials, nuclear fuels and nuclear reactors, the radiation exposure level of the radiation workers (workers who work in the radiation environment) is set at 100 milli-sieverts cumulative over 5 years, with 50 milli-sieverts as maximum per year. In an emergency, the exposure level can be raised to 100 milli-sieverts, but the national government has raised this emergency limit to 250 milli-sieverts for the work related to Fukushima I Nuclear Power Plant.

Friday, April 29, 2011

#Fukushima I Nuke Plant: Murphy Wins, TEPCO Stops "Water Entombment" Experiment on Reactor 1

After the pressure inside the Containment Vessel of the Reactor 1 dropped down very, very close to the atmospheric pressure, TEPCO decided to stop the experiment of pumping extra water into the Pressure Vessel of the Reactor 1.

The idea was to pump extra water into the Pressure Vessel, which then would leak extra water into the Containment Vessel, which then would be filled with water to the level that's high enough to cool the fuels inside the Pressure Vessel.

For now, the idea of turning the "unintended" water entombment into the "intended" is out.

Snippets from Asahi Shinbun (9:58PM JST 4/29/2011):


On April 29 TEPCO reduced the amount of water being injected to the Reactor 1 [Pressure Vessel] from 10 tonnes/hr back to 6 tonnes/hr for the "water entombment" experiment to fill the Containment Vessel with water, because the temperature and the pressure dropped [more than expected]. TEPCO will continue to observe the changes.

　当初は、注水量を毎時１４トンまで増やす予定だった。ところが、温度や圧力が予想以上に低下。注水を増やす前の１３２度、１．５気圧が、２９日午前５時 現在では１１３度、１．１気圧になった。注水によって格納容器内を満たしていた水蒸気が冷やされて水になり、圧力が下がったとみられる。

The plan, initially, was to increase the amount of water to 14 tonnes/hr. However, the temperature and the pressure [of the Containment Vessel] dropped more than expected. The temperature of 132 degrees Celsius and the pressure of 1.5 atmospheric pressure before the experiment dropped to 113 degrees Celsius and 1.1 atmospheric pressure at 5:00AM on April 29. The steam inside the Containment Vessel is thought to have turned into water with the injection of cold water, lowering the pressure.

　圧力が１気圧を下回ると、酸素を含む外気が吸い込まれ、格納容器内にたまった水素が爆発を起こしかねない。爆発を防ぐための窒素の注入も進めているため 「水素の濃度は１％未満とみられ、爆発のリスクはさほど高くない」とはいうものの、４８時間が過ぎた２９日午前１０時すぎの段階で、注水量を元に戻すこと にした。

If the pressure drops below 1 atmospheric pressure, the outside air that contains oxygen may get sucked inside the Containment Vessel, and cause a hydrogen explosion. As nitrogen gas is being injected, TEPCO thinks "the concentration of hydrogen is less than 1%, and the risk of explosion is not that high." Still, TEPCO decided to reduce the amount of water back to 6 tonnes/hr at 10:00AM on April 29, 48 hours after the start of the experiment.

It was good that the temperature dropped, but the pressure drop was the Murphy..

Here are the precise numbers for the Containment Vessel dry well pressure (from the Plant Parameter sheets from NISA, the latest is linked). It did come awfully close to the atmospheric pressure:

1 atmospheric pressure = 0.1013 MPa

April 29 11:00AM: 0.105 MPa
April 28 5:00AM: 0.125 MPa
April 27 5:00AM: 0.155 MPa (when the experiment started)

Thursday, April 28, 2011

Japan's Minister of Education to Koriyama City: "You Make Me Look Bad" (My Very Liberal Translation)

The Minister is not too happy about Koriyama City removing the radioactive surface soil from the school yards to reduce radiation for the kids.

The public officials in Koriyama City in Fukushima are doing something to proactively protect children by removing the big source of radiation (soil in the school yards) that could harm them gravely. A very rational and compassionate thing to do, though it's just too bad that Fukushima I Nuke Plant continues to spew out radioactive plume far and wide and Koriyama's effort may be in vain in short order.

But it still seems infinitely better than letting the children play outdoors based on an arbitrary number (3.8 micro-sieverts/hr) picked by the national government for this emergency.

But what does the Minister of Education say about this effort? He effectively says to Koriyama officials "Don't be ridiculous. We've told you it is safe at 3.8 micro-sieverts/hr. You're overreacting, and you're making me look bad by implying 3.8 micro-sieverts/hr is not safe for small children!"

From NHK News Japanese (4/28/2011; now my more formal translation):


Japan's Minister of Education and Science Takagi commented on the effort by Koriyama City, Fukushima Prefecture to remove the surface soil in the school yards in the city's public schools in response to the TEPCO Fukushima I Nuclear Power Plant accident, and said "Outdoor activities are possible without replacing the soil and sand," and called for a calm and rational response [to the crisis, the radiation level?].

福島第一原発の事故を受けて、福島県内の一部の学校で屋外での活動を取りやめているなか、郡山市で は、これまでの調査で放射線量が比較的高かった小中学校と保育所の合わせて２８か所で、校庭などの表面の土を取り除く作業を行うことにしています。これに ついて、高木文部科学大臣は閣議のあとの記者会見で、「郡山市の独自の判断だが、土や砂を入れ替えなくても、政府が目安として示した１時間当たり３．８マ イクロシーベルト未満の放射線量なら通常の屋外活動ができる。３．８を若干超えても、１日１時間に収めれば屋外活動ができる」と述べました。そのうえで、 高木大臣は「大事なのは継続的に放射線量の測定をしっかりやることだ。学校の先生に線量計を持ってもらい、安全性の確保を心していくことが重要だ」と述 べ、冷静な対応を呼びかけました。

Some schools in Fukushima Prefecture have stopped outdoor school activities. Koriyama City is planning to remove the surface soil from the school yards of 28 elementary schools, middle schools, and nursery schools that have had relatively high levels of radiation. Minister Takagi said in the press conference after the cabinet meeting, "It is Koriyama City's own decision. However, as long as the radiation level is below 3.8 micro-sieverts/hour which is the guideline provided by the government [his Ministry, actually], children can engage in the normal outdoor activities. Even if the radiation level slightly exceeds 3.8 micro-sieverts/hr, they can engage in the outdoor activities as long as the activities are limited to 1 hour per day." Takagi added, "What is more important is to continuously measure the radiation level. School teachers should be fitted with dosimeters, and they should secure the safety [of the pupils]", calling for a calm and rational response [from Koriyama City].

#Fukushima I Nuke Plant: Why Are the Radiation Levels in Reactors 5 and 6 So High? Or Is There Some Data Mix-up?

(UPDATE 4/29/2011) It seems that has been presenting the temperatures of the Spent Fuel Pools of Reactors 5 and 6 as the dry well radiation levels for Reactors 5 and 6. It does seem like a data mix-up (or data link mix-up). I have notified the site ( of the mix-up.


I don't know where the site "" gets the data (I can't find them in Nuclear and Industrial Safety Agency's press release about the status of the plant and plant parameters), but I've noticed the radiation levels of the dry wells (of the Containment Vessels) in Reactors 5 and 6 have been high, according to, the site that automatically compiles the Fukushima I Nuke Plant accident-related data.

The radiation levels are actually higher than the more troubled Reactors 2 and 3. The Reactor 1's dry well radiation measurement stopped after the radiation registered 100 sieverts/hr on April 8.

As of April 29, Reactor 5's dry well radiation level is 40.3 sieverts/hr, and Reactor 6's dry well radiation level is 33.5 sieverts/hr.

In comparison, Reactor 2's dry well radiation level is 22.1 sieverts/hr, Reactor 3's 14.1 sieverts/hr.

Here are the numbers for the Reactor 5 dry well radiation, from

日付 D/W S/C
4/29 40.3 _
4/28 41.1 _
4/27 40.1 _
4/26 39.5 _
4/25 37.3 _
4/24 38.6 _
4/23 38.2 _
4/22 37.7 _
4/21 37.2 _
4/20 36.7 _
4/19 37.2 _
4/18 36.7 _
4/17 35.9 _
4/16 36.3 _
4/15 35.8 _
4/14 36.1 _
4/13 35.6 _
4/12 35.7 _
4/11 36.3 _
4/10 36.4 _
4/09 35.2 _
4/08 34.8 _
4/07 36 _

And for Reactor 6 dry well radiation, also from

日付 D/W S/C
4/29 33.5 _
4/28 27 _
4/27 28.5 _
4/26 33.5 _
4/25 30 _
4/24 35 _
4/23 26.5 _
4/22 35 _
4/21 26.5 _
4/20 33.5 _
4/19 25 _
4/18 34 _
4/17 24.5 _
4/16 33.5 _
4/15 25 _
4/14 30 _
4/13 23 _
4/12 30 _
4/11 26.5 _
4/10 31 _
4/09 24 _
4/08 30.5 _
4/07 21.5 _


FNN News Network in Japan has a rare footage of Fukushima I Nuclear Power Plant from the ground-level. The video was taken by Shigeharu Aoyama, a member of Japan's Nuclear Safety Commission on April 22.

Mr. Aoyama, a former Kyodo News correspondent, went into Fukushima I Nuke Plant on April 22 as a member of the Nuclear Safety Commission. He said in the other video (that shows the workers) that he was told he could go inside the plant as an expert (Nuclear Safety Commission member), even when the entry was denied for journalists.

You can view the video at this link, or click on the screenshot below

Mr. Aoyama wanted to stop at the Reactor 3, but was told by a TEPCO employee that the radiation was too high to stop. Mr. Aoyama was speechless when he saw the devastation on the ocean side. "I can't believe I'm seeing a nuclear power plant," he said. After 5 minutes into the video, you will see a pipe that goes to the Central Waste Processing Facility, where the highly radioactive water is being transported. The pipe is laid on the ground and protected by lead sheets to protect the workers. Mr. Aoyama was told again that the radiation was too high to venture outside.

I hope the link stays, but the Japanese media, particularly the major TV networks, do not keep the link available for very long.

Youtube has the video that combined three separate videos (the one I linked above is the 2nd part), here -->

US 2012 Election: "The Fed Will Make Sure Obama Wins in 2012"

According to a strategist quoted by CNBC.

From CNBC (4/28/2011):

As we approach next year's presidential elections, the chances of President Barack Obama being ousted by a rival from either side of the political divide are low, according to Thanos Papasavvas, the head of currency management at Investec Asset Management.

“History is very much on the side of the incumbent President and unless we have a double-dip recession with a significant increase in unemployment I don’t believe Obama will lose 2012,” Papasavvas said in an interview with CNBC on Thursday.

On the economic side, any signs of a deteriorating economic environment will see the Fed enacting QE3 (the third round of quantitative easing, or creating money) and hence indirectly reducing the probability of the economy derailing Obama,” Papasavvas added.

With the Republicans divided and no major rival yet to emerge, Papasavvas believes the American right wing will keep its powder dry for 2016 when four years of fiscal austerity will play into their hands.

“With no credible Republican heavyweight to face Obama, even those who have indicated their intent to run like Mitt Romney are unlikely to burn significant political or actual capital for 2012 preferring instead to wait for the 2016 election,” said Papasavvas.

On the separate news, CBS's Bob Schieffer says Donald Trump is a racist for raising doubts about Obama's school grades.

From Mail Online (4/28/2011):

'Trump is a racist': Bob Schieffer attacks The Apprentice host... as liberals desert reality show in protest at anti-Obama campaign

* Trump: 'I am the last person this should be said about.'




The furore came soon after the President released his full birth certificate - finally putting the question of his citizenship beyond reasonable doubt.




(The article continues.)

The campaign theme seems to have been set, and it's "racism" again.

Chubu Electric Wants to Restart Hamaoka Nuclear Power Plant in July

Aaaahhhh please don't....

From Kyodo News English (4/28/2011, full article by subscription):

Chubu Electric Power Co. plans to restart a nuclear reactor at its Hamaoka plant in Shizuoka Prefecture after the present regular checkups in July, the utility said Thursday despite mounting local concerns about the plant's safety amid a nuclear crisis in Fukushima Prefecture.

Chubu Electric President Akihisa Mizuno said the restart of the No. 3 reactor is contingent on local consent, but Shizuoka Gov. Heita Kawakatsu indicated again his intention not to approve the restart in the immediate future.

''Measures against tsunami waves are insufficient. We think that it would be difficult to restart it in July,'' Kawakatsu told reporters in Shizuoka, adding whether to approve the restart will depend on ''new anti-tsunami measures.''

Chubu Electric's Hamaoka Nuclear Power Plant is dubbed by the opponents as "the world's most dangerous nuclear power plant". The plant sit right in the center of the expected Tokai earthquake zone, and the plant itself sits on earthquake faults.

Measures against tsunami waves being insufficient is irrelevant, although they are indeed insufficient (Hamaoka's protection against tsunami is 10 to 15-meter sand berms). As it sits on the earthquake faults and on the soft rock and in the dead geographical center of the expected Tokai earthquake zone, it will be a miracle if the plant remains intact when the big one hits.

Shizuoka Governor Kawakatsu, an Oxford PhD in economic history, seems now to be making it hard for Chubu to re-start the operation after the protests by the local municipalities. But back in March, he was all for re-starting as soon as the then-current emergency measures were satisfactorily carried out. What were the measures? Emergency safety drills. (For more, see my March 24 post.)

Wednesday, April 27, 2011

#Fukushima I Nuke Plant: "Water Entombment" of Reactor 1 Meets Murphy, Pressure and Temperature Dropping

In other words, not as planned by TEPCO.

Asahi Shinbun (11:58AM JST 4/28/2011) reports:

　東京電力福島第一原発１号機の格納容器を水で浸す「水棺」が難航している。東電は原子炉への注水量を２．５倍にして内部の温度や圧力の変化を見る予定で ２７日に作業を始めたが、まず毎時６立方メートルから１０立方メートルにしたところで温度や圧力の低下が長引いた。２７日中に予定していた１４立方メート ルにできずにいる。

"Water entombment" of the Reactor 1 Containment Vessel at TEPCO Fukushima I Nuclear Power Plant is having some problems. On April 27, TEPCO started to increase the water injection to 2.5 times the normal amount to observe the change in temperature and pressure. However, when the water was increased from 6 cubic meter/hour to 10 cubic meter/hour, there was a prolonged decline in temperature and pressure, and the water wasn't increased to 14 cubic meters/hour as planned for later in the day.

　東電が特に気にしているのが、格納容器の圧力が低いことだ。冷たい水が増えたことで、水蒸気が水になっているとみられる。もし１気圧を下回れば外部から 空気が入り込みかねない。水素爆発を避けるために窒素を注入しているが、酸素濃度が高まると、水素と混合して爆発する危険が高まる。東電は２８日、さらに ２４時間、１０立方メートルのまま様子を見ると発表した。

What particularly worries TEPCO is that the pressure inside the Containment Vessel is low. It is thought that the steam has turned to water in the presence of increased, cold water. If the pressure goes below 1 atmospheric pressure the air may enter from outside. Nitrogen gas is being injected inside the Containment Vessel to prevent a hydrogen explosion, but if the amount of oxygen increases [because of the air coming in from outside] the danger increases for hydrogen explosion. TEPCO has announced on April 28 that they will observe the condition for 24 more hours at the water injection rate of 10 cubic meters per hour.


The temperature within the Pressure Vessel was 132 degrees Celsius in the morning of April 27 [when they started the test]. 24 hours later it dropped to 107 degrees Celsius, and it is still dropping.

1 cubic meter of water weighs 1 tonne.

The latest plant parameter (as of 6:00AM JST 4/28/2011) shows the pressure of D/W (dry well) of the Containment Vessel for Reactor 1 at:

0.125 MPa [megapascal] abs [absolute].

1 atmospheric pressure in MPa is 0.1013 MPa.

On April 27 at the start of the test, it was 0.155MPa.

Japan's Ministry of Health to Get Rid of Annual Radiation Limit for Nuclear Plant Workers

The normal limit of 50 milli-sieverts per year is to be eliminated, but 5-year total of 100 milli-sieverts limit remains.

If the limit is eliminated, the workers who will have been exposed to the radiation of more than 50 milli-sieverts but less than 100 milli-sieverts at Fukushima I Nuke Plant will still be able to work at other nuke plants, as long as 5-year total remains under 100 milli-sieverts.

Ministry of Health, Labor and Welfare is for the nuclear industry's health, labor and welfare. Of course, the argument is that unless these workers are able to maintain the power plants (there are 17 of them, with 54 reactors, according to this site), everybody's health, labor, and welfare will be threatened.

From Mainichi Shinbun (3:09AM JST 2/28/2011):

被ばく線量：年５０ミリシーベルト　上限撤廃検討…厚労省

Ministry of Health, Labor and Welfare is considering eliminating the annual radiation exposure limit of 50 milli-sieverts


On April 27, Ministry of Health, Labor and Welfare started to discuss the elimination of the annual radiation exposure limit of 50 milli-sieverts for nuclear plant workers during a normal operation [as opposed to an emergency situation like Fukushima I], while keeping the 5-year limit of 100 milli-sieverts. The nuclear plant workers from all over Japan have been sent to Fukushima I Nuclear Power Plant, and there is a concern expressed by the nuclear industry that there won't be enough workers to do the maintenance work at other nuclear power plants if the current annual limit is kept.


As to the emergency radiation exposure limit, Ministry of Health already raised the 100 milli-sieverts per year limit to 250 milli-sieverts last month, specifically for the work related to Fukushima I Nuclear Power Plant accident.

Hilarity of the Day No.2: NY Post "Russia's nuclear chief says Japan exaggerating Fukushima crisis"

in order to give a break to the insurance companies, says Sergei Kiriyenko, the head of Russia's state nuclear agency Rosatom.

From New York Post (4/26/2011):

SANYA, China -- The disaster at the Fukushima atomic power plant cannot be compared to Chernobyl, Russia's nuclear chief said Wednesday, suggesting that Tokyo was exaggerating the emergency possibly for financial reasons.

"It is hard for me to assess why the Japanese colleagues have taken this decision," Sergei Kiriyenko, the head of Russia's state nuclear agency Rosatom, told reporters in the southern Chinese city of Sanya on the eve of the BRICS summit. "I suspect this is more of a financial issue than a nuclear one."

Earlier this week Japan upgraded its month-old nuclear emergency to a maximum seven on an international scale of atomic crises, placing it on a par with the Chernobyl disaster in 1986. Kiriyenko appeared to suggest that the Japanese authorities were seeking to reduce the burden on insurance companies.

Kiriyenko added that at first the Japanese authorities had thought to downplay the scale of the disaster but now the situation at the plant was improving.

"Our estimates have shown that the level was between five and six," Kiriyenko said. "Today it doesn't reach the sixth level."

France's nuclear safety agency also said this week that the impact of the Fukushima accident was not comparable to the Chernobyl disaster.

Fukushima has had three reactors that have hit problems, compared with one at Chernobyl.

But the Japanese plant has released only one-tenth of the radioactivity disgorged by Chernobyl because its reactor vessels have so far remained intact, thus keeping almost all of the nuclear fuel enclosed.

The previous rating of five had placed the unfolding disaster at the tsunami-hit Fukushima plant northeast of Tokyo on the same level as the 1979 Three Mile Island accident in Pennsylvania.

Level seven of the UN's International Nuclear Events Scale describes events with "major release of radioactive material with widespread health and environmental effects, requiring implementation of planned and extended countermeasures.

2 Radioactive Used Cars from #Fukushima Found Their Way to Nakhodka, Russia

59 Used cars and used small machinery exported from Japan to Vladivostok and Nakhodka in Russian Siberia this month have been found to be radioactive, though the radiation level is negligible.

NHK Japanese reported on April 24 that:

関係者によりますと、このうち、少なくとも今月１６日に新潟港からナホトカに輸入された中古車のうち２台については、福島県からのものであることが車に備 え付けられていた書類から確認できたということです。放射性物質は、タイヤについた泥などから検出され、放射線量は、通常のおよそ６倍に当たる０．７マイ クロシーベルトで、直ちに健康への影響を与える値ではないということです。

According to people involved, at least two of the used cars imported to Nakhodka from the Port of Niigata on April 16 have been confirmed to have come from Fukushima Prefecture by the documents that accompanied the cars. Radioactive materials were found in the dirt on the tires, and the radiation level was 0.7 micro-sievert/hr, 6 times the normal level. There is no immediate ill effect on health at that level.

Hilarity of the Day: Obama Releases "Long-Form" Birth Certificate

Here it is:

And someone opened it in Adobe Illustrator and found "layers". So what? you ask?

My question is not "so what?" but "why now?"

From (4/27/2011):

When the PDF file given from is opened in Adobe Illustrator it shows up in different layers.

Our analysis of the latest controversy: The original birth certificate was probably in a ‘negative’ form, and someone at the White House took it upon themselves to doctor it up so the form can be readable.

Arnie Gunderson: Unit 3 Explosion May Have Been Criticality in Spent Fuel Pool

So, Christopher Busby may not be a total "fiction" after all?


#Fukushima I Nuke Plant: Americium and Curium Found in the Soil

From the samples taken on March 27, from the same places where plutonium and uranium were detected. Now they tell us one month later.

From TEPCO's press release on April 27, 2011 (English):

As part of monitoring activity of the surrounding environment, we conducted an analysis of plutonium contained in the soil collected on March 21st and 22nd at the 5 spots in Fukushima Daiichi Nuclear Power Station. As a result, plutonium 238, 239 and 240 were detected.
(previously announced)

As the result of the plutonium analysis in the soil from the sample from the 3 periodic sampling spots on April 14th, plutonium 238, 239 and 240 were detected as shown in Attachment 1. In addition, as the result of gamma ray nuclide analysis from the same sample, radioactive materials were detected as shown in Attachment 2.

Besides, as the result of the americium and curium analysis in the soil from 2 samples among the 3 periodic sampling spots in which plutonium was detected on March 28th amerium [sic] 241, curium 242, 243, and 244 were detected.

We have reported the results of analyses to the Nuclear and Industrial Safety Agency and the government of Fukushima Prefecture.

We will continue to conduct the similar analysis.

Here's the Attachment 3 that shows the analysis:

Americium and curium do not exist in nature. Half-life of the nuclides are as follows:

Am-241: 432 years
Cm-242: 162.8 days
Cm-243: 29.1 years
Cm-244: 18.1 years

#Fukushima I Nuke Plant: 1120 Milli-Sieverts/Hr Inside the Reactor 1 Bldg, But "Water Entombment" Has Started Anyway

(Picture from TEPCO: Packbot in Reactor 1 reactor building, 4/24/2011)

That high level of radiation would indicate the highly radioactive water from the Pressure Vessel may be leaking outside the Containment Vessel, but TEPCO has decided to go ahead with the plan.

From Yomiuri Shinbun (1:17 PM JST 4/27/2011):


On April 27, TEPCO started the test to increase the amount of water being injected into the Pressure Vessel of the Reactor 1 at Fukushima I Nuclear Power Plant.


The purpose of the test is to observe the change in water level by increased water injection. It is a step toward the "water entombment" that will involve filling the Containment Vessel with water to cool the Pressure Vessel.


The amount of water was increased from the previous 6 tons/hour to 10 tons/hour at 10:00AM on April 27. It is to be increased to 14 tons/hour starting at 4:00PM for 18 hours, and then to be decreased to 6 tons/hour again in the morning of April 28. After that, the robots will go in to check whether there is any leak.

　東電は、２６日のロボットを使った事前調査で、建屋内の数値としては最高の毎時１１２０ミリ・シーベルトの放射線量を記録した場所があったことを 明らかにした。原子炉からの高濃度の汚染水が漏れている可能性があるが、東電は約２時間にわたる調査で漏れ箇所が発見できなかったとして、水棺作業の実施 を決断した。

TEPCO disclosed that during the preliminary survey of the reactor building using the robots on April 26 there was a location that registered 1,120 milli-sieverts/hour, the highest so far for the radiation level inside the plant buildings. It is possible that the highly radioactive water is leaking from the reactor, but TEPCO decided to go ahead with the "water entombment" after no leak was found during the 2-hour survey.

Total 312 tons of water is to be injected before the test is over. We'll find soon enough if there's more Murphy..

Tuesday, April 26, 2011

#Fukushima I Nuke Plant: Charts Showing Release of Radioactive Iodine and Cesium into Air May Be Going Up Again

Found them @Physics Forums, posted by clancy688 today. The poster doesn't link to the original site where the charts came from. Labels are in German, so they could be from DWD (Deutscher Wetterdienst), as CTBTO does not have a mandate to disclose the data.

CTBTO stands for "Comprehensive Test Ban Treaty Organization", and "38" is their Takasaki Station in Gunma Prefecture in Japan.

It looks as if something had happened around April 18, and both cesium 137 and iodine-131 are on the rise again in a volatile fashion in Japan. The US West Coast is following suit.

I do not know and do not guarantee the authenticity of the charts.

Unit is becquerels in cubic meter, and the red dotted line indicates the highest daily amount in Germany (May 1, 1986 in Bavarian Forest) during the Chernobyl accident.


TEPCO has put the Survey Map (radiation contamination map) online. Maps for March 23, 31, April 7, 12, 14, 17, 23 are available for your viewing pleasure.

Maps in English:

Maps in Japanese:

#Fukushima I Nuke Plant: Picture of Reactor 3 Containment Vessel in 1972

From Mainichi Shinbun. More pictures at the link.

Fukushima I Nuclear Power Plant Reactor 3 Containment Vessel, May 1972.

#Fukushima I Nuke Plant: Reactor 1 "Water Entombment" - Same News, Different Spin

First, the Kan administration's favorite Yomiuri Shinbun (4/26/2011):


According to TEPCO, [Reactor 1] building's outer walls were severely damaged by the hydrogen explosion on March 12, but there is no discernible water leak on the Containment Vessel...

Never mind that the hydrogen explosion only blew up the 4th and 5th stories, above the Containment Vessel.

Now, not so favorite but still major news Mainichi Shinbun (4/26/2011):


Also, TEPCO disclosed on April 26 that the survey by the robots inside the Reactor 1's reactor building could not pinpoint the location of the damage on the Containment Vessel.

But no matter. TEPCO and NISA are going with their "accidental entombment" and about to gradually pour over 7,000 tons of water in the Reactor 1 Containment Vessel.


Uh oh. The water level in the Reactor 4 Spent Fuel Pool is not rising enough, and TEPCO suspects a leak.

That's by the way what AREVA said in their presentation in March.

From Mainichi Shinbun (9:57PM JST 4/26/2011; links, emphasis added):


TEPCO disclosed on April 26 that there was a possibility of water leaking from the Reactor 4 Spent Fuel Pool. TEPCO has been injecting water into the Pool, but the water level hasn't risen to the level that they anticipated. [If there is a leak] it would require additional works to remedy the problem, and that may affect the "roadmap" to wind down the crisis.

　東電によると、プールには、使用済み核燃料集合体が１～３号機より多い１３３１体入っている。コンクリート圧送車での放水は、２４日１６５トン、 ２５日２１０トン、２６日１６０トン。しかし、１日の推定蒸発量約７０トンを差し引いても水量が想定より１２～４８トン少ないという。東電は「格納容器へ 流れ出している可能性もある」と説明している。

According to TEPCO, the Reactor 4 Spent Fuel Pool contains 1,331 spent nuclear fuel rods, more than the Spent Fuel Pools in the Reactors 1 through 3. Using the concrete pump, 165 tons of water was injected on April 24, 210 tons on April 25, and 160 tons on April 26. Subtracting the daily estimated evaporation of 70 tons, the amount of water in the pool is 12 to 48 tons less than expected. TEPCO says it is possible that [the leaked] water is going into the Containment Vessel.


Earlier this month, the Reactor 4's reactor building's basement was found to be almost completely flooded with 5-meter deep contaminated water. Radioactive materials in the contaminated water in the turbine building was found to be 250 times as much as 1 month ago. The large amount of contaminated water [in the Reactor 4] poses a new challenge.

Busby: One of the #Fukushima Explosions Was Nuclear

Christopher Busby speaking with Russia Today on April 25.

He thinks one of the "hydrogen" explosions that took place in Fukushima I Nuclear Power Plant was not hydrogen but nuclear. He thinks it was the Reactor 3; the explosion was not inside the Containment Vessel but in the Spent Fuel Pool.

He sticks by his words that Fukushima is much worse than Chernobyl.

He's been having a shouting match (figuratively) with his fellow British nuclear scientists over the gravity of the Fukushima accident, whom he accuses of being in the pocket of the powerful nuclear industry and downplaying the accident.

Busby also called the Guardian writer George Monbiot "criminally irresponsible" for downplaying the Fukushima accident. George Monbiot is the one who wholeheartedly embraced nuclear power BECAUSE OF FUKUSHIMA, back in March 21 in his Guardian article:


Mr. Monbiot should have a PR job waiting for him at the Japan's Prime Minister's Office with his pro-nuclear, anti-CO2 stance, a perfect fit for the embattled PM.

No Foreign Correspondent Showed Up On April 25 Press Conference But the Show Must Go On

NISA's Nishiyama, representatives from other government agencies and TEPCO's representatives gave their regular press conference in English for the foreign correspondents in Japan, except on April 25 no one showed up. They went ahead anyway, reporting the details of Fukushima I Nuke Plant status, asked for questions, and ended the presser.

I find it immensely sad.

(Screenshot from Nico Nico Live video (members only)):

williambanzai7: ARe You EXPeRieNCeD?

By williambanzai7 at Zero Hedge: "There's a White House over yonder... "

Go Dr. Paul!

OT: #Fukushima I Nuke Plant Mascot Bird Was an Ostrich

I'm sorry for the birds but I couldn't help noticing the irony. Sort of "Schadenfreude".

Ostrich was the symbol bird (or mascot bird) for Fukushima I Nuclear Power Plant...

(The photo is NOT one of the poor birds in Fukushima.)

Yomiuri Shinbun (in Japanese; 4/26/2011) reports that 30 ostriches in the ostrich farm in Ookuma-machi in the no-entry zone are left to die, because there will be no one to feed them. Already 15 of them died.

The ostrich farm is owned by a former council member of the town nearby (Futaba-machi).

Fukushima I Nuclear Power Plant, which straddles Ookuma-machi and Futaba-machi, started to keep ostriches on the plant compound in 2000 as part of the PR campaign. The reason for picking the ostrich as the symbol for the plant?


"Just like an ostrich that grow big on small feed, the nuclear power plant that generates large amount of electricity with small amount of uranium"

Well, the plant had over 1,700 tons of uranium and MOX fuels when the earthquake/tsunami hit on March 11 which don't seem "small", but never mind.

The ex-councilman decided to raise ostriches himself at about the same time.

The owner, according to the article, having visited nuclear power plants in Japan and abroad, knew immediately that it was a very serious accident when the hydrogen explosion happened, and he escaped immediately.

Monday, April 25, 2011

#Japan #Earthquake: Ground Noise in Yonezawa, Yamagata Prefecture

Yonezawa City is in southern-most part of Yamagata Prefecture, bordering Fukushima Prefecture.

A curious bit of news from Yomiuri Shinbun (in Japanese; 4/26/2011), that Japan Meteorological Agency's Yamagata Branch has been receiving reports of loud ground noise in Yonezawa City since early April.

JMA Yamagata Branch speculates that the noise may be caused by small, shallow earthquakes that have been happening very frequently since March 18 in the adjacent Kitakata City and Kita Shiobara-mura in Fukushima Prefecture, and is telling the Yonezawa residents to remain calm.

There is no marked volcanic activity in the Mount Agatsuma on the south of the city.

PM Kan's Incoherent Op-Ed on Fukushima I Nuke Plant Accident

Why did he bother?

From the Op-Ed piece that Kan wrote, no doubt in Japanese, and had it translated and appeared in the International Herald Tribune/New York Times on April 15, 2011, taken from the Prime Minister's Office website:

I take very seriously, and deeply regret, the nuclear accidents we have had at the Fukushima Daiichi plant. Bringing the situation at the plant under control at the earliest possible date is my top priority. Leading a unified effort by the government, I have mobilized all available resources to combat the risks posed by the plant, based on three principles: first, give the highest priority to the safety and health of all citizens, in particular those residents living close to the plant; second, conduct thorough risk management; and, third, plan for all possible scenarios so that we are fully prepared to respond to any future situations. For example, we continue to make the utmost efforts to address the issue of outflow of radioactive water from the plant into the ocean. In addition, the government has taken every possible measure to ensure the safety of all food and other products, based on strict scientific criteria. We have taken great precautions to ensure the safety of all Japanese food and products that reach the market and will continue to do so. To assure domestic and foreign consumer confidence in the safety of Japanese food and products, my administration will redouble its efforts to maintain transparency and keep everyone informed of our progress in the complex and evolving circumstances at the Fukushima Daiichi plant.

"I take very seriously, and deeply regret"

Well that's good to know.

"Leading a unified effort by the government,"

Then why is it that the "Unification headquarters" of his to deal with the accident had its first presser on April 25, more than 6 weeks after the accident started? And why is people like Nishiyama of NISA saying at every awkward question that "it is basically the problem of a private company, TEPCO"?


This is the most cynical statement of the whole thing. Why? Because...

  • This government hasn't even checked the health of the residents closest to the plant since the accident started. For the residents in the now-planned evacuation zone like Iitate-mura, this government had been telling them and everybody else that the radiation there did not pose serious negative effect on health, and this government laughed at the IAEA's recommendation on March 31 to evacuate the residents of the village ASAP.

  • This government is more than willing to expose toddlers and small children in Fukushima to radiation higher than what nuclear plant workers in the normal operation are exposed, and feed school children in Fukushima with lunches made from foodstuff made and harvested in Fukushima Prefecture, insisting they are safe.

  • This government sent its shills (prominent professors in prominent national universities) to cities and towns in Fukushima preaching safety as long as they were outside the 20-kilometer radius from the plant, when the government was flying blind in the late March regarding the true situation of the plant.

  • This government didn't bother telling the citizens that the enormous radioactive materials had been released after a series of explosions because they didn't feel like announcing it, exposing residents in Kanto and Tohoku to high radioactive iodine and cesium without them knowing it.

  • This government didn't bother sharing over 2,000 simulations done by one of the Ministries as to where radioactive iodine and cesium may fly. They finally agreed to release the data on April 25, when for all intent and purposes it was too late by 40 days.

  • This government didn't bother alerting the foreign governments about the huge release of airborne radioactive materials, or the dumping of the radioactive water into the ocean. It kept attacking (still does) the foreign media for "sensationalizing" the accident. Now the whole northern hemisphere has been wrapped in the radioactive plume from Fukushima.

  • This government is still lying to the citizens of Japan that the natural radiation exposure per year is 2.4 milli-sieverts, which is the international average; the Japanese average is much lower at 1.4 milli-sieverts per year, with Tohoku and Kanto average less than 1 milli-sievert per year.

So what does Kan propose to do now, to ensure the safety and health of all citizens? What does he say?

Other than testing the food, not much. So much for his "concerns" for citizens.

He talks about the effort to stop the leak into the ocean, and how they are scientifically testing the food for radioactive materials (i.e. scrubbing the vegetables under running water before testing) so that people have "confidence" in consuming Japanese foods. As if anyone with a brain cell left would believe the government numbers, other than those who want to believe.

The next paragraph shows Kan has no intention of winding down the nuclear power generation in Japan. He claims all it takes is the safety precaution. Uh huh. And he still babbles about global warming.

I pledge that the Japanese government will promptly and thoroughly verify the cause of this incident, as well as share information and the lessons learned with the rest of the world to help prevent such accidents in the future. Through such a process, we will proactively contribute to the global debate to enhance the safety of nuclear power generation. Meanwhile, regarding a comprehensive energy policy, we must squarely tackle a two-pronged challenge: responding to rising global energy demand and striving to reduce greenhouse gas emissions to combat global warming. Going forward, I would like to present a clear vision to the world that includes the aggressive promotion of clean energy that may contribute to solving global energy issues.

At this point, I think the rest of the world would rather have Japan burning away fossil fuels and create CO2, rather than spewing endless amount of radioactive materials into the air, the soil, and the ocean.

Ability to handle nuclear power generation is not in the DNA of the Japanese. Not, when they needed a secret manual of how to transport liquid uranium in a bucket (the 1999 accident of Tokai Nuclear Power Plant). Smoking cigarettes at the same time was optional.

BBC: Chance of a Big One in Tokyo

Is it time for the Philippine Plate to get active?

Also, the Japanese researchers have gone very quiet on the subject, says BBC's Richard Black and Jonathan Amos.

From BBC News (4/21/2011):

...Seismic activity has definitely increased since the M 9.0 event, with the incidence of small earthquakes registered in some parts of Japan, hundreds of kilometres from the source, increasing by a factor of 10.

Hazard assessment in the region is therefore a pressing priority for researchers; but it is far from easy.

"The Kanto region is very complex, and the size of quakes triggered there is probably going to be limited by that complexity," says Chris Goldfinger from Oregon State University in the US, who works in collaboration with Japanese researchers.

"But given the proximity to Tokyo, even a limited quake there would be damaging."

Kanto sits very close to a tectonic triple junction - a point where vast slabs of the Earth's surface grind past each other.

The tectonic plate making up the Pacific Ocean floor is moving westwards under Japan towards Eurasia.

The Pacific plate is being pulled down (subducted) underneath Japan; and crowding in on this collision is the Philippine Plate, further south, also trying to get under Japan.

Ross Stein from the US Geological Survey (USGS) is one of a US/Japanese team that has modelled the region around the triple junction to help gauge future risks.

They used seismic signals from 300,000 tremors of various sizes to build a three-dimensional view of what was going on deep in the Earth, much like a doctor might use X-ray tomography to scan tumours in the brain.

They found a 25km-thick fragment broken off one of the plates that they now believe plays a significant role in shaping seismic activity in the Kanto region - and by implication, the outlook for Tokyo.

"When it comes to Tokyo, things get immensely complicated," said Dr Stein.

"There seems to be broken pieces of plate that are jammed under Tokyo like a pill that won't go down your throat. And on top of that we have the two different slabs of plates beneath it, so there's really a triple stack of faults beneath Tokyo."

To make matters more complicated, there is some disagreement among researchers about the most important geological factors around Tokyo, with some pointing to the Sagami Trough (a subduction zone leading off the triple junction) as the likely cause of big earthquakes, and others citing Dr Stein's "pill", known as the Kanto Fragment.....

And lastly,

One curiosity is that Japanese researchers are currently very reluctant to talk on the issue.

Scientists we contacted - in one case, someone known to one of us for years - did not want to go on record.

Given the devastation caused by the tsunami and the fact that an event near Tokyo could do even more damage, the reluctance to talk is eminently understandable.

It can, however, be interpreted as a signal of real concern.

(They've been probably told by the Japanese government not to talk without permission.)

The BBC article has an audio of the interview with Dr. Stein of USGS.