JAEA to Recreate a Core Melt to Better Understand #Fukushima I NPP Accident

Japan Atomic Energy Agency (JAEA) of Monju fame (most recently with free video playback software download that infected the PC in the central control room at Monju) will conduct an experiment that creates a small-scale core melt (commonly referred to as "meltdown").

Let's see. JAEA had a fire at Monju, which they hid. They dropped the fuel handling machine in the reactor. There were so many irregularities that Nuclear Regulation Authority was recommending shutting down the organization, when the pro-nuclear Abe administration came in and pledged to continue fuel recycle using Monju operated by JAEA.

(I would be much more comfortable if it weren't JAEA who will be doing the experiment.)

From Yomiuri Shinbun (1/8/2014):

炉心溶融を実験で再現…原子力機構、事故対策へ

JAEA to recreate core melt in an experiment, [result] to be utilized in dealing with Fukushima I NPP accident

日本原子力研究開発機構は、東日本大震災の際に東京電力福島第一原子力発電所で起きた炉心溶融（メルトダウン）を再現する小規模実験を、新年度に行う。

Japan Atomic Energy Agency will conduct a small-scale experiment in the new fiscal year (that starts April 1, 2014) that will recreate a core melt that happened at Fukushima I Nuclear Power Plant after the March 11, 2011 earthquake/tsunami.

事故の際、核燃料の過熱や溶融がいつごろ、どのように進んだのかは、これまで限られたデータを基にコンピューター計算で推定されただけで、不明な点が多い。実際の核燃料を冷却水のない「空だき」で過熱させる実験により、機構は「事故で起きた現象を明らかにして、今後の原発の事故対策に役立てたい」と話している。

So far, the progression of core melt has only been simulated by computer models based on limited data, and there is much that are still unknown. By using an actual fuel rod and overheat it without coolant [water], JAEA hopes to "better understand what actually happened in the accident and utilize the knowledge gained from the experiment in dealing with the accident."

実験は、茨城県東海村にある原子炉安全性研究炉で行う。研究炉の中心部にステンレス製のカプセル（長さ１・２メートル）を入れ、ミニ燃料棒（同３０センチ）１本を水に触れないようにして収める。カプセルの周囲の核燃料から飛んでくる中性子によって、ミニ燃料棒の中のウランも核分裂し、２０００度以上の高温になって溶ける。

The experiment will be carried out in JAEA's Nuclear Safety Research Reactor (NSRR) in Tokai-mura in Ibaraki Prefecture. A stainless steel capsule (1.2 meter long) will be inserted in the center of the reactor, and a miniature fuel rod (30 centimeters long) will be placed in the capsule without touching water. Uranium in the miniature fuel rod will undergo nuclear fission as it is being hit by neutrons emitted from the nuclear fuels surround the capsule, causing the temperature to rise above 2,000 degrees Celsius and causing the fuel rod to melt. [See the diagram by Yomiuri. English labels are by me.]

機構によると、実際の原発で使う長さ約４・５メートルの燃料棒の束に比べて少量で、核分裂はすぐに止まり、溶けて数分後には冷えて固まるという。固まった燃料は分析した後、他の核燃料と同様に、敷地内のプールで冷やして保管する。

According to JAEA, since [the fuel rod to be used] is much smaller than 4.5 meter-long fuel rods used in a real nuclear power plant, nuclear fission will stop shortly, and the melted fuel will cool and solidify in a few minutes. The solidified fuel will be analyzed, and then stored in the pool on the premises with other nuclear fuels.

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Goshi Hosono Admits to Harvard Professor: "We Should Have Admitted to a Core Melt Possibility"

Goshi Hosono, as the minister in charge of the nuclear accident, met with the Harvard political professor Michael J. Sandel, to whom Hosono said that his government should have admitted a core melt (meltdown) possibility earlier.

Well, the government actually did, very early, like the very next day of the disaster on March 11, 2011. But the Kan administration quickly replaced the official of the Nuclear and Industrial Safety Agency who spoke about the possible core melt in the press conference at noon on March 12, 2011. So they officially admitted, as if by mistake, in the initial confusion. Then, they were busy backtracking from that statement until several weeks later. Even for those who heard and read about the statement, I don't think it registered on them as people weren't as educated about things nuclear at that time as they are now.

For that matter, the government, with Mr. Edano as the spokesman, didn't officially tell the public that there was an explosion of Reactor 1 on March 12, 2011, until after 5 hours had passed.

When Goshi Hosono as a personal assistant to then-Prime Minister Kan went on a TV program in April 2011 and said "We knew it was a meltdown but we just didn't feel like telling people", there was hardly any reaction from the media or the general public.

And now here's what Goshi Hosono said to the Harvard professor, via Kyodo News (5/29/2012):

細野氏「溶融認めるべきだった」　米のサンデル教授と対談

Mr. Hosono met with US professor Sandel, said "We should have admitted to a core melt"

細野豪志原発事故担当相は２９日、熱気あふれる政治哲学講義で知られる米ハーバード大のマイケル・サンデル教授と内閣府の担当相室で対談し、東京電力福島第１原発事故直後の対応に関し「炉心溶融している可能性があることを率直に認めた上で対応していれば、政府発表に対する信頼もかなり変わっていたかもしれない。問題があったと思っている」と述べた。

Goshi Hosono, minister in charge of the nuclear accident, met with Professor Michael Sandel of Harvard University, known for his lively lectures on political philosophy, in his office in the Cabinet Office on May 29. Concerning the government response right after the start of the Fukushima I Nuclear Power Plant accident, Hosono said, "If we had frankly admitted to the possibility of a core melt, people's trust in the government announcement may have been different from what it is now. I think there was a problem."

　情報公開の在り方をめぐり細野氏は「国民は総体としては非常に冷静で、さまざまなことについて議論ができる」とした上で「そういう国民に対する情報の出し方、コミュニケーションの取り方は変わっていかなければならない」と強調した。

Over the information disclosure, Mr. Hosono said "On the whole, Japanese citizens are very calm and able to discuss various subjects". He went on to emphasize that "With such citizens, the information disclosure and the communications should be changed."

"We should have admitted to a core melt", Hosono now says. Several years down, he may be saying "We should have never done the wide-area debris disposal", says one of my Japanese twitter followers after reading the Kyodo News.

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March 12, 2011 NHK News at Noon: "Reactor 1 Fuel Rods Are Exposed..." - "Oops, We're Not Supposed to Say That..."

After the announcer read the news about the fuel rods in Reactor 1 getting exposed and the situation becoming very dangerous, someone in the background said "Hey we're not supposed to use that information..."

The audio of that segment is uploaded on Youtube, here. I have no proof that the recording is authentic, though it does sound authentic and there are people tweeting that they do recall hearing the news.

From the transcript of the news, NHK March 12, 2011 noon:

そして原子力発電所に関する情報です。

Now the information on [Fukushima I] nuclear power plant.

原子力安全保安院などによりますと、福島第一原子力発電所１号機­では、原子炉を冷やす水の高さが下がり、午前11時20分現在で­、核燃料棒を束ねた燃料集合体が、水面の上最大で90センチほど­露出する危険な状態になったということです。このため、消火用に­貯めていた水など、およそ2万7000リットルを仮設のポンプを­使うなどして、原子炉の中に流し込み、水の高さを上げるための作­業を行っているということです。この情報繰り返します。

According to the government agencies including the Nuclear and Industrial Safety Agency, the level of water to cool the reactor has gone down in Reactor 1 of Fukushima I Nuclear Power Plant. As of 11:20AM today, the maximum 90 centimeters of the nuclear fuel bundles are exposed above water and the situation is getting dangerous. The work is currently ongoing to pour 27,000 liters of water stored for fire extinguishing into the reactor using a temporary pump, in order to raise the water level back up. Let me repeat the news ...

（しばらく無音…。）
(Then, there is silence.)

「ちょっとね、今の情報使っちゃいけないんだって」

[in the background] "Wait, we're not supposed to use that information, I've been told."

改めて原発に関する情報です。

Again, information about the nuclear power plant.

福島県にある福島第一原子力発電所の１号機では、原子炉が入った­格納容器の圧力が高まっているため、東京電力が、容器内の空気を­外部に放出する作業を始めましたが、格納容器のすぐ近くにある弁­を開く現場の放射線が強いことから、作業をいったん中断し、今後­の対応を検討しています。

The pressure inside the Containment Vessel is getting high at Reactor 1 at Fukushima I Nuclear Power Plant in Fukushima Prefecture. TEPCO has started the work to release the gas inside the Containment Vessel. However, the valve that needs to be opened is located right near the Containment Vessel and the radiation level is very high. So TEPCO has halted the work temporarily to figure out how to proceed.

At least someone at NHK wrote the first news up, and managed to get that out on air.

The reactor building blew up on that day 3 and a half hours later, at 3:36PM.

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#Fukushima I Nuke Plant Reactor 1: TEPCO and NHK's Obfuscation on Corium in the Concrete

In the first post on the subject, I translated what NHK reported:

東京電力福島第一原子力発電所の事故で、メルトダウンが起きた１号機の燃料は、鋼鉄の原子炉の底を突き破って相当の量が格納容器に落下し、容器の底のコンクリートを溶かして最大で６５センチ浸食していると推定されることが、東京電力の解析結果から分かりました。

It has been discovered by TEPCO's analysis that the significant amount of Reactor 1's melted fuel pierced through the steel Reactor Pressure Vessel and dropped onto the Containment Vessel, then melted the concrete at the bottom of the CV. It is estimated that the melted fuel may have eaten into the concrete to maximum 65 centimeters deep.

Maximum 65 centimeters deep from the bottom of the concrete floor, right?

Well no. It's 65 centimeters from the bottom of the deep groove on the concrete floor.

And neither NHK nor TEPCO would bother to tell you how deep the groove is.

At least, NHK Kabun (NHK's last remaining conscience, as far as I'm concerned) tweeted and gave the link to its blog post, where NHK's analysis of the concrete-eating corium is shown with the screenshots from the program:

The text below the screen says: "In the worst case, it [the corium] may have reached 65 centimeters from the surface of the concrete. Where the concrete is the thinnest, it may have reached within 37 centimeters from the steel plate [of the Containment Vessel].

The "surface of the concrete" turns out to be the surface of the bottom of the groove that is X centimeter deep.

It's one thing for TEPCO's Matsumoto to say "surface of the concrete" (as we've gotten used to hearing technically correct explanations from him), but for NHK to say so while showing the graphics indicating it is the surface of the bottom of the groove is at once deceptive and covering its behind. NHK can now say "We showed it in the graphics that it was 65 centimeters from the bottom of the groove, and people should have paid attention."

(I'm asking NHK Kabun if they know the depth of the groove, but does anyone know or have access to a schematic diagram with measurement?)

Well, it does look like the Institute of Applied Energy is more right than TEPCO in saying the corium has eaten 2 meters into the concrete. And perhaps people like Hiroaki Koide of Kyoto University and the engineers who designed the reactors at Fukushima I Nuke Plant may be more right than the Institute of Applied Energy, and the corium has indeed escaped the Containment Vessel long time ago.

As the wiki entry on "corium" states, the corium can eat into the concrete 1 meters in the first one hour, and several centimeters per hour afterwards:

The fast erosion phase of the concrete basemat lasts for about an hour and progresses into about one meter depth, then slows to several centimeters per hour, and stops completely when the melt cools below the decomposition temperature of concrete (about 1100 °C). Complete melt-through can occur in several days even through several meters of concrete; the corium then penetrates several meters into the underlying soil, spreads around, cools and solidifies.[3] During the interaction between corium and concrete, very high temperatures can be achieved.

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TEPCO Says Corium Would Stop at 70 Centimeters into CV Pedestal, So No Worry

(Update: Institute of Applied Energy says it could be 2 meters deep. See new post.)


Update to my previous post on the corium eating into the CV pedestal in Reactor 1 of Fuku I:

TEPCO says they are pretty sure that the corium would stop at 70 centimeters deep, and the core concrete reaction has stopped.

The company is pretty confident that the corium escaped from the RPVs of Reactors 2 and 3, if any, remains on the pedestals of the CVs and not eating into the concrete.

From their presentation on November 30, 2011, Reactor 1:

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TEPCO Had the Dust Sampling Data from March 11, and Didn't Tell the Rest of Us Until November 24

From the tweets (here, here and here; in Japanese) of independent journalist Ryuichi Kino, from the TEPCO/government joint press conference on November 24, 2011:

前回聞いたモニタリングカーの仕様、ダストサンプリング、空間放射線量率、中性子、風向風速設備などありと松本さん。で３月11日からダストを採っていたのではないか？と聞くと。採っていたと、サラリと。当時は採ってないという説明。

Specs of the monitoring car that I asked about in the last press conference: dust sampling, air radiation level, neutron detection, wind speed and strength, etc., according to TEPCO's Matsumoto. So I asked, "Weren't you then doing the dust sampling from March 11?" Matsumoto answered as a matter of fact, "Yes." At that time in March, TEPCO said they weren't.

東電が初めてダストサンプリングを発表したのは21日頃だったかな。１８日と19日に採取したものを福島第二に持っていって分析という説明だった。１Fの分析装置が使えなくなったので、当初はサンプリングもしてない、必要はないという話だった。

I think it was March 21 when TEPCO announced the result of the dust sampling for the first time. The explanation was that the samples were collected on March 18 and 19, and they were brought to Fukushima II and analyzed. Since the analyzer at Fuku-I was unusable, they weren't doing any dust sampling, there was no need - that was the explanation.

松本さんの話では、分析結果は保安院のＨＰに出ていることを確認していると。なんで東電のＨＰに出てないかは確認するらしい。３月の情報公開の姿勢は、大問題だな。。。当時にダスト分析が出てれば、炉心溶融の証拠にもなっただろうに。隠したのかあ。

Matsumoto said he confirmed that the data was uploaded at the NISA's home page, and he will find out why it is not on TEPCO's home page. This TEPCO's attitude toward disclosure of March information is very problematic... If the result of dust sampling analysis was disclosed at that time, it might have proven the core meltdown. Did they hide?

I wonder. If you believe TEPCO (and the government), you will ______ (fill in the blank as you like).

I'll try to find that data on the Nuclear and Industrial Safety Agency's website tomorrow.

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More on Fukushima II (Daini): Loss of Function to Remove Residual Heat for Up to 2 Days and 23 Hours, March 11 to 14

I hardly paid any attention to Fukushima II (Daini) Nuclear Power Plant in the early days of the crisis, but I got curious reading the comment from the reader "Joe Neubarth" to the post on the eyewitness account of Fukushima II on the day of the earthquake:

"Core Damage comes from a loss of cooling. I know of no report of loss of cooling at that facility. Did they go dark when the one electrical transmission tower fell north of Fukushima during the earthquake? Did they then have a delay if the startup of Emergency Diesel Generators? If there was a delay or if they lost the EDG's totally THEN there might be a melt down, BUT I have not heard of this happening."

I didn't know either (or I totally forgot). Did they or didn't they? So I went to TEPCO's site and see what they say.

Fukushima II Nuke Plant has 4 reactors. When the earthquake hit on March 11, control rods were successfully inserted in all 4 reactors at 2:48PM. Then the tsunami hit, and at 6:33PM on March 11:

Occurrence of a Specific Incident Stipulated in Article 10 of the Act on Special Measures Concerning Nuclear Emergency Preparedness (loss of function to remove residual heat)

This happened on Reactors 1, 2, and 4, at the same time.

Then, the Residual Heat Removal System re-started one by one, on March 14:

Reactor 1: 1:24AM, March 14
Reactor 2: 7:13AM, March 14
Reactor 4: 3:42PM, March 14

So, the reactors weren't cooled for as long as 69 hours in case of Reactor 4, and 55 hours in case of Reactor 1.　Is 55 hours long enough for the coolant (water) inside the Reactor Pressure Vessel to evaporate and for at least part of the fuel rods to be exposed and get damaged?

For all 4 reactors, the Reactor Coolant Filtering System came online between June 4 and July 17.

TEPCO also says the Suppression Chambers of Reactors 1, 2 and 4 suffered some event that caused the "loss of function to suppress pressure" in the morning of March 12. The function was restored on March 14 morning.

The above information is from TEPCO's status report on Fukushima II (Daini) Nuclear Power Plant as of August 21 (click to enlarge, or go to the link):

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US Government Considered Evacuation of 90,000 US Citizens in Tokyo

According to Kevin Maher, a US diplomat and the former director of the Japan Desk at the US State Department in Japan, the US government considered evacuating all 90,000 US citizens in Tokyo right after the Fukushima I Nuclear Power Plant accident.

From Yomiuri Shinbun (10:30PM JST 8/17/2011):

東京電力福島第一原子力発電所の事故直後、米政府が、東京在住の米国人９万人全員を避難させる案を検討していたことが分かった。

The US government was considering the plan to evacuate all 90,000 US citizens living in Tokyo right after the Fukushima I Nuclear power Plant accident, according to a new book.

元米国務省日本部長のケビン・メア氏が、１９日に出版する「決断できない日本」（文春新書）で明らかにした。９万人避難が実行されていれば、他国の政府対応はもとより、日本人にもパニックを引き起こしかねないところだった。

The book, which is to be published on August 17, is titled "決断できない日本 (Japan that cannot decide)" (Bunshun Shinsho) and was written by Kevin Maher, former Japan Desk director at the US State Department. If the plan to evacuate 90,000 Americans had been carried out, it could have triggered reactions from other foreign governments, and caused panic among the Japanese.

　メア氏は震災直後、国務省内の特別作業班で日本側との調整にあたり、著書にその内幕をつづった。

Maher's book recounts the inside information that Maher obtained as he was part of the special task force within the State Department right after the March 11 disaster, communicating with the Japanese side.

　米国人の避難が提起されたのは、３月１６日未明（現地時間）の会議だった。米側は無人偵察機グローバルホークの情報から原子炉の温度が異常に高いことを把握し、「燃料が既に溶融している」と判断。菅政権が対応を東電任せにしているとみて、「不信感は強烈」な状況だったという。米国人の避難を求めた政府高官に対し、メア氏らは「日米同盟が大きく揺らぐ事態になる」と反論し、実行に移さなかったとしている。

The subject of evacuating the US citizens was raised in the early hours on March 16 (local time). The US had already knew about the unusually high temperature of the reactors from the Global Hawk data, and determined that "the fuel has already melted". The US thought the Kan administration was simply leaving the disaster response to TEPCO, and "distrust [in the administration] was intense". The US high-ranking officials wanted to evacuate the US citizens [from Tokyo] but the local officials including Maher objected, as "it would severely undermine the US-Japan alliance". The plan was never implemented.

It's very heart-warming to know they left 90,000 US citizens in Tokyo under the radioactive plume, which literally rained on them on March 15, 16 and 21, for the sake of "alliance", isn't it?

I also remember back in March that the US investment bank Goldman Sachs flew in high-ranking executives to Tokyo, and told the US employees there in no uncertain terms that they were to stay put in Tokyo, or they would lose their jobs.

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Japanese Researcher Says Reactor 3's Fuel Melted Twice, Dropped to Containment Vessel

From Asahi Shinbun (3:02AM JST 8/8/2011; not the literal translation):

Fumiya Tanabe, former head of the research at Japan Atomic Energy Agency, will present the result of his research on Reactor 3 at Fukushima I Nuclear Power Plant in the upcoming Atomic Energy Society of Japan's conference next month.

Tanabe thinks the fuel melted and dropped to the bottom of the Reactor Pressure Vessel of Reactor 3 by March 14's explosion; then the melted fuel stayed there, cooled by more than 300-tonnes/day water. However, the amount of water injected dropped to only 24 tonnes per day from March 21 to 23, and 69 tonnes per day on March 24, probably due to increased pressure within the RPV.

It caused the melted fuel to heat up again, and the fuel melted through the RPV and dropped onto the Containment Vessel (pedestal; see the diagram from Asahi).

According to Tanabe, the amount of water from March 21 to 24 was only about 11 to 32% of what was needed to remove the decay heat, and within one day the melted fuel would attain the melting temperature again.

Tanabe thinks this massive "re-melting" caused the release of a large amount of radioactive materials into the environment which caused a spike in air radiation in wide areas of Tohoku and Kanto including Tokyo, and most of the re-melted fuel dropped from the RPV to the Containment Vessel.

The article doesn't say what Tanabe thinks has happened to the melted fuel that dropped onto the Containment Vessel since.

But the article does say this:

東電は原子炉圧力容器底部の温度が低下した状態（冷温停止）を事故収束の目標としているが、炉心の大半が溶けて格納容器に落下しているなら、収束に向けた工程表に影響する可能性もある

TEPCO hopes to have a "cold shutdown" where the temperature at the bottom of the RPV is low [below 100 degrees Celsius] as the target for winding down the nuclear accident. But if the fuel core is mostly melted and has dropped down to the Containment Vessel, it may affect the "roadmap".

No kidding. Yes it may. Where have you been, Asahi, for all these months? Is this news to you?

Tanabe's chart (from Asahi article) plotting the air radiation level (in microsieverts/hour) shows a spike on March 21. It rained that day in Tokyo.

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#Fukushima I Nuke Plant Reactor 3 Bldg Has Over 6,400 Tons of Contaminated Water

What a surprise.

Workers braved the high radiation (up to 100 millisievert/hour) in the Reactor 3 reactor building on June 9 and found water in the basement. TEPCO says it expected to find water there, but didn't bother to tell us until the water was actually found.

Have I seen this before? Yes, the Reactor 1.

To state the obvious, if there's water in the basement of the reactor building, that means 1) the Reactor Pressure Vessel (RPV) is broken; 2) the Containment Vessel is broken.

The only question is: Where's the corium?

From Asahi Shinbun (10:45PM JST 6/10/2011):

東京電力は１０日、福島第一原発３号機の原子炉建屋地下でたまり水を確認したと発表した。東電は原子炉を冷却する注水量などから、５月末現在で６４００トンの水がたまっていると推計していたが、実際に存在が確認された。

TEPCO announced on June 10 that they confirmed the presence of water in the basement of the Reactor 3 reactor building at Fukushima I Nuclear Power Plant. TEPCO had estimated that 6,400 tons of water would be in the basement as of the end of May, based on the amount of water injected into the RPV. Now its existence has been confirmed.

　東電によると、９日に作業員が原子炉建屋内に入り、１階から地下に行く階段を下りて、水がたまっているのを確認した。地下の床から５．８メートルのところまで水が来ていたという。量は東電の推計よりやや多い模様。水の近くの放射線量は毎時５１ミリシーベルトだった。

According to TEPCO, workers entered the reactor building and descended the stairs from the 1st floor to the basement, and saw the water. Depth of the water was 5.8 meters [19 feet] from the basement floor, and the amount of water looked to be slightly more than TEPCO's estimate. The radiation level near the surface of the water was 51 millisieverts/hour.

　１号機同様、炉心溶融によって原子炉圧力容器が破損し、水が外に漏れ出している可能性があるという。近く、水を採取して放射性物質を調べる。

According to TEPCO, it is possible that the RPV has been damaged by the core meltdown, leaking the water. TEPCO plans to test the water for radioactive materials.

　１階を確認したところ、計器盤の扉がゆがんだり、はしごが上層階から落下したりしていた。また、機器の一部がすすのようなもので黒くなっていた。東電によると、水素爆発の影響とみられるという。

Survey of the 1st floor found distorted doors of the instrument panel and a ladder dropped from the floor above. Part of the equipment was blackened with what looked like soot. TEPCO thinks they were caused by the hydrogen explosion.

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Containment Vessels of Reactors 1, 2, 3 Were Possibly Damaged Within 24 Hours of March 11 Earthquake

Someone at Yomiuri Shinbun who was made to read the TEPCO's report to the Nuclear and Industrial Safety Agency (NISA), the government overseer, found this bit of information in the main report (225 pages, in Japanese; English translation is on-going at TEPCO): Containment Vessels were damaged within 24 hours of the quake.

It is not in the summary slides (10 slides, in Japanese), which I did read. In the TEPCO's press conferences since May 15, Matsumoto never admitted to the Containment Vessel damage but he didn't deny it either. He specifically said in a press conference I watched that he "cannot deny the possibility of the Containment Vessel having been damaged." (I will link my post reporting that if I ever retrieve it; Google deleted it in their "maintenance".)

Looks like a fun reading. I will report back when I see the exact words from TEPCO on the subject.

It's also amusing to see the Japan's MSMs now use the word "core meltdown (炉心溶融) quite often, which was a taboo word for 2 months until TEPCO officially admitted it on May 15.

Yomiuri Shinbun (9:53PM JST 5/24/2011):

　東京電力が福島第一原子力発電所の炉心溶融（メルトダウン）について詳しいデータ解析を行った結果、１～３号機では、圧力容器だけではなく、その外側を覆う鋼鉄製の格納容器も、地震後２４時間以内に損傷していた可能性があることが分かった。

It's been revealed that the steel Containment Vessels of the Reactors 1, 2 and 3 that house the Reactor Pressure Vessels (RPV) may have been damaged within 24 hours after the earthquake on March 11, according to the detailed analysis of the core meltdown at Fukushima I Nuclear Power Plant by TEPCO.

　解析結果の報告書は２３日に経済産業省原子力安全・保安院に提出された。

The result of the analysis was compiled into a report and submitted to the Ministry of Economy and Industry's Nuclear and Industrial Safety Agency on May 23.

　原子炉の運転データなどに基づいて地震後の状況を詳しく計算したところ、１号機は緊急冷却装置の「非常用復水器」が十分に働かず、炉心溶融の進行によって、地震後１５時間で圧力容器の底部が破損したことがわかった。底部には制御棒や中性子計測装置の貫通部が多数あり、強度の弱い溶接部分などが壊れて、溶けた燃料を含む高濃度汚染水が漏れ出したとみられる。

The detailed calculation of the reactors' operation data after the earthquake revealed that the bottom of the Reactor 1 RPV was broken after 15 hours after the earthquake because the emergency core cooling system didn't function well and the fuel started to melt down. There are many openings through which the control rods and the neutron measurement device goes through. The welded parts at the bottom, which do not have the same strength as the other part of the RPV, broke, and highly contaminated water that included the melted fuel may have leaked from there, according to the report.

I've been thinking about the "Level 7" designation of the Fukushima I Nuke Plant accident. When the NISA announced "Level 7", they were still publicly (at least) assuming that the majority of the fuel rods were more or less intact and inside the RPVs; that the RPVs were intact, and the Containment Vessels were intact, except for the Reactor 2 (the Suppression Chamber was damaged).

So, is it more likely now, that far more radioactive materials have escaped the reactors than the NISA or the Nuclear Safety Commission calculated? "Don't worry it's only 1/10 of Chernobyl" was another lie?

Or, were their calculations based on the secret knowledge that the RPVs and Containment Vessels were broken in the very early stage of the accident?

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TEPCO Stating the Obvious After 2 Months: Reactors 2, 3 Total Meltdown More Likely

Here we go. It's official now. All three reactors at Fukushima I Nuke Plant had a total meltdown. What a surprise. We're so shocked, aren't we?

Yomiuri Shinbun (3:03AM JST 5/24/2011):

　東京電力は２３日、福島第一原子力発電所２、３号機について、地震発生直後の原子炉の各種データをもとに解析を進めた結果、１号機と同様に核燃料がメルトダウン（炉心溶融）していたとする報告書をまとめた。

TEPCO reported on May 23 that the Reactors 2 and 3 at Fukushima I Nuclear Power Plant had a core meltdown just like the Reactor 1, based on their analysis on the reactor parameters right after the earthquake on March 11.

　経済産業省原子力安全・保安院に提出する。

The company will submit the report to METI's Nuclear and Industrial Safety Agency.

　報告書では、２、３号機について〈１〉炉内の水位が水位計の表示通りだった〈２〉水位計のデータは信頼できず、１号機と同じ様に核燃料が全露出し ている――の二つのケースに分けて、模擬計算を行い、結果を示した。それによると、いずれの場合にも核燃料が溶融して、原子炉圧力容器底部に崩落した状態 になっていると評価。特に、水位計が故障しているケースでは、核燃料全体が溶融して、崩壊しているとした。

In the report, TEPCO did two simulations regarding the Reactors 2 and 3: 1st, based on the assumption that the water level was what the water gauge had been showing all along; 2nd, based on the assumption that the data from the water gauge were not to be trusted, and the fuel rods were completely exposed, as in the Reactor 1. In both cases, the result showed that the nuclear fuel had melted and dropped to the bottom of the Reactor Pressure Vessel. In the 2nd case where they assumed the faulty water gauge, the result showed the entire fuel rods had melted, according to the report.

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Mainichi English: US Researcher Says Fukushima Reactor Had Meltdown 3.5 Hours after Cooling System Collapsed

A US researcher Chris Allison did the simulation of one of the Fukushima reactors (Reactor 1) and concluded that the meltdown occurred 3.5 hours after the cooling system stopped. It was reported to the IAEA in late March.

So they all knew, except for the hapless citizens of Japan and the rest of the world.

Or they say "Oh we didn't know for sure until May 15 when TEPCO finally announced it," like Japan's PM Kan has said.

We do not know for sure, because no one has looked inside the RPV and reported back to us. All we can do is to collect the evidence and hypothesize, and that has been pointing to a meltdown. Even the PM Assistant has admitted that they knew it was a meltdown early on.

Here's the summary of the simulation by Allison, as described in the Mainichi English article (linked below):

1. The emergency core cooling system (ECCS) fails;

2. 50 minutes later: reactor core starts to melt;

3. 1 hour 20 minutes later: control rods and other pipes inside the RPV start to melt;

4. 3 hours 20 minutes later: most of the melted jumble ("corium") drops to the bottom of RPV;

5. 4 hours 20 minutes later: temperature at the bottom of the RPV reaches 1,642 degrees Celsius, damaging the RPV stainless steel lining [melting point of stainless steel is 1,510 degrees Celsius].

It is not clear from the TEPCO's log on the day exactly when the emergency core cooling system failed. After the earthquake on March 11 at 2:46PM JST, the ECCS for the Reactor 1 started to operate at 2:52PM JST, but failed only after 10 minutes. And that was before the tsunami arrived at about 3:30PM JST. Attempts were made to restart the ECCS until 1:48AM JST on March 12, when the pump that feeds water to the ECCS broke. (From the summary at Yomiuri Shinbun, 5/16/2011.)

If you can read English, you can read Wikipedia's various entries on nuclear reactor and reactor accidents, and would have figured out that there was no way that the Reactor 1's reactor core had not melted once the cooling system failed. I read several wiki entries ("corium", "meltdown", "Three Mile Island accident", "Chernobyl accident" and others), and that was my conclusion as a layman. I kept scratching my head right after the accident, watching the Japanese government vigorously attack anyone who hinted at a core meltdown and hearing TEPCO insist that the fuel rods were only partially "damaged".

And why has this scientist kept quiet? A confidentiality obligation with a threat of jail time like Professor Kosako?

From Mainichi Shinbun English (5/23/2011):

A meltdown occurred at one of the reactors at the Fukushima No. 1 Nuclear Power Plant three and a half hours after its cooling system started malfunctioning, according to the result of a simulation using "severe accident" analyzing software developed by the Idaho National Laboratory.

Chris Allison, who had actually developed the analysis and simulation software, reported the result to the International Atomic Energy Agency (IAEA) in late March. It was only May 15 when Tokyo Electric Power Co. (TEPCO) admitted for the first time that a meltdown had occurred at the No. 1 reactor at the Fukushima nuclear plant.

According to Allison's report obtained by the Mainichi, the simulation was based on basic data on light-water nuclear reactors at the Laguna Verde Nuclear Power Plant in Mexico that are about the same size as that of the No. 1, 2, and 3 reactors in Fukushima.

According to the simulation, the reactor core started melting about 50 minutes after the emergency core cooling system of the No. 1 reactor stopped functioning and the injection of water into the reactor pressure vessel came to a halt. About an hour and 20 minutes later, the control rod and pipes used to gauge neutrons started melting and falling onto the bottom of the pressure vessel. After about three hours and 20 minutes, most of the melted fuel had piled up on the bottom of the pressure vessel. At the four hour and 20 minute mark, the temperature of the bottom of the pressure vessel had risen to 1,642 degrees Celsius, close to the melting point for the stainless steel lining, probably damaging the pressure vessel.

TEPCO, the operator of the crippled Fukushima nuclear plant, had tried to fill the containment vessel of the No. 1 reactor with water, but it decided to abandon the plan after it discovered that a meltdown had occurred at the reactor.

Masanori Naito, director in charge of safety analysis at the Institute of Applied Energy, said, "TEPCO could have conducted similar analysis at an early stage and assumed the meltdown had occurred. TEPCO should have prepared other cooling methods besides the method of filling the reactor with water."

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Hiroaki Koide of Kyoto University: "No One Knows How Fukushima Could Be Wound Down" As the Corium May Be Melting Through the Foundation

So says Hiroaki Koide of Kyoto University Research Reactor Institute, in a telephone interview on May 19 with independent video-journalist Tetsuo Jinbo of Videonews.com (who did the video report of the 20-kilometer radius evacuation zone back in April, showing cows and dogs prowling the deserted towns).

Koide is practically agreeing with Christopher Busby that there's not much anyone can do to stop the release of radioactive materials and further contamination of air, soil and water, other than somehow "entomb" the reactors (a.k.a. Chernobyl solution).

Koide reiterates his view that the corium (he says "melted fuel" and "melted core" in the interview for lay people, but it is melted fuel, and anything else that melted with the fuel inside the RPV) may have already escaped the Containment Vessel in the Reactor 1.

Following is my notes as I jotted down the salient points Koide made in the interview:

• (Assuming that TEPCO is telling the truth) the worst-case scenario of a hydrogen explosion inside the reactor caused by the melted fuel seems to have been avoided.

• I believe the Reactor Pressure Vessel has a large hole, not the small holes that TEPCO says.

• TEPCO cites the pressure and the temperature data as the reasons to believe the melted fuel still stays inside the RPV. However, I wonder if the pressure and the temperature data of the Reactor 1 is accurate. After all, the data on the water level was completely wrong.

• That much water has leaked (4,000 tons in the reactor building basement) and yet TEPCO says there's still pressure inside the RPV. It is impossible, given the structure of the reactor.

• There is no definite data as to whether there is any water in the Containment Vessel. Considering the reactor building basement is flooded with water, I think it is possible that the melted fuel already damaged the Containment Vessel.

• Outside the Containment Vessel, what's left as containment is the concrete foundation of the building.

• In order to have a reactor in "cold shutdown", you need to have the RPV intact so that the cooling water can circulate. No point in talking about cold shutdown when we don't even know whether the fuel is still inside the reactor.

• We're in the uncharted territory that we enter for the first time ever since the human race started to use nuclear power.

• As to whether the radioactive materials are going to be released into the atmosphere [from the meltdown and breach of RPV and Containment Vessel], I don't think it is likely as of now. The concrete foundation of the reactor building may have sustained some damage, but as a whole I don't think it is completely broken.

• I cannot properly assess the possibility of the corium melting through the concrete foundation and reaching the water table. If that should happen, the radioactive materials will flow into the ground water and contaminate the ocean even more.

• As to the the corium, I think the inside of the corium is not solid even if there's water in the reactor.

• The Suppression Chamber in the reactor building basement is torus-shaped. The location where the corium may have dropped is the center of the torus, and it is concrete. The thing to worry about is how far down the concrete the corium will go.

• The water circulation system using water in the building proposed by TEPCO is tantamount to admitting that the Containment Vessel is broken. It is a much more serious situation than I envisioned, and there's no other way to cool [the corium] other than the one proposed by TEPCO.
  
  [Koide was proposing a system that circulate water inside the Containment Vessel back into the RPV, as he had assumed correctly that the RPV had been breached.]
  

• However, if the corium goes into the concrete, no point in talking about circulating water to cool. There will be nothing you can do. The only way may be to entomb the whole building in a concrete coffin.

• I suspect that TEPCO's "roadmap" was created by the TEPCO headquarters under political pressure, and not by the TEPCO people in Fukushima I Nuke Plant who struggle everyday to contain the situation. If anything, the "roadmap" should be created by them, not by the headquarters.

• According to TEPCO's data, even now the fuel rods in the Reactors 2 and 3 are soaked in water up to half the height.

• Comparing Chernobyl and Fukushima, Fukushima is still on-going. There is a possibility of further hydrogen explosion, and it is still possible that Fukushima exceeds Chernobyl in terms of magnitude of the disaster.
  

For those of you who understand Japanese, here's the interview:

If you are curious about this maverick nuclear researcher, here's a good interview of him done in 2007 (translated from original Japanese). Koide entered the field of nuclear science full of hope for the peaceful use of nuclear technology in 1968, only to see the reality two years later when he saw Onagawa Nuke Plant being forced upon the residents and understood why. Ever since, he has continued to research nuclear energy as an opponent of nuclear energy.

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#Fukushima I Nuke Plant: Workers Enter Reactor 2 Bldg in Tungsten Vest

It is the first time the workers enter the reactor building since March 15 when there was an explosion in the Suppression Chamber.

According to Mainichi Shinbun (11:13AM JST 5/18/2011), 4 workers entered the reactor building of the Reactor 2 at 9:30AM to survey the interior of the building to prepare for the equipment calibration and installation of the cooling system. The workers will also go to the 2nd floor of the reactor building. The workers wear a "tungsten vest" to prevent external radiation exposure. They also carry oxygen tanks on them.

Never heard of a tungsten vest...

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Hiroaki Koide of Kyoto University: "Melted Core Outside the Containment Vessel"

Hiroaki Koide of Kyoto University Research Reactor Institute is quoted by Mainichi Shinbun as saying that the melted core of the Reactor 1 is not just out of the Reactor Pressure Vessel but out of the Containment Vessel.

From Mainichi Shinbun, Koide's comments only (5/16/2011):

小出裕章・京都大原子炉実験所助教は「電源喪失で原子炉が冷やせなくなれば、早い時期に炉心溶融に至ることは想定できていたはずだ。燃料の損傷が限定的だとしてきた東電の説明は完全に誤っていたことになる。データの公表も遅すぎる」と指摘する。

Hiroaki Koide of Kyoto University Research Reactor Institute points out that "[TEPCO] could have foreseen the core melt at an early stage when the cooling of the reactor stopped due to the power failure. TEPCO's assessment that the damage to the fuel was limited has turned out to be completely wrong. The disclosure of the data came too late."

　東電は今回の解析で「圧力容器の損傷は大規模ではない」と説明するが、小出助教は「圧力容器は完全に破損し、溶けた燃料が格納容器の底に穴を開け、原子炉建屋の地下に大量の汚染水が漏れ出す原因になっている」と推定する。

According to TEPCO, the data analysis shows that damage to the RPV is not extensive. However, Koide thinks "The RPV has been completely damaged, the melted core bore a hole at the bottom of the Containment Vessel, causing the large amount of contaminated water to leak into the ground beneath the reactor building."

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Asahi Shinbun: Core Meltdown in Reactors 2 and 3 at #Fukushima

Fun to see the spin by one of the MSM in Japan. Now they are all saying core meltdown, complete core meltdown, we knew from the beginning, we knew in March. It's hysterically comical.

Particularly hilarious is Haruki Madarame, who now basically says "we knew that", while he was the one who told the PM on March 12, "Don't worry, the nuclear reactor doesn't break."

Yes, there were nuclear experts and independent journalists in Japan and around the world who said it was a meltdown, and they were attacked by the government and the MSM like Asahi as "fear-mongering". I thought so too, after reading the entries on wiki on Three Mile Island, Chernobyl, and corium, among others.

But it isn't true until the official, government-approved sources say so, and it is now, after more than 2 months: complete core meltdown in all three operating Reactors at Fukushima I.

What's next? Recriticality, maybe, announced in two months or so?

Quick and dirty translation, subject to later revision.

Asahi Shinbun (3:01AM JST 5/17/2011):

東京電力福島第一原子力発電所の２、３号機でも炉心溶融が起こり、原子炉圧力容器の底に燃料が崩れ落ちるメルトダウンが起きていたとみられること が、１６日に東電が公表したデータで裏付けられた。３号機では溶けた核燃料がさらに下の格納容器内に落ちた恐れもある。専門家は事故直後から指摘してお り、細野豪志首相補佐官も１６日の会見で２、３号機でのメルトダウンの可能性を示唆した。

The data disclosed by TEPCO on May 16 shows that core meltdown may have occurred in the Reactors 2 and 3 at Fukushima I Nuclear Power Plant. In the Reactor 3, the melted fuel may have dropped to the Containment Vessel. Nuclear experts have pointed to the possibility [of meltdown in the Reactors 2 and 3] and Prime Minister's Assistant Goshi Hosono hinted at the possibility in the May 16 press conference.

　東電が４月１７日に示した工程表は、６～９カ月で原子炉を安定した状態で停止させるとした。１号機に続き２、３号機でもメルトダウンの可能性が出てきた ことにより、工程表の大幅な見直しは必至だ。炉心を冷やすシステムづくりに時間がかかり、高濃度の放射能汚染水の処理も膨大になるからだ。

According to TEPCO's "roadmap" on April 17, it was going to take between 6 to 9 months to shut down the reactors. The revision of the "roadmap" will be inevitable now that both Reactor 2 and Reactor 3 may have had a meltdown, as it will take more time to build a cooling system for the reactor core, and the massive amount of highly contaminated water will need to be processed.

　今回公表された地震直後のデータは原発内の中央制御室にあり、電源復旧に時間がかかったことや、記録紙に放射性物質が付着しているため整理に時間がか かっていた。公表されたのは、記録紙に打ち出されたグラフや当直長がつける運転日誌などで、大型ファイル４冊分にあたる。

The data disclosed on May 16 was the data right after the earthquake on March 11. It took TEPCO some time to retrieve the data from the central control room of the plant because of the long period of power outage and the radioactive materials on the recorded printout. The data in 4 large binders includes graphs on the printout and operation diaries kept for each shift.

　データによると、圧力容器内の圧力が、２号機は３月１５日午後６時４３分に、３号機は３月１６日午後１１時５０分に、それぞれ下がった。圧力容器の密閉性が損なわれ、圧力が抜けたとみられている。

According to the data, the pressure inside the Reactor 2 RPV (Reactor Pressure Vessel) dropped at 6:43PM on March 15 (JST), and the pressure inside Reactor 3 RPV dropped at 11:50PM on March 16. The integrity of the RPVs were compromised, it is thought, and the pressure went down.

　圧力容器の底には制御棒や計測機器を外から通すための数多くの貫通部がある。メルトダウンした核燃料が圧力容器の底にたまり、その熱の影響で機器が溶け るなどした結果とみられる。３号機内の汚染水からは、原子炉内の核燃料が損傷して出るテクネチウムなどの放射性物質も確認されていることから、溶けた燃料 がさらに圧力容器から格納容器内に落ちた可能性もある。

There are many channels that go through the bottom of the RPV [16 centimeters thick] to insert control rods and measurement devices. The melted fuel went down to the bottom of the RPV, and may have melted the devices at the bottom. The contaminated water from the Reactor 3 has been found to contain the radioactive materials like technetium that are produced when the nuclear fuel gets damaged, indicating that the melted fuel may have dropped from the RPV into the Containment Vessel.

　東電は会見で「プラント全体の事象を追いかけられておらず、評価できていない」と明確な判断を示さなかった。

In the press conference, TEPCO refrained from saying anything definite. "We haven't fully grasped the situation at the plant, and we haven't been able to evaluate it."

　一方、細野氏は会見で炉心に水が入らなかった時間について「１号機は１４時間９分、２号機は６時間２９分、３号機は６時間４３分と短くない」とし「炉心の完全な溶融（メルトダウン）の可能性をみておかないといけない」と話した。

PM Assistant Hosono said that there was no water being poured into the Reactor 1 for 14 hours and 9 minutes, Reactor 2 for 6 hours and 29 minutes, and Reactor 3 for 6 hours and 43 minutes. He said "We should be prepared for the possibility of the complete meltdown of the reactor core."

　また原子力安全委員会の班目（まだらめ）春樹委員長は１６日の定例会後の会見で「３月下旬に２号機で高濃度汚染水が発見された時点で、メルトダウンして いたという認識があり、助言した。１号機と３号機も、事故の経緯を考えると同じことが起こっているとの認識を持っていた」と語った。

Haruki Madarame, chief commissioner of the Nuclear Safety Agency spoke after the regular meeting of NSA on May 16. "When the highly contaminated water was found coming from the Reactor 2 in late March, we recognized that the reactor had had a meltdown, and advised [the government]. We also knew that the Reactor 1 and 3 had the same situation, looking at how the accident unfolded."

　東電によると、機器の記録から、運転中だった１～３号機は地震によっていずれも自動停止。配管の破断などの兆候はみられないとしている。非常用ディーゼ ル発電機も正常に起動していたという。東電はこれらの記録や地震計のデータをもとに、地震直後は機器が正常に作動し、津波到達までは大きな損傷はなかった とみている。（中村浩彦、佐々木英輔）

According to TEPCO, based on the records, the Reactors 1, 2 and 3 stopped automatically after the quake, and there was no sign of any physical damage to the reactor. Emergency diesel power generators were working. TEPCO concluded that all the equipments were working normally after the quake and there was no major damage to the plant until the tsunami hit.

Well, this last bit is highly questionable. Other reports say that the emergency core cooling system stopped working even before the tsunami hit, and that a very high level of radiation was detected at the reactor building of Reactor 1 on the night of March 11, too high unless the RPV and the Containment Vessel were breached by the earthquake, not by tsunami. (On these, later.)

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Asahi Shinbun: #Fukushima Reactors 2, 3 Also Had Core Meltdown

Oh what a surprise.

Asahi Shinbun, one of the MSM in Japan, says in the article published at 3:01AM JST 5/17/2011 that core meltdown may have occurred in the Reactors 2 and 3 at Fukushima I Nuclear Power Plant, according to the data that TEPCO disclosed on May 16.

That data is here, as I posted in my previous post.

Translating Asahi's article right now, and will post ASAP.

Posted.

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(UPDATED) TEPCO's Analysis of Reactor 1 Core Meltdown

From their press release, their English.

It's in "secure" mode, and I can't even do the screen capture. Take a look at page 3 and page 4.

The temperature reached the core melting temperature in about 4 hours, when the water level dropped to the bottom of the fuel. From there, nothing could stop the melt, all of it.

OK, here we go. (h/t Hope, culture of insanity)

Page 3:


Page 4:

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TEPCO Stating the Obvious After 2 Month: Reactor 1 Meltdown Occurred Within 16 Hours of March 11 Earthquake

"Almost of all the fuel rods melted and dropped to the bottom of the pressure vessel by 6:50 am on March 12th." (NHK WORLD news)

NHK WORLD, whose outlandish report that there was a 300 millisievert/hr debris on a nearby mountainside is still uncorrected, says that TEPCO has disclosed the Reactor 1 meltdown occurred within 16 hours of the March 11 earthquake:

Tokyo Electric Power Company, the operator of the Fukushima Daiichi nuclear power plant, says most of the fuel rods in the No.1 reactor had dropped to the bottom of the pressure vessel within 16 hours of the earthquake on March 11th.

The utility revealed its study on the subject on Sunday.

TEPCO said it analyzed the data and calculated a timeline for the developments in the No. 1 reactor on the assumption that the reactor lost its cooling system as soon as it was hit by the tsunami.

The firm said that within about 3 hours after the reactor automatically shut down, the cooling water had evaporated to a level at the top of the rods.

In the next hour and a half, parts of the fuel rods are believed to have begun melting.

The temperature of the fuel rods is believed to have reached 2,800 degrees Celsius at this stage, and the meltdown advanced rapidly.

Almost of all the fuel rods melted and dropped to the bottom of the pressure vessel by 6:50 am on March 12th.

TEPCO said the temperature dropped after water was poured into the reactor starting at 5:50 am on the same day.

The firm says the melted rods created small holes on the bottom of the vessel, but that no major problems are developing there. It believes that the amount of radioactive substances that could spread from the reactor will be limited.

Sunday, May 15, 2011 23:29 +0900 (JST)

For people who can read the Wikipedia entry on "Corium", it's abundantly clear what happens once the water is no longer cooling the fuel rods:

During the Three Mile Island accident, slow partial meltdown of the reactor core occurred. About 19,000 kg of material melted and relocated during about 2 minutes, about 224 minutes after the reactor scram.

In the case of Chernobyl:

The first phase lasted only several seconds, with temperatures locally exceeding 2600 °C, when a zirconium-uranium-oxide melt formed from no more than 30% of the core.

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