#Fukushima I Reactor 2: Thermocouples in Containment Vessel Are Acting Up Again

The temperature is either 88 degrees Celsius, or 20 degrees Celsius, depending on which thermocouple you believe.

Or none of the above, and both thermocouples are broken. Given the previous history (from 2012 when one thermocouples after another was failing inside the Containment Vessel of Reactor 2), it is possible that both are broken.

Mainichi Shinbun (4/7/2015) reports:

福島第１原発:２号機格納容器内の温度計が異常な上昇表示

東京電力は７日、福島第１原発２号機格納容器内の温度計が異常値を示したことを明らかにした。

３日午前５時に２０．９度だった温度が同１１時に７０度に急上昇。５日午後５時には８８．５度まで上昇したが、２号機の別の温度計は平常値を示しており、東電は「原子炉の制御に影響はない」として、原因を調べている。

Thermocouple inside the Containment Vessel of Reactor 2 at Fukushima I Nuclear Power Plant shows abnormal rise in temperature

On April 7, TEPCO disclosed that a thermocouple inside the Containment Vessel of Reactor 2 at Fukushima I Nuclear Power Plant showed abnormal temperature.

The temperature was 20.9 degrees Celsius at 5AM on April 3 but it rapidly rose to 70 degrees Celsius at 11AM. On 5PM on April 5 it further rose to 88.5 degrees Celsius. Other thermocouples show normal temperatures. TEPCO says "It does not affect the control of the reactor," and is currently investigating.

Here's the latest temperature parameters for Reactor 2 Containment Vessel from TEPCO's plant parameters page, which omits the particular thermocouple that spiked:

So which thermocouple spiked? It is the thermocouple "supply air D/W cooler(TE-16-114K#1)". There is a site that continues to plot charts from the plant parameter data disclosed by TEPCO, and here's the chart plotting all "supply air D/W cooler" thermocouples:

Looking at the chart, it is more likely that this particular thermocouple broke, and the temperature inside the Containment Vessel remains between 20 and 30 degrees Celsius.

Quickly checking the measuring devices installed inside Reactor 2 (information from TEPCO's site), broken and malfunctioning devices are numerous.

As of July 2014, only 8 thermocouples out of 24 inside Reactor 2 Containment Vessel are monitored in accordance with the safety procedures set by regulatory authorities (meaning only 8 are properly functioning), according to TEPCO's information.

In contrast, 16 thermocouples out of 21 are functioning properly in Reactor 1 Containment Vessel, and all 19 thermocouples are functioning properly in Reactor 3 Containment Vessel.

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Video of Inside Reactor 2 Containment Vessel, 8/12/2013

I finally managed to download the video properly from TEPCO's Photos and Videos Library page.

For more about TEPCO's latest attempts to probe the Reactor 2 CV, see my posts, here and here.

By the way, I happened to watch a BBC news clip August 6, 2013 on Fukushima I Nuke Plant, and saw in amusement the snippet of the video inside the Reactor 2 Containment Vessel (the one I posted on my August 4, 2013 post). The snippet was used while the announcer was saying "It [groundwater]'s now so high the water will soon reach the surface. Then it will start flowing overground into the sea."

BBC seems to be trying to pass off the grating inside the Containment Vessel as a grating over some underground drain, about to be flowing overground...

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#Fukushima I Nuke Plant Reactor 2 Containment Vessel Probe: Camera Stopped Just Short of Pedestal Opening

So close. TEPCO posted a short report on August 12 with photos as if that was what had been planned all along - to stop right at the opening of the pedestal.

However, the worker who tweeted from Fukushima I Nuke Plant and now tweets from somewhere else, "Happy", said in his August 10 tweet that the probe was done on August 9, but TEPCO couldn't retrieve the camera and the water sample and had to abandon the probe.

I'm not sure the August 12 attempt was a third one (if "Happy" is correct), instead of second. But it's clear from TEPCO's report that they didn't collect the water, and they do not have the video.

On their initial attempt on August 2, 2013 and the video, see my post on August 4, 2013. TEPCO clearly intended, from the first attempt, to insert the camera inside the pedestal.

From TEPCO's Photos and Videos Library, 8/12/2013:

Temperature at (1) was 41 degrees Celsius, and temperature at (2) was 45 degrees Celsius, according to the same document. The radiation levels at those points are "under evaluation".

Click to enlarge the photos.

(1)

(2)

(3)

(4)

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(Video) Inside Containment Vessel of Reactor 1 at #Fukushima Nuke Plant: CCD Camera Dips Into the Water Under the Grating

It took 51 workers (from TEPCO and Hitachi-GE Nuclear Energy, most likely) 3 hours on October 11, 2012 to probe again the Containment Vessel of Reactor 1 at Fukushima I Nuclear Power Plant.

TEPCO's handout for the press (Japanese, 10/11/2012) says the maximum radiation exposure for the workers was 1.83 millisievert. TEPCO does not say how many groups of workers went in, and how long each group spent inside the reactor building.

Tomorrow (October 12), TEPCO will send in the workers again (no information if they are the same ones who have been going there every day since October 9) to collect water samples. On October 13, the workers will go there again, and install a thermocouple and a water gauge inside the Containment Vessel, again using the same penetration.

This is the abbreviated version of the full video which is nearly 1 hour and 40 minutes long (which you can download for your record, here):

It is simply infuriating to think all this work may not have been needed if enough people at TEPCO had dared to break the rules and social niceties on March 11, 12, 13. Even more infuriating that most Japanese still don't get it.

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Video of Inside the Smoke/Steam-Filled Reactor 1 Containment Vessel at #Fukushima I Nuke Plant

TEPCO released the 40-minute video on September 27, 2012, with no explanation of when the video was taken, or how much radiation exposure the workers manipulating the drill and the camera got. (The workers had been practicing on the mockup.)

The video starts after a 130-mm diameter hole was drilledAt first, nothing seems to be happening, until 50 seconds into the video when the aperture of the ball valve opens. What you see at the end of the hole is the inside of the Reactor 1 Containment Vessel. The camera gets inserted at about 2 minutes into the video.

The inside seems to be filled with whitish smoke or steam, though it doesn't look dripping wet like in Reactor 2's Containment Vessel. At about 4 minutes, some sort of structure is discernible. At 5 minutes, a rust-colored wall starts to appear on the left side of the screen.

At about 18 minutes, the camera focuses better, and you start to see what looks like metal and concrete(? it may be mangled metal) debris.

What destroyed the inside like this? Earthquake? Explosion?

TEPCO used Penetration X100B, which is on the northwest corner of the Containment Vessel above the equipment hatch door, not the high-radiation southeast corner.

According to TEPCO's monthly progress report as of September 24, 2012 (page 24 of the PDF), workers from Hitachi-GE Nuclear Energy are doing the work. (Workers from Toshiba are doing the investigation of the Reactors 2 and 3 Containment Vessels.)

In June this year, TEPCO did the survey of the Reactor 1 torus room, where they found the radiation level just above the water surface to be over 10 sieverts/hour.

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(UPDATED) #Fukushima I Nuke Plant: Nitrogen Injection System for Reactors 1, 2, 3 Stopped, TEPCO Trying to Restart

(UPDATE: TEPCO started the backup system at 12:30PM, and nitrogen injection has started. Still no word about why the system stopped in the first place. Since TEPCO is incurious, don't hold your breath for the answer.)

(2nd UPDATE 4/4/2012: TEPCO monitors the system every 6 hours. A worker just happened to look at the monitor screen and noticed the amount of nitrogen injected showed zero. No one seems to know how long the system had stopped, and no one seem eager to find out.)

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From Jiji Tsushin (4/4/2012, 12:24PM):

１～３号機の窒素封入装置停止＝水素濃度抑制へ、復旧急ぐ－福島第１原発

Nitrogen injection system for Reactors 1, 2, 3 at Fukushima I Nuke Plant stopped, TEPCO trying to restore the system to keep the hydrogen concentration low.

　東京電力福島第１原発事故で、東電は４日、１～３号機の格納容器に窒素を封入する装置が停止したと発表した。窒素は水素爆発の原因となる格納容器内の水素濃度を抑えるために封入されているが、東電は水素が危険な濃度になるまでは３０時間かかるとしており、復旧を急いでいる。

TEPCO announced on April 4 that the system that injects nitrogen gas into the Containment Vessels of Reactors 1, 2 and 3 had stopped. Nitrogen is being injected into the Containment Vessels to suppress the rise of hydrogen gas concentration , which could cause hydrogen explosions. According to TEPCO, it takes 30 hours before the hydrogen concentration reaches a dangerous level. The company is currently trying to restore the system.

　東電によると、同日午前１１時前、窒素封入装置が止まっているのを作業員が見つけた。同社は装置の復旧作業を進めるとともに、原因を調べている。

According to TEPCO, before 11AM on April 4, a worker found the nitrogen injection system had stopped. The company is restoring the system, and trying to identify the cause.

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Full Video of Inside the Reactor 2 Containment Vessel

For those of you who need to see the full version, not just the digest. TEPCO for some unknown reason uploaded 4 separate videos that are available for download for about a week. The total video length is about 40 minutes, with the last video being the longest (22 minutes). File sizes are big, and I will add to this post as I upload them on Youtube.

The scenes remind me of the movie "Alien".

Again, 40 unnamed workers in 10 teams prepped the site on January 17, receiving 3 millisieverts radiation exposure, and 34 unnamed workers operated the Olympus endoscope right outside the Containment Vessel, receiving 3 millisieverts radiation. Though Reactor 2's radiation levels are tame compared to those in Reactor 1 and Reactor 3, the air radiation level at the job site was over 20 millisieverts, according to TEPCO.

By the way, TEPCO released the photographs of the endoscope that was used, as if it was the hero of the operation.

Part 1 (Oh wait, it is supposed to be 8-plus minute video... What happened? Well enjoy while I try to figure that out.)

Part 2



Part 3



Part 4

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TEPCO's Endoscopic Probe of Reactor 2 CV: Mockup Was Done on Novmeber 30, 2011

The picture was released on January 18, 2012. They did the mockup using Reactor 5, and the photo is that of inside the Reactor 5 Containment Vessel.

From TEPCO's handout for the press (1/18/2012), Japanese only for now. The photo on the right side is what you would expect to see in Reactor 2's Containment Vessel. Not.

"Colonoscopy" of Reactor 2's CV using the endoscope from Olympus will be on January 19 in Japan. I don't know the time, and TEPCO is not saying.

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Just In: Japanese Expert Says Fukushima II (not I) Nuke Plant's Containment Vessel Has Been Damaged by the Quake

Information from Iwakami Yasumi's USTREAM channel netcasting the workshop of an Osaka citizens' group "Kansai network to stop the disaster-debris acceptance" with a panel of experts including European experts.

One Japanese expert, Hiromitsu Ino, said a Containment Vessel at Fukushima II (Daini) is broken, and they are trying to repair it. It was probably caused by the earthquake, not tsunami.

The workshop is on-going at this link: http://www.ustream.tv/channel/iwj-osaka1#utm_campaign=t.co&utm_source=8481429&utm_medium=social

Hiromitsu Ino is professor emeritus at Tokyo University. His area of specialty is metallic materials science. He is the head of the Group of Concerned Scientists and Engineers Calling for the Closure of the Kashiwazaki-Kariwa Nuclear Power Plant.

I still remember a tweet last summer (I think) saying an acquaintance fleeing from the area near Fukushima II Nuke Plant right after the earthquake saw a smoke coming out of one of the reactor buildings (there are 4). Fukushima II, unlike Fukushima I, has 4 Mark-II type boiling water reactors built by Toshiba and Hitachi.

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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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#Fukushima I Nuke Plant Reactor 3: Videos of Packbots Cleaning the Guide Rail and Finding 1.6 Sievert/Hr Spots

First, the video of Packbots' cleaning operation on November 18 of the guide rails to the Containment Vessel hatch in Reactor 3 reactor building 1st floor. As one Packbot wipes the rail and holds the towel up in the air, you see the water is dripping. The droplets look clear, and not sludge-like.

By the way, it is false information that the video was taken by a human worker on the scene. No way even TEPCO would knowingly send a carbon-based worker to videotape in 1.3 sievert/hr (as of November 14) environment. (Human workers entering and finding high-radiation spots is another matter.) One Packbot did the cleaning, while the other videotaped the effort by its colleague. Both were remotely operated by carbon-based colleagues from the PCs.

And here's the video where Packbots went back the next day (November 19) to the guide rails to inspect the cleaning job and measure the radiation again. We know that they found out their cleaning operation didn't reduce the radiation levels along the rails; the levels went up (see yesterday's post). The guide rails, despite the cleaning operation, look wet:

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#Fukushima I Nuke Plant Reactor 1 Hydrogen Gas Conundrum

So TEPCO tried to expel hydrogen gas inside the pipe that leads to the Containment Vessel of Reactor 1 yesterday. But the word is that the work is stopped, because the hydrogen gas in the pipe, which initially had dropped to 0.1% concentration with nitrogen gas injection, went back up again after 2 hours, indicating continuous supply from somewhere (like the CV, maybe).

As the pipe is originally for the water spray system not for hydrogen gas or any type of gas, the hydrogen gas seems to permeate, even if the valves are closed off.

Ooops.

From Yomiuri Shinbun (10/8/2011):

東京電力は８日、福島第一原子力発電所１号機の格納容器につながる配管から高濃度の水素を抜く作業を行ったが、濃度が目標の「１％未満」まで下がらなかったと発表した。

TEPCO announced on October 8 that the concentration of the hydrogen gas in the pipe that leads to the Containment Vessel of Reactor 1 at Fukushima I Nuclear Power Plant didn't go down to the intended level of "less than 1%".

　配管内に窒素を入れて水素を押し出す作業の結果、約６３％だった配管内の水素濃度は０・１％以下に下がった。しかし、１～２時間後に最高３・９％まで再上昇した。水素が依然、配管内に残っているとみられ、東電は９日も同様の作業を行うとしている。

Injection of nitrogen gas in the pipe to expel hydrogen gas lowered the concentration of hydrogen gas in the pipe from 63% to less than 0.1%. However, it wet back up to 3.9% in 1 to 2 hours. Hydrogen gas is considered to still remain in the pipe. TEPCO said it will do the nitrogen injection again on October 9.

　この配管には、格納容器内のガスに含まれる放射性物質をフィルターで除去する「ガス管理システム」を新設する予定。水素濃度が高いと、設置作業中に爆発する恐れがある。

The company plans to install the "gas management system" that will filter the radioactive materials in the gas inside the Containment Vessel. If the concentration of hydrogen gas is high, it may explode during the installation of the system.

Independent journalist Ryuichi Kino tweeted yesterday that TEPCO either doesn't know (or is not telling) the hydrogen gas concentration, if any, inside the Containment Vessel. The company remain curiously incurious.

The Fuku-1 worker tweeted that he suspects hydrogen gas may be coming from the "torus" (= suppression chamber). He says, as does Kino, that the valves for a water system would not stop hydrogen gas even if they are closed.

TEPCO will repeat the same procedure on October 9, hoping to lower the concentration below 1% so that the pipe can be cut safely to install the gas filtering system. And if hydrogen gas keeps coming through the pipe? TEPCO apparently don't care to know.

To recap, their optimistic diagram of the attempt:

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#Fukushima I Nuke Plant: TEPCO Has Started to Expel Hydrogen Gas from the Pipe Leading to Reactor 1 CV

Remember that pipe filled with 63% hydrogen gas (the rest was nitrogen gas, according to TEPCO) that leads to the Containment Vessel of Reactor 1?

TEPCO is removing the gas from the pipe right now. They started at about 2 hours ago (12 noon on October 8, 2011 Japan Standard Time), according to NHK News Japanese (12:57PM JST 10/8/2011):

東京電力福島第一原子力発電所１号機で、格納容器につながる配管に高濃度の水素がたまっている問題で、東京電力は、８日正午すぎから水素を抜き取る作業を始めました。東京電力は、作業は配管に窒素を入れて水素の濃度を下げながら行うため、爆発のおそれはないとしています。

Regarding the hydrogen gas in the pipe that leads to the Containment Vessel of Reactor 1 at Fukushima I Nuclear Power Plant, TEPCO started the operation to expel the gas from the pipe at noon on October 8. TEPCO says there is no danger of explosion as the nitrogen gas will be injected in the pipe to lower the concentration of the hydrogen gas.

福島第一原発１号機では、先月下旬格納容器につながる配管に水素がたまっていることが分かり、東京電力が配管の水素濃度を測定したところ、６１％から６３％と全体の３分の２近くを占める高い濃度だったことが分かりました。この配管の中に酸素はないとみられ、今のところ、爆発のおそれはないとしていますが、今後の復旧作業で配管を切断する計画があるため高濃度の水素が外部に放出されると爆発するおそれがあるとして、８日正午すぎ、配管から水素を抜き取る作業を始めました。水素を抜き取る作業は、配管の中に窒素を入れて、水素の濃度を下げるとともに、発火につながる静電気が起こりにくい特殊なホースをつなぎ込んで、建屋の外に放出するということで、爆発するおそれはないとしています。東京電力は、２号機と３号機についても配管などの水素濃度を調べるよう国から指示を受けていて、今後、１号機と同じように調査を行うことにしています。

In late September it was discovered that the hydrogen gas was in the pipe that leads to the Containment Vessel of Reactor 1. When TEPCO measured the concentration of the gas, it was very high between 61 and 63%. It is considered that there is no oxygen in the pipe, and there is no danger of explosion so far, according to TEPCO. The company plans to cut the pipe later, and to eliminate the danger of explosion if the hydrogen gas in the pipe is released it started to expel the gas at noon on October 8. Nitrogen gas will be injected in the pipe to lower the concentration of the hydrogen gas there, and a special hose that suppresses static electricity which could trigger explosion will be attached to expel the gas outside the building. There will be no danger of explosion, TEPCO says. TEPCO has been ordered by the national government to check the concentration of hydrogen gas in the similar pipes in Reactors 2 and 3, which the company has said it will do in the near future.

TEPCO hasn't said anything definite about where this hydrogen gas came from, other than saying it may be the remaining gas from zirconium (in the cladding) and steam reaction when the fuel was melted down. The company doesn't seem eager to find out.

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Fuku I Hydrogen Gas Update: It Was 63% Concentration

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

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

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

From Yomiuri Shinbun (9/28/2011):

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

(H/T WaveCepter311)

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#Fukushima I Nuke Plant: Reactor 2 Containment Vessel May Have Had a Hole Right After March 11 Earthquake

according to a government researcher at Japan Atomic Energy Agency (JAEA).

Yomiuri Shinbun (9/22/2011):

東日本大震災直後に、東京電力福島第一原子力発電所２号機の格納容器が損傷、直径約７・６センチ相当の穴が開いた可能性のあることが、日本原子力研究開発機構の柴本泰照研究員の模擬実験で分かった。

The simulation done by Yasuteru Shibamoto, researcher at Japan Atomic Energy Agency, shows that the Containment Vessel of Reactor 2 at Fukushima I Nuclear Power Plant may have been damaged, and had a hole about 7.6 centimeters in diameter right after the March 11 earthquake.

　格納容器の損傷度を示す具体的な数値が推定されたのは初めて。北九州市で開かれている日本原子力学会で２１日、発表された。

It is the first time that the degree of damage on the Containment Vessel is estimated in numbers. It was announced on September 21 at the fall conference of the Atomic Energy Society of Japan in Kitakyushu City.

　柴本さんは、交流電源が喪失した後に、蒸気で注水を継続する非常用冷却装置「原子炉隔離時冷却系」（ＲＣＩＣ）の動作状況、圧力の推移など東電が発表したデータを活用。ＲＣＩＣへの水の供給源は、震災１４時間後に、枯渇した復水貯蔵タンクから格納容器の底部の「圧力抑制室」に切り替わった。

In simulation, Shibamoto utilized the data TEPCO had announced regarding the operation of the reactor core isolation cooling (RCIC) system and the change in pressure [inside the Containment Vessel]. In 14 hours after the earthquake hit, the water supply to the RCIC was switched from the condenser storage tank that had run dry to the suppression pool at the base of the Containment Vessel.

　この場合、熱が外部に逃げないため、圧力は、震災後、２日程度で設計圧力（約５気圧）の２倍まで急上昇する。しかし、実際は、圧力の上昇は緩やかで、７気圧に達するまで３日以上経過していた。

As the heat wouldn't dissipate, the pressure should have risen to about twice the design pressure (the design pressure is about 5 atmospheric pressures) within 2 days after the quake. However, in the actual data, the rise of the pressure was gradual, and it took more than 3 days to reach 7 atmospheric pressures.

I see. So when the water source was switched from the tank to the suppression pool, the pressure didn't rise because the Containment Vessel already had a hole in it. Then the suppression pool blew up on March 15.

The article doesn't say where the hole might be, or exactly when it may have been created and how.

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Multiple 10-Centimeter Holes in Reactor 2 Containment Vessel at #Fukushima I Nuke Plant

So says the Mainichi Shinbun reporters who must be reading the report submitted by TEPCO on May 23 and released on May 24.

Multiple 10-centimeter holes in the Reactor 2 Containment Vessel, and one 7-centimeter hole in the Reactor 1 Containment Vessel.

Hiroaki Koide of Kyoto University was so right. The Containment Vessels' integrity has been long gone. TEPCO should have known all along, and all the experts, including Koide, must have known.

From Mainichi Shinbun Japanese (2:30AM JST 5/25/2011):

　東京電力が２４日公表した福島第１原発２、３号機で炉心溶融があったとする報告書の中で、１号機は原子炉圧力容器の外側にある格納容器に直径７センチ相当の穴、２号機では格納容器に直径１０センチ相当の複数の穴が開いている可能性が初めて示された。

In the report that TEPCO disclosed on May 24 regarding the core meltdown in the Reactors 2 and 3, the possibility of holes in the Containment Vessels of the Reactors 1 and 2 is mentioned for the first time. The Reactor 1 Containment Vessel may have a hole 7-centimeter in diameter, and the Reactor 2 Containment vessel may have multiple holes 10-centimeter in diameter.

According to the Mainichi article, TEPCO came to the conclusion of multiple 10-centimeter holes in the Reactor 2 Containment Vessel and one 7-centimeter hole in the Reactor 1 Containment Vessel from the analysis of the pressure data.

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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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#Fukushima I Nuke Plant: Unintended "Water Entombment" of Reactor 1

They didn't mean to, but ended up doing what some experts had suggested as a way to cool the melted fuel in the Reactor 1's Pressure Vessel.

Mainichi Shinbun (10:01 PM JST 4/23/2011; emphasis added) reports that TEPCO is "entombing" the Reactor 1 with water by accident:

Fukushima I Nuke Plant: 6 meters of water inside the Reactor 1 Containment Vessel

TEPCO disclosed on April 23 that there is 6-meter deep water inside the Reactor 1 Containment Vessel at Fukushima I Nuclear Power Plant. The "water entombment", whereby the Containment Vessel is to be filled with water above the level of the fuel rods [inside the Pressure Vessel] is one of the goals listed in TEPCO's "roadmap" within the next 3 months. What is happening seems to be the de facto "water entombment", not by design but by accident. It is not clear whether the water continues to rise above the level of the fuel rods.

According to TEPCO, about 70% of the fuel rods are damaged in the Reactor 1, and the total 7,000 tons of water have been poured into the Pressure Vessel in an effort to cool the Vessel. The steam from this cooling effort may have escaped into the Containment Vessel and condensed into water, or the pipes that connect the Pressure Vessel and the Containment Vessels may have been damaged in the earthquake, allowing the water to leak into the Containment Vessel.

The water level is an estimate by TEPCO from the change in pressure within the Containment Vessel as they injected the nitrogen gas to prevent a hydrogen explosion. TEPCO believes the Suppression Chamber near the bottom of the Containment Vessel is now completely filled with water, and the flask-shaped dry well (17.7 meter in diameter) is filled with 6-meter deep water.

Water is also being injected into the Pressure Vessels of Reactors 2 and 3. In Reactor 2, the Suppression Chamber is damaged and the highly radioactive water has been leaking from the Containment Vessel; it is not known whether any water remains inside the Containment Vessel.

The "water entombment" method is not without problems. In the Reactor 1's Containment Vessel, 10,700 cubic meters of nitrogen gas, twice the capacity of 6,000 cubic meters, have been injected but the pressure has stopped rising. It is possible that the Containment Vessel is damaged, and the water may leak from the damaged area if the water keeps rising. Also, the vulnerability of the Containment Vessel to an earthquake due to increased weight from the water is "under the final examination", according to Nuclear and Industrial Safety Agency. In addition, it will be necessary to treat the highly contaminated water [inside the Containment Vessel] at some point.

福島第１原発：１号機格納容器内に水６メートル

　東京電力は２３日、福島第１原発１号機の原子炉格納容器に深さ約６メートルの水がたまっていることを明らかにした。格納容器を燃料棒の上部まで水 で満たして原子炉を冷やす「水棺」作業は、事故収束に向けた工程表で最初の３カ月目標に掲げた対策の一つ。同社が意図しない形で事実上の水棺状態が進行し ているとみられるが、このまま燃料棒上部まで水位が上がるかどうかについては不確定要素もある。

　東電によると、１号機は燃料棒の損傷が推定７０％と最も激しく、圧力容器にこれまで約７０００トンを注水して冷却を続けてきた。ここで発生した蒸 気が格納容器に移って水になっている可能性や、圧力容器と直結する配管などが地震で損傷し、格納容器に水が漏れ出ている可能性が考えられるという。

　水位は、水素爆発を防ぐための窒素注入による格納容器の圧力変化から東電が推計した。その結果、格納容器下部にある圧力抑制プールは既に満水と なっており、「ドライウェル」と呼ばれるフラスコ状の球形部（直径１７・７メートル）も深さ約６メートルの水がたまっていることが分かった。

　２、３号機も同様に圧力容器への注水が続けられているが、２号機では圧力抑制プールが破損し、高濃度の放射性汚染水が外部へ漏れ出ており、格納容器内の水のたまり具合は分かっていない。

　一方、水棺方式には課題もある。格納容器には既に容量（約６０００立方メートル）の２倍近い窒素約１万７００立方メートルを注入しているが、一定 以上に圧力が高まっていない。容器の損傷も考えられ、このまま水位が上がれば、損傷部からの水漏れが懸念される。また、水の重量の負荷に伴う耐震性は「最 終チェックしている段階」（経済産業省原子力安全・保安院）の上、長期的には高濃度に汚染された水の処理も必要となる。【八田浩輔、阿部周一】

Mainichi has a diagram that they created, based on the information from TEPCO. 11.8 meters to go for the water to rise above the level of the fuel rods.

At least TEPCO didn't claim this "entombment" was by design. Some honesty here. I have a feeling that TEPCO has grown so weary and worn out to make up stories any more.

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