(For Record) #Fukushima I NPP Reactor 3 Operating Floor Situation Summary as of 12/31/2013

The post is for my own record and for those who missed the news in July this year about the steam rising from a gap near the shield plug on the operating floor of Reactor 3 at Fukushima I Nuclear Power Plant.

For more posts on the subject, go here.

0. The steam looks like this:

TEPCO's hypothesis from July is that it is part rainwater part leak from the Containment Vessel.

1. The steam was first noticed in July this year, and since then it has been observed numerous times when and after it rains in the geographical area where the plant is located in Fukushima Prefecture (Futaba-machi and Okuma-machi on the Pacific Ocean). It has probably been there since after the March 2011 explosion. Why wasn't the steam noticed earlier? Most likely because of piles of debris on the operating floor, which looked like this from the top, until September 2012 when TEPCO/Kajima started to remove the debris:

(March 24, 2011)

(Video taken on 11/5/2011)

2. Infrared images, taken on July 24 this year, from TEPCO (labels are mine), showing a warm spot with a red X (34.3 degrees Celsius, or 93.74 degrees Fahrenheit) right where the steam was (and still is, occasionally) rising:

3. The air dose rates (gamma radiation) on the operating floor of Reactor 3, particularly around the shield plug, are very high (the latest measurement from November and December this year, presented at the December 26, 2013 meeting to discuss progress of the "roadmap toward decommissioning" - PDF file in Japanese):

The upper numbers: air dose rate in millisievert/hour, at 5 meters off the floor
The lower numbers: localized surface rate in millisievert/hour, measured by a survey meter fitted with collimeter, at 50 centimeters off the floor

(I marked the location of the steam with a blue X.)

But it is more likely that the high air dose rates are not from the occasional weak steam from the spot as seen in the infrared images above, but from the contamination from the fallout in March 2011, from several vents including dry vent (releasing the highly radioactive gas inside the Containment Vessel to outside, without having it go through water to reduce radioactive materials) and the March 14, 2011 explosion of Reactor 3 and steam/smoke afterwards. The steam/smoke in March 2011, as TEPCO casually admitted during the regular press conference on July 24, 2013 (there was no follow-up question from the press), came from a breach in the Containment Vessel of Reactor 3, "as you all know".

As a piece of that evidence,

4. Nuclides analysis result of the radioactive materials in the air, July 25, 2013 shows radioactive cesium in the air where the steam is observed on the operating floor of Reactor 3 is two orders of magnitude lower than the density limit by the nuclear regulation, at 3.3E-05 Bq/cm3 (3.3x10^-5 Bq/cm3 or 0.000033 Bq/cm3, or 0.033 Bq/L, or 3 Bq/m3) for cesium-137, too low to account for several hundred millisieverts per hour radiation:

5. Reactor 3's Spent Fuel Pool is filled with debris big and small, but there are fuel assemblies inside the pool which are cooled with water (water temperature at 11.2 degrees Celsius as of 12/27/2013, from TEPCO's handout for the press.

Video taken in May 2011:

Video taken in September 2012:

Video taken in February 2013:

Again, photos of the Reactor 3 operating floor: (from TEPCO's photos and videos library) March 16, 2011:

March 24, 2011:

July 11, 2012:

September 21, 2012 (SFP, when TEPCO started removing the debris):

May 25, 2013:

October 10, 2013:

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(OT) Is This the Level of Understanding on Fukushima I NPP Accident in the US?

(UPDATE 12/31/2013) For those who want the summary of the steam incident since July this year and the Reactor 3 operating floor condition since the March 2011 accident, I have a new post.

====================

An acquaintance who casually follows the Fukushima I NPP accident sent me a link, quite worried. I opened the link, and I started laughing, then I despaired - realizing that this may be the current level of understanding in the US when it comes to the Fukushima I NPP accident.

I have no idea who this is ("Turner Radio Network - Free Speech, No Matter Who Doesn't Like It"), but it has an urgent news flash on December 28, 2013:

Persons residing on the west coast of North America should IMMEDIATELY begin preparing for another possible onslaught of dangerous atmospheric radiation from the Fukushima nuclear disaster site in Japan. The Tokyo Electric Power Company (TEPCO) says radioactive steam has suddenly begun emanating from previously exploded nuclear reactor building #3 at the Fukuishima disaster site in Japan. TEPCO says they do not know why this is happening and cannot go into the building to see what's happening due to damage and lethal radiation levels in that building. Experts say this could be the beginning of a "spent fuel pool criticality (meltdown)" ...

The page shows a photograph of Reactor 3 steaming vigorously to lend support to the contention above.

The problem? It is a photo from March 2011 right after the building blew up.

Further down the post,

The video below was taken several months ago by TEPCO. It shows that the roof is totally blown off reactor building # 3

Uh... no. All the debris on the operating floor of Reactor 3 has been painstakingly removed, piece by piece, by remote-control cranes and shovels supervised by carbon-based human workers wearing tungsten vests who were physically there on the platform surrounding the reactor building.

The readers of this blog know (I hope) about the story of this "steam" rising from Reactor 3's operating floor. The best hypothesis so far is that this is a combination of rainwater going through the gaps and reaching the Containment Vessel below and being heated up and the steam leaking from a breach somewhere in the Containment Vessel as nitrogen gas is injected into the CV. The steam tends to get observed when it is raining or after it rains.

The steam rising from the gap in the Reactor 3 operating floor looks like this:

I suppose it is free speech to claim this is vigorous enough to reach the height of the jet stream and hit the west coast of North America. Or, to use the favorite refrain among many Japanese, "erring on the side of caution".

The lack of coverage of the Fukushima nuclear accident by the established media in the US has been being filled by the alternative media. For good or bad.

For those who care to know, this is what the operating floor of Reactor 3 looked like, and looks like now (from TEPCO's photos and videos library):

March 16, 2011:

March 24, 2011:

July 11, 2012:

September 21, 2012 (SFP, when TEPCO started removing the debris):

May 25, 2013:

October 10, 2013:

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#Fukushima I Nuke Plant Reactor 3 Steam: Part Rainwater, Part Leak from Containment Vessel, TEPCO Now Speculates

So, at least part of whatever is steaming on the operating floor of Reactor 3 is coming from inside the Containment Vessel after all.

Here we go again?

From TEPCO's email notice for the press on Reactor 3 operating floor steam, No.14 (latest), 7/26/2013:

〈湯気の発生メカニズム〉
シールドプラグの隙間から流れ落ちた雨水が原子炉格納容器ヘッドに加温されたことによるもののほか、原子炉圧力容器、原子炉格納容器への窒素封入量（16m3/h）と抽出量（約13m3/h）に差が確認されていることから、この差分（約3m3/h）の水蒸気を十分含んだ気体が原子炉格納容器ヘッド等から漏れている可能性が考えられ、これらの蒸気がシールドプラグの隙間を通して原子炉建屋５階上に放出した際、周りの空気が相対的に冷たかったため蒸気が冷やされ、湯気として可視化されたものと推定されます。

Mechanism of steam generation

In addition to rainwater seeped in from a gap in the shield plug and warmed by the Containment Vessel head, there is an observable difference(3 m3/hr) between the amount of nitrogen gas being injected into the Reactor Pressure Vessel and Containment Vessel (16 m3/hr) and the amount of nitrogen gas being extracted (about 13 m3/hr), and it is possible that this gaseous body (3 m3/hr) containing enough water vapor is leaking through the Containment Vessel head. We presume that when the vapor leaks through the gap in the shield plug onto the 5th floor of the reactor building, it is chilled by the air which is relatively colder than the vapor, and is visualized as steam.

Nitrogen injection into the Containment Vessel of Reactor 3 has been on-going since July 14, 2011. Start of nitrogen injection into Reactor 3 on July 14, 2011, only four months after the explosion, marked the completion of "step 1" of the famous "roadmap" to decommissioning.

I wonder whether the difference in the amount of nitrogen going in and coming out has always existed. As per TEPCO's open admission (that no one apparently noticed or cared) during the press conference that the steam rising from Reactor 3 in March 2011 was from inside the Containment Vessel, it looks safe to assume that the difference, if any, has been leaking from inside the Containment Vessel all along.

Whether the leak is through the CV head, as TEPCO says, or through somewhere else (like the open equipment hatch on the 1st floor) remains to be seen, I think.

Now that TEPCO has figured out why the steam is rising, the company will resume the work to clear the debris from the Reactor 3 operating floor to "test the validity of the evaluation", according to the notice.

By the way, the infrared thermography taken on October 14, 2011 seems to show the same location where the steam is rising now. The images use different temperature scales, but in both images the location temperature is between 30 and 35 degrees Celsius. It is just as hot today as it was in October 2011.

Infrared thermography of the location of the steam on July 24, 2013, from TEPCO (labels are mine):

Infrared thermography of the same location (or very close to it), on October 14, 2011, from TEPCO (labels are mine, and the white circle indicating the location):

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Latest Infrared Thermography of Reactor 3 Operating Floor Shows Steam Location at 34.3 Degrees Celsius from 5 Meters Above

(UPDATE) TEPCO now says it may be part rainwater, part leak from CV. See my latest post.

=====================

and 30.7 degrees Celsius from 40 meters above.

Infrared thermography seems to show an odd-shaped heat source, possibly partially covered by something else.

TEPCO, who had finally taken infrared thermography on July 20 at the order of Nuclear Regulatory Authority but had done so on a wrong (sunny) day, re-did it in the early morning of July 24 with the similar condition as the day when the steam was first observed on July 18.

From TEPCO's Photos and Videos Library (English), 7/24/2013:

- Measurement date: 4:40 AM - 6:04 AM on July 24, 2013
- Weather condition as of 5:30 AM: Air temperature 18.6°C, humidity 91.1%, wind speed 1.3m/s, wind direction west-southwest
- Measurement height: 5 - 40m above the operating floor of the Reactor Building
- Measurement method:
An infrared camera, which was in continuous automatic shooting mode, was suspended by a
crane at the upper part of the Reactor Building, and it photographed at varying height.
Data was checked after the infrared camera was collected

Steam location, from 5 meters above:

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#Fukushima I Nuke Plant Reactor 3's Steam: TEPCO Spokesman Says "As You All Know, the Area Was Contaminated by the Steam Coming Out of Containment Vessel" After Explosion in March 2011

(UPDATE 7/25/2013) Just as back then, TEPCO now says the current steam may be from the Containment Vessel after all, at least in part. See my latest post.

======================

So that steam back then was actually coming from inside the Containment Vessel???

In the regular press conference on July 24, 2013, TEPCO's spokesman said the steam coming out of Reactor 3 in March 2011 after the explosion was from inside the Containment Vessel, and that is known to everybody.

11 minutes 39 seconds into his briefing (video is at TEPCO's site but only for one week), TEPCO's PR manager Ono says,

ご存知の通り、３号のシールドプラグ近辺ということで言いますと、発災直後に原子炉の格納容器の中から出ている蒸気、というものが、この周辺を含めて、出ていた場所でございますので、そうした影響で高い線量がシールドプラグの雰囲気、周りですね、近辺で観測されている、ということではないか、と考えてございます。

As you all know, speaking about the area near the shield plug of Reactor 3, it was around this area where the steam was coming from inside the reactor's Containment Vessel right after the accident [explosion of Reactor 3 on March 14, 2011]. We think the current high radiation levels observed around, near the shield plug, are probably due to the effect of that steam.

"As you all know"??? Since when?

As far as I remember, the explosion of the Reactor 3 building is explained by TEPCO as hydrogen explosion (initially some TEPCO workers, including Plant Manager Masao Yoshida, thought it was a steam explosion), but the company never explained where the steam seen rising from the wreckage of the Reactor 3 operating floor after the explosion was coming from.

Now, according to TEPCO, everyone is supposed to know, as a matter of fact after two years and four months later, that the steam in March 2011 was coming from inside the Containment Vessel.

I watched the Q&A section of the press conference, but no one seemed to be bothered by Ono's remark. Was it just me who didn't know about it as the established fact? I had suspected as much from the beginning, but didn't know that's now an accepted fact.

How and what did I miss? I searched my own blog for Reactor 3's posts from the beginning, and the closest reference I found was that the steam looked to be rising from near the Containment Vessel.

Well, on further research on the net, what I seem to have missed was the morning press conference on　March 16, 2011 by then-Chief Cabinet Secretary Yukio Edano　(link is in Japanese, Asahi Shinbun). He said, about the steam that started to vigorously rise from Reactor 3 around 8:30AM that day and the sharp rise in radiation levels at the plant after 10AM,

専門家による分析を鋭意しているが、現在において可能性として一番高いと思われるのは、あくまでも確定ではない、可能性として一番高いと思われるのは、２号炉において生じたように、格納容器の一部から水蒸気が放出されて煙が上がっている。そのため、たまっていた放射性を帯びた水蒸気なので、一時的に高い数値が計測されたのではないかというのが、繰り返すが確定ではない、現時点の分析として最も高い可能性として見られている状況。

We are having experts analyze the situation, but at this point, the highest possibility, not confirmed yet, but the highest possibility seems to be that the steam is being released from some part of the Containment Vessel, just like it happened in Reactor 2. Since it is radioactive steam that was inside the Containment Vessel, high levels of radiation were observed temporarily. Let me repeat that it is not yet confirmed, but that is the most likely scenario at this point.

(Wait a minute. Just like it happened in Reactor 2???)

In the afternoon press conference at 6PM on March 16, 2011 (link is in Japanese, Asahi Shinbun), Edano somewhat backed off and said he had heard the steam might be from the suppression chamber (it is still part of the Containment Vessel, I suppose, but below the 1st floor). NISA thought the rise in radiation levels at the plant in the morning of March 16, 2011 was because of Reactor 2, not Reactor 3.

Mr. Edano talked about it as the hypothesis, that the steam rising from Reactor 3 after the March 14, 2011 explosion was from the Containment Vessel, and that was 2 years and 4 months ago. I do not think (I may be wrong) anyone paid attention to this particular remark or followed up on it.

But now, according to TEPCO, that's what everyone should know, that the steam seen rising from the Reactor 3 wreckage in March 2011 was from the Containment Vessel.

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(UPDATED with Data) #Fukushima I Nuke Plant: Radiation Level at the Location of Steam in Reactor 3 Is 562 Millisieverts/Hour, TEPCO Says

This does not necessarily mean that the steam is radioactive, as the top floor (or what's left of it) of Reactor 3 after the March 14, 2011 explosion remain highly radioactive.

There has been only one measurement of radiation (page 30 of the link), probably from the boom of the crane, above the top floor of Reactor 3, and that is 500 millisieverts/hour (at 8 meters above the floor, if I remember right, but not 100% sure).

According to TEPCO's email notice for the press on July 23, 2013,

• TEPCO measured the radiation levels at 25 locations in the area around where the steam has been observed (the entire shield plug).

• Maximum was 2,170 millisieverts/hour, minimum was 137 millisieverts/hour.

• Radiation level at the location where the steam has been observed was 562 millisieverts/hour.

Radiation levels are simply too high for human workers to investigate on the floor, which is not negotiable at all by robots either because of debris.

(UPDATE) TEPCO just released (7/24/2013) the document containing the measured radiation levels (English labels are by me):

The same page as above, but with visualization, from Tomohiro Endo, nuclear researcher at Nagoya University:

If the steam was coming from inside the Containment Vessel, I would assume the location would see much higher radiation level.

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#Fukushima I Nuke Plant Reactor 3: It's Steaming Again from the Same Place, TEPCO Again Says Rainwater Warmed on CV Head

(UPDATE 7/23/2013) TEPCO measured the radiation levels around the area. See my latest post.

=========================

It rained in the morning at the plant. So, just like the previous incident on July 18, this one is explained as rainwater hitting the warm (about 40 degrees Celsius) Containment Vessel Head.

From NHK (7/23/2013; part):

原発３号機から再び“湯気”

"Steam" rising again from Reactor 3

福島第一原子力発電所では３号機の原子炉建屋の上部で、今月１８日に続いて２３日も湯気のようなものが上がっているのが確認され、東京電力は、建屋上部の放射線量などに変化がないことから、朝、降った雨が建屋内部に入り込んで温められたのが原因とみて監視を続けています。

At Fukushima I Nuclear Power Plant, what looks like steam is seen rising from the top floor of Reactor 3 building on July 23, following the same incident on July 18. As there is no change in radiation level above the building, TEPCO thinks it is the rain in the morning that seeped inside the building and warmed up. The company continues to monitor the situation.

東京電力によりますと、２３日午前９時すぎ、福島第一原発３号機の原子炉建屋上部の床で湯気のようなものが上がっているのが、現場に設置したカメラの映像で確認されました。

According to TEPCO, the image captured by a video camera installed [on the top floor of Reactor 3] showed what looked like steam rising from the floor of the Reactor 3 building on 9AM on July 23.

建屋上部の放射線量に変化はなく、原子炉や使用済み燃料プールの冷却も安定しており、異常を示すデータは確認されていないということです。

There is no change in radiation level above the building, and the cooling of the reactor and the Spent Fuel Pool is stable. There is no data that indicate abnormality, according to TEPCO.

Since the steam was first observed on July 18, TEPCO has stopped the work to clear the debris on the operating floor of Reactor 3.

Nuclear Regulatory Authority told TEPCO to take infrared thermography of the location under the condition similar to the fist incident (raining), but TEPCO only heard the first half of the order - take infrared thermography. And take they did, on a sunny day on July 20.

I wonder if they had wits about them to take thermograph today (July 23), when it was raining. It looks like TEPCO will have another chance on July 24 and 25 (weather forecast in Fukushima is rain).

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(UPDATED with Video) #Fukushima I Nuke Plant: Whiff of Steam from Reactor 3 Is "Rainwater Warmed on Containment Vessel Head and Evaporated", Says TEPCO

(UPDATE) TEPCO says the steam has stopped.

======================

In their update of the steam seen coming from between the reactor well and the DSP (device storage pool/pit) of Reactor 3 at Fukushima I Nuclear Power Plant, TEPCO says it was probably the rainwater that evaporated on contact with the Containment Vessel.

From TEPCO's email notice for the press, 7/18/2013:

この測定結果およびこれまでのプラント状況の確認結果により、湯気の発生原因は雨水がウェルカバーのすき間から入って、格納容器ヘッド部にて加温されたことによるものと推定されます。

Considering the result of the measurement [dust sampling, which showed no elevated levels of cesium or iodine] and plant parameters, we presume that the steam was generated when rainwater seeped in through the gap of the reactor well cover, got heated by the Containment Vessel head.

So, there is the CV head (cap), and it is warm enough to turn water into vapor, according to TEPCO. The temperature at the bottom of the Pressure Vessel inside the Containment Vessel, as of July 18, 2013, is about 40 degrees Celsius. (Hmmm... How warm could the top of the CV be?)

(UPDATE: TEPCO added the information of the temperatures at the top of Pressure Vessel inside the CV. See below.)

The company released the photos of the location on the operating floor of Reactor 3 (in Japanese only so far, so I put English labels). It's hard to see the steam in the still photos, but it is evident in the video (to be uploaded here later):

Larger photos:

No.1

No.2

No.3

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(UPDATED) Just In from TEPCO: Whiff of Steam from Reactor 3 Operating Floor at #Fukushima I Nuke Plant

(UPDATE-2) From Ryuichi Kino's tweets (here and here), who asked TEPCO's PR:

湯気が出ているのは機器ピット（定期点検時に原子炉内の構造物を収納しておくプール。使用済み燃料プールくらい大きい）と格納容器の間くらいだが、具体的にどこからというのは確認できていない。止まったらメールでお知らせする

The location of the steam is somewhere between the DSP and the Containment Vessel. Cannot pinpoint the exact location yet. TEPCO will notify if the stem stops.

機器ピットのプールは、定期点検の時に原子炉内の構造物を取り出して入れておくためのものなので、今はなにも入ってません。プールに水は張ってあったと思うのですが、東電本店は「水素爆発もあったので、わからない。どこまで見れているのか」と。

The DSP is empty. [Kino thinks] the pool was filled with water, but TEPCO HQ says "We don't know for sure, after the hydrogen explosion. We don't know how much we can see".

I wonder if TEPCO will make the video available.

(UPDATE-2) TEPCO says it is rainwater evaporated on the CV. See my latest post.

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(UPDATE-1) TEPCO says the steam is still being observed as of 1PM. No significant changes in plant parameters. The company says it has confirmed that there is no re-criticality happening.

========================

From TEPCO's email notice to the press (7/18/2013), via TEPCO's tweet about 15 minutes ago (at 9:51AM):

福島第一原子力発電所３号機原子炉建屋５階中央部近傍（機器貯蔵プール側）で湯気らしきものの確認について

Observation of what looked like steam near the center of the 5th floor of Reactor 3 (on the side of the Device Storage Pool) at Fukushima I Nuclear Power Plant

本日（７月18日）午前８時20分頃、瓦礫撤去作業前のカメラによる現場確認において、３号機原子炉建屋５階中央部近傍（機器貯蔵プール側）より、湯気らしきものが漂っていることを協力企業作業員が確認しました。

Today (July 18) at about 8:20AM, an affiliate company worker spotted what looked like steam floating near the center of the 5th floor of Reactor 3 (on the side of the Device Storage Pool) during video monitoring prior to the start of the debris removal work.

なお、主要プラント関連パラメータ（原子炉格納容器・圧力容器圧力の温度および圧力、キセノン濃度）に有意な変動はありません。

There is no significant change in the major plant parameters (temperature, pressure, xenon density).

また、モニタリングポストおよび連続ダストモニタの値に有意な変動はありません。

There is no significant change in the measurements at monitoring posts and continuous dust monitoring.

What could be in there steaming? I don't know if there is anything in the DSP of Reactor 3. There shouldn't, as Reactor 3 was in operation when the earthquake hit on March 11, 2011. Reactor 4's DSP is filled with water, and it has the removed core shroud and other equipments.

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