Thursday, July 25, 2013

#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):

11 comments:

Anonymous said...

Aaaaw, I guess, there goes the dragon ...

And according to TEPCO, 1. the steam is not radioactive and 2. unit 3 is in cold shutdown. These two statements still stand or do we all know something else that just slips my mind/understanding at the moment?
*mscharisma*

arevamirpal::laprimavera said...

It's "cold shutdown state", remember? Dust sampling data does show the steam is not radioactive, with cesium less than 1/100 of what nuclear workers are allowed to breathe in the air.

Apolline said...

Just because I read carefully for translation, at the third line of your first translation, it is written "nigrogen" instead of "nitrogen".

;-)

Friendly

Anonymous said...

Is looks more and more like a mystery novel where the reader can't find the truth, as the author, although he (she etc...) has the cards in his hand, doesn't know how the story will end, as he is in a writing process.

Tepco & co did a huge cover up, that doesn't mean they actually and reliably know what's happening.

Before the astounding explanation / hypothesis that smoke and other gases from F1, 3 could come from F1, 2, I wouldn't have imagined units would share a commune ventilation system.
Looked like paving the way for a disease in block 1 to spread to block x, y, z.

So I'll wait and mind my own business for a while.

Hélios, bravo pour tes traducs, bien que je lise l'anglais sans problème, tu joues à la nigaude ou tu azozotes, là ?

Thanks, Phiphi.

arevamirpal::laprimavera said...

Thank you Helios...

Phiphi, someone (former Chairman of US NRC) recently said, "TEPCO may be clueless as to what they are doing."

Anonymous said...

I am a dedicated and appreciative reader...

Would you consider writing a post with your cultural analysis of the Japanese custom of bowing? I have learned much from prior posts in which you analyze the ritual of formal apology, and I think many of your western readers (like myself) would appreciate understanding more about it. How low do you go? How long do you hold it? What does it all mean?

I have long wondered about Asian genuflection, and upon watching this video today, http://www.youtube.com/watch?v=hJxbTdlUqzI&feature=player_detailpage&t=62, I decided to ask you to post about it.

Thank you for your consideration of this request.

-RB

Anonymous said...

RB
much time ago bowing and genuflection was a Western custom as well, in general indicating submission. Similarly, people used to greet each other saying something like "at your service" and 'ciao' has similar origins (formally expressing submission).

Bowing in Japan is about the same, the deeper/longer the more emphatic, and is used both as a greeting and when apologizing. The Japanese greeting 'yoroshiku' goes along the same line of expressing submission/goodwill, possibly perfunctorily.

Beppe

Anonymous said...

The saddest thing is how Tepco lies out of their ass on a daily basis and everyone still defends them and accuses you of being crazy if you ever point out how full of shit they are.

Self-delusion has no boundary.

Anonymous said...

TEPCO is playing fast and loose with the numbers anyway. Yes they are measuring air dose, but at the plant boundary. They did not measure the steam itself, or at least that's what I gather from their (characteristically terse) press releases.

arevamirpal::laprimavera said...

TEPCO did measure air dose over the shield plug on Reactor 3. http://ex-skf.blogspot.com/2013/07/fukushima-i-nuke-plant-radiation-level.html

They measured steam via dust sampling, with extremely low cesium content. http://www.tepco.co.jp/en/nu/fukushima-np/f1/smp/2013/images/airupper03_130726-e.pdf

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