Japan Earthquake: Nuclear Plants at Fukushima Daiichi

In summary: RCIC consists of a series of pumps, valves, and manifolds that allow coolant to be circulated around the reactor pressure vessel in the event of a loss of the main feedwater supply.In summary, the earthquake and tsunami may have caused a loss of coolant at the Fukushima Daiichi NPP, which could lead to a meltdown. The system for cooling the reactor core is designed to kick in in the event of a loss of feedwater, and fortunately this appears not to have happened yet.
  • #6,686
pdObq said:
I didn't really want to get into this discussion, but I have to admit, that I also noticed that round shape in the roof structure when I first looked at the pictures. However, I have no firm hypothesis why it's there or if it really means anything.

So, considering your idea, wouldn't you expect the metal structure to be bent outwards if some heavy object ejected from the inside caused it? But on all pictures I have seen it looks more like it is bent inwards, no? I always had the impression it looks more like a large amount of heat at that point caused the steel to deform and bend downwards (Like when one puts a lighter under a sheet of plastic). It might be related to that fireball (which I currently believe to be hydrogen burning in a non-optimal mixture with oxygen) on that side of the building during the explosion.

EDIT: Oh, similar points have been raised in post above while I was writing this.
OK, two posts describing "bent in". Can you help me better understand what you mean by that?
 
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  • #6,687
ihatelies said:
The item that landed beyond the shared pool is clearly visible in the 2 flights over Fukushima video. I can't find the original anymore - here is one version on youtube - pause it between 2:17 and 2:32 and the thing is plainly visibile in the parking lot. Doesn't look like a crane to me, or a cap, I don't know what it is. Most of the pictures are deliberately cropped to avoid showing it, though so it must tell some kind of story.

Can't it be something left there by tsunami, before explosion?
 
  • #6,688
MadderDoc said:
Forget about it, it is not something from unit3. The video taken from a helicopter one hour after the tsunami shows the same junk in that parking lot. (frame attached)

Ok, I'll buy that. Mystery junk solved - something from the earthquake or tsunami. It certainly doesn't look like something that went 1500 feet high and came back down.

Something fell over to that side of Unit 4, but if it wasn't this it must have been something else.
 
  • #6,689
Temperatures in unit 3 still rather "jumpy":
http://www.nisa.meti.go.jp/english/files/en20110511-2-5.pdf [Broken]
E.g. upper part of RPV bottom head went from 235 to 296 °C within 6 hours (sensor failure not ruled out).
 
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  • #6,690
unlurk said:
Common TCups, you know better than that.

Just my twisted sense of humor . . . |Fred and I aren't going away.
 
  • #6,691
ihatelies said:
Let me try the links again. I screwed up the links the first time.

Here is the picture of the hole:

Thanks for the picture, now I see which one you mean. (Because if I wanted to I could highlight several other vaguely round roof holes on the same photo, albeit much smaller in diameter).

OK here is the problem. It only just looks round in that photo, from an even slightly different angle it does not. From the variety of other images we have of reactor 3 roof itnever looks round. And far from being so wonderfully round that you insist only a round object could of created it, its barely round at all. Its a vague circle that's composed of slightly deformed triangle and rectangle patterns, other beams/struts going off at different angles and heights, and possibly also some railing from the service floor, railing that may even have been round before the explosion, depending on where it came from.

The only thing its got going for it is that its in an important area of the building. The FHM exiting the building from this vicinity cannot be ruled out.
 
  • #6,692


StrangeBeauty said:
This discussion probably deserves a diff thread

Feel free to start a new one. Once you do let me know which posts from THIS thread should be moved there.
 
  • #6,693
Borek said:
Can't it be something left there by tsunami, before explosion?

Yes, it was there after the tsunami and before the explosions. I think Joe N. pointed that out in response to one of my posts within the first day or so after the tsunami. It was confirmed by the Digital Globe images. It was a piece of roof that came off one of the smaller out-buildings, as I recall, as was a bunch of other stuff. (yawn)
 
  • #6,694
TCups said:
Yes, it was there after the tsunami and before the explosions. I think Joe N. pointed that out in response to one of my posts within the first day or so after the tsunami. It was confirmed by the Digital Globe images. It was a piece of roof that came off one of the smaller out-buildings, as I recall, as was a bunch of other stuff. (yawn)

In the meantime MadderDoc posted an image confirming it, I really shouldn't answer before reading all new posts.
 
  • #6,695
ihatelies said:
So you don't have any analysis, or can't find any in the past?

Then this is a very significant piece of information then. Steel does not deform into perfect arcs without significant heat and pressure. It doesn't deform into perfect arcs in a random explosion where "lots of stuff is messed up".

If you've studied explosive reconstruction, you would know that details such as this tell the story.

Yeah we'd all love to have the complete pictures of the place so we can find the interesting equipment - and prove theories like this right or wrong immediately - but all we are given is grainy video from several kilometers away, and we all can speculate as to why.

And, visual evidence is one of the best kinds of actual scientific data.

I hate lies, I must admit, I haven't read beyond this post yet. (takes me quite a while to get caught up every day, if I ever do) And after studying your photos, I agree with you that there is a hole in the roof. But my analysis is that it was made from a downward motion, not upward, which leads me to believe what is in the SPF pool bent/broke the roof. But I am not a professional, and my eyesight is not that great. So I will go back to reading, and let you prove it wrong or right.
 
  • #6,696
http://news.tbs.co.jp./newsi_sp/youtube_live/ [Broken]

The live cam is still showing three distinct plumes from #2, 3 & 4
It's been daylight for an hour now and there has been plenty of mist about, particularly low down in the foreground but that is all horizontal, flattish stuff. The plumes can clearly be seen rising quite swiftly vertically before drifting to the right. The plumes are currently rising to about the hight of the stack towers before fading into the background.
 
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  • #6,697
Hey folks if this is just board clutter i request moderator delete it. I try to back up my speculations, so give me credit for that. If you discussed this already i simply missed it so please just say so i'll not get rowdy over it...

to add to the round hole fray, i'll suggest it is an access hole put in the roof 1997-1998 when they replaced the core shroud on unit 3.

Two hundred pages ago there was speculation that an access panel in side of building at ground level was removed to make way for the shroud. They could scoot it in at ground level and lift it up inside if there's adequate clearance and no floors in the way, and the big overhead crane can reach down that far..

I'd expect them instead to lift it to operating floor level with a crawler crane and slide it in horizontal through a blowout panel then upright it, or else lift it above building and set into D/S laydown pool through the roof.
Photos of unit 4 right now show a "doghouse" sticking up that is probably to enclose the D/S while shroud replacement was to go on in that unit. They use half the D/S pool for shroud and stack dryer on top of separator in other half to make room for it. But that leaves top of D/S exposed so they build a doghouse over it and pile lead shielding on that as described here on page 4 of 5.
http://www.irpa.net/irpa10/cdrom/00584.pdf

There's a photo of shroud here at House of Foust, almost last one on page with a pretty girl standing next to it.
http://www.houseoffoust.com/fukushima/phototour.html

Here's a blurb on shroud replacement job but no details on the lift.
http://www.jsme.or.jp/monograph/pes/1999/ICONE7/PAPERS/SPECIAL/FP7903.PDF [Broken]

i'm more interested in the energy source for explosion.
Thank you SteveElbows for looking at and debunking my snaggletooth apparition in that video; as somebody else said one sees what one is looking for that's why i asked for another eyeball on it.
 
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  • #6,698
elektrownik said:
Something is bad, reactor 3 appear to by on fire
15wmi34.jpg

The signal-to-noise ratio in that picture is approaching that of this thread.
 
  • #6,699
jim hardy said:
Hey folks if this is just board clutter i request moderator delete it. I try to back up my speculations, so give me credit for that. If you discussed this already i simply missed it so please just say so i'll not get rowdy over it...

http://www.houseoffoust.com/fukushima/phototour.html

With a couple more sets of plans and pics, you can begin building a NPP in your own backyard.

Cracked shrouds (stainless steel) would have normally caused decommissioning of the reactors. And then there was the welding of cracks as a temporary fix which was a no no. So the idea of replacing shrouds was pioneered. So you think a sky-hook was used to lower the replacement shroud through a roof opening?
http://www.houseoffoust.com/fukushima/tepco_pics/shroud.jpg
 
  • #6,700
MiceAndMen said:
The signal-to-noise ratio in that picture is approaching that of this thread.

You might be right if you judge only by that single frame/screen capture. If you watched it live there was still a lot of noise, but in between you actually could make out a lot of smoke (no 3) and steam (nos 2+4). Then before the dawn the lights went out and everything was pitch black, and a little later there was dawn with a lot of fog/mist.
 
  • #6,701
turi said:
Temperatures in unit 3 still rather "jumpy":
http://www.nisa.meti.go.jp/english/files/en20110511-2-5.pdf [Broken]
E.g. upper part of RPV bottom head went from 235 to 296 °C within 6 hours (sensor failure not ruled out).

No this is a typing error 236°C http://www.tepco.co.jp/nu/fukushima-np/f1/images/032_1F3_05110600.pdf
 
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  • #6,702
ihatelies said:
OK, two posts describing "bent in". Can you help me better understand what you mean by that?

I never saw where this was answered so I thought I'd help you out. If you look at the "round area" you will see where the metal is pointing downward like it wants to go inside the "hole" that would be bent in. If it were point upward, that would be bent out.

That said, I don't see were re-hashing the same arguments about what might have happened day after day are accomplishing much. There is nothing to be learned from it because we will NEVER know what really happened. Nobody will ever be proven right or wrong. What matters now is what IS happening or what WILL happen. Hopefully it will be whatever is best to reduce radiation and get this major cluster under control instead of making it worse.
 
  • #6,703
""So you think a sky-hook was used to lower the replacement shroud through a roof opening? ""

no, as i said a big crawler crane.

i thought somebody else might have run across old photos and they'd put an end to the speculation. That shroud job was surely well documented in the TEPCO archives since they were the first in the world to do it. There would have been other papers published on it. I'll see if i can track something down.

Simple logic. When you can't prove something right you got to prove it false and move on to next wild-*** idea. Else you're just swapping insults. If you can't disprove it you admit it as a possibility and weigh it against the other possibilities.
 
  • #6,704
I would like to thank Nancy Foust, while I do not share most of her assessments , thumb up for the picture collecting job!
<3

http://www.houseoffoust.com/fukushima/tepco_pics/R3_july18_6.jpg
[URL]http://www.houseoffoust.com/fukushima/tepco_pics/R3_containmentcap2.gif[/URL]

Now about the falling down Unit 4.. New better quality allow imo to conclude that the unit it not falling .. perspective + what I see as a fire hose + no DOF is what it was about
[PLAIN]http://k.min.us/ikXNpC.jpg [Broken]

About the hole theory, first of all I stand corrected the picture summited was new (to me at least) , having said that I toke a look at the same spot under 3 different but close angle , and I can not see that as a hole made by an inner force. Some of the roof structure is missing some are bent , but in my repeated opinion not in the suggested way
[PLAIN]http://k.min.us/jntf3c.jpg [Broken]
 
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  • #6,705
Re lifting a shroud through a round hole in roof with a crane
here's what TEPCO proposed in a 1995 paper, for a somewhat bigger lift

{ does anybody know how to embed a PDF picture? }
this link., page 6 of 8

http://www.jsme.or.jp/monograph/pes/1999/ICONE7/PAPERS/TRACK04/FP7292.PDF [Broken]

edit tried to insert image no luck
 
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  • #6,706
Fred,
Did you notice that the reactor pictures are stamped R/5, that would lead me to believe that this is reactor #5,

I only mention this so we do not have to have ten pages discussing the channel which is shown more narrow on other pictures.

I do not care the with of the cahnnel, I think I understand your intented use.. just wanted to point out that info.
 
  • #6,707
SFP 3 went critical

There is something which hasn't been mentioned recently, the gamma ray burst which was detected in Tepco's bunker at the time of the #3 blast.

Has anybody come up with any new theories about that recently?
 
  • #6,708
jim hardy said:
Re lifting a shroud through a round hole in roof with a crane
here's what TEPCO proposed in a 1995 paper, for a somewhat bigger lift

{ does anybody know how to embed a PDF picture? }
this link., page 6 of 8

http://www.jsme.or.jp/monograph/pes/1999/ICONE7/PAPERS/TRACK04/FP7292.PDF [Broken]

Interesting find, it's not only the shroud, it's a study about replacing the whole RPV! I wonder if any of their RPV are in a state that might need full replacement?

The shroud goes into the RPV. It probably doesn't fit through the refueling tunnel and that vertical shaft for cask and fuel and whatever transfer in the SW corner, does it?

EDIT: The documents in your other post are also pretty interesting (It's kind of interesting that all this stuff can be found on the internet...). So, it is extremely likely they had welding equipment inside unit 4, as there seems to be a whole bunch of welding involved there and they mention that in one of those documents. They also write they sliced the old shroud into small pieces and "put the containers in DSP". They used "underwater plasma slicing".

EDIT2: With respect to https://www.physicsforums.com/showpost.php?p=3292292&postcount=6332 , one of the documents you found mentions that N2 nozzles are recirculation inlets, N4 is feedwater as we know, and N5 is core spray. (Just for completeness.)

[I don't think there is any reasonably easy way to link to a picture in a pdf file. Attached is a simple screenshot.]
 

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  • #6,709
etudiant said:
Thank you for this interesting picture. It is the first I've seen of the storage tanks that will need to hold the roughly 100,000 cubic meters of water accumulating in the plant by the time the water decontamination plant starts operations.
The site however seems planned for 20 tanks, each about 6 meters high and about 10 meters in diameter, for a volume of only some 10,000 cubic meters. Where is the rest of the installation?

The video mentions that more tanks are being built near Unit 6.

These may not be storage tanks, but filtering tanks.

There was something shown on the news a couple of weeks ago about passing contaminated water through various stages of filtering, so that it can be re-used for cooling the reactors without having to continuously pump in (and contaminate) new water.
 
  • #6,710
jim hardy said:
Re lifting a shroud through a round hole in roof with a crane
here's what TEPCO proposed in a 1995 paper, for a somewhat bigger lift

{ does anybody know how to embed a PDF picture? }
this link., page 6 of 8

http://www.jsme.or.jp/monograph/pes/1999/ICONE7/PAPERS/TRACK04/FP7292.PDF [Broken]

edit tried to insert image no luck

Jim,
This is an excellent find, and I would guess this may be one of the reasons that several weeks ago Tepco/Media had mentioned removal of damaged componets interms of "one unit".

The reversal would not work quite the same, but it appers the industry has some background work learking in the past to draw on, such as I am sure every option is be considered. Simialar concepts could be possible depending on the conditions of the building contents.

And with the exception of building two they don't need to cut the hole in the roof..
 
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  • #6,711


unlurk said:
There is something which hasn't been mentioned recently, the gamma ray burst which was detected in Tepco's bunker at the time of the #3 blast.

Has anybody come up with any new theories about that recently?

Could be something as simple as gamma shine from radioactive debris in the cloud
 
  • #6,712


unlurk said:
There is something which hasn't been mentioned recently, the gamma ray burst which was detected in Tepco's bunker at the time of the #3 blast.

Has anybody come up with any new theories about that recently?

Brought it up just a few pages back, too (and before that, 50 pages or so back). Just questioning what it means, really. I can not see how definite answers on that can be given with the little we know.

We don't really know where the bunker is situated and how he is shielded, or do we? We only know that the burst was supposedly 12x higher than normal (measured by humans on a personal counter/dosimeter/stationary or handheld counter?).

We also don't know if there were any neutron dectectors running and if there's any data on that. Due to the power outage no stationary sensors were online. We don't know the exact state of #3 and the SFP during the explosion which could explain the gamma burst xD.

A gamma burst would suggest criticality before/during the explosion. I could think about other explanations, but these sound crank to me so I rather not post them. Maybe I'm missing something really obvious though.
 
  • #6,713


I see no post of mine supporting TCup's theory of the origin of the event at unit 3 on March 14th so I'll go on record here.

I believe that some amount of oxygen was generated in the reactor vessel or the torus assembly which provided enough Oxygen in some localized spot to create a flash of a hydrogen explosion. We know there was plenty of Hydrogen in the drywell.

I also believe that Hydrogen was leaking out through the shield plugs (in small quanities) and thus there may have been hydrogen in the fuel transfer chute.

At 11:06 on March 14th a hydrogen flash was powerful enough to dislodge the shield plugs and to eject some flame and quantity of hydrogen (and for sure some hot steam) into the region above the plug(s).

This was the initiating event for the explosion which sent a fireball out of the south side of reactor building three - which is caught on video in the early time slices of the big blast.

I think of that event as the reactor secondary containment vessel "belching."

I think it may have happened again a few mornings ago when there was such activity just before dawn and then again this morning. But there hasn't been any secondary explosions associated with this process since March 14th.
 
  • #6,714
maddog1964 said:
...
aye you are right to make this point as I did not legend them ,none the less it is the closest representation at hand , and it give some good perspective on how big this area is
 
  • #6,715


RealWing said:
Could be something as simple as gamma shine from radioactive debris in the cloud

That's some pretty energetic gamma "shine" don't you think?

Do you think there may have been a fizzle of criticality in the release of radioactive particles?

It just doesn't seen that Fukushima 3 released that much airborne plutonium. And it would have to be plutonium to create a fizzle in the air don't you think?
 
  • #6,716
unlurk said:
There is something which hasn't been mentioned recently, the gamma ray burst which was detected in Tepco's bunker at the time of the #3 blast.

Has anybody come up with any new theories about that recently?

Gamma rays have been linked to terrestrial lightning. Could a local thunderstorm be the culprit? Sorry if this is the stupidest question of the week.
http://news.nationalgeographic.com/news/2007/10/071011-lightning-rays.html

Respectfully submitted,
Steve
 
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  • #6,717
Dotini said:
Gamma rays have been linked to terrestrial lightning. Could a local thunderstorm be the culprit? Sorry if this is the stupidest question of the week.
http://news.nationalgeographic.com/news/2007/10/071011-lightning-rays.html

Respectfully submitted,
Steve

The weather was clear that morning, there were no thunderstorms in the Tohoku region.
But I guess it's good to consider all possibilities.
 
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  • #6,718
elektrownik said:
Something is bad, reactor 3 appear to by on fire
15wmi34.jpg

TEPCO has responded that the photos from the previous time was steam from the spent fuel pools of reactor #3 and #4.

http://www.digtriad.com/news/national/article/174708/175/Japan-New-Smoke-At-Nuclear-Plant [Broken]
 
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  • #6,719
Astronuc said:
Ah thanks for that. I was thinking the other picture was looking from E or W, but wasn't sure.

If that is looking north at the DS pit then, the back wall is the structure between the DS pit and reactor cavity. They would not transfer fuel through there, but they would transfer the steam separator and possible steam dryer. The steam leakage then would seem to be coming from containment - possibly the reactor cavity.

From the pictures I have seen posted here, it seems building 3 has steam coming from 3 areas, and they all seem to be at what I believe would be the edge of the reactor core. Is it possible that this is where all the steam is coming from? Containment, or reactor cavity escaping around weak spots at the edge? (Not a critical SPF3?)

And if so, is it possible that there had also been part of the explosion occur on floors below the refueling deck? Which would explain the damage to the north west corner?

If that is entirely possible, I would love to hear the mechanics of how it could have happened. In layman terms, obviously! :D

Thanks in advance...
 
  • #6,720
yakiniku said:
TEPCO has responded that the photos from the previous time was steam from the spent fuel pools of reactor #3 and #4.

http://www.digtriad.com/news/national/article/174708/175/Japan-New-Smoke-At-Nuclear-Plant [Broken]

elektrownik's post was a few hours ago, the news piece you cite was released on the 8th
 
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<h2>1. What caused the Japan earthquake and subsequent nuclear disaster at Fukushima Daiichi?</h2><p>The Japan earthquake, also known as the Great East Japan Earthquake, was caused by a massive underwater earthquake that occurred on March 11, 2011. The earthquake had a magnitude of 9.0 and was the strongest ever recorded in Japan. The earthquake triggered a massive tsunami, which caused extensive damage to the Fukushima Daiichi nuclear power plant and led to a nuclear disaster.</p><h2>2. What is the current status of the nuclear reactors at Fukushima Daiichi?</h2><p>As of now, all of the nuclear reactors at Fukushima Daiichi have been shut down and are no longer in operation. However, the site is still being monitored for radiation levels and there is an ongoing effort to clean up the radioactive materials that were released during the disaster.</p><h2>3. How much radiation was released during the Fukushima Daiichi nuclear disaster?</h2><p>According to the International Atomic Energy Agency, the Fukushima Daiichi nuclear disaster released an estimated 10-15% of the radiation that was released during the Chernobyl disaster in 1986. However, the exact amount of radiation released is still being studied and debated.</p><h2>4. What were the health effects of the Fukushima Daiichi nuclear disaster?</h2><p>The health effects of the Fukushima Daiichi nuclear disaster are still being studied and monitored. The most immediate health impact was the evacuation of approximately 160,000 people from the surrounding areas to avoid exposure to radiation. There have also been reported cases of thyroid cancer and other health issues among those who were exposed to the radiation.</p><h2>5. What measures have been taken to prevent future nuclear disasters in Japan?</h2><p>Following the Fukushima Daiichi nuclear disaster, the Japanese government has implemented stricter safety regulations for nuclear power plants and has conducted stress tests on all existing plants. They have also established a new regulatory agency, the Nuclear Regulation Authority, to oversee the safety of nuclear power plants. Additionally, renewable energy sources are being promoted as a more sustainable and safer alternative to nuclear power in Japan.</p>

1. What caused the Japan earthquake and subsequent nuclear disaster at Fukushima Daiichi?

The Japan earthquake, also known as the Great East Japan Earthquake, was caused by a massive underwater earthquake that occurred on March 11, 2011. The earthquake had a magnitude of 9.0 and was the strongest ever recorded in Japan. The earthquake triggered a massive tsunami, which caused extensive damage to the Fukushima Daiichi nuclear power plant and led to a nuclear disaster.

2. What is the current status of the nuclear reactors at Fukushima Daiichi?

As of now, all of the nuclear reactors at Fukushima Daiichi have been shut down and are no longer in operation. However, the site is still being monitored for radiation levels and there is an ongoing effort to clean up the radioactive materials that were released during the disaster.

3. How much radiation was released during the Fukushima Daiichi nuclear disaster?

According to the International Atomic Energy Agency, the Fukushima Daiichi nuclear disaster released an estimated 10-15% of the radiation that was released during the Chernobyl disaster in 1986. However, the exact amount of radiation released is still being studied and debated.

4. What were the health effects of the Fukushima Daiichi nuclear disaster?

The health effects of the Fukushima Daiichi nuclear disaster are still being studied and monitored. The most immediate health impact was the evacuation of approximately 160,000 people from the surrounding areas to avoid exposure to radiation. There have also been reported cases of thyroid cancer and other health issues among those who were exposed to the radiation.

5. What measures have been taken to prevent future nuclear disasters in Japan?

Following the Fukushima Daiichi nuclear disaster, the Japanese government has implemented stricter safety regulations for nuclear power plants and has conducted stress tests on all existing plants. They have also established a new regulatory agency, the Nuclear Regulation Authority, to oversee the safety of nuclear power plants. Additionally, renewable energy sources are being promoted as a more sustainable and safer alternative to nuclear power in Japan.

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