Japan Earthquake: Nuclear Plants at Fukushima Daiichi

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The Fukushima Daiichi nuclear plant is facing significant challenges following the earthquake, with reports indicating that reactor pressure has reached dangerous levels, potentially 2.1 times capacity. TEPCO has lost control of pressure at a second unit, raising concerns about safety and management accountability. The reactor is currently off but continues to produce decay heat, necessitating cooling to prevent a meltdown. There are conflicting reports about an explosion, with indications that it may have originated from a buildup of hydrogen around the containment vessel. The situation remains serious, and TEPCO plans to flood the containment vessel with seawater as a cooling measure.
  • #4,471
ascot317 said:
Really weird to see the taped-on detector. It's looking almost like a bad student project.

That about sums it up doesn't it.
 
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  • #4,472
I_P said:
That about sums it up doesn't it.

The packbot does feature some sensors, I can see radiation and atmospheric data on the two screens. So, why the taped on counter? Does anyone have proper specs of the hazmat packbots? I'd like to know about the abilities of its sensors.
 
  • #4,473
ascot317 said:
The packbot does feature some sensors, I can see radiation and atmospheric data on the two screens. So, why the taped on counter? Does anyone have proper specs of the hazmat packbots? I'd like to know about the abilities of its sensors.

"[URL
http://www.irobot.com/gi/ground/510_PackBot/for_HazMat_Technicians

Specs pdf:
http://www.irobot.com/pass.cfm?li=http://www.irobot.com/gi/filelibrary/pdfs/robots/iRobot_510_PackBot.pdf"

http://www.popularmechanics.com/technology/military/robots/how-battle-tested-robots-are-helping-out-at-fukushima-5586925"
 
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  • #4,474
TEPCO had earlier rejected offers of specialized robots designed for nuclear work from France as well as Germany and probably the US. Still, the French are now training Japanese robot operators, so there will eventually be added capability, once under full Japanese control.
Still, the clear message is that there is no urgency, a stance again underlined by the minimal scale of the cleanup and the glacial pace of the dewatering effort.
This makes some sense if the situation is indeed quiet, which the lack of pollution from the recent inland winds and rains suggests. If the site is no longer poisoning the countryside, then there is no benefit to expending lavish effort to clean it up fast. Better let it sit and cool down beforehand.
Do the experts on this site believe that this is what is happening and if so, is it a sound approach?
 
  • #4,475
No expert here but as long as you don't consider a quadrillion tons of contaminated water as being part of the environment then everything is fine. The company is in a holding pattern because they are basically screwed, the areas that need the most attention are to contaminated for humans to work around for more than an hour, even the bots are refusing to go in.

To check groundwater you could test a well or drill one but the immediate area is a no go zone (catch 22) but fear the worst.

If the Company could start cleaning up Unit 4 to access the SFP, how do you remove oversized garbage without disturbing the pool?

Even if they could attempt one closed loop setup for the cooling of anything they are going to be up to their neck in contaminated water before they are done.

But I suppose no news is good news for the time being.
 
  • #4,476
ascot317 said:
Videos of the packbot missions have been leaked on Youtube. Not much to see, looks like a cellphone video.

Unit 1:
Unit 2:
Unit 3: (1/2)
Unit 3: (2/2)

Really weird to see the taped-on detector. It's looking almost like a bad student project.


You can download all 23 videos from Tepco. http://www.tepco.co.jp/en/news/110311/"
 
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  • #4,477
The packbot videos had me laughing out loud. They're fine for having a quick look around and taking radiation measurements, but they're little better than toys. Show me the robots that can scale exposed ironwork with cutting torches and able to exert some substantial force on debris, and then I'll be impressed.

I watched a fair amount of the videos and one sarcastic thought after another went through my head. Japan, with first its nuclear power plant fiasco and now these silly robots, is giving technology a bad name.

Discussion is probably now focusing on how to pay for the cleanup effort. Once they figure out how to get everyone but TEPCO to foot the bill the real work will start. These robots are a joke.
 
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  • #4,478
MiceAndMen said:
Japan, with first its nuclear power plant fiasco and now these silly robots are giving technology a bad name.
Don't forget Tepco's ****ups on the isotope concentrations.

It took the regulator a very long time to discover that there was something wrong with those numbers.

And it took Tepco even longer to publish the corrected numbers, with some kind of an explanation:
http://www.tepco.co.jp/en/press/corp-com/release/11042008-e.html

The Cl-38 is gone now.
 
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  • #4,481
Watched bot adventures in Unit 3 1st floor, lots of blown covers on electrical boxes. Looks like pressure found its way to conduits that carry the electrical cables and traveled until hitting something like access panel then blew them off the cabinets.

Last I saw, one bot was trying to remove a ladder hung up on a blast door...
 
  • #4,482
  • #4,483
tsutsuji said:
Does anyone know the definition of "daily deposition" as mentioned in http://www.slideshare.net/iaea/radiological-monitoring-and-consequences-19-april-2011 ? Is it the difference of the measured radioactivity from soil samples between that day and the day before ? How do "daily depositions" and "gamma dose rates" relate with each other ?
Deposition is probably measured by some plastic sampling film. A new clean sheet every day, of which the activity is then determined by gamma spectroscopy (to get all the different nuclides).

Gamma dose rates can be measured by geiger counters etcetera.
 
  • #4,484
flyingblind said:
You can download all 23 videos from Tepco. http://www.tepco.co.jp/en/news/110311/"

Yeah, saw that later. A lot of snippets, as if taken from a cellphone.
It looks like taken from a HD-cam though, just rendered to a lower resolution.
I take back my earlier assessment, it's doesn't look like a bad student project, rather like something from high school.

razzz said:
Watched bot adventures in Unit 3 1st floor, lots of blown covers on electrical boxes. Looks like pressure found its way to conduits that carry the electrical cables and traveled until hitting something like access panel then blew them off the cabinets.

Last I saw, one bot was trying to remove a ladder hung up on a blast door...

"Adventures", I like that. Fukushima will offer a good basis for video games, just like Chernobyl. Regarding the blown-off covers, don't forget the quakes.

I was wondering about the ladder. It looks like as if someone put it there on purpose. The door appears to be open.
 
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  • #4,485
ascot317 said:
Yeah, saw that later. A lot of snippets, as if taken from a cellphone.
It looks like taken from a HD-cam though, just rendered to a lower resolution.
I take back my earlier assessment, it's doesn't look like a bad student project, rather like something from high school.



"Adventures", I like that. Fukushima will offer a good basis for video games, just like Chernobyl. Regarding the blown-off covers, don't forget the quakes.

I was wondering about the ladder. It looks like as if someone put it there on purpose.

I think it is part of the ceiling. Like a drop ceiling.. No pun intended. ;-)
 
  • #4,486
ascot317 said:
I was wondering about the ladder. It looks like as if someone put it there on purpose.

You are going to see a lot of strange things as time goes on. This is like the House of Horrors in four different versions.

There were some readings but I am not sophisticated enough to understand them, not sure I want to know.
 
  • #4,487
razzz said:
You are going to see a lot of strange things as time goes on. This is like the House of Horrors in four different versions.
That's why I'd like to see the KHG bots in there, they have 3d-laser-sensors and more sophisticated handling tools. Or, for starters, a HD cam on a looong stick held into the upper floor of the reactor buildings.


flyingblind said:
I think it is part of the ceiling. Like a drop ceiling.. No pun intended. ;-)

Maybe. But look at its feet.
 

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  • #4,488
ascot317 said:
That's why I'd like to see the KHG bots in there, they have 3d-laser-sensors and more sophisticated handling tools. Or, for starters, a HD cam on a looong stick held into the upper floor of the reactor buildings.
Maybe. But look at its feet.

It is ladder on 100%
 
  • #4,489
ascot317 said:
That's why I'd like to see the KHG bots in there, they have 3d-laser-sensors and more sophisticated handling tools. Or, for starters, a HD cam on a looong stick held into the upper floor of the reactor buildings.




Maybe. But look at its feet.

Yeah very possible now that I look closer..
Here is the vid from the tepco site http://www.tepco.co.jp/en/news/110311/images/110420_1f_23.zip"
 
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  • #4,490
tsutsuji said:
<..> I think the 600 nGy/h peak shown on March 21st was caused only by rain, without being related to any specific incident at the plant.

That's possible, however on March 21st, as a new development, quite a lot of grey and black smoke was seen coming out the unit 3 reactor top, and going inland. Here's from unit 3, March 21st:
20110321_b_Screenshot-5.png
 
  • #4,491
ascot317 said:
It looks like taken from a HD-cam though, just rendered to a lower resolution.
It's a common solution for every remote controlled vehicle that the 'live' feed for the operator is reduced in resolution to preserve bandwidth, and the HD recordings are stored locally or sent/taken only by request.

The same with the T-Hawk. The very first footage was the live feed for the operator, with awful resolution, clearly with analog transmit. Then later on there was some digital HD recordings.
 
  • #4,492
Rive said:
It's a common solution for every remote controlled vehicle that the 'live' feed for the operator is reduced in resolution to preserve bandwidth, and the HD recordings are stored locally or sent/taken only by request.

The same with the T-Hawk. The very first footage was the live feed for the operator, with awful resolution, clearly with analog transmit. Then later on there was some digital HD recordings.

Have a look at the footage, none of it is directly from the bots. It's all filmed by someone else with a camera, watching over the operator's shoulder. There's no reason to provide it as 320x180 pixels as they do. The aspect ratio suggests it was filmed with a HD camera.
 
  • #4,493
MadderDoc said:
That's possible, however on March 21st, as a new development, quite a lot of grey and black smoke was seen coming out the unit 3 reactor top, and going inland. Here's from unit 3, March 21st:
http://www.gyldengrisgaard.dk/fuku_docs/20110321_b_Screenshot-5.png

Thanks. I checked the NISA reports and found the following :

Grayish smoke generated from Unit 3. (At around 15:55 March 21st)

The smoke was confirmed to be died down. (17:55 March 21st)

Grayish smoke changed to be whitish and seems to be ceasing. (As of
07:11 March 22nd)
http://www.nisa.meti.go.jp/english/files/en20110324-1-1.pdf

But these smoke events appear to come too late, because the peak was already showing up as early as at 6 a.m. on that morning in Mito according to http://www.bousai.ne.jp/vis/tgraph.php?area_id=108&post_id=1080000014 .

So perhaps the best line of explanation is the one mentioned by I_P

I_P said:
Edit: Unit 3 experienced a rise in pressure on the 20th and TEPCO said they might need to vent it, however the pressure subsequently rapidly fell without intervention. I would be willing to make a serious bet that it 'self-vented' at that time leading to the radiation spike in the surrounding region.

The plot for the Yoshizawa district of Mito city includes the rainfall data. It started raining at around 8 a.m. on that morning. So I must withdraw my comment about the rain. Coming too late, the rain alone cannot explain the peak. See attachment below (the radiation is the red line, the rainfall is the blue histograms below). Source : http://www.bousai.ne.jp/vis/tgraph.php?area_id=108&post_id=1080000037
 

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  • #4,494
ascot317 said:
Have a look at the footage, none of it is directly from the bots. It's all filmed by someone else with a camera, watching over the operator's shoulder. There's no reason to provide it as 320x180 pixels as they do. The aspect ratio suggests it was filmed with a HD camera.
After the first flights of the T-hawk it was some days to release the analog footage and after that even more days waiting for the HD recordings. So maybe within some days we will see.
 
  • #4,495
Rive said:
After the first flights of the T-hawk it was some days to release the analog footage and after that even more days waiting for the HD recordings. So maybe within some days we will see.

This isn't the signal transmitted by the robots, it's taken by a handheld camera, aimed at the controller's screen, so your analogy to the T-Hawk (there has been no releases of "HD" footage either) isn't really fitting. Btw, the T-Hawk is made for real time combat recon. The unit itself doesn't store video, the ground control station does. The "ground control station" itself is a simple laptop you can strap to your chest. It stores the video as it is (in "LD").
The T-Hawk can also offer IR video (SFP, please!), and I bet Tepco has a lot of footage, but they're not releasing it.

What we're seeing here is very likely the unwillingness to inform the public properly, paired with technical incompetence.

Same with the robots. KHG had offered its assistance (KHG is a German company specialised in nuclear disaster response). Their robots are designed exactly for this environment, hardened against radiation (100Gy/h), able to navigate through difficult terrain and fitted with all kinds of different tools. Instead, Tepco went with "HazMat" combat robots and taped a geiger counter to it. In the end, they couldn't even read the counter due to fog.

Tepco could have uploaded it as it is, in HD, but instead decided to reduce the resolution. The resolution is just bad enough to be unable to read most of the sensor data. This isn't the ISS where downloading HD takes some time, this is Japan, where people can have 1GBit-connections at home. And even if they had to stay on site, there are more than enough ways of getting high speed internet access (one way would be driving to the next city). Okay, this being Tepco, I bet they're using phone lines (56k dial up, yay).

I'd like to know what's going on, but what Tepco is giving us isn't much, and even worse, it seems like they don't know much for themselves.
 
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  • #4,496
To etudiant (probably french like me ;o))

I wouldn't share your view of just letting the stuff resting "quiet" like that on purpose! The problem is what alternative (credible) can they have right now other than flooding the all plant at a rate of around 6 to 7 m3 of water per hour on each n°1 to n°3 reactors with water injected inside the cores or the vessels which go in direct contact with fuel and so get charged with high radiaoctivity? They are not in close loop for water cooling and i don't see how they could go that way in the near or even mid term considering the mess, destructions and radioactivity around the reactors vessels which annihilates any efforts to repair the damages (if even it could be possible) to go in close loop.

Then this thing still has to continue to be cooled anyway, cold stop is a misleading term because you tend to think that the stuff is "cold" but it is not: it is only cold and somewhat stable because of active cooling, even at reactor n°5 and 6 or at Daini. The thermal power to remove is decreasing with time following an exponential decay but it is still there.

Then the contaminated water volume on site is growing and growing, and if we can consider that this contamination in water is less susceptible to travel at long distances from the plant (it can though ocean currents and underground travel, but it is of course a process much slower that what happens with direct release through the air masses), the consequence is also that water on site will concentrate contamination and release it in the surroundings through leaks and/or overspilling. Even if they manage to install on site a water treatment facility for all this water, the leaks will still be there...

Underground water is a very sensitive compartment, because it can travel a very long way at quite small speeds, with wery little possibilties to treat the contamination. Then it means pollution of soils and of all the usages by humans of this underground water (drinkable water, agricultural use in the fields, etc.). Depending on the phreatic structure in the area, you can also have pollution of the rivers of course.This is a very tricky situation which is far from "quiet". If you intend "quiet" as no "big boum", yes it is quiet. But some quietness and silence can be worse than impressive images in medias right after the beginning of the catastroph. Tchernobyl has been a high pace disaster (with long consequences), Fukushima turns to be a much smaller pace disaster but with very very long consequences.

This has nothing to do to with the "strategy" chosen to deal with the mess: it's just the mess that is different. But both are fist class (or INES 7 if you want, to express it in technical wording...).

Concerning the robots: i agree that if Tepco is releasing so many useless videos from the robots, it's maybe to feed the dog with something and try to show that high tech is there like cavalry in bad situations scenarios! But if you consider that these expensive toys can only go in environments with small debris (they have also wires following them for power!) no way these can do more than a little bit of surveyance and small operations, which is a scale much different that the scale of the damages and the operations to be conducted on site...
 
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  • #4,497
Regarding the radioactive contaminated underground water in the basements of Unit 5 and 6:

I have just read a very interesting post regarding this matter in a german Fukushima board - http://fukushima.physikblog.eu/discussion/33/radioaktivitaet-im-grundwasser-noch-so-ein-thema

It's very large, so I'll try translating the most vital parts. All thoughts come frome user Silene in the german forum, I'm only reciting. But I think it's very plausible.

Here is an image of the sweetwater/saltwater levels at coasts:
440px-Saltwater_Intrusion.gif

Notice that the saltwater is forming a wedge which's pressing inland. Since saltwater is more dense than sweetwater, sweetwater is pushed upwards near the coast, it's floating on the saltwater.
The water leak which was sealed earlier this month can't be responsible for the big seawater contamination which was measured since there was only a release of 7m³/h. It's more likely that the saltwater, which was previously used to cool the reactors, seeped through the ground, passed through the sweetwater (because it's denser) and mixed with the saltwater. That way, it could have gotten into the ocean.
Now the reators are cooled with sweetwater. The sweetwater is staying with the groundwater and the overall groundwater level is rising -> radioactive groundwater begins seeping into Units 5 and 6.
 
  • #4,498
jlduh said:
To etudiant (probably french like me ;o))

... Concerning the robots: i agree that if Tepco is releasing so many useless videos from the robots, it's maybe to feed the dog with something and try to show that high tech is there like cavalry in bad situations scenarios!...

"to feed the dog with something" that is how the public is feeling about the information "policy" of TEPCO.

But why are they doing so?
To hide the real size of the disaster? -> It's INES 7 already.
To secure "engineering secrets"? -> I do not belief the Iran like to copy this crap.
TEPCO itself do not have more data, pictures and information? -> God forbid.
 
  • #4,499
Maybe they're trying to not lose their face or something like this...? I hear it's very common in japan.
 
  • #4,500
There's a version of the robots they use, which includes built in radiation monitor.

Does anyone here recognize the model of that monitor they strapped onto a bot? Would be fun to look at it's specs.
 

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