Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[PietKuip]

The increases on April 9th, April 10th, and April 12th as shown on pages 4 and 5 of that document

A) are quite small as you can see on page 2 of that document
B) can you rule out that they are caused by rainfall depositing onto the ground "old particles" that have been flying in the air for weeks, rather than "new particles" extracted from the nuclear plant a few hours before their arrival at that measurement location in Ibaraki prefecture ?

For example, I attach the measurements at the Ishikawa district of Mito city, Ibaraki prefecture (Source : http://www.bousai.ne.jp/vis/tgraph.php?area_id=108&post_id=1080000014 - you need to adjust the maximum level by clicking on the 最小・大値の入力　button to a suitable value like 2000 nGy/h and to click on the 90 days button : ９０日). 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.

There are continuous emissions at the plant - see the smoke and the steam!

A kilobecquerel per square meter at such distances is a high level of fallout. It is consistent with wind directions. See the April 10 weather data for Mito http://www.wunderground.com/history...ml?req_city=NA&req_state=NA&req_statename=NA"

 

[Jorge Stolfi]

some nice 3d modeling has already been done ;) but they are not entirely accurate

Thanks, they will be helpful! In any case I am more interested in modeling the insides.

Don't know if that helps you, but here are Blueprints of Unit 1:

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

VERY helpful, thank you! Now if only I could find the floor plans... And the blueprints of the other 3 units...

Does anyone know the WIDTH (East-West) of the SFPs and equipment pools? Are they centered in the East-West direction with the reactor axis?

In the #1 blueprint there is an elevation marked "Reactor invert", near where the bottom of the RPV should be. What is that?

 

[tsutsuji]

There are continuous emissions at the plant - see the smoke and the steam!

A kilobecquerel per square meter at such distances is a high level of fallout. It is consistent with wind directions. See the April 10 weather data for Mito http://www.wunderground.com/history...ml?req_city=NA&req_state=NA&req_statename=NA"

Thanks for the meteorological data website link. North-East winds are in line with your explanations. The rainfall seems to be 0 cm everyday so I don't think the rainfall data on that website are reliable, though.

 

[Jorge Stolfi]

When i consider the layout of the Daichi plant, and especially the transversal cut of the buildings, it is clear that the reactor building and the turbine building go deep in the ground of the platform, so the basement of these buildings (for example where the torus sits) is i think something like almost 10 meters below the ground (more data on this would be needed though).

According to the unit #1 blueprints, the ground outside the building is at OP+10 meters, and the lowest floor (of the room that houses the suppression torus) is at OP-1.23 meters. Presumably OP is the "Osaka piel", explained in a previous post, namely the lowest sea level recored in Osaka. So the basement seems to be below sea level indeed.

 

[rowmag]

The increases on April 9th, April 10th, and April 12th as shown on pages 4 and 5 of that document

A) are quite small as you can see on page 2 of that document
B) can you rule out that they are caused by rainfall depositing onto the ground "old particles" that have been flying in the air for weeks, rather than "new particles" extracted from the nuclear plant a few hours before their arrival at that measurement location in Ibaraki prefecture ?

For example, I attach the measurements at the Ishikawa district of Mito city, Ibaraki prefecture (Source : http://www.bousai.ne.jp/vis/tgraph.php?area_id=108&post_id=1080000014 - you need to adjust the maximum level by clicking on the 最小・大値の入力　button to a suitable value like 2000 nGy/h and to click on the 90 days button : ９０日). 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.

I believe the wind was blowing towards Mito from Fukushima Daiichi that day.

Note that on 3/21, the wind was coming from the north-east: http://www.data.jma.go.jp/obd/stats...C%CB&year=2011&month=3&day=21&elm=daily&view=

Likewise on 4/9 and 4/10: http://www.data.jma.go.jp/obd/stats...90%85%8C%CB&year=2011&month=04&day=21&view=p1

[Add: Now I see PietKuip has provided similar data. I would add that 3/21 and 4/9 it was raining in Mito, 4/10 it was not. 4/12 it was sunny in Mito, and wind was from the north. To know if the (possibly curving) wind path links up with Fukushima Daiichi one really needs the 2-dimensional AMEDASU plots for the region, but they only seem to go back 2 days.]

I'm not in Mito, but from what I have seen locally, fallout from Fukushima Daiichi is only observed when the wind is blowing our way from there, regardless of rain. We have had both sunny and rainy days when the wind was not blowing towards us, with no rise in background counts. We have also had sunny and rainy days when the wind was blowing towards us, with a rise seen. I imagine the rain helps flush out the local atmosphere more efficiently, but I don't think there is a cloud of old radioactive particles hanging over eastern Japan to be flushed out by rain.

 

[mscharisma]

Well, this would then relate to the post i just added concerning the level of the phreatic water relative to basement of the buildings: it seems the basement is in fact surrounded by underground water , so below phreatic surface? This is a very surprising info...

If water can enter the buildings, one can imagine how contaminated water can go inside underground water...

This nuclear plant turns to an interesting mess to deal with, to say the least.

I'm sorry, but I cannot possibly comment on this. I am so nontechnical that I feel almost guilty for just reading along with you technical folks. It was just the first time that I saw a possible explanation for the water in unit(s) 6 (and 5), so I thought I post the info.
Hopefully someone much more knowledgeable than I can shed more light on the entire subject.

 

[tsutsuji]

I believe the wind was blowing towards Mito from Fukushima Daiichi that day.

Note that on 3/21, the wind was coming from the north-east: http://www.data.jma.go.jp/obd/stats...C%CB&year=2011&month=3&day=21&elm=daily&view=

Likewise on 4/9 and 4/10: http://www.data.jma.go.jp/obd/stats...90%85%8C%CB&year=2011&month=04&day=21&view=p1

[Add: Now I see PietKuip has provided similar data. I would add that 3/21 and 4/9 it was raining in Mito, 4/10 it was not. 4/12 it was sunny in Mito, and wind was from the north. To know if the (possibly curving) wind path links up with Fukushima Daiichi one really needs the 2-dimensional AMEDASU plots for the region, but they only seem to go back 2 days.]

I'm not in Mito, but from what I have seen locally, fallout from Fukushima Daiichi is only observed when the wind is blowing our way from there, regardless of rain. We have had both sunny and rainy days when the wind was not blowing towards us, with no rise in background counts. We have also had sunny and rainy days when the wind was blowing towards us, with a rise seen. I imagine the rain helps flush out the local atmosphere more efficiently, but I don't think there is a cloud of old radioactive particles hanging over eastern Japan to be flushed out by rain.

Thanks for finding the rainfall data for Mito with the "jma.go.jp" link.

On the plot for Ishikawa district of Mito ( https://www.physicsforums.com/attachment.php?attachmentid=34676&d=1303339897 ) the two highest peaks are for March 15th and March 16th. They are both related to incidents happening at the plant : the unit 4 fire and the unit 2 explosion on March 15th and the white smoke on March 16th: see page 16 of http://www.isis-online.org/uploads/...s/Accident_Sequence_Fukushima_31March2011.pdf .

So I think it is strange that we find another quite big peak at Mito (though smaller than the 2 previous peaks) on March 21st without any known specific trouble at the Power Plant on that day or the day before.

 

[MadderDoc]

Well, this would then relate to the post i just added concerning the level of the phreatic water relative to basement of the buildings: it seems the basement is in fact surrounded by underground water , so below phreatic surface? This is a very surprising info...

If water can enter the buildings, one can imagine how contaminated water can go inside underground water...

This nuclear plant turns to an interesting mess to deal with, to say the least.

Perhaps since it appears to be your field you can make something out of this Tepco document:
http://www.gyldengrisgaard.dk/fuku_docs/20110401014-4.pdf

To me it does appear to show something about, er, cracks in the underground leading to groundwater to the basement of unit 6? Sounds silly, and could well be something else, but there you are.

 

[I_P]

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.

I strongly disagree with this assessment. The peak on the 21st was recorded at many stations and its only analog is the similar peak on the 15th tied to known releases and fires. The level in Ibaraki has been slowly descending since the peak on the 21st and has only recently receded back to the levels it was around the 20th of March. When it rains the level often wobbles slightly higher and lower till the weather clears.

Monitoring at the plant by TEPCO was pretty rudimentary for the first month - mostly driving around with a hand-held meter from time to time - and they didn't have any way to keep track of what was happening at the plants it seems. The explosions of units 1 and 3 were recorded by news crews - otherwise there wouldn't be any visual record. What happened at unit 4? No one knows. How many explosions were there? No one knows. What was burning at the various units? Where has the steam been coming from - no one knows precisely...

 

[tsutsuji]

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 ?

The peak on the 21st was recorded at many stations

Perhaps because it rained all over Japan on that day.

 

[I_P]

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 ?

I would assume that 'daily deposition' is a measure of the rate of contamination of a surface due to the buildup of radioactive compounds - probably there are fixed instruments to measure this.

'Gamma dose rates' would refer to radiation levels, specifically gamma radiation as opposed to alpha, beta, or neutron sourced. This is like a Geiger counter.

 

[Astronuc]

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 ?

The deposition would be in atoms (or picrograms) per m², but multiplying that by the decay constant would give disintegrations (activity) per m². Applying a gamma energy per decay, would give dose rate. Then integrating the dose rate over time gives a cumulative dose (for some given period). There are likely geometric and shielding factors to consider.

 

[I_P]

Perhaps because it rained all over Japan on that day.

The peaks associated with rainfall are nothing like the peaks on the 15th and the 21st. The later are characterized by an abrupt rise to very high levels followed by a smooth exponential decay. The problem is that TEPCO simply has no idea what was going on at their facility. The radiation monitoring system went down with the power outage and wasn't restored for many weeks (maybe it still isn't fully operational). There was no attempt to put cameras in place to monitor the reactors, on-site inspections were sporadic with many evacuations. The whole response was characterized by shock and confusion for quite a long time. Many of the official pronouncements about the state of things were mere guesses based on very little hard information. This is why there is still so much uncertainty about what the situation is - other than the fact that the cooling water injection has been successful enough to keep further rapid deterioration from occurring. The longer they keep it up and nothing bad happens the cooler the remaining fuel becomes...slowly, very slowly now.

Since the direct leaks to the ocean have been plugged contaminated water is building up throughout the site and leaking into the water table. It may be that the ground subsidence following the quake has raised the water table as well. First class mess really.

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.

 

[tsutsuji]

By the way, we have a series of "Reading of radioactivity level in fallout by prefecture" expressed in MBq/km² for iodine and cesium in daily reports at the bottom part of http://www.mext.go.jp/english/radioactivity_level/detail/1304083.htm . I wonder if it is the same thing as the "daily depositions" mentioned by http://www.slideshare.net/iaea/radiological-monitoring-and-consequences-19-april-2011

The peaks associated with rainfall are nothing like the peaks on the 15th and the 21st. The later are characterized by an abrupt rise to very high levels followed by a smooth exponential decay. The problem is that TEPCO simply has no idea what was going on at their facility.

If nobody has any idea of what happened on March 21st, then it could happen today or tomorrow again. To rule out that something can happen again you need to understand the causes that made it happen.

 

[I_P]

If nobody has any idea of what happened on March 21st, then it could happen today or tomorrow again. To rule out that something can happen again you need to understand the causes that made it happen.

See the edit to my post above for a possible cause.

 

[rowmag]

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.

There was also an observed outbreak of grey-ish smoke coming from Reactor 3 on the 21st.

Also, white smoke from Reactor 2 on the same day.

 

[rowmag]

http://www.gyldengrisgaard.dk/fuku_docs/20110401014-4.pdf

To me it does appear to show something about, er, cracks in the underground leading to groundwater to the basement of unit 6? Sounds silly, and could well be something else, but there you are.

It is something else. It is talking about accelerations due to the earthquake; 550 Gal were measured in the east-west direction at Unit 2, which was only designed to handle 438 Gal. Nothing to do with groundwater, sorry.

 

[Cire]

That was the thing I want to point at. But this would mean that TEPCO reports wrong data readings or the instruments are all gone crap.

I've mentioned this a few times back a hundred pages or so. The temperature sensors where damaged when they exceeded their operating point. I personally believe that the reactors that are not producing steam are actually at the cold shutdown point.

A good example of this was the photo's from the leak into the ocean they fixed. The water temperature leaking from the plant was supposedly >> boiling, yet the leak from the crack was not hot. High temperature water/steam in the RPV flowing out somewhere and Cold water leaking out of the plant? I doubt it. After weeks of "hot" water flowing out of the RPV to the crack everything would have been heat soaked and very little temperature drop would have occurred along the leak path.

[PLAIN]http://img859.imageshack.us/img859/3528/radioactiveleakfukushim.jpg

Air temperature is around 10-15C.. There should have been a large water vapor cloud pouring out of that leak.

 

[ascot317]

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.

 

[I_P]

I've mentioned this a few times back a hundred pages or so. The temperature sensors where damaged when they exceeded their operating point. I personally believe that the reactors that are not producing steam are actually at the cold shutdown point.

A good example of this was the photo's from the leak into the ocean they fixed. The water temperature leaking from the plant was supposedly >> boiling, yet the leak from the crack was not hot. High temperature water/steam in the RPV flowing out somewhere and Cold water leaking out of the plant? I doubt it. After weeks of "hot" water flowing out of the RPV to the crack everything would have been heat soaked and very little temperature drop would have occurred along the leak path.

[PLAIN]http://img859.imageshack.us/img859/3528/radioactiveleakfukushim.jpg

Air temperature is around 10-15C.. There should have been a large water vapor cloud pouring out of that leak.

Very large volumes shot from fire hoses all over the place, tsunami residual water, long flow paths and flow into already flooded trenches... why would the water leaking into the sea be expected to be hot? Air in unit 2 saturated from steam:

TEPCO says humidity inside the Number 2 reactor was 94 to 99 percent, fogging up the robot's camera lens.

The company says the humidity indicates that radioactive steam leaked into the building. It says it will need to install air conditioners to ventilate and clean the air of radioactivity before people can work there.

http://www3.nhk.or.jp/daily/english/21_04.html"

I doubt those things are 'cold' just yet.

 

[I_P]

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.

 

[ascot317]

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.

 

[I_P]

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"

 

[etudiant]

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?

 

[razzz]

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.

 

[flyingblind]

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/"

 

[MiceAndMen]

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.

 

[PietKuip]

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.

 

[biffvernon]

I've not seen any very recent fallout data. Winds blew inland on Sunday and Tuesday, 19th April and there was rain. The plume forecast at http://www.zamg.ac.at/pict/wetter/sonderwetter/fuku/20110419_I-131_FUKU.gif was not too healthy.

 

[biffvernon]

And the forecast for the next couple of days is not good for northern Japan.

http://www.zamg.ac.at/pict/wetter/sonderwetter/fuku/20110421_I-131_FUKU.gif

 

[razzz]

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...

 

[PietKuip]

I've not seen any very recent fallout data. Winds blew inland on Sunday and Tuesday, 19th April and there was rain. The plume forecast at http://www.zamg.ac.at/pict/wetter/sonderwetter/fuku/20110419_I-131_FUKU.gif was not too healthy.

Live data on the radiative dose is at http://atmc.jp/

(In Japanese, but you can read the graphs: some small blips on April 19th. Deposition data will certainly show clearer spikes.)

 

[PietKuip]

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.

 

[ascot317]

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.

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.

 

[flyingblind]

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. ;-)

 

[razzz]

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.

 

[ascot317]

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.

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

Maybe. But look at its feet.

 

[elektrownik]

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%

 

[flyingblind]

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"

 

[MadderDoc]

<..> 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:

 

[Rive]

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.

 

[ascot317]

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.

 

[tsutsuji]

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

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

 

[Rive]

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.

 

[ascot317]

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.

 

[jlduh]

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...

 

[clancy688]

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:

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.

 

[Samy24]

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.

 

[clancy688]

Maybe they're trying to not lose their face or something like this...? I hear it's very common in japan.

 

[Dmytry]

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.