Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[tsutsuji]

That is not quite true. When winds are inland, there is fallout in Ibaraki and as far away as Tokyo; see pages 4 and 5 of http://www.slideshare.net/iaea/radiological-monitoring-and-consequences-19-april-2011

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.

 

[mscharisma]

Does somebody understand this strange statement:

"The company says water levels are also rising in the Number 5 and 6 turbine buildings."

http://www3.nhk.or.jp/daily/english/21_03.html

Why would the water level rise in these buildings?

Just happen to have read a reason for that a few minutes ago for the first time. This is what the WSJ wrote in a somewhat unrelated article:

"Meanwhile, at Reactor No. 6, one of the two units that have survived the March 11 earthquake and tsunami, workers Tuesday pumped 100 tons of water from the basement of the turbine building into the reactor's condenser unit. NISA said underground streams are a possible source. Before the crisis, streams beneath reactors No. 5 and 6 were pumped to divert water, a process that hasn't been conducted since the quake."

http://online.wsj.com/article/SB100...622.html?KEYWORDS=fukushimaKEYWORDS=fukushima

 

[jmelson]

Jon



well, your are right, that may be the main difference in fact. In this case, that would be more a big LUCK, considering the flooding of the plant...

Oh YES! Totally luck that none of their high tension towers fell down. And, you shouldn't be leaving reactors to just luck! Also, some design changes and elevation helped at Dai ni.

Jon

 

[jlduh]

Just happen to have read a reason for that a few minutes ago for the first time. This is what the WSJ wrote in a somewhat unrelated article:

"Meanwhile, at Reactor No. 6, one of the two units that have survived the March 11 earthquake and tsunami, workers Tuesday pumped 100 tons of water from the basement of the turbine building into the reactor's condenser unit. NISA said underground streams are a possible source. Before the crisis, streams beneath reactors No. 5 and 6 were pumped to divert water, a process that hasn't been conducted since the quake."

http://online.wsj.com/article/SB100...622.html?KEYWORDS=fukushimaKEYWORDS=fukushima

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.

 

[tsutsuji]

Because restoring sea water cooling might be too difficult, they are studying the possibility to use air cooling instead : http://www.asahi.com/special/10005/TKY201104200745.html

 

[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