Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[etudiant]

I would be grateful if someone knowledgeable about such things would post a brief explanation of the principles of operation of a plant for decontamination of water containing a range of radioactive elements in solution.

I can see that distillation would do the job in principle but I find it difficult to imagine it being used on the scale needed here.

The idea is to precipitate out the radioactives by introducing chemicals that reacts with the cesium, iodine etc to form insoluble compounds that can then be filtered out. The usual illustration in chemistry textbooks is using H2S to precipitate silver sulfide out of a silver chloride solution. It is possible that for this case there needs to be more than one precipitation to sequester the different materials in the water. No idea exactly what the Areva chemistry is, how many steps are involved and what the individual stage efficiencies are.
The hope is of course that the volume of seriously radioactive material can be very much reduced

Distillation is probably not a way forward, as the boiling point for iodine or cesium is low enough that both materials have high enough vapor pressure at 100*C to contaminate the steam produced.

 

[Atomfritz]

I would be grateful if someone knowledgeable about such things would post a brief explanation of the principles of operation of a plant for decontamination of water containing a range of radioactive elements in solution.

I can see that distillation would do the job in principle but I find it difficult to imagine it being used on the scale needed here.

It is not done by destillation, but chemically.
Lots of chemicals are poured and mixed into the water and the precipitation remains as radioactive sludge.

Here some details (excerpted from http://rapidsavr.com/french-plan-to-clean-fukushimas-radioactive-water-detailed-including-risks/ )

Areva treats contaminated water from reactor cooling systems by injecting chemicals that bind to radioactive isotopes and settle out.
Areva has not revealed which chemicals it will use at Fukushima, but a 1995 report commissioned by the U.S. Department of Energy (pdf) details the process it uses at La Hague. According to DOE, Areva uses:
nickel and potassium ferrocyanide to capture cesium

France also uses hydroxides of sodium, manganese, titanium, and iron, according to other sources. The chemicals and radionuclides are removed from the water in a highly radioactive chemical sludge.

http://rapidsavr.com/french-plan-to-clean-fukushimas-radioactive-water-detailed-including-risks/

This means that the "cleaned" water will be full of hazardous chemical substances.
I doubt that these chemicals allow it to be recycled as reactor cooling water, even if they say:

Areva has said the cleaned water could be recycled as coolant for the reactor cores as crews work to shut them down, a process that will take months and could take years. But there is far more water flooding the Fukushima plant than is needed to cool it.

The advantage is just that it no longer counts as dangerous radwaste, even if around 1% of the original radioactivity remains in it, and can be disposed of in the sea without causing too much international disturbance.

 

[Joe Neubarth]

Somewhere in the 496 pages of this string there was a photo of a BWR in the shipyard/construction yard. It had the main components and was all metal with a single man who looked tiny on the structure. Can anybody repost that again? It was a great photo but I can not find it.

 

[tsutsuji]

Here is a small Areva video in French with a few diagrams showing the water treatment : http://www.industrie.com/it/energie/fukushima-comment-areva-va-decontaminer-l-eau.11458

Japanese journalists paying a visit to the Areva plant in France :

A video showing a process developed by Tokyo Institute of Technology based on Prussian Blue (ferric ferrocyanide). The video says they plan to use it to decontaminate ponds or Earth in the areas close to the plant :

 

[Astronuc]

Somewhere in the 496 pages of this string there was a photo of a BWR in the shipyard/construction yard. It had the main components and was all metal with a single man who looked tiny on the structure. Can anybody repost that again? It was a great photo but I can not find it.

Construction photo of BF1 mentioned here.
https://www.physicsforums.com/showthread.php?p=3275289&highlight=Browns#post3275289

 

[DSamsom]

Tepco released a computer simulation showing dispersal routes and densities of radioactivity released form Fukushima NPP.

http://www3.nhk.or.jp/daily/english/21_22.html

Interesting: is this simulation available somewhere (other than the screenshots in this NHK item)?

 

[razzz]

Somewhere in the 496 pages of this string there was a photo of a BWR in the shipyard/construction yard. It had the main components and was all metal with a single man who looked tiny on the structure. Can anybody repost that again? It was a great photo but I can not find it.

Might mean this one with a women standing next to a stainless steel shroud.

 

[jlduh]

Whoa, NISA comes clean about isotope ingestion resulting in considerable exposures to thousands who were involved early on at Dai-ichi.

http://mdn.mainichi.jp/mdnnews/news/20110521p2a00m0na021000c.html

Some dose calculations these poor guys got, or are expected to get:

http://www.falloutphilippines.blogspot.com/

I always suspected that they were understating potential exposures, but i still find this a bit unsettling. Information is constantly subject to change out of the Japanese agencies, and most often, for the worse.

Hummm... it seems that this is a move towards what we discussed here:(see posts 76,
77, 80, 81, 87, 88, 90, 95 and several others) :

https://www.physicsforums.com/showthread.php?t=486089&page=5

Does this article tend to show that there is, as some developped it in the mentionned thread, some kind of contradiction between the "low doses" received by the workers, based on Tepco communication, and the levels of this INGESTED contamination?

How can you explain this if the measured doses, released by officials and Tepco, are supposed (as supported by some in the thread, but criticized by others, including me) to take into account external AND internal doses from ingested (inhalated and /or eaten and drunk) isotopes?

Where is the flaw, taking into account these new facts?

I would like to have CLEAR explanations to understand, with many other people, all those apparent important contradictions between communications and facts and reality...

By the way, thanks Intric8 for this info!

 

[Sabbatia]

Okay, I'm blonde and maybe I just don't get it...but in the article above it says

"According to Kakizawa, one worker at the Shika Nuclear Power Plant operated by Hokuriku Electric Power Co. in Ishikawa Prefecture returned to his home in Kawauchi, Fukushima Prefecture, on March 13 and stayed there for several hours. He then stayed in Koriyama in the prefecture with his family for one night before moving out of Fukushima. On March 23, he underwent a test at the Shika Nuclear Power Plant that showed his internal exposure to radiation had reached 5,000 cpm. He was thus instructed by the company to remain on standby. The radiation reading dropped below 1,500 cpm two days later, and then he returned to work."

So he had the test 10 days after he had been to the area and it was that high. The half life for iodine is like 8 days right? two days later he was down to 1500 and went back to work. 10 days is time for one halflife before he was tested...but somehow the math isn't working for me. Can someone explain this??

 

[Astronuc]

Okay, I'm blonde and maybe I just don't get it...but in the article above it says

"According to Kakizawa, one worker at the Shika Nuclear Power Plant operated by Hokuriku Electric Power Co. in Ishikawa Prefecture returned to his home in Kawauchi, Fukushima Prefecture, on March 13 and stayed there for several hours. He then stayed in Koriyama in the prefecture with his family for one night before moving out of Fukushima. On March 23, he underwent a test at the Shika Nuclear Power Plant that showed his internal exposure to radiation had reached 5,000 cpm. He was thus instructed by the company to remain on standby. The radiation reading dropped below 1,500 cpm two days later, and then he returned to work."

So he had the test 10 days after he had been to the area and it was that high. The half life for iodine is like 8 days right? two days later he was down to 1500 and went back to work. 10 days is time for one halflife before he was tested...but somehow the math isn't working for me. Can someone explain this??

Does one have a reference or citation? It is not possible to answer without knowing what kind of counting/survey was done. Possibly the person was scanned with a whole body counter. Normally one is scanned in and out of restricted (controlled access) areas at an NPP. The objective is to prevent radioactive substances from entering or leaving.

 

[Jakeh]

...

Fascinating stuff as ever. If [insert descriptive term] extract that kind of insight by way of refutation, maybe I should feel more tolerant of them.

I say that as a long term thread watcher who spends most of his time biting his lip, so as not to dilute the thread with yet more non-scientific opinion of which there is an excess, and increasingly so, to the point where I am questioning the worth of following the thread at all.

Your post reminds me of why I joined this forum in order to follow this thread.

 

[Sabbatia]

Does one have a reference or citation? It is not possible to answer without knowing what kind of counting/survey was done. Possibly the person was scanned with a whole body counter. Normally one is scanned in and out of restricted (controlled access) areas at an NPP. The objective is to prevent radioactive substances from entering or leaving.

No real reference...it was just from the article posted above. I was just reading it thinking...how high was it 10 days earlier if these numbers are correct.

 

[Astronuc]

No real reference...it was just from the article posted above. I was just reading it thinking...how high was it 10 days earlier if these numbers are correct.

It may not reflect one isotope, but several.

In such cases, one would apply retrospective dosimetry - at least, I would hope so.

http://www.sckcen.be/en/Our-Research/Scientific-Institutes-Expert-Groups/Environment-Health-and-Safety/RP-Dosimetry-and-Calibration/Retrospective-dosimetry

 

[jim hardy]

"" The half life for iodine is like 8 days right? two days later he was down to 1500 and went back to work. 10 days is time for one halflife before he was tested...but somehow the math isn't working for me. Can someone explain this?? ""

well having worked in such a plant, those numbers aren't scary.

But no i can't explain it absolutely.
Could be as simple as two different individuals scanned the guy. After a "Technicium Stress Test" of my heart i was so radioactive that i set off the plant exit monitors from a hundred feet away . Of course i was not allowed around the radiation area - they wouldn't be able tell the internal radioactive medicine from contamination so i was not allowed around any contamination until the stuff went away. Took about three weeks.

The HP (Health Physics- radiation monitoring guy) who scanned me at first was very thorough, read close to my thyroid and other organs, hair, intestines, and wrote down several readings on a chart to get a feel for where my body was stashing the stuff. Afterward they were less thorough because they knew what i had was not from the plant.
The initial numbers were high enough they were in micro-r/hour not individual counts. When the counts are so high they run together to form a continuous stream you switch to dose rate not count rate - like a leaky faucet it can be individual drips per minute or a continuous stream measured in milliliters per minute.
So long as they were still reading individual counts on me i wouldn't worry.

So my guess is the two numbers might be highest one day and average another day, or maybe his body eliminated some of the stuff by biology - iodine pills would do that.

I hope he got some rest.

old jim

 

[MiceAndMen]

The second group of 3 pictures on this TEPCO page is interesting. They might show the location of the "very high dose rate material that had to be bulldozed over between Units 3 and 4".

http://www.tepco.co.jp/tepconews/pressroom/110311/index-j.html

This one shows the area which looks to me like it is between units 3 and 4.
http://www.tepco.co.jp/en/news/110311/images/110521_3.jpg

This one shows a sign in front of a pile of rubble that reads in part "1000 mSv/h"
http://www.tepco.co.jp/en/news/110311/images/110521_1.jpg

And the third one is the same pile of rubble with some annotation in Japanese.
http://www.tepco.co.jp/en/news/110311/images/110521_2.jpg

There is some interesting green material in the area that looks to be broken metal of some sort. I don't think it's current location is much help in trying to determine where it came from since the bulldozing would have moved it from its original location on the ground after the explosions.

The barricade the sign is hanging from looks more like a velvet rope entrance to a fancy nightclub than it does a warning of dangerous conditions.

Edit: UPDATE: This story at NHK says they found 1000 mSv/h debris on Friday south of unit 3. That's probably what's shown in the pictures above. http://www3.nhk.or.jp/daily/english/22_07.html

The story also says it's the highest level of radiation they've found in the debris, which leaves the question open as to what they found in the first weeks that they bulldozed.

 

[MadderDoc]

<..> I don't think it's current location is much help in trying to determine where it came from since the bulldozing would have moved it from its original location on the ground after the explosions.

It cannot be excluded that the object has been moved from even the other end of the plant and has been dropped here for some exciting and mystifying reason, but the simplest explanation does seem to be that it has been found rather close to where it fell.

The position of the pile itself and the marked location for the object in it, suggests to me that the object has probably not been moved by more than a few meters from its original location.

The pile itself appears to be the one formed, when access to sfp3 for the concrete pump was superficially cleared at some time between March 20th and March 24th. Since then the pile seems to have had only removed from it, e.g. the easily recognizable corrugated iron strips originating from the roof -- they may have been picked out to be moved to some other place for disposal -- however otherwise this pile does not appear to have perceptibly changed.

The barricade the sign is hanging from looks more like a velvet rope entrance to a fancy nightclub than it does a warning of dangerous conditions.

A very fine sign and barricade indeed.

Edit: UPDATE: This story at NHK says they found 1000 mSv/h debris on Friday south of unit 3. That's probably what's shown in the pictures above. http://www3.nhk.or.jp/daily/english/22_07.html

The story also says it's the highest level of radiation they've found in the debris, which leaves the question open as to what they found in the first weeks that they bulldozed.

It could be the same piece.

 

[Uagrepus]

This one shows the area which looks to me like it is between units 3 and 4.
http://www.tepco.co.jp/en/news/110311/images/110521_3.jpg

Yes. There is a small evidence for slightly higher temperatures around this pile of rubble. But maybe just warm pipes:

 

[tsutsuji]

NISA issued a long statement on May 16th about the transfer of contaminated water from unit 3 to the Radioactive Waste Treatment Facility's incinerator building :

The high-temperature incinerator building’s floors and walls possesses the necessary water-tightness according to leakage volume assessment.
(...)
every visually-identified crack was confirmed to have been repaired with polymer cement waterproof coating.
http://www.nisa.meti.go.jp/english/files/en20110520-2.pdf

Does one have a reference or citation?

Are you looking for http://mdn.mainichi.jp/mdnnews/news/20110521p2a00m0na021000c.html ? Or for Mainichi's sources ? I tried to look at NISA's latest press releases, but could not find anything related so far. There is a full video record of the House of Representative's Budget Committee meeting on May 16th at http://www.shugiintv.go.jp/jp/video_lib2.php?u_day=20110516

 

[MiceAndMen]

It could be the same piece.

That had crossed my mind too. It was probably originally on the ground somewhere between units 3 and 4, so it wasn't moved a great distance. I was thinking more along the lines of whether it fell from the east or west side of the building (unit 3 seems most likely).

 

[Borek]

Somewhere in the 496 pages of this string there was a photo of a BWR in the shipyard/construction yard. It had the main components and was all metal with a single man who looked tiny on the structure. Can anybody repost that again? It was a great photo but I can not find it.

Perhaps

 

[robinson]

Edit: UPDATE: This story at NHK says they found 1000 mSv/h debris on Friday south of unit 3. That's probably what's shown in the pictures above. http://www3.nhk.or.jp/daily/english/22_07.html

The story also says it's the highest level of radiation they've found in the debris, which leaves the question open as to what they found in the first weeks that they bulldozed.

I'm wondering what is the material in that picture that is the source of that much radiation, and how did it get from inside the reactor (or fuel pond) to that location. Is it just me, or does it seem like the explosions caused radioactive fuel to be ejected? If it's not fuel, what could it be?

 

[tsutsuji]

Tepco releases a gamma ray photograph taken at the ground floor of unit 1 reactor building. It shows some parts of ventilation ducts suffer a high level of radiation :

http://www.hokkaido-np.co.jp/news/dogai/294071.html
http://www.tepco.co.jp/nu/fukushima-np/images/handouts_110522_01-j.pdf (bigger pictures)

 

[elektrownik]

here is image from tepco, with description where exactly radioactive part is: http://www.tepco.co.jp/en/news/110311/images/110521_7.jpg

 

[MadderDoc]

here is image from tepco, with description where exactly radioactive part is: http://www.tepco.co.jp/en/news/110311/images/110521_7.jpg

But, seeing that the white circle as well as the splotch of red painted concrete to the left of it are both landmarks perhaps 5 meter across it is not exactly an X marks the spot situation :-)

 

[maddog1964]

RCIC is powered by steam, so fluctuations in amount of steam = fluctuations in RCIC

I see you are online, you may have missed my request for the following info, as i did not see your post until much later... would appreciate it if you could answer the following...

Am interesteded in the original source of the info about RCIC powered by steam, and do you know the "supply source of the steam" to operate? thanks

 

[Bandit127]

Tepco releases a gamma ray photograph taken at the ground floor of unit 1 reactor building. It shows some parts of ventilation ducts suffer a high level of radiation :

http://www.hokkaido-np.co.jp/news/dogai/294071.html
http://www.tepco.co.jp/nu/fukushima-np/images/handouts_110522_01-j.pdf (bigger pictures)

The "gamma camera". It might look a bit Heath Robinson but I salute the ingenuity in it. It's the kind of engineeriing I think a lot of us were hoping to see some time ago.

There are some new images of the Megafloat arriving here:
http://www.tepco.co.jp/en/news/110311/index-e.html"

 

[Rive]

This one shows a sign in front of a pile of rubble that reads in part "1000 mSv/h"
http://www.tepco.co.jp/en/news/110311/images/110521_1.jpg

I can't recognize anything on the picture... But it's still very interesting. There are several 'overexposed' spots across the picture - are those traces of radiation hitting the CCD chip?

 

[elektrownik]

Am interesteded in the original source of the info about RCIC powered by steam, and do you know the "supply source of the steam" to operate? thanks

Reactor is source of steam, then steam is going to turbine, this turbin is connected to pump, water source is torus, pump is pumping water from torus to RPV and steam which go to turbine is condensated in torus.
http://a2.sphotos.ak.fbcdn.net/hphotos-ak-ash4/188425_211896475487877_113650851979107_876237_7212984_n.jpg

 

[radio_guy]

I can't recognize anything on the picture... But it's still very interesting. There are several 'overexposed' spots across the picture - are those traces of radiation hitting the CCD chip?

I wondered the same thing, you see it in a lot of pictures. and the underwater video of the SFP i just can't see some of the wildly zipping white spots as bubbles..


I never questioned it, just assumed since it hasn't been mentioned here that it wasn't anything abnormal.

 

[elektrownik]

I can't recognize anything on the picture... But it's still very interesting. There are several 'overexposed' spots across the picture - are those traces of radiation hitting the CCD chip?

I don't think so, it can be some plastic radiation shield which make quality bad

 

[Borek]

There are several 'overexposed' spots across the picture - are those traces of radiation hitting the CCD chip?

Lens in a simple camera is not able to collimate neither of the possible radiation types, if anything, whole image should be overexposed the same way.

 

[Uagrepus]

Lens in a simple camera is not able to collimate neither of the possible radiation types, if anything, whole image should be overexposed the same way.

The most of these pixel errors I saw near Unit 2 (please zoom into the darker areas). Good to hear, radiation can't be the reason:

http://img542.imageshack.us/img542/4963/no2fallout.th.jpg

 

[maddog1964]

Reactor is source of steam, then steam is going to turbine, this turbin is connected to pump, water source is torus, pump is pumping water from torus to RPV and steam which go to turbine is condensated in torus.
http://a2.sphotos.ak.fbcdn.net/hphotos-ak-ash4/188425_211896475487877_113650851979107_876237_7212984_n.jpg

Thank you, that's what I thought I had also seen, but also thought I saw conversation that someone was saying that the shutting of the main steam isolation valve deprived the system of steam to operate the turbine. According to your diagram the tap for the steam to the cooling system is before the main isolation vavle and would not effect the operation of the system. Being a simple diagram and not showing all vavles/and controls there still could be other things that would efffect the operation. Thanks, to many threads to find!

 

[v13]

Lens in a simple camera is not able to collimate neither of the possible radiation types, if anything, whole image should be overexposed the same way.

So http://www.youtube.com/watch?v=jFNvYA7731o" is a wrong interpretation?

I mean (while I don't claim that this is correct because of the lack of knowledge) most of the images in "suspicious" places have those artifacts (i.e. inside the factory), while images looking elsewhere (i.e. distant, looking at the sea, outside, etc) don't. If true then those can also be burned pixels from previous shots and may not be the result of the current shot.

 

[Most Curious]

I see you are online, you may have missed my request for the following info, as i did not see your post until much later... would appreciate it if you could answer the following...

Am interesteded in the original source of the info about RCIC powered by steam, and do you know the "supply source of the steam" to operate? thanks

I'm not who you asked but maybe this will help.


The RCIC is used on units 2,3, 4. Unit one has a a Core Isolation Condenser instead.

The RCIC is shown on many different diagrams of the plants but I don't have one handy. The steam source is the reactor. When the reactor is shut down, it is still hot and makes lots of steam. Prior to the steam isolation valve feeding the main turbine there is a tee that taps off steam for the RCIC turbine. As long as the reactor is hot enough to make enough steam, the RCIC is available. When the decay heat is decreased too far to make adequate steam then other cooling systems are ASSumed to be available. The RCIC pump can take water from the torus or the condensate tank as selected by the operator.