Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[tsutsuji]

http://mdn.mainichi.jp/mdnnews/news/20110606p2a00m0na009000c.html

Airborne contamination estimates revised upwards by NISA "from 370,000 terabecquerels to 850,000 terabecquerels", counting from the start of the accidents to April 5 (yesterday).

April 5 is two months ago. (Yesterday is June 5)

 

[jlduh]

Yeah, there are not too many places that make MOX fuel. This article is about a year old and says:
Taken from http://www.world-nuclear-news.org/WR_Japanese_firms_stick_with_Sellafield_MOX_Plant_1305101.html

Also we can see how the MOX stuff has been a very slow process with many delays along the way, with this article which seems to be over a decade old:

http://www.atimes.com/japan-econ/AI18Dh01.html

You have a quite detailed summary of some Japanese reactors MOX conversion here, with dates (many delays...):

http://cnic.jp/english/topics/cycle/MOX/pluthermplans.html

Somebody (maybe Jim? I don't remember exactly sorry!) wrote that Belgonucleaire was making MOX for Areva.

This was true (Belgo made rods and Areva assembled them and sold them) until Areva started their big MOX production plant in Marcoule (France). Areva has been a customer for Belgo for years but obviously then shifted to use their own fuel/rods. Belgo quality standards for MOX have suffered criticism in the past.

Belgo has stopped producing MOX in 2006. This is stated on their site: http://www.belgonucleaire.be/uk/default.htm

WELCOME TO THE BELGONUCLEAIRE WEBSITE

During more than 20 years, BELGONUCLEAIRE has produced
MOX (Mixed OXides) fuel for nuclear power plants.
The last fabrication campaign has been completed on 15 August 2006.

Their Dessel plant is now to be decommissionned. So It's pretty clear that they didn't make the MOX delivered in 2010 for Fukushima N°3. Areva did it.

Interestingly, the Areva site doesn't list Tepco being one of their suppliers:

http://www.areva.com/EN/operations-1095/melox-operations-production-of-mox-fuel-assemblies.html

But... is it surprising really? Or is it just communication strategy
On the other hand, they already made MOX with plutonium grade:

In 2003, the AREVA group was chosen by the United States to produce 4 MOX fuel assemblies from American plutonium of military origin.

The production of these assemblies was carried out on 2 sites.

Fabrication of pellets and rods took place at the AREVA NC Cadarache facility in the fall of 2004.
Fuel assembly operations took place at the MELOX plant in early 2005.
The 4 assemblies produced were loaded in June 2005 into the Catawba nuclear power plant, owned by the American electrical utility company Duke Power. They have enabled the production of power sufficient to meet the electricity demands equivalent to those of a city of nearly 10,000 inhabitants a year. The American program demonstrates that civil nuclear applications, and the use of MOX in particular, can contribute to the non-proliferation of nuclear weapons.

 

[tsutsuji]

Following the (still untranslated ?) May 24th Tepco report explained on http://www.tepco.co.jp/en/press/corp-com/release/11052412-e.html , the NISA asked JNES to cross-check the Tepco study about the state of the cores of units 1,2,3. While Tepco used a software called MAAP, JNES used another software called MELCOR. The conclusions have been published by NISA on a document dated June 6th : http://www.meti.go.jp/earthquake/nuclear/pdf/20110606-1nisa.pdf (in Japanese). Page 26/59 is a series of diagrams showing the state of the core of unit 1 after 6, 12 and 18 hours.

Concerning Tepco's response to the ever-growing amounts of contaminated water, NISA published the following documents :

On June 2nd an 18 page document : http://www.meti.go.jp/press/2011/06/20110602002/20110602002.pdf including, page 9, a map with the various trenches, electric cables, sea water pipes, etc... with their elevations, between the turbine buildings and the water intake canal. The dot lines show the various leaking paths that must be closed. Page 16 is a schedule for the works undergoing in May and June.

On June 3rd, a 17 page document : http://www.meti.go.jp/press/2011/06/20110603002/20110603002.pdf including simulation plots showing the contaminated water levels in the turbine buildings until September.

 

[zapperzero]

April 5 is two months ago. (Yesterday is June 5)

yes, of course. edited

 

[swl]

Now it's 20% Chernobyl...

Another year of contaminated steam, then add in the water leaks, and we should be well on our way to that elusive #1 spot (of all time accidents).

Rainy season is upon us. Anyone taking bets?

 

[Rive]

Rainy season is upon us. Anyone taking bets?

http://www3.nhk.or.jp/daily/english/06_15.html
So, actual amount is ~105000m³, pacing with 500m³/day, overflow expected on 06.20.
Water decontamination facility may be online on 06.15. They are installing new storage capacity of 30000m³.

It'll be a close run... But they have some chance. If nothing unexpected happens.

Ps.: the facility will be online at 06.15... Edited.

 

[WhoWee]

If nothing unexpected happens.

That is one big "IF" - isn't it?

 

[joewein]

Another year of contaminated steam, then add in the water leaks, and we should be well on our way to that elusive #1 spot (of all time accidents).

Rainy season is upon us. Anyone taking bets?

At 500 t a day injected for cooling, I suppose in the worst case TEPCO (or JP tax payers) will have to purchase steel tanks equivalent to about 200,000 t over the next 12 months, if the AREVA plant that is supposed to reprocess 200,000 t by the end of the year turns out to not work as advertised. We know 40,000 t are on order already.

Does anyone know at what stage the desalination takes place in the AREVA plant? I am curious how they'll separate the cesium from the sodium/potassium.

I guess one possibility would be not to bother and keep all alkali ions together, putting the sodium/potassium in long term storage too for now. At 0.5x-0.8x salinity compared to sea water there should be 170-180t of salt in 100,000 t of brackish water from the reactors, turbine basements and various tanks.

 

[rowmag]

At 500 t a day injected for cooling, I suppose in the worst case TEPCO (or JP tax payers) will have to purchase steel tanks equivalent to about 200,000 t over the next 12 months, if the AREVA plant that is supposed to reprocess 200,000 t by the end of the year turns out to not work as advertised. We know 40,000 t are on order already.

I still wonder at what point it makes sense to seal up the harbor entrance and declare it a giant storage/evaporation pond.

 

[jlduh]

Concerning the 950 mSv/h debris:
http://www3.nhk.or.jp/daily/english/06_28.html

On Monday, a piece of debris about 5 centimeters in diameter with radiation levels of 950 millisieverts per hour was removed from the west side of the Number 3 reactor building. It had been found on Saturday.In May, debris with a radiation dose of 1,000 millisieverts per hour was discovered in the area, while rubble contaminated with 900 millisieverts per hour was found in April.

Tokyo Electric Power Company has so far removed about 280 containers of radioactive debris, but radiation levels still remain high near the reactor building that was badly damaged by a hydrogen explosion.

 

[elektrownik]

http://www3.nhk.or.jp/daily/english/06_33.html"

 

[jlduh]

http://www3.nhk.or.jp/daily/english/06_33.html

No.1 reactor vessel damaged 5 hours after quake

Japan's nuclear regulator says the meltdown at one of the Fukushima reactors came about 5 hours after the March 11th earthquake, 10 hours earlier than initially estimated by the plant's operator.

[...]

The report says the fuel rods in the Number 1 reactor began to be exposed 2 hours after the earthquake due to the loss of the reactor's cooling system in the tsunami. Its fuel rods may have melted down 3 hours later, causing the damage to the reactor. This means the meltdown occurred about 10 hours earlier than TEPCO estimated last month.

The nuclear agency also says a meltdown damaged the Number 2 reactor about 80 hours after the quake, and the Number 3 reactor 79 hours after the quake.

The agency's analysis shows that the Number 2 reactor damage came 29 hours earlier than the TEPCO estimate, and the Number 3 reactor damage came 13 hours later than in the utility's assessment.

The agency says the total amount of radioactive iodine 131 and cesium 137 released from the Numbers 1, 2 and 3 reactors for the 6 days from March 11th is estimated at 770,000 terabecquerels. That is about twice the figure mentioned in April when the agency upgraded the severity of the accident to the highest level of 7 on an international scale.

 

[etudiant]

At 500 t a day injected for cooling, I suppose in the worst case TEPCO (or JP tax payers) will have to purchase steel tanks equivalent to about 200,000 t over the next 12 months, if the AREVA plant that is supposed to reprocess 200,000 t by the end of the year turns out to not work as advertised. We know 40,000 t are on order already.

Does anyone know at what stage the desalination takes place in the AREVA plant? I am curious how they'll separate the cesium from the sodium/potassium.

I guess one possibility would be not to bother and keep all alkali ions together, putting the sodium/potassium in long term storage too for now. At 0.5x-0.8x salinity compared to sea water there should be 170-180t of salt in 100,000 t of brackish water from the reactors, turbine basements and various tanks.

There is a more detailed schematic of the process given on EX-SKF here:
http://ex-skf.blogspot.com/2011/06/fukushima-i-nuke-plant-arevas-water.html
The key element appears to be the selective cesium removal, before precipitating out the other radio nucleotides. Desalination is only done after that.
The cesium removal material is supplied by Kurion, ( http://www.kurion.com ) a private company in Irvine, CA. Their website gives links to papers suggesting their inorganic adsorption material is extraordinarily selective for cesium, at a 100,000 to 1 ratio. They also claim to have supplied some earlier material for the TMI cleanup.
As has been noted earlier, we will soon find out how well this works for Fukushima. We can only hope for a complete success.

 

[tsutsuji]

Concerning the 950 mSv/h debris:
http://www3.nhk.or.jp/daily/english/06_28.html

The 00:12 time-frame of the video is circling with a yellow circle the red-coloured debris at the bottom of the cone.

Here are the links for the Tepco picture: http://www.tepco.co.jp/en/news/110311/images/110605_02.jpg and map: http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/f1-sv-20110605-e.pdf again.

An employee interviewed by http://mainichi.jp/select/weathernews/news/20110531ddm041040136000c.html says he is afraid to work without a radiation control technician coming along, while he suspects that debris are "falling" (from walls or ceilings ? or from rubble stacks ?). Their own radiation monitor is inside their clothes so they can't see it, and they can't hear the alarm if it rings because they are wearing a mask.

 

[robinson]

http://www.tepco.co.jp/en/news/110311/images/110605_02.jpg

Am I the only one who is thinking, "Why not use a long pole and pick that up and remove it to the storage area for radioactive crap?".

Why leave it there? Or did they already do that you think?

 

[Bioengineer01]

AREVA does not fabricate MOX fuel in the US.

Please post the export permits that one 'saw'.

TEPCO has reprocessing contracts with AREVA. There is strict control of spent fuel and MOX fuel. TEPCO indicates that MOX is derived from spent fuel.
http://www.tepco.co.jp/en/challenge/csr/nuclear/cycle-e.html

The status of MOX fuel is posted earlier in this thread.

I found the place where I saw it, it was a permit for 35 Tons of Uranium Oxide UOX for Fukushima Daiichi. Not MOX, the guy called it MOX, and my brain didn't remember right.
http://lunaticoutpost.com/Topic-Nuclear-Power-plant-Onagawa-on-fire-Fukushima-malfunctions?pid=916175#pid916175
The link to the permit was at http://www.box.net/shared/g6sm3p376b , I did see it myself along many others in the thread I reference above, you can check it yourself, there is discussion about it for several pages. But It is gone now.

 

[tsutsuji]

http://www.tepco.co.jp/en/news/110311/images/110605_02.jpg

Am I the only one who is thinking, "Why not use a long pole and pick that up and remove it to the storage area for radioactive crap?".

Why leave it there? Or did they already do that you think?

Jlduh's quote at https://www.physicsforums.com/showthread.php?p=3341761#post3341761 says it has been removed.

 

[Bioengineer01]

Really good observation.
You remind me what happened in russia then...
Mr. Dyatlov, manager of the blown-up block in Chernobyl insisted that the reactor was still there, intact, being cooled.
He was unable to be convinced that the reactor was damaged until helicopters filmed the situation from above next noon.
This delayed many emergency measures.


In Russia military quickly took over to remedy the situation.
In Fukushima also constantly new procedures are being developed.

First step should always be a thorough assessment of the situation.
Then the necessary measures must be developed or improvised.
Layman input at least is not restricted by procedure thinking obsoleted by new situations.

So to get back to the reactor problem:
There are questions not asked before even in this thread.

What fraction of the short-lived fission products can be expected to already have left the reactors and taken away by the cooling water?

If, for example, as some sources say, almost all iodide and cesium has been dissolved into the tens of thousands cubic meters of water, then a big part of the residual heat could now have left the reactor remains.

So my second and third question:
Does this bleed-out of FPs reduce residual heat substantially?
If so, what magnitude could be the probable reduction of core remains' residual heat?

Why I ask this:
There will eventually be a point of equilibrium when the heat can sufficiently passively dissipate through floors, walls etc slowly without melting anything more.
From this point on, the way most economical solution would be entombing.


I'd be happy if some nuclear professional could comment on how much of the FP inventory is still in the reactors.
Thank you!

Two points: The pilots of the helicopter paid Mr. Dyatlov's mistake with their lives soon thereafter the fly by...

The answer to the second question depends on the geommetry of the situtation, if the Corium is in the form of a blow with the external layer solidified by the contact with water vapor and the inside of the mass is liquid, very little of what goes on inside will be extracted by the water. If on the contrary it is distributed in a granular way all over the place presenting multiple surfaces of contact to the water vapor, the a lot would be washed by the water.

 

[Bioengineer01]

I think TEPCO has plans to formulate their own MOX fuel in the future, but I was also under the impression that the MOX fuel in use there currently came from AREVA and shipped from France.

http://www.world-nuclear-news.org/ENF-Japan_starts_using_MOX_fuel-0511094.html

So up until now, it was devrived from Japanese spent fuel and it did come from France. Both statements are true.

Funny then that the spent fuel is Japanese, the UOX is from the USA and the MOX from France :)

 

[robinson]

Jlduh's quote at https://www.physicsforums.com/showthread.php?p=3341761#post3341761 says it has been removed.

Thanks. I somehow missed that.

 

[tsutsuji]

http://www3.nhk.or.jp/daily/english/06_33.html
No.1 reactor vessel damaged 5 hours after quake

This is probably what is meant on the diagram page 17 of the report I mentioned :

the NISA asked JNES to cross-check the Tepco study about the state of the cores of units 1,2,3. While Tepco used a software called MAAP, JNES used another software called MELCOR. The conclusions have been published by NISA on a document dated June 6th : http://www.meti.go.jp/earthquake/nuclear/pdf/20110606-1nisa.pdf (in Japanese).

 

[Bioengineer01]

There has been considerable math and forumlas developed, but there are still a lot of unknowns. Kids not even born yet will be writing their PhD theses about Fukushima a few decades from now.

Anyone interested in the corium aspects of this situation should have a look at the following pdf reports:

http://www.tec-sim.de/images/stories/lecturenotes-late-in-vessel-phenomena.pdf
http://www.tec-sim.de/images/stories/severe-accident-phenomenology.pdf

They are fairly recent and summarize the current state of knowledge regarding "corium". The most interesting thing I found out, is that 25 years after TMI2 there is still no explanation for why the molten corium did not melt through the reactor vessel. All simulations indicate that it should have happened, but it didn't. To this day nobody can explain it. There is a lot we don't know.

Interesting bullet point on re-criticality on second link:
"Recriticality
If there water in the lower head, recriticality due to U235 cannot be
excluded.
Rule-of-thumb: If there is no water, recriticality can be excluded if
Uranium enrichment is below 5%
The amount of Pu239 is more than enough for recriticality but this would
require local Pu accumulation, which has not yet been investigated."

 

[dh87]

http://mdn.mainichi.jp/mdnnews/news/20110606p2a00m0na009000c.html

Airborne contamination estimates revised upwards by NISA "from 370,000 terabecquerels to 850,000 terabecquerels", counting from the start of the accidents to April 5.

The previously reported 370,000 TBq release is from p. 20 of this document (dated 4/25): http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/f12np-gaiyou_e.pdf

The document says 130,000 TBq of I-131 and 6,000 TBq of Cs-137. Then, there's a mysterious "Iodine value conversion" before apparently adding the numbers to get 370,000 TBq.

I could not find a breakdown of the new numbers to determine what they think is different. The Mainichi article linked earlier says "The Cabinet Office's Nuclear Safety Commission of Japan (NSC) had estimated that the total level of radioactivity stood at around 630,000 terabecquerels, but this figure was criticized as an underestimation." If enough people criticize the new estimate, maybe it will be revised too.

 

[radio_guy]

All this talk of AREVA and their treatment plant..

whatever happened to this guy?
http://blogs.wsj.com/japanrealtime/2011/04/21/chemist-i-can-clean-fukushima-water-faster/

They are working a close (5 day) deadline to overflowing... maybe they should give it a shot? I'm sure areva won't lend their new on site plant for testing, but they really don't have a lot to lose if it doesn't work as planned...

this is one of those situations where they should give this guy and the company what they want and use the solution, no politics, less industry nepotism, pick THE best solution and run with it.

 

[thehammer2]

All this talk of AREVA and their treatment plant..

whatever happened to this guy?
http://blogs.wsj.com/japanrealtime/2011/04/21/chemist-i-can-clean-fukushima-water-faster/

They are working a close (5 day) deadline to overflowing... maybe they should give it a shot? I'm sure areva won't lend their new on site plant for testing, but they really don't have a lot to lose if it doesn't work as planned...

this is one of those situations where they should give this guy and the company what they want and use the solution, no politics, less industry nepotism, pick THE best solution and run with it.

Well, one source of reticence to use new things that people come up with only after the disaster has hit is because if it is tried and doesn't work, then they'd still have the radioactive water to deal with. However, in addition, they'd have the new cleanup material itself to deal with. Because of the contact with the radioactive water, it would become radioactive waste that would have to be decontaminated.

In any disaster, people always come out of the woodwork with these seeming revolutionary fixes. While some of them may actually work, testing them in the face of a crisis is not wise, as introducing fresh unknowns is the exact opposite of what to do during a crisis and can make things worse.

New methods of mediation are to be tested under controlled conditions, not the chaos of a disaster, and especially not when there is a method that works but is on a timescale that seems to be "too slow" or faces logistical hurdles that can be overcome with time.

 

[clancy688]

The document says 130,000 TBq of I-131 and 6,000 TBq of Cs-137. Then, there's a mysterious "Iodine value conversion" before apparently adding the numbers to get 370,000 TBq.

INES Manual, page 5 paragraph 1.4.1, page 15f paragraph 2.2

The mystery behind iodine value conversion is explained there.

http://www-pub.iaea.org/MTCD/publications/PDF/INES-2009_web.pdf

 

[mscharisma]

Well, one source of reticence to use new things that people come up with only after the disaster has hit is because if it is tried and doesn't work, then they'd still have the radioactive water to deal with. However, in addition, they'd have the new cleanup material itself to deal with. Because of the contact with the radioactive water, it would become radioactive waste that would have to be decontaminated.

In any disaster, people always come out of the woodwork with these seeming revolutionary fixes. While some of them may actually work, testing them in the face of a crisis is not wise, as introducing fresh unknowns is the exact opposite of what to do during a crisis and can make things worse.

New methods of mediation are to be tested under controlled conditions, not the chaos of a disaster, and especially not when there is a method that works but is on a timescale that seems to be "too slow" or faces logistical hurdles that can be overcome with time.

Would agree that one should proceed with extreme caution to avoid making a bad situation even worse. However, what would keep TEPCO (or anyone) from conducting such a controlled experiment? Time is clearly running out as far as the contaminated water and storage solutions are concerned. While I as a non-technical person lack the understanding of most technical aspects discussed here and elsewhere, I very much miss the Plan B (or C etc.) planning that one would look for from a common sense perspective, especially in a disaster this profound. So why not test alternatives?

 

[thehammer2]

So why not test alternatives?

Oh, I'm definitely not suggesting that they don't test what this guy's developed. Test the hell out of it and do it quickly if possible, just don't do it at any nuclear plant currently going through a severe accident. We're talking long cleanup timeframes, so test it offsite and once we know the new procedure is more effective than what we've got, only then implement it.

 

[Jorge Stolfi]

I am not sure that your statement that the volatile elements would be trapped if the uranium oxide remained solid is correct. My argument doesn't invalidate your guesstimate of 10%, but my guesstimate would be higher.

Indeed, according to the Cristoph Mueller slides posted earlier, once the fuel is completely molten, the radioactive elements that remain in the liquid melt (corium) will produce 30% of the decay heat power that would be produced by the intact fuel; the other 70% of the decay heat power is due to more volatile elements that will end up elsewhere.

Some of that 70% will escape to the atmosphere, some will be washed out by the cooling water, and perhaps some will be deposited inside the reactor or containment in places and forms that cannot be easily washed out. In any case those 70% are a big contamination problem but should not pose much of a heat management problem. Is this correct?

On the other hand the corium will contain many long-lived isotopes which could be a huge health hazard if they were ejected to the atmosphere. While the contribution of an element to the heat production rate is inversely proportional to its half-life (among other things), its potential for health damage is largely independent of it, at least for lifetimes up to a decade or two. So, while the corium keeps 30% of the decay heat production, it may include a larger fraction of the total health damage potentia of the original fuel.

 

[etudiant]

Well, one source of reticence to use new things that people come up with only after the disaster has hit is because if it is tried and doesn't work, then they'd still have the radioactive water to deal with. However, in addition, they'd have the new cleanup material itself to deal with. Because of the contact with the radioactive water, it would become radioactive waste that would have to be decontaminated.

In any disaster, people always come out of the woodwork with these seeming revolutionary fixes. While some of them may actually work, testing them in the face of a crisis is not wise, as introducing fresh unknowns is the exact opposite of what to do during a crisis and can make things worse.

New methods of mediation are to be tested under controlled conditions, not the chaos of a disaster, and especially not when there is a method that works but is on a timescale that seems to be "too slow" or faces logistical hurdles that can be overcome with time.

Well, there are a couple of easily answered questions. notably as how well, if at all, the process works in a salt water environment and how easily it scales.
The test demo used 15 milligrams of material for 100 ml of contaminated water, or 150 grams/ton.
At Fukushima, we have about 100,000 tons of water to deal with, so we need 15,000 kilograms of material.
The claim is the material components are 'easy to obtain and rich in supply' .
To be useful, or at least comparable to the AREVA effort, the new approach must clean up 1000 tons/day of contaminated water. That takes about 1500 kg of material. Can/will Dr Ohta and his partners deliver at that pace?

 

[Bioengineer01]

http://www3.nhk.or.jp/daily/english/06_33.html

This is good news for the location of the Corium in Unit 3 and very bad news for the location of the Corium in Units 1 and 2, a lot more of decay heat production present in the melted fuel than originally thought...

 

[Bioengineer01]

Would agree that one should proceed with extreme caution to avoid making a bad situation even worse. However, what would keep TEPCO (or anyone) from conducting such a controlled experiment? Time is clearly running out as far as the contaminated water and storage solutions are concerned. While I as a non-technical person lack the understanding of most technical aspects discussed here and elsewhere, I very much miss the Plan B (or C etc.) planning that one would look for from a common sense perspective, especially in a disaster this profound. So why not test alternatives?

Answer: Human beings: Patents; Licenses; Agreements -- Summary: "Greed"

 

[mscharisma]

Well, one source of reticence to use new things that people come up with only after the disaster has hit is because if it is tried and doesn't work, then they'd still have the radioactive water to deal with. However, in addition, they'd have the new cleanup material itself to deal with. Because of the contact with the radioactive water, it would become radioactive waste that would have to be decontaminated.

In any disaster, people always come out of the woodwork with these seeming revolutionary fixes. While some of them may actually work, testing them in the face of a crisis is not wise, as introducing fresh unknowns is the exact opposite of what to do during a crisis and can make things worse.

New methods of mediation are to be tested under controlled conditions, not the chaos of a disaster, and especially not when there is a method that works but is on a timescale that seems to be "too slow" or faces logistical hurdles that can be overcome with time.

Oh, I'm definitely not suggesting that they don't test what this guy's developed. Test the hell out of it and do it quickly if possible, just don't do it at any nuclear plant currently going through a severe accident. We're talking long cleanup timeframes, so test it offsite and once we know the new procedure is more effective than what we've got, only then implement it.

Glad to hear/read I'm not the only one seeing it that way: look for Plan B (and C etc.) while working on Plan A. Of course, my and probably most everyone's concern is the release into the ocean, certainly the easiest and cheapest for TEPCO.

I understand from discussions and links here that additional storage via containers and/or underground storage have been or are being considered, but how realistic is it that AREVA's cleaning and/or reuse of water for cooling (what I call Plan A) will suffice, especially in the typhoon season? (Sorry if this has been calculated and discussed here already and it slipped me by since ... well, me and numbers is a whole different disaster.)

So in lay(wo)man's terms, any educated guess from you knowledgeable people what the chances for success of the current Plan A are? Does anyone here know what TEPCO's plan is in case the contaminated water volume will exceed storage and/or cleaning capacity?

 

[Jorge Stolfi]

I still wonder at what point it makes sense to seal up the harbor entrance and declare it a giant storage/evaporation pond.

I believe that they plan to do that in fact. I saw a PDF somewhere, showing the temporary barriers thay have already set up and the plans for more permanent ones.

 

[radio_guy]

Answer: Human beings: Patents; Licenses; Agreements -- Summary: "Greed"

seems to be the way things go, and because of it we miss out on a lot of great advances.

I'm not saying it scales, I don't even think they know as they don't have any way to test it full scale, but if he's been developing similar things to clean up industrial pollution I would say he has a bit of credibility. I'm sure getting a plant to put to waste and large amounts of radioactive water isn't exactly an easy thing to obtain to prove a point..

from what I understand it's basically the same process Areva uses but it precipitates a lot, lot faster and that's why I suggested it could be tested out in their plant on site.

I am 100% convinced it comes down to patents, trade secrets, money, and exclusivity.


and to the other point, I don't see a whole lot of people jumping up and down screaming they have the gimmick to fix it all. I see someone who worked on similar things and modified a process to fit the extraordinary situation, and worked with a company to pitch the solution to the government, then disappeared from view apparently.

 

[jim hardy]

for a glimpse of what they could do with those fuzzy videos, check this video of a coal plant named Fukushima:

http://www.vision-systems.com/articles/2011/05/z-microsystems-image-processor-video-fukushima-power-plant.html

i still think there is considerable throttling of information.

 

[Bandit127]

http://www3.nhk.or.jp/daily/english/06_33.html

For the sake of clarity, a question and a curse.

Is the use of the term 'meltdown' used here to be considered a partial meltdown?

I understand this to mean the melting of fuel rods and the relocation of that melt within the reactor vessel. I understand that it does not necessarily mean that corium has formed (the fuel rods could have 'granulated') but that it could be the case.

I also think that it does not mean full meltdown, which I understand is the departure of corium from the reactor vessel to somewhere else - in this case the drywell.

My curse is that the term 'meltdown' is http://oxforddictionaries.com/definition/meltdown" and has been for years, but it has not been defined by the scientific community.

(Perhaps one of the legacies of Fukushima will include a reliable definition of the term and that people will learn it in journalism college).

 

[razzz]

http://ex-skf.blogspot.com/2011/06/arnie-gundersen-on-and-off.html" for a non-technical blogger does the best job of gathering together and translating some of the available information concerning the Fukushima disaster. His own mini-conclusions or comments are usually well founded.

As far 'Arnie' goes, the only defense I'll give him is that even he has a hard time comprehending the overwhelming events at Fukushima.

http://environment.about.com/od/nuclearenergywaste/a/Germany-To-Stop-Using-Nuclear-Energy.htm" is the only country regularly reporting fallout numbers (maybe a few others) and has drawn the conclusion to cease their nuclear energy production.

The workup on hydrogen explosion outputs report leads me to believe a (compression) shock-wave of that magnitude (Unit 3) is not a good thing to have traveling around or in your nuclear fuel possibly creating some sort of chain reaction.

 

[Jorge Stolfi]

NUCENG provided the following very informative post about the thermocouple temperature sensors used in nuclear reactors:

https://www.physicsforums.com/attachment.php?attachmentid=36115&d=1307050278

As Jim Hardy observed, thermocouples become useless if the two wires get connected by water, since the electrochemical (battery) effect will swamp the tiny thermoelectric signal. I woudl guess that the thermocouples used in reactors are encased in waterproof and insulating sleeves of some sort; is that so? But these may not have been designed for a "drywell" filled with very hot high-pressure steam...

Presumably that is the explanation for very low "temperatures" (down to -130 C or lower) recorded in the TEPCo datasheets.

 

[SteveElbows]

Is the use of the term 'meltdown' used here to be considered a partial meltdown?

I understand this to mean the melting of fuel rods and the relocation of that melt within the reactor vessel. I understand that it does not necessarily mean that corium has formed (the fuel rods could have 'granulated') but that it could be the case.

I also think that it does not mean full meltdown, which I understand is the departure of corium from the reactor vessel to somewhere else - in this case the drywell.

My experience during this crisis is that in the Japanese media, meltdown is indeed being used as a label for fuel melting, and in this context it does not tell us where the core has ended up at all.

As far as official estimates by government agencies and TEPCO, everything I've seen in english suggests that they don't like to talk about anything beyond the point of fuel melting and slumping in the bottom of the reactor vessel. They have not ruled out the possibility that some of the core has escaped the reactor vessel, because sometime a phrase along the lines of 'most of the fuel remains in the reactor vessel' has been used, and I have not seen anybody push them for estimates of what percentage of core might not be in reactor vessel anymore. Its quite possible that the analysis documents contain projections for how much of a variety of radioactive substances are believed tobe in the reactor vessel, the drywell, the suppression chamber, some of the graphs and tables look like they may be showing this, but as I can't read Japanese I am waiting a while before going on about this stuff in detail.

Personally although I have expressed skepticism with people who are convinced that core has left reactor in one or more cases, because I don't see concrete evidence of this, I don't rule it out either. And frankly most of the official analysis to date does not add enough to make me more certain one way or the other.

Likewise I certainly don't assume that the core melting & containment damage time estimates that TEPCO and now government agency have published match the reality. Their analysis may end up being close to the reality but it may not, as best I can tell its based on simulations and the bits of real data they have, and certain assumptions are bound to have been made either in terms of the data fed in or the model the software uses. Leaving aside the track record of TEPCO which may make us cynical, I cannot actually judge which of the 2 simulations, with their quite different time estimates for when various things happened, is closest to the truth. At some point I will compare the real data we have with the government analysis to see if it seems to fit better than the TEPCO one does, but I don't necessarily expect to gain too much from this exercise, in great part due to missing temperature data over a crucial time period in the early days.

 

[SteveElbows]

for a glimpse of what they could do with those fuzzy videos, check this video of a coal plant named Fukushima:

http://www.vision-systems.com/articles/2011/05/z-microsystems-image-processor-video-fukushima-power-plant.html

i still think there is considerable throttling of information.

Well as the article mentions, this tech is apparently already used by the long range TV camera feed.

Really I think its trying to solve some very different issues to those that the TEPCO on-site feed has. Its trying to overcome issues caused by vast distance. Most of the TEPCO cam quality issues are due to their compression & streaming setup, either because its just not great equipment, not setup very well or because they are dealing with bandwidth issues, eg trying to keep the server load down to a certain rate.

I've little doubt that it could be improved a fair bit, either by tweaking settings, or investing in a different server setup that has more grunt. There are also things that could be done with exactly what the camera is looking at that may help. For example the large portion of detailed green plants that we see shifting in the breeze are taking up a fair percentage of the available bandwidth, and its a waste.

There are also some issues with how things look at night, which is a typical issue with video and photography and may or may not be trivial to improve.

I don't think the feed quality is a significant part of a deliberate ploy to keep us ill-informed. I am sure their natural corporate instincts would not involve giving us a brilliant window into everything that happens there in realtime, and I doubt they are too dedicated to bringing us the best possible images from site. But compared to other coverups, and things that would make a bigger difference such as exactly where the camera(s) are sited and what can really be seen, the image quality doesn't seem like a difference maker.

Put it this way, there have been very few events that were happening at any point in a visible way on the live camera, that have made me cry out for better resolution & detail. Sure Id like that detail, but I can't actually think of a worthy event that I would actually have learned anything more about if the camera had been better quality. Mostly nothing is happening, sometimes we may see the arm of some equipment moving around, sometimes we will see clouds emerging from one or more reactor or fuel pools. I don't really feel like I am missing much by not seeing these things in better quality.

What would make a difference to me is camera shots from other vantage points, where I may actually get to see some of the day to day work being carried out, or more photo footage of the reactor buildings in higher detail. They probably don't want to do that for a number of reasons. In the grand scheme of things this does not bother me all that much, making sure we get to learn of things in a timely and detailed manner is far more important.

 

[Bioengineer01]

New Video from Arnie Gundersen about the evacuation zone size and how it was calculated for US nuclear power plants

http://www.youtube.com/watch?v=bB2mrr5pyrU&feature=player_embedded#at=18

 

[clancy688]

New Video from Arnie Gundersen about the evacuation zone size and how it was calculated for US nuclear power plants

http://www.youtube.com/watch?v=bB2mrr5pyrU&feature=player_embedded#at=18

"According to the nuclear regulatory commission, parents WON'T drive to school to rescue their kids. They'll drive away from the nuclear accident and wait for the school buses to come to them."

Riiiiiight... what planet are these guys coming from?

 

[radio_guy]

"According to the nuclear regulatory commission, parents WON'T drive to school to rescue their kids. They'll drive away from the nuclear accident and wait for the school buses to come to them."

Riiiiiight... what planet are these guys coming from?

Personally I would be driving through whatever I needed to to get to that school.. lawns other cars etc. and I'm pretty sure most parents would be the same way. guess it makes me feel a little better I live almost 40mi from the nearest N-plant.

edit: I also noticed the local plants are no longer blurred out in google maps satelite view, the 2 northern ohio plants used to just show up as a large blurry area of nothing.. wonder when that changed?

 

[MadderDoc]

For what it's worth, here is my effort at a quick translation of the online version. I'm not fluent, and my major is in media studies rather than atomic physics. So with those caveats:

Reactor number 3's explosion was a "detonation" <..>​

Thank you very much indeed for the translation, and I am sure you made a fine job of it.

OK, the analysis appears to be based from just a few, and not very controversial observations:
a) the apparent larger severity of the unit 3 event relative to the unit 1 event,
b) the shorter period unit 1 had before the event to produce hydrogen, and
c) the lower number of fuel rods in unit 1.

The analysis appears to attempt to explain a), solely based on b) and c), and for that purpose it makes the further assumption that unit 3 could have produced 540 kg hydrogen, while unit 1 -- due to b) and c) -- could have produced only half as much, 270 kg.

These assumed amounts of hydrogen would have been sufficient to produce a 30% hydrogen atmosphere at the service floor of unit 3, while only 15 % hydrogen at unit 1. Since unit 1 according to this figure wouldn't trespass a >18% hydrogen 'magical limit' for detonation, the combustion at unit 1 could have been nothing more powerful than a deflagration. Whereas -- in unit 3 -- it could have been a detonation. The analysis appears to conclude that this was indeed the case.
From this conclusion it follows rather effortlessly, that the combustion of the hydrogen in unit 1 could have lasted several seconds, while in unit 3 it could have taken at most 0.02 seconds. The observation that the steel frame (sic) of unit 3 has been warped and distorted is noted as support for a relatively high severity event at unit 3, and conversely, the existence of rubble close to unit 1 is cited as support for the relatively low severity of the unit 1 event.

Ahem. If the author had posted his analysis to this thread for review, I think someone here cruelly would have demolished it.

 

[MiceAndMen]

Interesting bullet point on re-criticality on second link:
"Recriticality
If there water in the lower head, recriticality due to U235 cannot be
excluded.
Rule-of-thumb: If there is no water, recriticality can be excluded if
Uranium enrichment is below 5%
The amount of Pu239 is more than enough for recriticality but this would
require local Pu accumulation, which has not yet been investigated."

Lots of good information in those presentations. I just noticed I should have said, "... 31 years after TMI2 ...", not 25. Must have been thinking about Chernobyl.

 

[Bioengineer01]

Thank you very much indeed for the translation, and I am sure you made a fine job of it.

OK, the analysis appears to be based from just a few, and not very controversial observations:
a) the apparent larger severity of the unit 3 event relative to the unit 1 event,
b) the shorter period unit 1 had before the event to produce hydrogen, and
c) the lower number of fuel rods in unit 1.

The analysis appears to attempt to explain a), solely based on b) and c), and for that purpose it makes the further assumption that unit 3 could have produced 540 kg hydrogen, while unit 1 -- due to b) and c) -- could have produced only half as much, 270 kg.

These assumed amounts of hydrogen would have been sufficient to produce a 30% hydrogen atmosphere at the service floor of unit 3, while only 15 % hydrogen at unit 1. Since unit 1 according to this figure wouldn't trespass a >18% hydrogen 'magical limit' for detonation, the combustion at unit 1 could have been nothing more powerful than a deflagration. Whereas -- in unit 3 -- it could have been a detonation. The analysis appears to conclude that this was indeed the case.
From this conclusion it follows rather effortlessly, that the combustion of the hydrogen in unit 1 could have lasted several seconds, while in unit 3 it could have taken at most 0.02 seconds. The observation that the steel frame (sic) of unit 3 has been warped and distorted is noted as support for a relatively high severity event at unit 3, and conversely, the existence of rubble close to unit 1 is cited as support for the relatively low severity of the unit 1 event.

Ahem. If the author had posted his analysis to this thread for review, I think someone here cruelly would have demolished it.

Am I the only Engineer that sees a two stage explosion on Unit 3? Stage 1: the detonation that creates the flash to the right and then, afterwards Stage 2: the upside going explosion that behaves very similarly to a nuclear detonation, and may be was...
Just loop the video in the link around the explosion and observe the two clear stages of it.

http://www.youtube.com/watch?v=7naSc81WSqA&feature=related

 

[Quim]

Your graph extends to 10 days. here's data for one year :
http://mitnse.com/2011/03/16/what-is-decay-heat/

The report you provide could be seen as supporting the numbers etudiant used as the base for his calculations: (4mw for unit 1 and 6mw for 1&3) however the report comes with this caveat:

*Values for the decay heat were calculated based on assuming an infinite reactor operation time prior to shutdown. Infinite operation is a conservative assumption, and actual values may be significantly lower than those that are shown in the figure and table.


So while in a real world situation, with no fuel damage, it appears that the 4mw and 6mw numbers are higher than what would be actually experienced we also need to factor in the point raised by Jorge Stolfi in post #9044.

once the fuel is completely molten, the radioactive elements that remain in the liquid corium will produce 30% of the decay heat power that would be produced by the intact fuel; the other 70% of the decay heat power is due to more volatile elements that will end up elsewhere.


So it appears that Fukushima is currently experiencing a residual heat in unit 1 of 30% of a number which is lower (maybe very much so) than the 4 mw number.

So the heat remaining in unit 1's containment is probably considerably lower than the residual heat in SFP4 on the day of the accident.

There may be reasons why pouring sand (or whatever) on the remainder of the cores is unworkable, but too much residual heat is not likely one of them.

However, if they continue pouring water on the corium the Japanese are certain to win the gold.
Re: #9020 swl "Another year of contaminated steam, then add in the water leaks, and we should be well on our way to that elusive #1 spot (of all time accidents)."

 

[MiceAndMen]

So in lay(wo)man's terms, any educated guess from you knowledgeable people what the chances for success of the current Plan A are? Does anyone here know what TEPCO's plan is in case the contaminated water volume will exceed storage and/or cleaning capacity?

My impression is that they initially underestimated the amount of contaminated water storage that would be necessary, possibly by an order of magnitude. They have already abandoned Plan A and moved on to Plan B.

 

[Bodge]

Evidence of recriticality in reactor 1?

I noticed the increase in I-131 detection on the CTBTO chart matched up with the "erroneous" recordings of radiation spikes in reactor 1's drywell:

http://www.bfs.de/de/ion/imis/ctbto_aktivitaetskonzentrationen_jod.gif
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/out/plot-un1-t-T-full.png

edit: Just noticed at http://ex-skf.blogspot.com/2011/06/arnie-gundersen-on-and-off.html" commenters claim that the CTBTO Iodine spikes match up with increased temps at reactor 3's RPV flange.

Somebody needs to properly correlate the relevant data.