Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[zapperzero]

1. Does anyone know if the plutonium powder is bound into solid metal during the sintering process? 2. Did any of the spent fuel pool contain plutonium enriched rods ready to be loaded? and 3. If so, is this a danger if the #3 spent fuel blew up rather than the reactor?

Again, pardon my ignorance if this has already been discussed thoroughly.

It has indeed. Read, man, read!
1. http://tinyurl.com/3eh3rku
2. No. Also, see http://tinyurl.com/4xwp93t
3. Blew up, as in went prompt critical?

 

[rowmag]

I think you are referring to page 1 of this:

https://www.physicsforums.com/newreply.php?do=newreply&p=3310549

That caught my eye at first too, but then I looked at the following:

http://www.tepco.co.jp/nu/fukushima-np/plant-data/f1_2_Chart3.pdf

If you look at pages 3 and 4, you can see what looks like the same
behavior being recorded by a different sensor (?) on a paper strip
chart that has been scanned in. There are two scales at the bottom,
which differ in both offset and scale factor:

原子炉水位 (広帯域) [mm] = Reactor water level (wideband) [mm]
and
原子炉水位 (燃料域) [mm] = Reactor water level (fuel region) [mm]
[...]

My comment was based on the first page of:
http://www.tepco.co.jp/nu/fukushima-np/plant-data/f1_6_Katogensho3.pdf

Oops, cut-and-paste error on my part. That was the link I meant to refer at the beginning of my post.

Thanks for information. And thanks MiceAndMen for the Rosetta Stone, from which we can conclude that "(N/R)" means "Narrow Range" and "(W/R)" means "Wide Range" on page 1 of these plots:

http://www.tepco.co.jp/nu/fukushima-np/plant-data/f1_6_Katogensho3.pdf

And that Wide Range and Fuel Zone Range are what are indicated on pages 3 and 4 of these plots:

http://www.tepco.co.jp/nu/fukushima-np/plant-data/f1_2_Chart3.pdf

 

[mscharisma]

... 2. Did any of the spent fuel pool contain plutonium enriched rods ready to be loaded? ...

The attached document claims on page 4 there were new fuel rods in the spent fuel pool of #3 as well but, unless I overlooked something, does not address plutonium enrichment.

Edit: sorry, can't get upload to work. Please see attachment to post # 7552.

 

[tsutsuji]

http://www.tokyo-np.co.jp/article/national/news/CK2011052002000194.html?ref=rank includes a diagram showing the inlet canal repairs being planned. That part needing repair was damaged by the tsunami.

Together with the planned works to contain water leaks around buildings, this will provide a two-fold containment of the water leaks.

They say that the upcoming rainy season (the so-called "tsuyu" rain falling in June and July : see http://www.japan-guide.com/e/e2277.html) is also a worry, but my feeling is that these works will take time, so that the rainy season might be over when the works are finished.

 

[Ms Music]

So, many here have jumped on me about my theory that the explosion of #3 came from the reactor containment. Some argued that is not possible,

You must be confusing this forum with another. Most here, including one of the nuclear experts (Astronuc), agrees that it appears the explosion may have originated in the containment area.

Where we don't agree with you is when you insist the pressure vessel squirted out like a hotdog, somehow managed its way around the overhead crane support (whatever it is called), up through your hole in the roof, and then vanished.

 

[zapperzero]

http://www.tokyo-np.co.jp/article/national/news/CK2011052002000194.html?ref=rank
Together with the planned works to contain water leaks around buildings, this will provide a two-fold containment of the water leaks.

I wonder what happens if they manage to plug the leaks and the water reaches ground level inside the reactor buildings because they aren't pumping it out fast enough. I don't see them establishing loop cooling. Not while they have no idea which RPVs are leaking and how.

 

[SteveElbows]

The live video feed seems to be showing the Megafloat making its journey to the nuclear plant at the moment.

 

[zapperzero]

The live video feed seems to be showing the Megafloat making its journey to the nuclear plant at the moment.

Pics or it didn't happen.
EDIT: It's there allright. Pea soup also. :P

 

[imandylite]

[PLAIN]http://img17.imageshack.us/img17/8203/megafloat.jpg

Megafloat in process

from the livefeed

http://www.youtube.com/user/tbsnewsi?feature=feedlss#p/l/-ZPYlazljME"

 

[etudiant]

The live video feed seems to be showing the Megafloat making its journey to the nuclear plant at the moment.

With 10,000 ton capacity, versus about 100,000 tons of highly radioactive water currently in the plant, increasing by 500 plus tons/day, we can only hope TEPCO has more Megafloats on order.
Afaik, the water treatment plant from Areva will sharply reduce the radioactivity of the treated water, but it will still be 1000-10,000 times the prior limit for ocean discharge. So the site will need a huge amount of storage until TEPCO figures out how to clean the water further, or the government will have to waive the rules.
Given the level of outflow to date, that would probably add little incremental contamination.

 

[Gary7]

You are incorrect.

I fully understand and have never disputed the article's byline. I do not know the exact time it was published. Let us assume you are correct, and that it was published at 11:15pm on the 13th (EST). This means the article was published at Japan time of 1:14pm on the 14th. This was just two hours after Unit #3 exploded.

The assertion that a helicopter flew from Daiichi to the USS Ronald Reagan, and that the ship took evasive action for two hours (as quoted by the crew member), and that this information was released in time for the New York Times to publish the article two hours after the explosion, is, frankly, quite hard to believe. Then, when the AP reported all of this happening on Sunday the 13th "two days after the earthquake", we have to believe they really mean it all happened on Monday the 14th (three days after the earthquake), but that they are converting a portion of the time for the benefit of readers in the US (and to the confusion of readers everywhere else in the world).

Furthermore, we would have to believe the NYT actually referenced a press release posted earlier by the Pacific Fleet, despite no such reference being made. Bear in mind if the NYT actually did reference the Pacific Fleet's press announcement, it means the Pacific Fleet had even less than two hours to produce this announcement.

I have no personal interest in deleting anyone's posts; they all stand or sink on their own merits. I do not believe the movings of the USS Ronald Reagan are particularly germaine to the meltdown(s). I suppose I would also say that I am somewhat disappointed that the very high standards of discussion on this forum have been slightly compromised by the continued musings of a certain conspiracy theorist, but this is a personal opinion.

 

[Atomfritz]

With 10,000 ton capacity, versus about 100,000 tons of highly radioactive water currently in the plant, increasing by 500 plus tons/day, we can only hope TEPCO has more Megafloats on order.
Afaik, the water treatment plant from Areva will sharply reduce the radioactivity of the treated water, but it will still be 1000-10,000 times the prior limit for ocean discharge. So the site will need a huge amount of storage until TEPCO figures out how to clean the water further, or the government will have to waive the rules.
Given the level of outflow to date, that would probably add little incremental contamination.

Maybe the megafloat's purpose is just to take up 10k tons of water, being pulled out to the ocean, then emptied, towed back and so on?

In case of storage tank capacity problems Tepco would probably be happy to be "forced" to get rid of the lesser radiocative waters in the ocean, somewhat distant to the coast, to make room for new highly contaminated effluents.

I hope I am wrong...

 

[Luca Bevil]

Maybe the megafloat's purpose is just to take up 10k tons of water, being pulled out to the ocean, then emptied, towed back and so on?

In case of storage tank capacity problems Tepco would probably be happy to be "forced" to get rid of the lesser radiocative waters in the ocean, somewhat distant to the coast, to make room for new highly contaminated effluents.

I hope I am wrong...

That would not b epoliticaly acceptable.

I remember watching Arnie Gundersen say that a decontamination on such a scale (as per amount of water processed, I think) has never been attempted before.

Does anyone have any idea about what tha capabilities of the AREVA plant could be ?

Both in terms of hourly flow treated and performance in contamination removal ?

 

[Atomfritz]

5 Tons of Seawater Has Entered Hamaoka N-Plant Reactor Core

Nagoya, May 19 (Jiji Press)--Chubu Electric Power Co. <9502> officials said Thursday about 5 tons of seawater is estimated to have entered a reactor core at the company's Hamaoka nuclear power plant in central Japan.
During work to shut down the No. 5 reactor in accordance with a government request, Chubu Electric found an estimated 400 tons of seawater has flooded into the main steam condenser.
In addition, the firm's assessment of the purity of water inside the reactor's pressure vessel, which contains nuclear fuel, showed some 5 tons of seawater came from the condenser, the officials said.
Water that circulates through the vessel should not be salty but fresh, because salt causes corrosion.
The steam condenser, designed to convert waste steam from a power-generation turbine into water, has some 64,000 tubes, each 3 centimeters in diameter, in which seawater is injected to cool the steam. Normally, the steam-converted pure water never has direct contact with the seawater running through the tubes, the officials said.

(2011/05/19-18:46)

http://jen.jiji.com/jc/eng?g=eco&k=2011051900816

This is strange.
Wasn't the plant shut down on government request?

I am no expert, but i think this should have been detected by the water purity systems?!?
In the Soviet Union it was regular to have reactors shut down to weld damaged condenser pipes when leaks were developing.

Maybe they are running their plants even if seawater is leaking in, to avoid even more electric shortages?

(I think small leaks, leading to only trace impurities that can be remedied by water purity systems could be unproblematic, and be repaired at the next scheduled refuelling outage. But I may be wrong)

Hope some nuclear expert can comment on the things happened in Hamaoka.

Does anyone have any idea about what tha capabilities of the AREVA plant could be ?

Both in terms of hourly flow treated and performance in contamination removal ?

I remember a number about 3.5 cubic meters a day, but I am not sure if it was data from this decontamination plant or another one. I think I read it in a powerpoint presentation.

 

[etudiant]

The Areva plant was listed as having a 1200 ton/day capacity, reducing the radioactivity of the processed water by up to 99.99%, Presumably this means that if the incoming water is contaminated to 1 million times the allowable level, it will deliver output at about 100 to 1000 times the allowed amount.

Afaik, the plant works by precipitating out the contaminants, rather than by absorption or filtering, so there will be a quantity of radioactive residue to be managed.
Japan is also getting a shipboard waste water treatment they built for the Russians back from them,
but this has only 7000 tons/yr capacity and is designed to handle low level contaminated liquid.

 

[Luca Bevil]

The Areva plant was listed as having a 1200 ton/day capacity, reducing the radioactivity of the processed water by up to 99.99%, Presumably this means that if the incoming water is contaminated to 1 million times the allowable level, it will deliver output at about 100 to 1000 times the allowed amount.

Afaik, the plant works by precipitating out the contaminants, rather than by absorption or filtering, so there will be a quantity of radioactive residue to be managed.
Japan is also getting a shipboard waste water treatment they built for the Russians back from them,
but this has only 7000 tons/yr capacity and is designed to handle low level contaminated liquid.

Thanks.

i found some more info at
http://rapidsavr.com/french-plan-to-clean-fukushimas-radioactive-water-detailed-including-risks/

 

[zapperzero]

Wasn't the plant shut down on government request?

I am no expert, but i think this should have been detected by the water purity systems?!?
Maybe they are running their plants even if seawater is leaking in, to avoid even more electric shortages?

I am no expert either, but: it has been detected by water purity checking. They were not "running the plant" - i.e. they were no longer producing electricity, but the fuel in the reactor still needed (and indeed still needs) cooling.

 

[tc399]

I am no expert either, but: it has been detected by water purity checking. They were not "running the plant" - i.e. they were no longer producing electricity, but the fuel in the reactor still needed (and indeed still needs) cooling.

I might have a bit of expertise in this incident. The three reactors SCRAMMED automatically during the earthquake. At least one containment and probably all three were breached before the tsunami hit. A high-radiation warning sounded on the plant perimeter before the tsunami arrived.

tergeist.wordpress.com and Hawaii News Daily since March 17.

 

[zapperzero]

I might have a bit of expertise in this incident.
tergeist.wordpress.com and Hawaii News Daily since March 17.

You might, but we were talking about an incident during shutdown at a different NPP - Hamaoka.

EDIT: here's a picture, via the invaluable ex-skf blog:
http://3.bp.blogspot.com/-Pk9ESR44uSc/Tdak3oG09PI/AAAAAAAABq4/u9wx-PJk5_U/s1600/hamaoka5.JPG

 

[htf]

This is strange.
Wasn't the plant shut down on government request?

I think there is more behind this story. It is not only fear of a future earthquake that triggered the government to have the NPP shut down. Not now as they are already short of electric power and the economy is on its way into a recession.

400to of sea water is a lot. How can this happen? There must be heavy leaks. In addition since they also found sea water in the reactor core also the primary cooling system must be leaking. So, what does this tell you about the NPP's condition?

 

[turi]

Regarding Hamaoka:
Starting at
https://www.physicsforums.com/showthread.php?t=480200&page=466
posts 7454, 7464 and others have some interesting insights.

 

[zapperzero]

So, what does this tell you about the NPP's condition?

Well, it tells me that it is maintaining cold shutdown using emergency systems only, until the condenser is repaired. Correct?

 

[tsutsuji]

Tepco released details about the contaminated water leak discovered at a pit near unit 3's seawater inlet on May 11th

The leak started on May 10th, lasted 41 hours, leaking a total amount of 250 cubic meters and 20 trillion becquerels of radiations, worth 100 years of allowed sea discharge.

A total of 27 such pits are planned to be filled with concrete by the end of June to prevent such leaks to occur again.

http://mainichi.jp/select/weathernews/news/20110521dde007040024000c.html
(edited per

I think the amount is 20兆 which is 20 trillion becquerels.

thanks)

 

[htf]

Well, it tells me that it is maintaining cold shutdown using emergency systems only, until the condenser is repaired. Correct?

Technically correct. Nothing to worry about. It is quite normal for Japanese NPPs to have severe damages that are only discovered by chance. Same maintenance policy as African truckers: as long as the wheels are turning, there is no need to fix things?!

 

[tsutsuji]

More on Hamaoka :

a metal lid measuring about 20 cm in diameter and weighing around 3.5 kilograms was found to have fallen nearby.

Chubu Electric suspects the metal lid may have hit the pipes when it fell and is examining other pipes in the condenser.
http://mdn.mainichi.jp/mdnnews/news/20110521p2g00m0dm005000c.html

 

[yakiniku]

The leak started on May 10th, lasted 41 hours, leaking a total amount of 250 cubic meters and 2 billion Becquerels of radiations, worth 100 years of allowed sea discharge.

I think the amount is 20兆 which is 20 trillion becquerels.

 

[ernal_student]

I think the amount is 20兆 which is 20 trillion becquerels.

British (and European continental) billions, American trillions...

 

[zapperzero]

British (and European continental) billions, American trillions...

Why not just use exponent notation like NORMAL PEOPLE and be done with it.

 

[yakiniku]

British (and European continental) billions, American trillions...

Haha, ok shall we use 'tera' so there is no ambiguitity?

 

[ernal_student]

Why not just use exponent notation like NORMAL PEOPLE and be done with it.

Indeed. Although Japanese 兆 is perfectly clear, the problem is English where anything larger than hundreds of millions should really be expressed using exponents to avoid this kind of confusion.

 

[Astronuc]

In my opinion . . . .

First, we acknowledge that in both the reactor and the spent fuel has plutonium in it. The plutonium comes from two sources: First it comes as a by product of the fission reaction in the reactor. I don't think that plutonium is a great risk, because the molecules are interspersed in the rod fuel. In a complete catastrophic explosion, it would not travel far from the reactor.

Pu is produced by n-capture and successive beta decay according to U238 + n => U-239 (ß-decay) => Np-239 (ß-decay) => Pu239. Higher isotopes of Pu are formed similarly by n-capture in U or Np and subsequent beta, or n-capture in Pu 239, Pu 240, Pu 241. Pu-239 and Pu-241 are more likely to fission. Pu is chemically dispersed in the ceramic matrix since it simply is a U atom transformed into Pu in a UO₂ matrix, but there can be complex oxide compounds formed with other fission products, such as Cs₂(U,Pu)O₄.
This is useful - http://nobelprize.org/educational/physics/energy/fission_2.html

The second source of plutonium is the mixing of finely ground (nanometer) plutonium powder with the uranium in the new fuel rods that were placed into the #3 reactor in August. Alternatively known as MOX fuel, they mix between 6% and 15% plutonium powder in. I believe the Fukushima rods were somewhere in the lower half of this range.

Not quite. The Pu and U are in the form of a stoichiometric oxide, PuO₂ and UO₂, which is usually a mechanical blend, or could have been formed from a co-precipitation process. If the Fukushima fuel is nominally 4% enriched in U-235, then the Pu would be about 5-6% Pu - give or take - to match the nuclear characteristics of the UO₂ fuel.

During manufacture, the powder is "sintered" into pellets. What is unclear in everything I have read is whether the sintering melts the powder into solid metal pellets, or whether it simply binds the material into a pellet, but the powder still remains on the inside. Given my knowledge of powder metallurgy it takes a lot of heat and pressure to render powder into solid metal, and I suspect they would not subject the plutonium to enough to completely bind it, for fear of a reaction during manufacturing.

U and Pu are sintered ceramics, not metals. The cold-pressed green ceramic is about 50-55% TD, and is sintered at about 1700-1800C in a reducing environment. PM processes such as HIP do not apply here.

Once the rods are brought to operating temperature in the reactor core, my guess is they reach a high enough temperature to bind the powder completely. I haven't found anything specific on this topic, . . .

The ceramic is a manufactured in solid cylindrical pellet form.

However there exists the possibility that new plutonium enriched rods were waiting in the spent fuel pools to be loaded. If my analysis above is correct, these rods would not have their plutonium bound yet, and in the case of an explosion, the nanometer powder could be released.

According to available records, the 32 MOX assemblies were loaded into the core and were operating. Otherwise fresh fuel was UO₂. Spent fuel contains Pu mixed in the pellets. If the spent fuel pool 'exploded', there would be a significant release of radioactive material. The status of the fuel in the pool is not clear given the large amount of debris that has fallen into the pool. It does not appear to have 'exploded'.

I guess this is more of a set of questions for discussion rather than a statement. My question would be this: 1. Does anyone know if the plutonium powder is bound into solid metal during the sintering process? 2. Did any of the spent fuel pool contain plutonium enriched rods ready to be loaded? and 3. If so, is this a danger if the #3 spent fuel blew up rather than the reactor?

Pu in the fuel is in a form of (U,Pu)O₂ ceramic. The fresh fuel appears to be UO₂. The SFP of unit 3 appears to be intact, although there may have been some damage, and some of the spent fuel could be damaged. That has yet to be determined. Fresh fuel has no fission products, so no decay heat from fission products.

The spent fuel pool of Unit #4 would have been more at risk for loss of cooling since the full core had been offloaded. The SFPs of units 1,2,3 had some fresh fuel and several batches of discharged fuel. One batch would have been discharged last year, one batch the year before, and so on. The older the fuel, the less the decay heat.

The explosions in Units 1 and 3 were attributed to hydrogen from the reactor. That hydrogen is expected to be from oxidation of the zirconium alloy cladding and channels in the core, as has been explained very early in this thread. In unit 4, it was thought that hydrogen was produced in the SFP for oxidation of the cladding/channels. The video of the fuel in SFP#4 seems to show that the fuel is largely intact, but the cladding/channels could have oxidized and produced hydrogen. Some quantity (presently unknown) of fuel rods could have been breached, in which case they would have released Xe, Kr, I and possibly Cs if the fuel temperature was high enough. TEPCO will have to retrieve/lift some assemblies and inspect them for integrity.

The fuel in the cores of Units 1,2,3 were at greater risk of overheating since they have been operating at time of the earthquake, and were generating significant decay heat when cooling was lost.

 

[tsutsuji]

The sentence where this appears could also mean something like "... TEPCO performed water leak countermeasures at a different building" - which, from what is written before that, could mean that the current facility is overburdened and they need to prepare another place.

I found the names of the buildings where they moved the contaminated water at http://news.tbs.co.jp/newseye/tbs_newseye4730375.html :

The contaminated water from unit 2 is being moved to プロセス主建屋 (process main building)

The contaminated water from unit 3 is being moved to 雑固体廃棄物減容処理建屋 (miscellaneous solid waste volume reduction treatment building)

If you have good eyes you can locate 雑固体廃棄物減容処理建屋 close to the lower right corner of the map at http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/f1-sv-20110323-e.pdf

They say that with a pace of 10 cubic metres per hour, the process main building will be full within 7 days and the solid waste reduction treatment building within 11 days.

So they're hoping the water treatment facility (is that the Areva plant ?) will start running from the second decade of June, early enough for the tsuyu rain.

The water levels in mm in both destination buildings (together with the difference over the last 24 hours) are provided at the top of http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110519_03-e.pdf (dated May 19th)

Some details were provided in the following attachments to a http://www.tepco.co.jp/en/press/corp-com/release/11051603-e.html :

Criterion : up to the floor level in the first basement of the buildings. However...
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/1110516e2.pdf (pdf)

Transfer plan : http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/1110516e3.pdf

See also

On May 17th we finished a leak check on transferring pipes and sta[r]ted to transfer at 06:04 PM (approx. 12 m^3/h)

p 7/19 http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110521e1.pdf

 

[maddog1964]

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

I must of missed it, could you please direct me to the information on RCIC being powered by steam and the "supply source of the steam" if known?
thanks

 

[intric8]

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.

 

[Calvadosser]

That would not b epoliticaly acceptable.

I remember watching Arnie Gundersen say that a decontamination on such a scale (as per amount of water processed, I think) has never been attempted before.

Does anyone have any idea about what tha capabilities of the AREVA plant could be ?

Both in terms of hourly flow treated and performance in contamination removal ?

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.