Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[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.

 

[MiceAndMen]

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).

Do schools still teach journalism? Coulda fooled me. Anyway... the term "meltdown" has no precise meaning, so any and all of your interpretations can be considered correct. In my mind I always associated "melted fuel rods = meltdown" without regard for where the molten core or debris bed relocated to. Maybe there will be new terms introduced to differentiate between melted fuel still in the RPV vs. out of the RPV vs. attacking concrete foundation vs. in the earth. The Eskimos, after all, have more than 1 word for snow. We'll probably end up with a few new acronyms, although once the fuel is out of the RPV it becomes a guessing game as to where it is and what state it's in.

 

[etudiant]

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)."

Useful insight, thank you.
It seems logical that the heat generated in the fuel would be less if a lot of the more active volatiles were washed away.
That also means that the amount of steam produced should similarly be less, with less contamination because the volatiles will have been dispersed through the body of lake Fukushima rather that being boiled out of the fuel residual.
Maybe TEPCO could reduce the water injections further, although it is murky whether any water is reaching the residual fuel or whether that fuel is shielded by a deep crust of salt.

 

[mscharisma]

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.

Sorry for my ignorance, but what is Plan B in that case? I don't recall seeing or hearing anything other than to continue cooling, add storage capacity for water, and hope that AREVA can clean up as much as possible. What did I miss?

 

[Atomfritz]

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.

These oscillations are indeed strange.
Remember, even Oklo was an oscillating reactor.
Does there exist any other explanation?
Maybe oscillations caused by water flow or such?

 

[MiceAndMen]

"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?

Does he have a cite for that? I seem to recall that during the Shoreham fiasco in New York local authorities claimed that (a) the roads during an evacuation would be clogged due (in part) to parents going to get their kids, and (b) school bus drivers would be AWOL anyway, having gone to look after their own families. I can't believe the NRC just arbitrarily claimed something else. In fact, now that I think about it, the NRC is concerned only with actual radiation releases and does not overly concern themselves with the details of accident response. Outside of seeing that there is some evacuation plan in place, those plans are outside of the NRC's purpose and scope of responsibility.

I'd really like to see him back that claim up, but if I had a nickle for every time I thought that about Gundersen I'd be rich.

 

[elektrownik]

Anyone know what is condition of unit 5&6 ? There is much data for 1,2,3, but not for 5&6, did they enter reactor hall ? RPVs were open because of refueling, so they should be able to make visual inspection of fuel, do we have raw data (like for unit 1,2,3) after earthquake and tsunami ? From simple data we can see that unit 5 was at 150-200C from tsunami time to 3/20 and unit 6 in the same time ~150C, but unit 5&6 were at atmospheric pressure, so there should be much steam, so what about contamination ? And fuel damage is possible ?
what about water level after blackout ?
simple temp data for unit 5&6: http://www.tepco.co.jp/nu/fukushima-np/f1/images/11051612_temp_data_56u-j.pdf

 

[MiceAndMen]

Sorry for my ignorance, but what is Plan B in that case? I don't recall seeing or hearing anything other than to continue cooling, add storage capacity for water, and hope that AREVA can clean up as much as possible. What did I miss?

http://search.japantimes.co.jp/cgi-bin/nn20110513x2.html

That took me about 1 minute to find with Google.

 

[dh87]

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 potential of the original fuel.

I can't find the slides that you refer to. Could you or someone provide a link? Thanks.

The residual material isn't volatile and isn't soluble in water. The only way it can be distributed is as dust in an explosion. It could be quite hazardous, but it's not very mobile.

 

[NUCENG]

These oscillations are indeed strange.
Remember, even Oklo was an oscillating reactor.
Does there exist any other explanation?
Maybe oscillations caused by water flow or such?

Questions:

1. Where is the Japan CTBTO sensor? Are the peaks in CTBTO data correlated with wind direction to the sensor from the Fukushima site?

2. Have the peaks been checked for increases in other short half life isotopes?

3. If the peaks are due to short recriticalities shouldn't the increase be followed by an exponential decay from the new peak? It looks like they drop right back to the decay trend that was in place before the short peaks.

4. Shouldn't the Unit 1 drywell radiation detectors show some time delay to the CTBTO sensor unless that sensor is on site.

 

[MiceAndMen]

I can't find the slides that you refer to. Could you or someone provide a link? Thanks.

https://www.physicsforums.com/showthread.php?p=3340995#post3340995

 

[jim hardy]

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

You are not the only person who noticed the event appeared to occur in two stages.
I saw it on TV that morning and have been obsessive about it since.


I can niether rule out nor prove that it may have had some help from neutrons.

There exists a group called "American Nuclear Society , Nuclear Criticality Safety Division" whom one would expect to have analyzed and reassured us by now. The silence is deafening.

One thing Arnie did get right - where information is concerned ranks are closed.

TPTB are avoiding the subject.


satellite 3 minutes after explosion:

http://www.satimagingcorp.com/galleryimages/worldview-2-fukushima-daiichi.jpg

 

[mscharisma]

http://search.japantimes.co.jp/cgi-bin/nn20110513x2.html

That took me about 1 minute to find with Google.

Thanks for the link although the page currently doesn't load due to "congestion." I could certainly have looked for it myself, but I don't know what you were referring to when you said TEPCO had a Plan B, so obviously I don't know what to search for.

Edit: Page now loaded and I think you may have misunderstood me. What's described in the article in my mind IS Plan A. My question is/was, what if they end up with more water than can be stored/decontaminated/recirculated, then what's Plan B?

 

[Bioengineer01]

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.

They don't correlate, I plotted the temperature data for Unit 3 until the 20th

 

[robinson]

http://www.satimagingcorp.com/galleryimages/worldview-2-fukushima-daiichi.jpg

I still want to know what is in the steam (and occasional smoke) that has been coming out from two locations in what used to be reactor building number three. For almost three months now.

It can't possibly be that nobody can measure this.

I'm especially interested in what looks like a huge tea kettle spout in the middle of the building.

 

[jim hardy]

http://www.satimagingcorp.com/galleryimages/worldview-2-fukushima-daiichi.jpg

I still want to know what is in the steam (and occasional smoke) that has been coming out from two locations in what used to be reactor building number three. For almost three months now.

It can't possibly be that nobody can measure this.

I'm especially interested in what looks like a huge tea kettle spout in the middle of the building.

Teakettle spout? mark up a photo ... are you speaking of this?