Cold Shutdown of Fukushima achieved
NBC is reporting that the Japanese Prime Minister reports that Fukushima has achieved "cold shutdown":
http://worldnews.msnbc.msn.com/_news/2011/12/16/9485735-cold-shutdown-fu...
Cold shutdown means that the reactor is stable, sub-critical, at atmospheric pressure, and the coolant temperature is below boiling.
As the article points out, much needs to be done to clean up after this accident. However, cold shutdown means that the prospects for this accident to become worse have essentially abated.
Must create technology o boy that's a biggie
http://www.nytimes.com/2011/12/22/world/asia/japan-needs-40-years-to-dec...
Is it even possible to build a robot that can withstand the type of radiation tepco can't deal with?
Sure - consider our satellites
The satellites that are in orbit around the Earth providing us with communications are subject to radiation fields due to cosmic rays that are much, much more energetic than what one finds in a nuclear power plant.
There's no reason that robots can't withstand the radiation, after all the instrumentation that monitors the reactor and helps operate it certainly can withstand the radiation.
TEPCO's 'babies' all now fertile? cycling with recriticality
Since the corium spikes are following a lunar calendar I think TEPCO and company is papa to some very dangerous teenage girls....
Every month there are DOCUMENTED spikes in temp and or radiation and or radionuclides.... The cores/corium are very much alive ....... Do they 'grow up' or 'give birth' when they hit water ?
Of course TEPCO hides, obscures or tries to preclude (if they only really could) these spikes as much possible which is WHAT THEY ARE SUPPOSED TO DO.....AFTER ALL THEY HAVE SOME VERY BIG AND IMPORTANT STOCKHOLDERS.......
NOVEMBER'S 'INSTALLMENT'
Xenon in Reactor 2: TEPCO Said "Spontaneous Fission" of Curium
After confidently saying it may have been criticality in the press conference on November 2, TEPCO's Matsumoto now says it is spontaneous fission of curium in the reactor.
On the other hand, the Nuclear and Industrial Safety Agency, who was skeptical of criticality yesterday, now says, "We cannot rule out the possibility of localized criticality."
OK it's a "good cop, bad cop" routine, or a "covering all the bases" approach. If both "spontaneous fission" and "criticality" are mentioned in the same news, the Japanese government/TEPCO can say "See, we told you, either way."
Nothing can go wrong
RIGHT ...
It is a kinda, sorta, demi, hemi 'cold-shutdown'
The outer surface of a multi-ton corium mass is less than 'boiling hot'
The actual mass of the 3 corium blobs are 'classified'
As there are 'many' tons of nuclear fuel ... MIA
We are 'assured' by the usual suspects ... that all is well.
Nothing can go wrong ... go rong ... go ron ... goro ... gor
It looks like Corzine stole
It looks like Corzine stole all the money.
Reuters actualy worth a read
UPDATE 5-Japan says stricken nuclear power plant in cold shutdown
http://www.reuters.com/article/2011/12/16/japan-nuclear-idUSL3E7NG02P201...
A Fine Goulash....
...of half truths, misnomers, distortions and outright lies justifying more murder of and theft from the Japanese people.
Nicely seasoned with a polite glimpse of their (and possibly our) future:
------------
'
Living in fear of radiation is part of life for residents both near and far from the plant. Cases of excessive radiation in vegetables, tea, milk, seafood and water have stoked anxiety despite assurances from public officials that the levels detected are not dangerous.
Chernobyl's experience shows that anxiety is likely to persist for years, with residents living near the former Soviet plant still regularly checking produce for radiation before consuming it 25 years after the disaster.
'
-------------
Fukushima daiichi wrong wrong wrong
It's a state of cold shutdown not a "cold shutdown" cold shutdown implies you can flood and remove fuel cores.
News
'Absolutely no progress being made' at Fukushima nuke plant, undercover reporter says
http://mdn.mainichi.jp/mdnnews/news/20111216p2a00m0na002000c.html
This term has to do with temp
This term has to do with temp in bottom of pressure vessel bieng under 100c correct?then with fuel bieng exvessel this has as much to do with the politics of allowing people to feel good then actual temp of fuel am i wrong?was it not last week hydrogen explosions were still a concern..eat the beef ,eat the rice ,drink the tea keep it in Japan and enjoy it.
A state of cold shutdown
“A stable condition has been achieved, and we can consider the accident itself contained,” Noda said.
http://news.businessweek.com/article.asp?documentKey=1376-LVTDCN6S972B01...
nothing of the sort
"Cold Shutdown" ? Nothing of the sort. Missing cores with temperatures in the thousands of degrees wherever they are is NOTHING like a cold shutdown. Other than those toeing the party line, a collective chorus of 'bullcrap' can be heard coming from the technical community.
Japan has a government that is on a losing streak, and like so many desperate losers continues to gamble. One can only assume that the cashier in the cage has taken the last shred of collateral the criminals could muster and let them hang themselves with perhaps their last throw of the dice. They are gaming away the lives of the Japanese people.
Read the article in Bloomberg Businessweek on this, especially the last few paragraphs. Smart money is working hard to both cover their tracks AND bet against the BS being proffered by the losers.
http://news.businessweek.com/article.asp?documentKey=1376-LVTDCN6S972B01...
Even missing cores obey the decay heat equation.
Missing cores with temperatures in the thousands of degrees wherever they are is NOTHING like a cold shutdown.
===========================
Even a missing core obeys the decay heat equation. Those fuel elements at one time were producing enough decay heat to be in the thousands of degrees. The decay power has been falling like the 1/5-th power of the time in seconds.
The decay power is a fraction of what it was 9 months ago.
http://en.wikipedia.org/wiki/Decay_heat
http://en.wikipedia.org/wiki/File:Decay_heat_illustration2.PNG
Gunderson doesn't know what he is talking about; never did.
However, the latest is that even Gunderson has started backpedaling:
http://enenews.com/gundersen-could-fukushima-have-a-china-syndrome-no-on...
I do not believe that the nuclear core can melt down through the containment and into the water table
Looking Into the Future
We all look forward to more and certain data as this is a very novel and STILL potentially a much greater catastrophic / cataclysmic disaster if any number of very possible scenarios unfold. We are STILL deep in uncharted territory.
Tracking the isotopes shows cycling fission events but the exact details are not being released and maybe not even collected. Very high radiation precludes approaching the reactor bottoms or corium pits so it may be some time before we really know. Of course an event that produces any type of large release will potentially give us lots of data. We can only hope that the cores / corium congeal into a sufficiently cool masses that it stop their descent. If the lost cores 'end up in the basement' water is still the enemy as it could trigger uncontrolled or prompt criticality restarting the disaster.
It would be nice to have more data. Are we headed out of the woods or continuing the descent into the water table ? We just don't know.
The only 'cold shutdown' we have was on the truth from the Nuclear Cabal and that happened IMMEDIATELY.
Fool me once....
You can't get a "prompt criticality"
You can't get "prompt criticality" if the percentage of fissile isotopes is below a threshold percentage.
For example, in a mixture of U-235 and U-238; you can't get a "prompt criticality" if the percentage of U-235 is less than 20% That's why the security precautions that one needs to take with 20% or less uranium are less than higher enrichment. 20% enriched is good for reactor fuel, but it won't work as bomb fuel.
Likewise, if the fissile isotope is Pu-239 in U-238; the threshold percentage is 14%. That is if the fraction of Pu-239 is less than 14%, again you have reactor fuel and not bomb fuel.
See the following paper:
http://www.princeton.edu/~ota/disk3/1977/7705/770508.PDF
Page 6 at the top of the 2nd column shows the limiting thresholds for obtaining "prompt criticality". Even at these isotopic mixes, the material would need to be compressed to greater than nominal density to achieve a prompt critical configuration, and the amount of explosive required to do that would be prohibitive due to the excessively high densities that would need to be achieved.
The normal fuel for the BWRs at Fukushima is uranium of 3-4% enrichment, which is way shy of the 20% threshold. Even reactor 3 with some MOX doesn't meet the threshold. MOX is about 7% Pu-239, which is shy of the 14% threshold by a factor of 2.
Recriticality is not possible, even with water added
If the lost cores 'end up in the basement' water is still the enemy as it could trigger uncontrolled or prompt criticality restarting the disaster.
==========================
A mixture of uranium and plutonium with the isotopic mix found in a nuclear reactor can not go critical even if water is added.
That's because the only reason a nuclear reactor can go critical with this mix is because the materials are held in a heterogeneous lattice. That is when the neutrons slow down in the water moderator, they are not in the presence of the U-238 with its large resonance parasitic absorption.
If you add water to corium, there's no provision to keep the slowing neutrons away from the U-238 which makes up 95-96% of the corium.
Therefore, even if water is added to the melted fuel; you will not get a recriticality.
This is one of the reasons why reactors use such low enriched fuel.
A recriticality (and super prompt..) accident is
STILL possible and IS in EVIDENCE.
First, Is A Recriticality Accident Possible?
.....a study of the type of reactor now having problems in Japan (BWR) shows that a recriticality accident is possible:
Recriticality in a BWR during reflooding of an overheated partly degraded core, i.e. with relocated control rods, has been studied for a total loss of electric power accident scenario. In order to assess the impact of recriticality on reactor safety, including accident management strategies, the following issues have been investigated in the SARA project: (1) the energy deposition in the fuel during super-promt power burst, (2) the quasi steady-state reactor power following the initial power burst and (3) containment response to elevated quasi steady-state reactor power. The approach was to use three computer codes and to further develop and adapt them for the task. The codes were SIMULATE-3K, APROS and RECRIT. Recriticality analyses were carried out for a number of selected reflooding transients for the Oskarshamn 3 plant in Sweden with SIMULATE-3K and for the Olkiluoto 1 plant in Finland with all three codes. The core initial and boundary conditions prior to recriticality have been studied with the severe accident codes SCDAP/RELAP5, MELCOR and MAAP4.
The results of the analyses show that all three codes predict recriticality - both super-promt power bursts and quasi steady-state power generation - for the range of parameters studied, i.e. with core uncovering and heat-up to maximum core temperatures of around 1800 K, and water flow rates of 45 kg/s to 2000 kg/s injected into the downcomer. Since recriticality takes place in a small fraction of the core, the power densities are high, which results in large energy deposition in the fuel during power burst in some accident scenarios
from ftp://ftp.cordis.europa.eu/pub/fp5-euratom/docs/09-sara.pdf
found at http://www.classicalvalues.com/archives/2011/03/is_a_recritical.html
Of course the other oft stated and erroneous assumption - loss of original configuration of the core precludes criticality - is now shown to be wrong. The math HAS been done:
http://www.osti.gov/bridge/product.biblio.jsp?osti_id=531065
AND from The Physics arXiv Blog at Technology Review at MIT (5/9/2011):
http://www.technologyreview.com/blog/arxiv/26738/
Chain Reactions Reignited At Fukushima After Tsunami, Says New Study: Radioactive byproducts indicate that nuclear chain reactions must have been burning at the damaged nuclear reactors long after the disaster unfolded (the core having long since slumped into a seething pool of corium...)
The mix and configuration of fissionables on the Corium can be modeled to death..... I can find no record of any experimental data involving that large mass or volume of corium. There very well could be a buildup of fissionables in a configuration that could create one hell of a mess. Also ANY part of the corium that is molten would HAVE to be quite dynamic and possibly given to sudden and possibly nasty changes.
from wiki:
A critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties (e.g. the nuclear fission cross-section), its density, its shape, its enrichment, its purity, its temperature and its surroundings.
And it is ongoing to THIS DAY. As recently as Dec 14 in the NYT:
Other experts disagreed. [Kazuhiko Kudo, a professor of nuclear engineering at Kyushu University] said that the restart of fission, a phenomenon known as recriticality, could not be ruled out until the reactors could be opened, allowing for an examination of the melted fuel. [...]
And:
Radioactive Iodine was measured in Gunma and Tokyo again. Officials announce the reason is unknown.
In Gunma, 4 ~ 10 Bq/kg of radioactive Iodine were measured at 3 sewage-treatment plants.
The samples were taken from 11/21~12/1/2011.
The sewage-treatment plants are in Tamamura cho, Kiryu, and Hiratsuka.
29 ~ 68 Bq/kg of Cesium were also measured at 5 sewage-treatment plants in Gunma.
Also, Iodine 131 were measured from incineration ash of garbage disposal facilities in Tokyo.
Rather that debate the obvious why don't we discuss how to get better data on the ongoing cyclic recriticality ?
Let's face it, it COULD go either way. Why not get real and finely identify the phenomena so we can PREPARE FOR THE WORST ? Like avert a ELE ?
But forgive me, first we have to overcome denial of the obvious, and since this situation was created by denial (and outright obfuscation through deceit of all kinds) why should there be expectation of anything other that further gambling and escalation through denial, after all there is a lot of money involved....
The arXiv article is not good evidence for recriticality
Back in May when that arXiv article came out, I commented on some of the scientific reasons why the article does not give good evidence for recriticality at the Fukushima reactors. My comment is here.
Mark [BRAWM Team Member]
Video of prompt critical power burst
>>The results of the analyses show that all three codes predict recriticality -
>> both super-promt power bursts and quasi steady-state power generation -
If anyone would like to see a video of a super-prompt critical power burst; you can see a video of the 10,000-th burst of the Annular Core Research Reactor(ACRR) at Sandia National Lab at:
http://www.youtube.com/watch?v=pa0Fmcv83nw
Nuclear Engineering 101
Recriticality in a BWR during reflooding of an overheated partly degraded core,
==========================
You completely missed the proviso for your entire post, given above:
"...of an overheated partly degraded core...
Evidently you are unfamiliar with the terminology, "partly degraded". A partly degraded core is one with very limited melting or damage
In a partly degraded core, the heterogeneous lattice that I spoke of in my previous post is still intact. Fukushima is NOT a partially degraded core. It is a seriously degraded, i.e. melted core.
When the heterogeneous lattice is damaged such that the moderating water and the U-238 with its parasitic resonance absorption, are not separated; the neutrons will be parasitically absorbed by the U-238 in the resonance region as they slow down. Thus the neutrons will not survive to experience the high fission cross-sections found at low energies.
This is Nuclear Engineering 101.
AND from The Physics arXiv Blog at Technology Review at MIT
Read some of the comments which state that prompt-criticality is not possible
Also read the footnote referenced by the Princeton paper. The threshold that prompt criticality will not occur below a Pu-239 to U-238 percentage of 14% with reactor grade plutonium is courtesy of the Lawrence Livermore National Laboratory, namely one Robert W. Selden.
Nuclear Engineering 101
Recriticality in a BWR during reflooding of an overheated partly degraded core,
==========================
You completely missed the proviso for your entire post, given above:
"...of an overheated partly degraded core...
Evidently you are unfamiliar with the terminology, "partly degraded". A partly degraded core is one with very limited melting or damage
In a partly degraded core, the heterogeneous lattice that I spoke of in my previous post is still intact. Fukushima is NOT a partially degraded core. It is a seriously degraded, i.e. melted core.
When the heterogeneous lattice is damaged such that the moderating water and the U-238 with its parasitic resonance absorption, are not separated; the neutrons will be parasitically absorbed by the U-238 in the resonance region as they slow down. Thus the neutrons will not survive to experience the high fission cross-sections found at low energies.
This is Nuclear Engineering 101.
Your not up to date and ignoring the evidence..
Nor did you read far past the first paragraph of my post. At this point you've posted twice in response, yet read half my post. Makes me wonder. Also even a cursory glance would see several citations (regarding fully degraded cores) and yet you proclaimed my entire post predicated on the first citation. I hope you read technical papers with greater care....
here let me make it easy .....
RESPOND TO THIS:
Of course the other oft stated and erroneous assumption - loss of original configuration of the core precludes criticality - is NOW shown to be wrong. The math HAS been done:
http://www.osti.gov/bridge/product.biblio.jsp?osti_id=531065
(BTW if you want to take issue with the above DOE document you can cite their own critique. The point is many LIKELY models for fully degraded, granulating or molten corium show criticality)
AND critical analysis of the disaster site from The Physics arXiv Blog at Technology Review at MIT show this:
Chain Reactions Reignited At Fukushima After Tsunami, Says New Study: Radioactive byproducts indicate that nuclear chain reactions must have been burning at the damaged nuclear reactors long after the disaster unfolded (the core having long since slumped into a seething pool of corium...)
http://www.technologyreview.com/blog/arxiv/26738/
AND IT CONTINUES......
Radioactive Iodine was measured in Gunma and Tokyo again. Officials announce the reason is unknown.
In Gunma, 4 ~ 10 Bq/kg of radioactive Iodine were measured at 3 sewage-treatment plants.
The samples were taken from 11/21~12/1/2011.
The sewage-treatment plants are in Tamamura cho, Kiryu, and Hiratsuka.
29 ~ 68 Bq/kg of Cesium were also measured at 5 sewage-treatment plants in Gunma.
Also, Iodine 131 were measured from incineration ash of garbage disposal facilities in Tokyo.
Rather that debate the obvious why don't we discuss how to get better data on the ongoing cyclic recriticality ?
Are you sure the course work for Nuclear Engineering 101 your familiar with is up to date ?
Your thinking if you deny the evidence long enough it will go away ?
Where are the calculations?
The author of the Argonne paper describes a methodology for computing recriticality ASSUMING Markovian statistics and a distribution that obeys the Kolmogorov equations which is a simplifying assumption.
The author of the paper did not do any calculations using this methodology on a mixture of BWR fuel.
Additionally, since Argonne deals mainly with fast reactors, their techniques are optimized for same. This may be a very nice technique for estimating re-criticality of a fast reactor.
However, fast reactors don't rely on the low energy fission cross-section of the fuel, and the need for neutrons to escape parasitic absorption while slowing down.
I would have to rate your choice of paper to support your ill-considered opinions as INAPPROPRIATE
Why do you look for some support in the literature on thermal reactors and not fast reactors.
OPINION
While a novel event, the melt-thru is not unknowable. Isn't it strange that this is a case where opinion, and not facts, rule the day ?
Is this refusal to let research get started REALLY about TEPCO's protecting 'trade secrets' ?
There is increasing stench about this secrecy crap and it should turn EVERYONE'S stomach.
Thanks for pointing out the less than perfect application of the corium paper.
Thanks for pointing out the less that perfect reasoning (yours) when you attack the opinions backed with solid data and crisp logic expressed in the Physics arXiv Blog at Technology Review at MIT.... (are they 'ill-considered' because I share them?)
The other poster is correct
The other poster is correct. The Argonne paper didn't present result, but only a methodology. For example, you could use the laws of structural mechanics and "do the math" in order to derive a mathematical expression as to how much of a load a bridge made out of a simple beam can carry. However, that will be a function of the structural properties of the material the beam is made from. A beam made from soft clay like Play-Doh won't hold as much weight as a beam made of steel.
The mathematics will tell you how much the bridge can hold, but only after you plug in the actual numbers of the structural properties of the material of which the beam is made. The Argonne paper didn't do that. It just presented the methodology. The paper offered in rebuttal by Adam certainly did plug in numbers.
Without plugging in the actual numbers for the properties of a beam, or the nuclear properties of the materials in the corium, one can't possibly draw any type of conclusions.
You are drawing conclusions about the properties of the Fukushima corium when the paper you offered as support didn't provide any calculations with the properties of the corium to support any opinion.
Only methodology; no results
The corium paper that you cite contains the mathematics for a proposed methodology for calculating re-criticality. However, it doesn't really do the calculation, it just outlines the methodology.
Let me give you an example of what a complete work would be. Here is a link to a paper in which, not only is the methodology derived, but the method has been coded into a computer program, and results are given for a series of specified test problems. The following paper is from Prof. Marvin Adams of Texas A&M university and a co-author ( student ). Beginning on page 7/18; one finds RESULTS, the analog of which is totally missing from the paper that you cite:
http://mathematicsandcomputation.cowhosting.net/MC09/pdfs/203275.pdf
A proposed methodology, without the actual computer calculations based on the method, can not be used as a justification for holding a particular opinion.
Contrary to your ill-considered ( untruthful ) claims, the Argonne paper did NOT contain "solid data". There was only a mathematical method derived, and it wasn't coded as a computer program, nor tested for validity. It certainly was not applied to the BWR reactor.
It's incomprehensible how someone can call that "crisp logic"; when it is only a mathematical derivation, and no calculations were presented.
Read the paper by Prof. Adams to see how a complete presentation would be made.
I have no beef with either Technology Review or Physics arXiv because they are not presenting the cited paper as some conclusive proof. You are the one citing it as some sort of proof without knowing what a real scholarly paper looks like.
Again, read the paper by Professor Adams.
Iodine-131 is detected
Iodine-131 is detected regularly in sewage plants all over the world, from medical waste and/or patients urine after receiving thyroid treatment with radioactive Iodine (the doses are several million becquerels per session.)
As for the garbage plants, either irregularly disposed medical waste or, who knows, the patients referenced above urinating in a park and contaminating fallen leaves later brought to garbage processing plants.
In any case, you cannot have recriticalities without increasing radiation levels, iodine detected in food or the rest of the isotopes that are created in such event being detected by air monitoring stations like the one the CBTO has in Japan: http://www.cpdnp.jp/pdf/111214Takasaki_report_Dec11.pdf
And don't forget Marco Kaltofen's research. He clearly stated that no Iodine was detected in any of his samples since April: http://www.youtube.com/watch?v=Xa88B44x0Ng&t=09m59s
Consistent with BRAWM
And don't forget Marco Kaltofen's research. He clearly stated that no Iodine was detected in any of his samples since April: http://www.youtube.com/watch?v=Xa88B44x0Ng&t=09m59s
=============================
This is consistent with the BRAWM results. If we had a recriticality in a molten core in a breached containment; then we would certainly have detections of I-131.
tests run by Marco Kaltofen and BRAWM
ARE IN THIS CONTEXT A RED HERRING
"This is consistent with the BRAWM results. If we had a recriticality in a molten core in a breached containment; then we would certainly have detections of I-131."
Not true. The topic is events in Japan. There have been steady and plenty of detections of I-131 in Japan. Continually and all over the place. They have been observed spiking in test results on a almost periodic basis which is a good indicator of cyclic releases / criticality.
The only 'likely of Fukushima origin' I-131 positive test results here where from the direct aftermath of the fairly cataclysmic events that released obscene clouds of all kinds of radionuclides. The cyclic releases of I-131 since then have been occasional and, here at a distant (time for decay, dispersion) point of collection , by comparison been below below testable, or rarely miniscule, brief and really of disputable origin. Samples collected in Japan later would also have to be collected at the right place and time (mostly within a few days after a release) to to show the I-131.
I know the CTBTO has to extrapolate... but WE don't need to.
I-131 tests here relate less to corium cyclic recriticality in Japan that quiet prayer and a fart in a pub across town.
This 'tests run by Marco Kaltofen and BRAWM' tangent is a cul de sac with a hasty red straw herring man with his head up his...
Marco Kaltofen gets his
Marco Kaltofen gets his samples from Japan.
About Iodine-131 being detected regularly in sewage treatment plants, check this.