I am still in the middle of trying to understand the whole picture, but there is a compelling argument (here (link in Japanese, post and comment section) and here) that construction of the impermeable wall along the ocean side, east of the turbine buildings at Fukushima I Nuclear Power Plant, may have caused and/or accelerated the leak of groundwater contaminated with high levels of tritium, strontium, and in one observation hole high cesium.
Construction of the impermeable wall started in early April this year, with steel pipe sheet piles driven into the pre-loosened soil using a vibratory hammer and a hydraulic hammer. Loosening of soil had started in June last year to prep the site for driving the steel pipe sheet piles using high-power hammer, probably to mitigate damage from the impact in the area probably already fragile from the earthquake and tsunami in March 2011.
From TEPCO's Photos and Videos, 4/2/2013:
At the end of April, they started to drive down the sheet piles in the sea right off the Reactor 1 turbine building. In early May, tritium levels inside the port started to increase.
The first section of the impermeable wall was finished by mid June, and that's when the samples taken from the observation holes dug to monitor the groundwater started to show elevated amount of tritium and all-beta including strontium, particularly in the observation holes No.1 (1-1, 1-2, and now 1-3).
From TEPCO's Photos and Videos, 6/26/2013, a section of the impermeable wall near Reactor 1-4 water intake:
From the same document, the location of the photograph in diagram:
The locations of groundwater observation holes, from NRA's document, with the finished impermeable wall marked in green:
I am still trying to understand the argument. I'll update.
But if they are right in their argument, will it be "soh-teh-gai" (beyond expectation) or "soh-teh-nai" (within expectation)? At this point, those who have followed the accident and have been attending TEPCO's press conferences are saying it's the latter.
(H/T TSOKDBA blog with meticulous, detailed study of the Fukushima nuclear accident, and the commenter "inja")
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21 comments:
This seems plausible, but is not good news.
It implies that the ground water contamination has been leaking into the ocean unchecked until the wall was built. That helps explain why the radioactivity in the harbor and the surrounding sea life has remained steady, rather than declining as expected.
Unfortunately it also suggests that with the completion of the wall, the site will gradually fill with contaminated water, like a tub with a plugged drain. So the construction of the upstream barrier to block the inflow of ground water should really be done before the sea wall work proceeds.
I'm more worried about what is going to happen to the site once the equilibrium of the water-flow from ground to sea is stopped. I hope they understand how precarious the balance of these reactors' stability already is. Will the reactors be able to withstand the change in water pressure? And what will be done about the presumably newly-upgraded intense radiation concentrations within the reactors?
Radioactive material found in Swiss lake near a nuclear power plant.
"No threat to human health," of course!
http://www.france24.com/en/20130714-radioactivity-found-swiss-lake-near-nuclear-plant
I don't understand it either. I am rather thinking that the BRUTAL increase in the radiation levels of the flowing water (which have peaked in recent days) are caused by the fact that the corium has actually reached the water table. It's what is to be expected when a "China syndrome" goes on, as is the case in Fukushima Daiichi (four "China syndromes"?)
As I understand it, the corium of at least one reactor has reached the water table and that's why the nearby sea spiked in just a week from "almost normal" levels of 100 Bq/l to absolute madness of 150 million Bq/l (and to 900,000 Bq/l in just three or four days). It's not more water flowing but that the water table has become extremely radioactive itself.
Naturally that is a major environmental and health concern for Japan, for all the Pacific Ocean and even for all Earth, because all that radioactive water will keep circulating: you can't enclose the sea, nor the atmosphere.
> It's what is to be expected when a "China syndrome" goes on
Impossible. The corium is no longer liquid, for a very long time.
"Impossible. The corium is no longer liquid, for a very long time".
How can you even know?
What you seem to be suggesting anyhow is that the temperature in the reactors is too low (thanks to "infinite" open-loop water administration, which also falls by the holes to the water table incidentally) for the corium to be liquid. I can't say for sure but most critical reports suggested already by the end of 2011 that the containment was breached early on in all three most affected reactors. For example, in Nov 2011 some experts cried: The fuel is no longer there: measuring the temperature of reactors is therefore meaningless.
Whatever the case and the particularities of each reactor (of which we know too little even in the best case), the most logical explanation for the ongoing radiation escalation is an advanced stage of the "China syndrome". That's what Fukushima emergency... pondered five days ago and the only explanation I can fathom for the current water-table/seaside radiation escalation.
The China syndrome term somehow envisions the corium melting through the planet, which is quite unlikely for a number of reasons. Having said so, I find it hard to believe that the corium has to be molten for the water that washes it not to erode away bits and pieces (mechanically), on top of the soluble fraction, and carry them into the soil and eventually into the ocean.
Another way Wikipedia describes "China syndrome" is as a breach of the containment. As we all know by now the very term "containment" is propaganda: when things go south in a npp you are bound to have a large release: through a hole opened into the containment (the "vent") in order to release outside the content of the containment, via explosions and fires, via the "spent" fuel pools, via cooling water-- the possibilities seem infinite.
Beppe
The corium is no longer molten. Study of the Three Mile Island fiasco shows what corium does--->not anything like the China Syndrome.
However, there may be something going on that was not observed in other accidents. I don't think anyone really knows yet. All that is known is that a bunch of money hungry morons who now own crapped up reactors, regulated by useless nuclear sales people, don't have a clue.
Of course that the "China syndrome" name is not really descriptive, beginning by the fact that China is not the antipodes of the USA (it'd be more like SW of Australia) but what it suggests about the corium gradually eroding whatever is under it and maybe even some day reaching the Earth's mantle, where it'd be dissolved presumably (or fall at most to the Earth's core, never to the other side of the planet) is essentially correct. However it has never before now been tested experimentally.
The main problem, besides uncontrolled radiation flow through the water table, IF the corium reaches it, is the possibility of a steam explosion, which would spread again the fissile materials all around, and maybe even cause important earthquakes.
But at the very least, as controlling the water table is a major engineering challenge (if feasible at all, especially so close to the sea), the spread of radioactive particles 'en masse' through the water, as seems to be happening now, is a clear most dangerous effect (as well as a symptom) of the China syndrome.
No, the temperature of the corium at this point, two years after the accident, would be such that it could not melt into the earth below it.
Please stop suggesting this. There is more likelihood of intermittant recriticallities, although also a little far fetched at this point, than any movement of the corium towards the earth's mantle.
Take a good look at the pics of the "elephant's foot" corium from Three Mile Island accident and tell me you still think the "China Syndrome" scenario is still possible.
Ohhh, What I wouldn't give to have a rather big molten blob of corium burn through the earth's core and show up on the other side in Justin Bieber's back yard.
I don't think Three Mile Island is comparable to Fukushima at all: only Chernobyl is and it still falls probably much down the unwritten scale in comparison (only one reactor affected, no sea nearby, very effective Soviet containment reaction after the first doubts and secrecy, no earthquake nor tsunami, no pretend and extend tactics, etc. - if Chernobyl was a 7, Fukushima should be an 8 or 9).
And in Chernobyl they did all they could to prevent the China syndrome by digging under the reactor and building a especial reinforced floor (at first they froze the soil but this was too costly, so they used a thick concrete layer instead). This was not enough, so other underground barriers were built to prevent as much as possible pollution of the Dniepr, however Kiev soon changed its water supply to the Desna river because it was obvious that it was all in vain. Radioactive pollution leaking through the water table has never ceased but has aggravated instead.
Prior to the construction of that artificial soil, they had to empty a huge artificial water deposit which was under the reactors, much as the Fukushima water table is. Why? Because that was the greatest risk of steam explosion.
I imagine that, once the corium reaches the water table and assuming it does not cause a steam explosion, it will remain cool enough (unless drought) not to keep penetrating but the problem of massive and persistent radioactive leak to the environment will remain and be completely unmanageable.
Maju, the simulations done by institutions and TEPCO and published in November 2011 show corium ate into the concrete of the dry wells, but not to the extent that corium is totally out of the reactor building foundations - the largest estimate was something like 2 meter into the DW floor. http://ex-skf.blogspot.com/2011/11/institute-of-applied-energy-corium.html
Below DW, there is 7.6 meter thick concrete foundation for the building.
It is possible that corium continued to eat into the concrete, a few centimeters per hour, and got out of the building in a week or two, without any cooling, but I don't think it is probable because the cooling did start long before that time-frame.
@11:16 "a bunch of money hungry morons who now own an unusable reactor, regulated by useless nuclear sales people" has recently been observed in San Onofre too.
What's worse, "bunches of money hungry morons who own *operating* reactors, regulated by lapdogs" are being observed all over the planet. (It could hardly be otherwise in a nuclear proliferation industry that would not exist without multiple types of government subsidies.)
OT: according to Jiji (2013-07-13), after the electoral reform in Fukushima prefecture only one Upper House seat is contested, down from two. Abepolitiks?
Beppe
Primavera-san
the corium is somehow coming out of the reactors, likely carried by water leaking out of the nuclear plant (cracks in concrete? leaking pipes or tanks?). Is there anyone who has doubts about this, besides Tepco? Where else could the Cesium be coming from?
Every day 400 tons of external water finds its way into Fuku 1 cooling hodgepodge but not a single drop is leaking out of it? 400 tons is something like 20+ large tank lorries, every day.
Beppe
"Below DW, there is 7.6 meter thick concrete foundation for the building".
OK, it seems like a good precaution I did not know about. I will assume that neither earthquakes nor explosions nor radioactive erosion nor all them together damaged it badly enough (although, honestly, the huge cannon-like explosion of reactor 3 could well have smashed it altogether).
"It is possible that corium continued to eat into the concrete, a few centimeters per hour, and got out of the building in a week or two, without any cooling, but I don't think it is probable because the cooling did start long before that time-frame".
The cooling began but how effective it is inside the corium mass (i.e. not just the outer crust)? The sometimes confusing temperature data we have is always from the containment vessel, which was breached in at least two cases, probably three, never directly from wherever the corium is.
It is effectively impossible nowadays to go (human or machine) to where the problem is, so there's no actual data, just estimates, speculations and either hope or desperation.
It may well be as Beppe says but, whatever the case, either the cooling water is bringing the radioisotopes from the corium to the water table or the corium itself (parts of it at least) has reached the water table directly. Or at least it is what seems to me when from ~100 Bq/l the measures jump to 900,000 in three days and then to 150 million in another three days (and which are the figures now?, we don't even know).
Groundwater that goes to subdrain pits around the reactor buildings are not contaminated. But groundwater that goes to those observation holes along the ocean is contaminated, as we've been seeing since mid June.
Maju,
No, Three Mile Island *is* a better example of what the corium in the busted Fuku reactors is probably like now. The Chernobyl accident involved a nuclear excersion in a type of very dangerous and now obsolete reactor design, where the highly radioactive graphite core was strewn about--a totally different reactor dynamic from Fuku.
I'm not trying to be arrogant or anything but please read up on the difference in reactor types and what is probable or not, for each type, after an accident. I know you are worried and it might allay your immediate fears. Nonetheless, any "accident", or should I use proper nuke-speak and downplay it to "incident", must be taken very seriously and never dealt with as being a completely foreseeable conclusion.
I remember well some people claiming exactly what you say and saying that meant the "impossibility" of a Chernobyl happening in the West. Apparently that was because Chernobyl did not have a containment vessel or something like that but it seems obvious that this is just an extra barrier and never enough to guarantee anything. It's like the Futurama episode about the thousand layers dark matter ship which naturally sinks, Fansworth then saying: "we should have put a thousand and one layers". Or it is, if you prefer the facts of the past over the sarcastic imagined future, about the alleged unsinkability of the Titanic.
You can take as many precautions as you can conceive but with nuclear energy and nuclear residues nothing will ever be good enough because the effects of just one serious disaster are destructive well above human imagination, sense of time, etc. An oil spill for example can be a brutal disaster but eventually it passes away but radiation is effectively forever: each radioisotope liberated to the environment (or at least many of them) have times of effective persistence that totally beat even the very time of existence of Homo sapiens: not human life, not centuries, not history but our very biological timeline as species.
No security can ever be enough. And as Fukushima and its persistent catastrophic effects show, it can happen anywhere for any reasons and go totally beyond any imagined control.
Security is never to reduce the risk of accidents to zero: that is impossible, it is to make accidents rare and its effects statistically less dramatic. But statistics are not good enough for nuclear because 99.99% of safety means 0.01% of risk and any risk is simply unbearable when we talk of nuclear.
We are destroying our only known habitable planet very fast and by many means but of all them nuclear "side effects" are the worst of all. Just a single accident like Fukushima and the whole Pacific Ocean (particularly its northern half) is bearing the unbearable, and only getting worse with time.
And even if they could manage to organize some sort of contention like Chernobyl's this would just be a patch: in the future if society is disorganized, in crisis, and unable to muster the resources for a new Chernobyl or Fukushima sarcophagus as needed, the monster inside will surface again... and it will be there for millennia, well beyond what our imagination can manage.
It's not like a chemical spill at all: this is uncontrollable, extremely destructive and effectively forever.
Personally I do not think there will be any Fukushima sarcophagus: the plant will keep leaking radiation uncontrollably for all the future I can imagine. Everything is just out of control since March 11 2011 and nothing that is done seems but people running in circles in panic or pretending that nothing of importance is happening. Neither attitude helps at all. What Japan and the World need is people who honestly evaluates the problem, evacuates the most affected areas and put all resources needed to contain that problem. I cannot imagine myself how it can be patched but maybe someone else can.
And then of course nuclear power must be discontinued globally: the risks are simply not worth it unless you only think of short term power mongering (which is really the problem Humankind has).
There are a lot of studies about the corium in the Chernobyl reactor. In that case, it solidified a few days after the explosion and accumulated in the basements under the reactor. It didn't even maintain enough heat to melt the pipes around it, as seen in some of the most famous photos of the elephant foot, not to talk about eating away meters of concrete and "reaching the water table". That idea is a bit bizarre.
The sanctimonious bullshid eaters of America have yet to figure out that the U.S./Shadow government's conduct in Japan caused this mess. They also are too blind to see the resultant radiation stacking up in locations around the U.S. and the damage it is causing. Some individuals in power in the U.S. are trying to slink off to colonies in places like Africa or underground to dodge the danger of extended low level exposure to the escaping radioactivity. The City of London's Associated Press and the Council on Foreign Relations' CFRtv are not helping one bit, preferring to cuddle up to the psychomorons in charge.
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