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Fukushima No 1 Data Interpretation
My longtime political readers may excuse that this will be a quite technical post. I'll get back to Iran etc tomorrow.
Someone in Denmark diligently collected the raw pressures and temperature readings of the Fukushima reactors which were published by various sources.
Being concerned about the state of reactor 1 I pushed the number 1 readings into an graph.
Reading that graph I come up with some interpretations that may well be of general interest.
- I find it likely that there was some direct release from the reactor vessel of no 1 to the atmosphere.
- I also believe that reactor 1 had a complete core meltdown.
- Additionally there is a pressure anomaly which escapes my grasp but needs some urgent attention.
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What concerns me most is the red line creeping up after diverging from the blue line. More on that below.
For orientation let's look at the schematics of the MK I type reactor 1 building.
The parts we need for reading the graph are the reactor vessel or core (RP, blue and red in the data) which contains the nuclear fuel. We also need the bulb steel and concrete shell called the dry well (D/W, green in the data) which is the primary containment structure. Connected to the dry well is the wet well (S/C, only in the raw data), a steel torus which usually holds 4 million gallons of water and acts as a suppression and condensation chamber. Steam can be relieved from the reactor vessel into the dry well. Several lines move steam from the dry well below the water of the wet well where it supposedly condensates.
The above graph does not show the spotty data from the first days of the event.
To recap: After the earthquake/tsumai incident on March 11 the few still available pressure readings showed some 0.85 Megapascal in the reactor vessel as well as in the dry well (1.0 Megapascal = 10 bar ~ 145 psi; regular air pressure is 0.1 MPa).
The steam pressure in the dry well relieved itself likely by slightly lifting the metal dry well lid bolted onto the top and gas crept into the secondary containment which is essentially the outer building structure. Mixed with the oxygen in the secondary containment hydrogen, which had developed in the uncooled core, exploded on March 12 and destroyed the top level of the secondary containment of the number 1 reactor building.
On March 13 the pressure in the reactor vessel was back at 0.480 MPa trending down. Pressures in the dry well and the wet well were at 0.600 MPa, above the reactor vessel pressure, but also trending down.
Interpretation: The pressure in the reactor vessel being lower than in the dry well can, in my view, only be explained by a willful direct venting from the reactor vessel into the atmosphere. If that has indeed happened such venting would explain some of the so far unexplained high radiation spikes (pdf) around the plant.
There is not much reasonable data between March 14 and 18 where the graph start.
Since March 18 we have two pressure readings from the reactor vessel (RP(A) [blue] and RP(B) [red]) with A being at this point at a relaxed 0.295 MPa and B being slightly below at 0.252 MPa. The dry well (D/W [green]) is at 0.180 MPa. Compared with the pressures a few days before this date these are reasonable low values.
But since the 18th we also have two temperature readings and those are quite too high. The feedwater nozzle, which in the upper part of the reactor is used to push water into the pressure vessel, has a temperature (FNT [orange, dotted]) of about 400 degree Celsius (~750 degree Fahrenheit). The bottom head temperature in the reactor vessel (BHT [brown, dotted]) is in the same range. These temperature values were higher than the normal operation temperature (285 degree Celsius) and needed to be brought down.
Some water was fed into the reactor vessel through a fire extinguish line, but this was not enough to achieve a change. More cooling was needed. The high temperature state continued until March 22nd.
On the 22nd/23rd the graph shows a sudden jump in the pressure values and a significant downtrend in the temperature levels. The Japanese regulator timeline report says:
The amount of injected water to the Reactor [1] Core was increased by utilizing the Feedwater Line in addition to the Fire Extinguish Line. (2m3/h→18m3/h).(02:33 March 23rd) Later, it was switched to the Feedwater Line only (around 11m3/h). (09:00 March 23rd)
The switching on of the additional feed as well as the following slight reduction with the fire line off can be seen in graph. Both reactor vessel pressure measurements went up to the 0.45-0.5 MPa range while the dry well pressure went up to the 0.35 MPa range and both temperature measurements dropped from the 400 degree Celsius level into the 200 degree Celsius range.
There is one very interesting point here. While the feedwater nozzle temperature and the bottom head temperature so far had essentially the same high reading they start to divert on March 23/24. The feedwater nozzle reading stays about 70 Celsius degrees above the bottom head temperature.
Interpretation: Before the additional water feed the reactor vessel did not hold any water but only very hot steam. The temperature at the bottom was the same as near the top. After more water was pushed into it the reactor the vessel bottom slowly filled up with fluid water (at 0.5 MPa the boiling point of water is some 150 degree Celsius). The temperatures between bottom and top started to divert. But as the reactor vessel, over several days, was only filled with steam and without any water covering the fuel rods at least partly it is likely that the fuel rod meltdown at number 1 was 100%, well beyond the 70% the reactor operator TEPCO estimated and announced on March 15.
On midday of the 26th the graph shows a new phenomenon. While up to then the pressure differences between RP(A) and RP(B), both in the reactor vessel, where neglectable they suddenly start to diverge. RP(A) (blue), in lockstep with the lower dry well pressure D/W (green), stays constant and is, after March 30, now coming down. But since the 26th pressure at measuring point RP(B) (red) is increasing and is now above 0.65 MPA entering possible dangerous territory. The bit of thermodynamics I learned says that pressure differences in a vessel should quickly equalize.
Interestingly a short while after this pressure divergence the temperature of the feedwater nozzle also further diverges from the temperature at the bottom head. While the difference between both was some 50 degree Celsius it quite suddenly increases to some 180 degree Celsius.
Interpretation: I do not yet have any interpretation for this phenomenon. How can there (except in a short millisecond explosion) be two different pressure readings within one vessel? How are those "pressure zones" related to the temperature zones and additional divergence of these as we can see in the graph? Please let me know.
The reactor vessel of number 1 has been "tortured" over the last three weeks. It is forty years old and over these years has been constantly radiated. It has lots of pipes welded to it. A level 9 earthquake shake went through it. It experienced extreme pressure and temperatures over several days. The seawater injections over the last weeks filled it up with an aggressive brine. Its core has melted. The vessel has been taken a beating over its design level in nearly all dimensions. If the increasing red line reading of RP(B) is correct the vessel may rupture from overpressure and release a lot of additional nasty stuff first into the drywell and then into the environment. This could make more parts of the land inhabitable.
Let us hope that the folks working on the issue have the understanding of and freedom to act on these issues.
(The exercise above was partly to also show that the fawning the NYT gave today to "simulations" and Secretary Chu as criticized here is unwarranted. Using the available date anybody with some reasonably broad background can come to the same, if not better founded conclusions.)
Some of the above factual statements may be wrong. Some of my conclusions from them may very well be wrong. If so, the comments are open to let me know.
@claudio I’m about the same, my retention of classical physics (well any physics really) has been poor one may say directly proportional to the number of times I’ve had a need to use the knowledge and inversely proportional to the amount of time which has passed since I learned it. However the essential thing we need to bear in mind are the direct relationships between temperature, pressure and volume.
As the temperature has risen so has the pressure and b’s point about the number of pipe joints welded into a 40 year old reaction vessel and containment chamber is an important one.
These reactors must have protocols for xraying welds regularly to spot any areas liklely to become flawed under stress, just as they must have maintenence routines which allow welding once the reactor has been commissioned. But I find it difficult to believe that either of those tricky and complex tasks could be completed in the current state the reactor vessel is in. Hell the maintenence areas were holding corpses of workers killed in the initial earthquake or Tsunami, only just discovered, so it requires a huge leap of faith to accept that many of the welter of programs and protocols which GE engineers developed when designing this system can be adhered to now the site is seemingly post meltdown.
I see GE ceo immelt is visiting Japan, ostensibly to promise that GE will:
“help the plant’s operator supply electricity in the coming summer when power demand soars. “ Yeah riiight jeff. I’m sure yer visit is about PR yeah, but that statement is likely just a smokescreen to prevent panic to enable statements like this “Chief Executive Jeff Immelt said Wednesday the U.S. should “remain committed” to nuclear energy despite the crisis unfolding in Japan.”
Without any knowledge of exactly how thermal sensors are effected by prolonged exposure to high levels of both thermal and nuclear energy, there is no choice other than to accept the readings as being correct. I would have thought that trend analysis would be more useful than absolute figures anyway. If the divergence between RP (A) and RP (B) continues, and these spaces are indeed adjacent, the stress on whatever sperates the spaces will increase as well, there must come a time when the pressure differential causes a failure of whatever material is separating the two spaces.
If the engineers want to avert that, they can only do so be either reducing the temperature or increasing the volume of the space whose pressure is reflected in the red line [RP(B)] or increasing the temperature or reducing the volume of that space reflected by the blue line [RP (A)].
Increasing temperature would be counter to the primary problem reactor overheating, and reducing containment volume would (presumably) also reduce the amount of coolant available to RP (A). So that means the engineers would have to tacle this divergence by attempting to alter conditions within the RP (B) space. Lowering that temperature would be an ideal solution except that the only way the engineers have achieved that end thus far is by increasing the volume of coolant available which, would probably be self defeating since it would per se increase the pressure within the RP (B) space.
That leaves increasing the volume available to at least some of the gases and liquids held within the RP (B) space – ie venting – allowing an amount of the gaseous or liquid matter contained within the space to escape into either the sea or the atmosphere.
That idea probably appals anyone who reads this, but for an engineer whose primary objective is to prevent an explosion that would allow all the matter to escape with little or no control over where the vessel’s contents went, venting would appear preferable.
I suspect that the senior nuclear engineers from (as far as we have been told) france, amerika, and japan have resigned themselves to exactly that scenario and are busy devising means for doing exactly that without too many people picking up on what they are up to.
Read any current mainstream media ‘story’ about Fukushima, and you will end up more confused than before you read it. eg This morning’s effort from my fishwrap:
More highly radioactive water spilled into the sea from a tsunami-disabled nuclear plant and authorities struggled to seal the leak, as frustrated survivors of last month’s disaster complained that Japan’s government was paying too much attention to the nuclear crisis.
The contaminated water will quickly dissipate into the sea and is not expected to cause any health hazard, but pooling water at the Fukushima Daiichi nuclear power plant has hampered the work of technicians trying to stabilise the complex’s reactors. Pouring concrete has so far failed to fill the crack. . . .
. . . On Saturday, workers discovered an 20-cm long crack in a maintenance pit, from which water containing levels of radioactive iodine far above the legal limit was spilling into the Pacific, said Japan Nuclear and Industrial Safety Agency spokesman Hidehiko Nishiyama.
Over the past 10 days, pools of contaminated water have been found throughout the plant and high levels of radioactivity have been measured in the ocean, but this marks the first time authorities said they had found a spot where the water was directly entering the sea. . . .
. . . A nuclear plant worker who fell into the ocean Friday while trying to board a barge carrying water to help cool the plant did not show any immediate signs of being exposed to unsafe levels of radiation, nuclear safety officials said Saturday, but they were waiting for test results to be sure. . .
see radioactivity isn’t dangerous. No attempt to advise the public of the way salts of radioactive metals accumulate and concentrate up the food chain. Just that some bloke went for a dip and didn’t get fried.
Meanwhile england’s indepedent pumps out the anodynes:
Engineers pinned their hopes on chemicals, sawdust and shredded newspaper to stop highly radioactive water pouring into the ocean from Japan’s tsunami-ravaged nuclear plant Sunday as officials said it will take several months to bring the crisis under control, the first time they have provided a timetable.
Concrete already failed to stop the tainted water spewing from a crack in a maintenance pit, and the new mixture did not appear to be working either, but engineers said they were not abandoning it. . . .
. . . The government said Sunday it will be several months before the radiation stops and permanent cooling systems are restored. Even after that happens, there will be years of work ahead to clean up the area around the complex and figure out what to do with it.
“It would take a few months until we finally get things under control and have a better idea about the future,” said Nuclear and Industrial Safety Agency spokesman Hidehiko Nishiyama. “We’ll face a crucial turning point within the next few months, but that is not the end.”
MoA readers will know and recognise the game being played. As long as nothing changes for a few weeks, or rather it appears that nothing has changed, most people will accept the situation as being OK even though the reactor is leaking radioactive material into the Pacific, because the assholes who caused this are pretending that they are not concerned. In a few weeks or months when the news is released about the horror that has been perpetrated, the story will have ‘lost its legs’ most humans will have ‘moved on’.
The news that a 7.1 magnitude earthquake occurred just south of Java this morning doesn’t bode well for any of us living in the Pacific. There have been big earthquakes in NZ in the last six months, combine that with the Japanese quakes and now ones in- between at indonesia and one is forced to wonder if we aren’t seeing a major tectonic plate re-alignment. The distances are huge and there must be several plates between each quake site, but three earthquakes over 7.0 richter in the pacific in less than 6 months feels like more than a coincidence. Japan isn’t the only ‘asian tiger’ (remember that old cliche) with nuclear power stations either.
Posted by: Debs is dead | Apr 4 2011 1:32 utc | 4
Elites engaged in running their polity and bio-region into the ground often indulge in wishful fantasies of personal escape, rescue by divine intervention, apotheosis, a magical ship coming to take them off the beach, etc. [Actually, commoners also cherish these thoughts. When, as a child, I first realised what “nuclear weapons” really mean, and are, I lay awake night after night longing passionately for some intelligent aliens to come and take me away. I’m too old, too mired in reality and reason, to believe in that narrative any more; I almost wish I could. Beam me up Scotty!]
The historical record is not encouraging in this regard. No one comes and magically bails out failing civilisations. The arc of hubris seems to me far more reliable than dear old MLK’s arc of history… it bends towards collapse. Things fall apart. Our greedy little primate reach exceeds our grasp. We think we can ride tigers. We tell the story of hubris and its fall over and over — from Aesop to “The Man Who Would be King” to our modern sci-fi fairytales — and yet no one ever really internalises the message.
Instead we internalise the exceptionalist fairytale, the “upstory”, the Cinderella narrative — that we are special and will be singled out and elevated to a royal style of life. The Cinderella narrative drives American (and capitalist) belief systems: it holds that we (our nation, our generation, our species) are just so damn special, nothing like us ever was, and we are too great to fail. We were Chosen (by linear evolution, by divine favour, by Destiny, by the staff at American Idol) and we cannot lose. We are the Champions my friends… from rags to riches!
And now I’m on a rant, so don’t expect this to be a dry discussion of physics, EROEI etc.
We have a very poor understanding of what really constitutes “riches”. We think the “3rd world peasant” building up her healthy soil, highly literate in her bioregion, surrounded by an abundance of food, receiving a hundred times return on her seed “investment”, watching her healthy children rolling and playing in the sun, is poor — she doesn’t have a TV! We think the urbanite holding tens of thousands of notional dollars, dependent for basic survival on vast fossil fuel expenditures, receiving 6 percent on a savings account or 20 on tenuous, often criminal financial shenanigans called “investments”, surrounded by inedible status objects and supplied with low-nutrition pseudo-food by a long and fragile energy-intensive chain of profiteers, popping handfuls of synthetic pharma products daily to “manage” the various biological insults inflicted by ambient toxicity and bone-idleness, is rich — he has not only a big TV but a car! The urbanite lives “like a king” (which is what the Cinderella story tells us is Heaven or a happy ending) and the peasant lives “like a peasant” (which is what Cinderella escapes from, never looking back).
When civilisational collapse comes (so Tainter, Diamond and Ponting suggest), the peasant survives and most of the urban elite perish. Wealth takes on different meaning. To avoid collapse would also mean shifting the meaning of wealth, changing our aspirations, changing the fairytale that we internalise and believe in.
The counternarrative is unpalatable from where we now sit, a “downer”, and no one wants to hear it: that Icarus flew too close to the sun, that the juggler can’t keep more than N balls in the air, that we are still flesh and blood creatures tethered to biotic reality and we saw off the branch we sit on at our own peril, that idle superwealthy elites tend over time to go a bit mad with boredom and uselessness. That moderation of our desires and appetites is a surer path to longevity than wild bingeing on treats and sweets. That Cinderella’s life mightn’t have been half bad if only the stepsisters had shared the work fairly instead of turning her into a slave in order to live out their own pathetic “Cinderella story” and crazy aspirations to live like queens (kings). That we could have used technology to ensure the wealth and happiness (and broaden the intellectual horizons and lighten some of the physical burden) of peasants everywhere — to enhance and enrich the subistence lifestyle — instead of thinking it was a ticket to the Pharaoh’s palace (total escape from subsistence activities) for a lucky few lottery winners (and then trying to expand the number of lucky lottery winners to a billion or two).
Nuclear power is one more face of the prince we were going to marry who would keep us in idle luxury and make us “happy ever after.” imho. When we despise subsistence activities, when we think we are “too good” to grow food, gut our own fish, make our own stuff, we become the slaves of our slaves (or rather of our overseers who keep our slaves in line for us). And we sign up eagerly for any genie — coal, nuclear, unobtainium — who will “rescue” us and keep us in luxury in a palace. When our overseers fail to manage our ever-growing army of slaves, we die. We have no access to the resources for subsistence (many of which have been pillaged or poisoned by now) and no skills to use them.
I’m sorry this is not really coherent. Fukushima has rattled me deeply and is even getting into my dreams. I too have signed the Faustian pact, but for several years now have been trying to figure out how to erase my name from the parchment.
Posted by: DeAnander | Apr 7 2011 16:26 utc | 48
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