Things Get Worse at Fukushima 1122
An anonymous reader writes "Radiation levels are skyrocketing around Japan's Fukushima nuclear plant as reports indicate that a radioactive core has overheated and melted through its containment vessel and onto a concrete floor. Radiation levels inside reactor two were recently gauged at 1,000 millisieverts per hour — a level so high that workers could only remain in the area for 15 minutes under current exposure guidelines."
Before everyone freaks (Score:3, Informative)
However, fingers crossed that nobody else dies. Japan's already had enough fatalities this month.
"Containment vessel" (Score:5, Informative)
Just to be clear, they are absolutely not implying it has melted through the containment, but, rather, the reactor pressure vessel.
Re:Before everyone freaks (Score:5, Informative)
Media Hysteria? (Score:5, Informative)
Re:Nuclear technologies (Score:4, Informative)
Re:Nuclear technologies (Score:4, Informative)
That confidence in our current strategy is being eroded rapidly. This isn't some second-rate system like Chernobyl, it is close-to-state-of-the-art.
I see your point about investigating alternative reactor technologies. However, the Fukushima reactors are certainly not state of the art. http://en.wikipedia.org/wiki/Advanced_boiling_water_reactor [wikipedia.org] reactors for instance are already in operation. Generation III reactors are currently the state of the art of reactors in operation, and the Fukushima reactors are firmly in the generation II category.
The Fukushima reactors have no doubt had safety upgrades during their lifetime, but there's only so much you can do when the fundamental reactor design is antiquated.
Re:Before everyone freaks (Score:4, Informative)
If you have a concrete that can set in that environment, and maintain integrity versus the decay heat that under that blanket of concrete, you should be up for a Nobel Prize.
Re:On the XKCD scale... (Score:4, Informative)
It's actually one red square - the measurement was off by a factor of 100 and later corrected.
http://www.eimai.in/incorrect-measurements-that-led-to-alarm-in-fukushima/3348/ [eimai.in]
Nobody outside TEPCO really knows (Score:5, Informative)
And they probably don't know either.
The reactor may have melted through the base of its pressure vessel, but it's hard to tell. The high radiation levels could either be from a melt-through or from a leak as attempts are made to force water into the reactor pressure vessel. The latest JAIF status report [jaif.or.jp] contains almost all the hard data that's coming out. Everything else is secondary speculation based on that limited data.
No data seems to be available about pressure or temperature inside the reactor. That's listed as "unknown" for unit 2. The sensors involved were probably destroyed in one of the fires, explosions, or building collapses. Pressure in the containment vessel for unit 2 is listed as "low", whatever that means.
A full meltdown is now a real possibility. The JAIF chart has been showing "Fuel rods exposed partially or fully" for units 1, 2, and 3 for ten days now. Reactor pressure vessels are tough, as are containment structures, but ten days of no core cooling is well beyond design limits.
Understand that the water spraying operation refers to the containment structure, which is normally dry. Inside the containment is the reactor pressure vessel, which is a boiler. Getting water inside there, which is needed to cover the core and achieve cold shutdown, requires forcing it in against steam pressure. This has to be done in a highly radioactive environment, in a fire-ruined building where the walls and beams have collapsed, the pumps are damaged, and valves which are usually operated remotely have to be operated by people turning handwheels. Some people are trying very hard to do that. Some of them will probably die. If they succeed, there will be a local mess, but it will be manageable. If they fail, there will be a meltdown.
Re:O.S.R. (Obligitory Simpsons' Reference) (Score:4, Informative)
160,000 three mile islands you mean.
it's now 10% of chernobyl, but hey, who's counting? this is slashdot. we're just denying.
https://www.nytimes.com/2011/03/30/world/asia/30japan.html [nytimes.com]
nuclear power: it's safer than ponies.
Re:Before everyone freaks (Score:5, Informative)
Hmm,
here's a graphic with the sun and planets drawn to scale, http://csep10.phys.utk.edu/astr162/lect/sun/interior.html [utk.edu]
I don't think the sun would notice if we threw the entire planet in to it, From that page
"the radius of the Sun is about 109 times that of the Earth, which implies that the volume of the Sun would hold approximately 1.3 million Earths"
Re:Before everyone freaks (Score:5, Informative)
Not going to be decommissioned (Score:5, Informative)
This misinformation has been bandied about quite a bit, but the fact is that while Reactor 1 had reached the end of its operating license in March, the Japanese government had actually just extended the license for another 10 years in February. The "entire complex" was not by any means scheduled for shutdown, particularly units 5 and 6, which are undamaged and will likely be restarted at some point.
Re:Before everyone freaks (Score:5, Informative)
Concrete is a mixture that's water-based. Start with some dry concrete powder (or some Jell-O Instant Pudding), and your radioactive water becomes radioactive concrete. Then, put more concrete on the outside of that to put as much mass between fish and isotopes, and you're golden.
The part the grandparent post is making fun with is "if you have a material science background". One thing I do know about, is ceramic linings for metal melting furnaces as I've built some. I have in fact poured my own aluminum castings and machined them on my own lathe and milling machine. This necessitates considerable research and book reading about melting furnaces, etc.
First of all, heat plus solid concrete = powered concrete ready to add water. Red hot and concrete do not go together. Red heat breaks down cement. Cement plus heat equals dust. Concrete plus heat equals dust and gravel. Industrially at (relatively) low temperatures it takes hours to break limestone into cement, so at reactor temperatures it'll likely literally never "set up" into a solid. Plain ole cement aka burned lime quicklime whatever is limestone with the water of crystallization burned out of it. Then you add the water back in and it sets up into artificial limestone. Did you know the pyramids in Egypt are made of "limestone" or is it cured cement? There is a pretty interesting book on that topic. Plain ole cement is pretty cool technology. But it is beyond an epic fail at high temps.
Now you can buy ultra high temp ceramic coatings for furnaces, kilns, etc.
Problem 1) very low strength. Like puddle under their own weight. You're likely to end up with a white hot reactor surrounded by a glass puddle.
Problem 2) explodes and fractures on contact with water and thats everywhere down there in the reactor and on the coasts.
Problem 3) as generations of steel mills have learned even the best ceramic coatings turn back to dust after at most a year or two of use. So you've bought a year at best, now you have the same problem plus a megaton of mid level contaminated concrete. Ugh.
Problem 4) It would take an epic amount of high temp ceramic coating to cover the plant. Not in stock, the harbor is wrecked, its too heavy to airlift, and which country will volunteer to shut down their steelmills for a year until more can be made? This is the stuff where a little "salt bag" sized bag weighs about 100 pounds. And you need like a million of those bags. Hmm.
Problem 5) Cements in general are porous at a like ionic level. Right now, say, 1 percent of whats in the reactor has leaked out. Lets think about this logically, if 100% had leaked out into the sea, the plant would not be an issue anymore... Anyway, if you concrete it, that guarantees that 100% of the reactor core will end up in the ocean (eventually) and it 100% guarantees they will not be able to get at it to stop it (because its buried under concrete).
Problem 6) Learn what distillation and vapor pressure are. Right now, at least some isotopes are solid and can't fly away. Encapsulate it in a great insulator like cement, it'll get hot enough all right to make an even bigger more dangerous mess.
So in the short term it doesn't really do anything other than blow a lot of money and look very busy. Once the reactions cease and it cools, slapping some concrete on it might isolate it from the environment, for at most a couple decades, at most. Sooner or later you'll have to clean it up and the concrete will just get in the way.
Reactor Design and Plate Tectonics (Score:5, Informative)
Construction on the Fukishima reactor began in 1967 (wikipage). It is easy to forget that Plate Tectonics was only accepted as a reasonable explanation of geological phenomenon in the 1960's. According to this excellent New York Times article,
"After an advisory group issued nonbinding recommendations in 2002, Tokyo Electric Power Company, the plant owner and Japan’s biggest utility, raised its maximum projected tsunami at Fukushima Daiichi to between 17.7 and 18.7 feet — considerably higher than the 13-foot-high bluff. Yet the company appeared to respond only by raising the level of an electric pump near the coast by 8 inches, presumably to protect it from high water, regulators said."
The tsunami that overwhelmed the plant recently was 46 feet high, far higher than anything they seemed to expect. If you read the NYTimes article, you get a sense that the nuclear safety bureaucracy hadn't adequately integrated modern plate tectonic theory into its safety programs. The 18 foot high maximum tsunami prediction is symptomatic of this.
From the article, it seems that Japan had based its tsunami predictions on historical records, instead of predictions from Plate Tectonic Theory. Computer simulations of plate movement would have given far larger predictions for maximum tsunami heights, predictions that would have agreed with the height of the recent tsunami. I think a strong argument can be made that Japan's nuclear bureaucracy had not taken into account modern Plate Tectonic Theory in its safety practices. They seem to have instead relied on past records of earthquakes and tsunamis. I am not suggesting that individual people were unaware of Plate Tectonic Theory, but instead that their bureaucratic rules didn't seem to acknowledge it. Since construction on the reactor began in 1967, planning of the reactor must have begun much earlier. It is easy to imagine that the initial reactor designers were unaware of the Theory of Plate Tectonics and its implications.
Re:Before everyone freaks (Score:5, Informative)
If they were so unconcerned with saving them, why did they wait on the sea water? they could have done that days sooner but didn't because it would render the reactors useless.
Because then you end up with radioactive salts to deal with. Pure water will cool without transporting radiation, since theres nothing in pure water that will take on the extra particles. Salt also accelerates corrosion, and when the water boils away, it leave a nice crust all over everything, possibly clogging pipes/pumps/valves, as well as adding insulation to stuff thats already too hot.
Re:"Containment vessel" (Score:4, Informative)
Wrong.
That's how it really goes:
Primary Containment: Fuel Rod Cladding (probably damaged in blocks 1 to 3)
Secondary Containment: Reactor Pressure Vessel (probably intact in blocks 1 to 3)
Tertiary Containment: Thick Concrete Containment (that's the one you forgot) (largely intact for blocks 1 to 3)
Quaternary Containment: Outside Reactor building (very damaged)
So where does the radioactivity come from? Probably mainly from the suppression chamber in block 2, which is damaged, and which has a connection with the RPV and the turbine building.
Re:Before everyone freaks (Score:4, Informative)
They say there's no danger of a Chernobyl style catastrophe, but what credibility do they have? These people--and quite a few nuclear proponents around here--told us all that there was "no danger" of any major leak in the days after the tsunami hit. Three weeks later the reactor is a molten puddle on a concrete floor,
They don't need any credibility at all. BWRs are not a zillion ton charcoal briquette like Chernobyl. You can't light the worlds largest charcoal briquette on fire and vaporize the works... if there is no charcoal briquette. From a credibility standpoint, sure with security theater you could sneak out the BWR and sneak in a RBMK and no one would notice (snicker) but lets be realistic here...
If the reactor is puddle on the floor, thats good, compared to Chernobyl where the briquette vaporized it for us to breathe... I'd much prefer it melted in a containment structure there, than vaporized here in my air.
Re:Before everyone freaks (Score:4, Informative)
Coal has significant operational issues, but few failure issues
Coal mine fires [wikipedia.org] are a huge problem, and have killed more people and left more land uninhabitable. As a kid I lived not so far from the Centralia fire, which started burning in 1962 and is still burning - and all my friends will back me up that none of us started it. And then there's the Door to Hell [wikipedia.org].
The energy stored in the fuel of a nuclear reactor is high, but small compared to the energy stored in large fossil fuel deposits.
Re:The *real* shame in all of this (Score:5, Informative)
But the biggest problem I think people are overlooking for wind is the sheer scale of the wind farm you need to replace a decent-sized power plant. Roscoe Wind Farm [wikipedia.org] is the largest wind farm in the U.S., with 781.5 MW peak capacity, 627 turbines, covering 400 km^2. Note however that that's peak capacity - how much electricity the farm generates under ideal conditions if each turbine is running at maximum power and efficiency. In practice, the average power generation from land-based wind farms has been about 20%-25% of peak [wikipedia.org]. Be generous and go with the high 25% capacity factor. So 627 turbines and 400 km^2 gives you 195.4 MW of power on average.
A single AP1000 nuclear reactor [wikipedia.org] generates 1154 MW. Figure maintenance and other reasons will drop that to about 90% capacity factor, or about 1000 MW. A plant will typically have at least two so one can remain operational while the other is shut down, so 2000 MW for the plant. How big would the wind farm need to be to replace that?
2000 / 195.4 = 10.3x bigger. To replace two AP1000 reactors will require nearly 6500 turbines covering over 4000 km^2. Each turbine requires 100-200 tons of steel [google.com], so that's around a million tons of steel. I don't even want to think about the transmission lines needed to string them all together. And wind turbines cost about $1.2 - $2.6 million per MW of peak capacity [windustry.org]. Since this hypothetical wind farm has ~8000 MW of peak capacity, that's $9.6 - $20.8 billion in construction costs. The AP1000 reactors are estimated to have a total construction cost of about $4-$5 billion [wikipedia.org] each. So $10 billion for two of them would actually line up with the low end of an equivalent wind farm's construction costs.
4000 km^2 is about 1% the land area of California. In 2010 California generated about 200 TWh of electricity [eia.gov], or an average of 22 GW. So even if you assumed lots of areas are as wind-productive as Roscoe Wind Farm, and that we developed some technology which could store 100% of generated electricity for later use, California would need to cover 11% of its land area with wind turbines to replace its current electricity generation with wind. That's a bit far-fetched to say the least.
Wind and to a lesser extent solar are not the panacea a lot of people seem to think they are. They're going to primarily be supplemental power generation technologies for a long, long time. My hopes had been on deep well geothermal, but that's run into significant problems [tnr.com] of its own.
Re:Where is the heat coming from (Score:5, Informative)
I realize this was not a chemical reaction, however, I still can't figure out that reaction was stopped at the time of earthquake according to various sources. Graphite rods were inserted into the core to stop the reaction.
So where is this heat coming from. Is the fission on going, wouldn't that mean the reaction wasn't stopped, it is still on going!
Can someone explain this to me?
When a Uranium atom splits by fission, it leaves behind two unstable isotopes. These isotopes soon undergo radioactive decay themselves. These decays produce a significant amount of heat, which can't be "turned off" because it is natural radioactive decay (as opposed to the original induced fission, which can be stopped by absorbing the neutrons which cause fission). The fuel rods are not merely hot and simply need to be cooled off - they are still generating their own internal heat due to these natural decays. The only way to get rid of these decaying isotopes is to wait for them to decay naturally, which is an exponential process.
Some of the isotopes have a short half life, which causes them to generate a lot of heat, but this large heat load decays away quickly and is gone after a couple days. A majority of the isotopes have half-lives in the years to decades range, which means they produce a moderate amount of heat for several years, which is why spent fuel needs to be stored underwater. Once the fuel is about 10 years out, enough isotopes have decayed that it can remain at safe temperature just by radiative cooling, and so can be stored in dry storage containers.
Re:The *real* shame in all of this (Score:4, Informative)
http://en.wikipedia.org/wiki/Intermittent_power_source#European_super_grid [wikipedia.org]
Re:The *real* shame in all of this (Score:3, Informative)
I don't disagree with your numbers, but your final conclusion on dedicating 11% of california to wind power is a little off. A single wind generator takes a plot of land that's a few hundred square feet. Between the generators is generally farm land (at least in the Midwest it's that way). The farmers have tons of productive land, and they mostly love the few grand per year that the power companies pay them to rent the land for the generators. Very little productive land is lost when a wind farm is build in an area.
Re:The *real* shame in all of this (Score:5, Informative)
Sorry, I don't want to debunk every little sentence, however the whole block I quoted is completely wrong and nonsense.
If you would place a solar thermal power plant covering whole Nevada you could produce 100 times the energy the planet needs right now.
If you would use the coast of three random states in the USA, like Oregon, Florida and perhaps Texas to place there wind farms it would cover the energy needs of the USA 2 or 3 fold.
You simply don't know anything about energy production ... 99% of the people don't know anything about it, so it is not your fault.
But repeating the lies of the energy companies is no good.
Dude, you sound like a politician. Starting a sentence with "believe me" is utter fail.
Anyway, if you had studied the "numbers" as you claim, you would not write such bullshit.
Perhaps you have problems with where to put the decimal point, my apologizes if that is the case.
angel'o'sphere