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Things Get Worse at Fukushima
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."
This is part of the planned failure mode of the reactor. To be sure, it's fairly far on the "stuff is breaking" scale, and there are definite consequences (such as fears of leakage into groundwater). But this is not going to be a Chernobyl-level catastrophe.
However, fingers crossed that nobody else dies. Japan's already had enough fatalities this month.
Just to be clear, they are absolutely not implying it has melted through the containment, but, rather, the reactor pressure vessel.
There are, as well, media sources that say this *isn't* so, and that this is mostly a Media Hysteria. For example: http://www.theregister.co.uk/2011/03/29/tv_news_goes_hollywood/
If you want news from today, you have to come back tomorrow.
Here's the thing: The reactors at Fukushima are ~40 years old and contain a design flaw that essentially caused this to happen. Newer designs for water boiler reactors have the water flow in via gravity feed instead of requiring manual pumps running on external power. While it's certainly possible that other problems might've caused a newer reactor to suffer potential meltdown, it's very likely that we would've never seen this occur if Fukushima Daiichi had a gravity-feed water cooling system. The takeaway should be that nuclear power plants need to be upgraded to keep up with the times, but unfortunately I think you're right, and the takeaway will be "OMG NUCLEAR BAD."
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 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.
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/
"I zero-index my hamsters" - Willtor (147206)
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 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.
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
nuclear power: it's safer than ponies.
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.
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.
This and no other is the root from which a tyrant springs; when first he appears as a protector - Plato (423 to 327 BC)
That's pretty much the conclusion I've reached. By cost, solar (20-45 cents per kWh) is currently nonviable except for places with extraordinarily high electricity costs (e.g. the more remote islands of Hawaii) or extraordinarily strong and consistent sunshine (e.g. the desert Southwest U.S.). Wind is getting there, down to about 7-12 cents per kWh wholesale, compared to 3-5 cents for coal.
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 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. 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 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, 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. 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 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, 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 of its own.
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.
http://en.wikipedia.org/wiki/Intermittent_power_source#European_super_grid
Yes, I'm left. You have a problem with that?
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.
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
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.