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Chain Reactions Reignited At Fukushima
mdsolar writes "Radioactive byproducts indicate that nuclear chain reactions must have been burning at the damaged nuclear reactors long after the disaster unfolded. Tetsuo Matsui at the University of Tokyo, says the limited data from Fukushima indicates that nuclear chain reactions must have reignited at Fuksuhima up to 12 days after the accident. Matsui says the evidence comes from measurements of the ratio of cesium-137 and iodine-131 at several points around the facility and in the seawater nearby."
That is all.
If you melt the fuel, you can get localized criticalities.
Comment removed based on user account deletion
http://www.energyfromthorium.com
We have no one to blame but ourselves for any accident that happens when a safer, cleaner, more efficient, and cheaper nuclear fuel is readily available and already has most of the hard problems with its implementation worked out through several running prototypes.
If the reactors had been successfully scram'd completely, heat from decay of by-products would have burned out in a very few days. As became obvious, that didn't happen.
I saw that movie. Not only does it end well but its got Neo in it. Don't worry. There is no spoon.
Seriously though... that's scary. It might not be Chernobyl but this has got to be the worst nuclear disaster of its type. Although since they're in Japan wouldn't it be called the South America Syndrome? (polar opposite of Fukushima is Chile)
Nobodies Prefect
Tidbits for Techs Technology Blog
How, without a moderator?
My understanding is that LEU (low-enriched uranium) cannot achieve criticality without a moderator to slow down the neutrons?
Can anyone with a nuclear physics/engineering background give any explanation of how you can get a chain reaction without moderator?
Ok, they were cooling the reactor with water, and water is a moderator, but the water was also boronated, which should cancel the moderation property of water, shouldn't it?
More and more I see the attempt to design and operate Nuke plant as a very dangerous game of Whack-a-mole. Operator error, Wham, Design error, Wham, Maintenance failure, Wham. Earthquakes. Wham. Tsunamis, Wham. Terrorism, Wham,
and, what do we do with the waste for the next 20,000 years? Wham, Wham, Wham, Wham........
Miss one time, game over.
Kurt
And operating a coal plant is akin to all the moles poked out of their holes and looking at you while you shrug and say "working as intended."
"I zero-index my hamsters" - Willtor (147206)
There are reactor designs that currently exist that are more resilient to meltdowns. Most notably, thorium molten salt reactors, but there are only a handful of experimental reactors in existence. There is also the CANDU reactor primarily used and designed in Canada which is a uranium heavy water reactor.
I will agree with you that the ancient nuclear technology most reactors use today is not that safe, but more modern reactors have solved that issue. The only problem has been rolling out thorium and CANDU reactors.
And WRT your comment on terrorism, there's a video on Youtube I've seen that debunks the whole "flying a plane into a reactor" myth. Nuclear plants have concrete walls that are like 10 feet thick and the plane collapses on it self and does nothing to the wall.
You can get rid of the waste whenever we are smart enough to switch to thorium fueled fluoride salt reactors which are inherently safer, much more efficient using only a fraction of a much more plentiful fuel to produce the same energy. The small amount of unusuable nuclear byproducts of a thorium reactor have much more manageable half-life of around 330 years. The useful byproducts include many things that are otherwise difficult to produce like the isotope of plutonium used to power deep space probes, bismuth-213 which is used in cancer treatments and has a 45-minute half life.
But to your point the best thing is the inherent safety, LFTRs (liquid fluoride thorium reactors) can be easily designed to passively shutdown rather than requiring active cooling inside the operating core which is the problem with all water cooled reactors which is all we have today. The funny thing is we have tested and proven this technology, we know it works, but the unsafe technology that produces weaponizable nuclear components and huge amounts of dangerous waste is so lucrative and entrenched that current nuclear players have no financial incentives to make the shift.
And the fact that a LFTR can reduce the waste we have produced from current nuclear technologies and turn it into more energy and more manageable waste.
As opposed to coal/oil/gas plants, where the game is Russian Roulette. They're going to kill people eventually from all the shit they pump out - the game is just hoping it isn't you.
Hydroelectric is a game of Jenga - lots of fun, but eventually something'll make the dam break, which is actually the most massively devastating type of power plant failure. The Johnstown Flood (caused by a dam failure) remains the deadliest disaster in US history. Estimates for a failure of the Three Gorges dam usually have 6-7 digit body counts.
Solar/Wind/Tidal/Geothermal/Fusion are all games of "how the hell can we make this actually work?". AFAIK, nobody has ever run an entire full-sized country, or even a significant fraction of a country, off any of those. It would be nice if we could, but so far, they are either not cost-effective, not able to produce enough to meet demand, or not even fully functional.
As well as that there has been some speculation that the explosion in unit 3 was more than just a hydrogen explosion. If you compare the unit 1 and unit 3 explosions, you see the unit 3 was far larger in magintude, plus there is a flash right where the spent fuel pool is located. Also pieces of nuclear fuel rods were found 2 km from the site. Arnie Gundersen speculates that this was caused by a "prompt criticality" in the fuel pool, triggered by the hydrogen explosion. http://fairewinds.com/updates
Miss one time, game over.
Hardly, chernobyl and fukushima were about as miss as you are going to get, reactors dont blow up in the same way that a fusion bomb does.
Granted, chernobyl has a 30 KM exclusion zone, and fukushima will likely need a permanent exclusion zone as well, but it's hardly game over for the human race. It would be a good idea to build these things far away from large cities (having tokyo inside the exclusion zone would suck), but in the grand scheme of things, these kind of events are rather survivable
No disrespect to the victims of chernobyl or fukushima by the way, i dont mean to trivialise their plight, just saying that on a world scale, this isnt that big of a deal
People, what a bunch of bastards
The thousands of people coal plants kill every year due to air pollution and mining accidents? Must admit I'm struggling to find an absolute number, but this'll have to do:
http://nextbigfuture.com/2011/03/deaths-per-twh-by-energy-source.html
Solar/Wind/Tidal/Geothermal/Fusion are all games of "how the hell can we make this actually work?". AFAIK, nobody has ever run an entire full-sized country, or even a significant fraction of a country, off any of those.
Iceland does - 66% geothermal.
But I agree that this is a very special case. Wind and (eventually) solar would be able to cover a large part of the energy needs of many countries - was it not for the tiny little problem of storage when it is winter, cloudy, and windless. Or just night.
Sensationalistic, atleast.
Did they restart? Techreview says "yes", Nature says "No":
http://blogs.nature.com/news/2011/05/analysis_suggests_fukushima_re_1.html
"The decay heat, which is 7% of 1000 MW"
IIRC, the reactors were 1000MW *electrical* output. Because of thermal efficiencies of steam generators of around 35%, I believe that means the thermal output of each reactor would have been about 1000/.35 ~= 2800 MW thermal energy.
So, instead of 7% of 1000MW = 70MW, I think you're looking at 7% of 2800 = 196MW.
That's a LOT of heat to get rid of, even if it is a small percentage of the 2800MW full output.
There are reactor designs that currently exist that are more resilient to meltdowns.
Yes, but it requires a different type of reactor. CANDU reactors can do it.
Rule of Slashdot #0: You and people like you are not representative of the larger population. - A.C.
and, what do we do with the waste for the next 20,000 years?
The part that is truly dangerous over that time span can be recycled. Just do that instead.
Know what? If we could use wind/solar/whatever during the day, and leave coal/oil/nuclear for just the night (and cloudy/windless days), that would still be a good 50% (give or take) reduction in dependence...
Sorry, You did not address waste issue. Wham. Wham
What waste issue, you do realize you're surrounded by radiation now right? Granite counter tops, bananas, air line travel [boom headshot]. Btw some thing will kill you, be it cold, or starvation b/c you don't live next to the food you eat, or perhaps bacteria growing in the natural environment that decided you were a good place to set up shop. But hey, you keep trying to make everybody confirm to your nanny-state, gaia fueled fantasy and let me know how that works out.
I laughed at the weak who considered themselves good because they lacked claws.
So what you're saying is:
It was the worst natural disaster in Japan's history, one that was the perfect storm of conditions, all affecting an ancient design of plant which was NOT designed to handle such disasters, and yet despite this- still to this very day- has not had a substantial meltdown (some radiation leakage is not crowd on the beach in Melbourne)... and you're *complaining*?
Inevitable car analogy is as follows. If I own a regular Toyota Prius, there's a reasonable expectation that if I get into a fender bender I won't die. It's engineered to tolerate that. The car may be a write off, but I'm fairly safe.
But if a TANK shoots my Prius? Well, then I'm fucked. I'll die and it's *not Toyota's fault*, much less the fault of the automotive industry at a whole. You accept that, right? You accept that anything built by anyone, ever, is built to a limited amount of tolerance, and beyond that failure is not the fault of the manufacturer, let alone the whole industry?
In this metaphore, a tank shot my Prius in the engine block... and to the astonishment of most the Prius fucking TOOK IT. That armour-piercing tank shell bounced off like a motherfucker, leaving a huge dent, and shaking the car so I wacked my head, but hey. I'm alive and whole. I walked away after the worst imaginable thing happened, far beyond the design specifications of the vehicle. Yeah, there was a little blood-slash-radiation leakage from my head, but it's not that bad. I could have a concussion. I should probably get checked out, but it could have been MUCH worse. Furthermore, I am astounded on how this Prius is eating tank shells. That's some serious engineering work right there. Damn, dog... ... and yet, people are still like, "Oh, but I'm bruised a little bit, it didn't protect me completely. Priuses are so unreliable!"
Seriously.
Tank.
Prius.
Tepco might be incompetent lying morons, but the reason why the old plant was still around was in no small part because of anti-nuclear fear-mongering ("Not in MY backyard!"). That's the reason that newer, far more safter, reactors are not everywhere. Because constructing new nuke reactors is verboten, like we're still in the 70's or some shit.
If we treated nuclear power with the respect it deserves, keeping the technology up to date and learning from our mistakes... then we can progress.
Check out my sci-fi book "Lacuna" at http://goo.gl/MVxX8
Boeing designed the 787 without isolation between the network running the in-flight entertainment system (some of which allow PAX to plug in USB storage devices) and the network on which flight systems sit.
Not exactly. They (Boeing and Airbus, the only two major civilian transport aircraft mfgrs left) were spanked by the FAA half a decade ago to very specifically not even think of doing that.
So conceivably a passenger could have hijacked the plane without ever leaving their seat, e.g. with a crafted media file to exploit, say, ID3 parser bugs.
I presume Boeing have been forced to fix this, but I havn't checked...
Well conceivably, a pig could fly given a high enough thrust to weight ratio via a ID3 parser bug.
Check out
http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=2008_register&docid=fr02ja08-5
aka "FAA Docket No. NM364 Special Conditions No. 25-356-SC"
More or less the FAA telling Boeing and Airbus they will absolutely not be allowed to fly a transport plane without guaranteeing they are not completely separate.
This was all fought out and resolved like half a decade ago but the meme that passengers can hack into the FCS just simply will not die. 20 years from now we'll still be hearing about how someone heard someone quote someone else as having heard that its done all the time by the mysterious someone or something.
Now magically proclaiming "it shall be done" does not mean it actually will be done. Also an argument based on "theoretically I could be an axe murder, because I do have two strong arms and own an axe" and claiming there may or may not be a law against specifically being an axe murder vs a regular old murderer murderer, does not say anything really useful about the venn diagram of me and axe murderers.
I'd worry a lot more about someone jamming GPS, or sabotaging the production facilities, or shooting at the planes from the ground. Basically, the traditional attacks work so much better, and are so much cheaper...
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
http://fairewinds.com/updates ha
Try the same news in video form from a US energy advisor with 39-years of nuclear power engineering (Bachelor's and Master's Degrees in nuclear engineering) experience.
http://fairewinds.com/content/who-we-are
Domestic spying is now "Benign Information Gathering"
ah well shit, it sounds dangerous. we all need to give up and go back to living like the amish.
I run: Windows, OS X, Linux, FreeBSD. Just because you have a hammer, doesn't mean everything is a nail.
Horse shit. Pure horse shit. Radiation levels at the moment are still extremely minor. Plant workers are still not exceeding their yearly allotment, they're being pulled out before hand. The yearly allotment is below the level that shows even a minor increase in cancer rates. The government has stopped fishing mostly for trust reasons - it's unlikely that anyone would've been made sick, but they want people to feel safe buying the fish when they do open it up.
This is a big problem, and it shouldn't have happened. But this event has made a few people sick (like a sunburn) for a few days because they didn't follow proper protocol. Meanwhile, the triggering event has killed, what, 20,000? Versus a couple people with minor injuries.
If you have evidence to refute the above points, I'd love to see your citations. I've been following this pretty closely, so I'd be very interested to see if I've been wrong.
But it seems like you're just making stuff up. There are plenty of facts in this debate. Don't go inventing nonsense just because the facts don't fit your opinion.
I'm not a nuclear fanboy, by any means. As an engineer, current plants make me nervous because they rely on active safety. But I'm more annoyed that NIMBYs aren't allowing research and production of the intrinsically-safe plants, than I am about the operators of the plant. Nuclear plants "feel" unsafe? Well they have just about the best safety record of all industrial facilities. This particular plant had multiple failures after design specifications were well exceeded, and even then the problems they've had have been extremely minor in relative and absolute terms.
In short, you're being irrational.
I have developed a truly marvelous proof of this comment, which this signature is too narrow to contain.
Depends if it is concentrated and whipped up into an inferno, out of reach of fire control equipment.
Unless you know of a reactor that's several hundred feet up in the air...
Good point. I can't think of any reason why firefighters couldn't put a fire out at a burning reactor building. Oh... wait a second... there was a fire at Windscale... and Chernobyl... and Fukushima for the most part is still too hot to get near, even without a jet fuel fueled fire... but yeah, except for the overwhelming evidence to the contrary, you're completely right.
The Admin and the Engineer
The comments below the Nature blogpost gives some additional info though:
.
(Blogpost author, Geoff Brumfiel)
So Matsui himself notes that it could be caused by contamination, not by reignition. In fact, the unit 2 results would suggest that that is the case.
(He then points to the MIT TechReview-article for the other perspective).
I very much doubt this, since the both the steel and concrete containment of block 3 are still intact. I think the difference may have been due to the difference of the outer shell, which was not made out of reinforced concrete in the case of block 1. Also, the power of block 3 was around double the one of block 1, so it is possible that more hydrogen was produced. On top of that, the hydrogen accumulated for two days longer in block 3 than in block 1.
Ah, just saw that a criticality in the spent fuel pool is claimed. This is also most unlikely. First, if this would have happened anywhere, it would have been in the spent fuel pond of block 4, which had much more fuel stored. Secondly, this was far too big an explosion for a criticality - the energy generated by a chain reaction would immediately boil the moderator and stop very quickly again. Thirdly, a massive amount of neutron radiation would have been measured in that moment - but it wasn't. I think very minor criticality events may have happened from time to time, which might explain the results of the article. It would also explain the dozen or so detections of neutron radiation at very low intensity.
In the grand scheme of the accident, I don't think it played a role.
Yadayadayada. You still did not address the waste issue. Are you saying that the nuclear waste in in the same league as a granite counter top? Who the fuck moderates this shit up?
It started to carry a negative connotation when some people started using junk science to raise false alarms. Look at Helen Caldicott telling everyone that Chernobyl resulted in millions of deaths, and that Fukushima will result in millions of cancers.
She repeatedly appeals to a single source - a Greenpeace "Report" which they somehow managed to get the NYAS to publish without any peer review, which specifically states that it does not use standard scientific analysis methods because those methods don't give the results the report author wants to find.
She ignores all the other science which has been done to determine the results of Chernobyl, decrying it all as a massive "cover up" and "fraud". There's only one report in the world, apparently, which tells "the truth". These people cherry pick their sources to get the alarming results they want to find.
See: Confirmation Bias
That is the sense that most people use when they pejoratively use the term 'alarmist' - someone who spreads FUD which is not based on sound science.
That was the cost of dealing with the whole Tsunami. Stop trolling.
You obviously haven't looked at the design of the plant. There are 3 layers:
- The outer cosmetic steel box, to keep the weather out
- The inner concrete containment chamber
- The inner steel pressure vessel that houses the actual reaction
Unit 1 reactor vessel was leaking into containment before the Tsunami hit and backup power and cooling were lost.
Unit 2, some part of containment, probably the suppression pool, ruptured and is leaking.
Unit 2, although there's still a roof, that concrete building isn't containing the leaking water. I thought the whole idea of a cooling system that used a heat exchanger and ran seawater through a secondary loop, was to have ALL contaminated water kept within the building.
One could argue that the newer buildings are much better, but the Unit 2 building is apparently intact and didn't contain the water? What's up with that? The heat exchanger and hot side pump is in the building, so that shouldn't leak outside. The turbine pipes are from the reactor vessel, not containment, so those should be a separate issue. So why is all that water getting out of the building?
Among the other oversights, it seems no one planned for explosions. What's up with that? Why were those unexpected?
It seems the first explosion occurred when they went to vent. There's something seriously wrong with the design. With nothing but the fuel pond loaded, unit 4 still blew up. More than one explosive failure mode?
What possible excuse is there for that? A billion dollar plus unit blown up because of stored fuel? Maybe it is time to re-examine fuel storage.
No doubt the U.S. will see some added breast and cancer cases in 10 or 20 years from people. mostly women, who drank the milk from the cows that ate the grass, when moderate rain brought down the Iodine 131. Some high levels in rainfall were seen. Most places weren't even checking for it. The spots that got hit probably had it happen just on one day or so, and otherwise saw "No levels harmful to human health". Oh boy. Most of the cancer in Sweden from Chernobyl is believed to be from rainfall on one day. Sometimes that's how it works.
The impact won't be huge, but it isn't zero either.
(info on Sweden and other places in this Chernobyl pdf)
http://www.strahlentelex.de/Yablokov%20Chernobyl%20book.pdf
http://www.strahlentelex.de/Yablokov%20Chernobyl%20book.pdf
actually, LEU can still go boom, it just requires a far larger critical mass than is practical for making bombs. A reactor however has plenty of mass for such an event. Even more so since as the reactor operates, it enriches the fuel... Granted the yield / yield % effective will be really low, but one doesn't need a very high efficiency with 100 tons of fuel to make a pretty big boom. Even the equivalent of couple of tons of TNT is a pretty nasty explosion, never mind 10 kilotons... Anyone who wants to know what 1 ton of TNT does, watch the myth-buster episode where they take on a cement truck.
-=Geoskd
I wish I had a good sig, but all the good ones are copyrighted
Prompt criticality would be suspiciously like an atomic bomb, because that's how they work. But it seems like there was only very minor fallout, of short-term fission products (iodine, etc), which indicates that it just released existing product.
Perhaps the explosion was larger because there was more hydrogen? Also, don't underestimate the power of explosions like that - Chernobyl's steam explosion threw (much heavier) graphite moderator blocks a tremendous distance.
The size of the explosion was only part of the issue. Two other issues also contradict a hydrogen-only hypothesis. The first is the bright orange flash at reactor building 3. Hydrogen burns/explodes translucent. This can be seen with the explosion at building 1: No fireball, but massive and highly visible shock-wave. That had all the hallmarks of a hydrogen explosion. Issue two was the shaped nature of the second explosion. Both the primary (probably hydrogen) blast, and the anomalous orange flash had a distinct upward vector, indicating that some factor was tamping these explosions upward. These two observations together suggest the spent fuel pool, or the primary containment. As there are lots of reasons to believe the primary containment is still intact, this leaves the spent fuel pool as the next most likely candidate.
-=geoskd
I wish I had a good sig, but all the good ones are copyrighted