Japan To Create a Nuclear Meltdown 222
Taco Cowboy writes "Japanese researchers are planning an experiment to better understand what transpires during a nuclear meltdown by attempting to create a controlled nuclear meltdown. Using a scaled down version of a nuclear reactor — essentially a meter long stainless steel container — the experiment will involve the insertion of a foot long (30 cm) nuclear fuel rod, starting the fission process, and then draining the coolant. The experiment is scheduled to take place later this year."
Great (Score:5, Insightful)
What could possibly go wrong?
By the way, didn't they have to hand in their license to do nuclear stuff already?
Re:Great (Score:5, Insightful)
I believe that's what they want to find out.
Re:Great (Score:5, Insightful)
And, it should be noted, they want to find out in controlled conditions with sufficient protective equipment in a facility explicitly configured for this kind of situation. This is science.
Re: (Score:3)
Yeah, the OPs attitude was my first impression, and yours is where I settled, quite quickly after reading the summary.
Re: (Score:2)
Yah, but can we please do it on the moon!
Re:Great (Score:5, Insightful)
This is science.
The problem is that it should have been done decades ago. You're supposed to test failure modes before you declare something safe. That's doubly true of something as potentially dangerous as nuclear meltdowns.
Re: (Score:3, Insightful)
The problem is that it should have been done decades ago.
Well at least we're getting round to it now. Nuclear energy was deployed well before it was ready to produce electricity in such scale, and the insecurities we built into the plants because our engineering wasn't up to the task yet produced many violent and unfortunate accidents. But we're going to have to embrace nuclear energy in one form or another if we plan to have a cheap source of clean and reliable energy in the coming centuries. It's best research into preventing nuclear core accidents and preventi
Re:Great (Score:5, Informative)
Re: (Score:3)
Similar has been done decades ago. The BORAX experiments for a start.
Re: (Score:2)
Similar has been done decades ago. The BORAX experiments for a start.
Followed more recently by the LORAX experiments, which turned out far worse. At least so far as Wall St. was concerned.
Re:Great (Score:5, Informative)
It was done decades ago.
Pacific Northwest National Laboratory conducted in-reactor experiments that involved total fuel failure in a controlled environment. The series of experiments took place in the Canadian research reactor NRU located at the Chalk River Laboratory in Ontario. There were a series of experiments over about a six year period in the 1980s.
Three Mile Island's accident was the trigger for this research program. There was financial support for the project from the US, Canada, Japan, Germany, and a consortium of around 20 other nations.
The most severe of the accidents that we simulated involved simulating a Loss Of Coolant Accident (LOCA) that resulted in fuel rod cladding failure (including melting in the worst cases) to try to recreate the near total blockage of coolant flow in the fuel bundle. There were around 200 thermocouples in the test rig, along with lots of flow meters, etc. The idea was to gather enough detailed data to allow the regulatory agencies to properly evaluate the computer programs developed and used around the world that would try to predict the test results.
We actually used full 12-foot commercial reactor sized fuel rods. The reactor had only a 3-meter long core so our experimental containment actually stuck out the top and bottom of the regular core. We had a tiny bundle of rods, fully instrumented, inside a specially designed containment and the whole thing was then inserted into a process tube inside the reactor.
You can do a Google (or other) search using the words "pnl nru loca" and you can find a lot of information.
I was the lead programmer for the data acquisition and control system for the experiments.
Re: (Score:2)
True of Justin Bieber too.
Re: (Score:2)
It was done. Many times, and most recently in the 2010's by Argonne scientists.
Re:Great (Score:4)
We don't understand the mechanics involved, and we didn't really need to in order to build safe containment vessel floors that can hold an ugly puddle of radioactive sludge.
So we did build such containment vessels? Then why did the Fukushima accident happen at all? The tsunami didn't breach the containment. It only shut down all the generators. Your language implies that nuclear powerplants are "run-away safe", i.e. if anything really bad happens, there's always the "safe" containment to contain it all, because "we" built it so it can contain the molten reactor core. But no existing plants really have that capability.
Re:Great (Score:5, Insightful)
Fukushima's containment vessel could (and did) contain the molten core... but not the hydrogen explosions that also occurred inside the reactor chamber because of the total coolant loss.
My language should imply that nuclear reactors are safe against the foreseen failure modes. At Fukushima Daiichi, it was not expected that all of the coolant systems would fail at once and that repairs would be hampered by the tsunami damage.
Re: (Score:3, Insightful)
Fukushima's containment vessel could (and did) contain the molten core...
I didn't claim otherwise. I said existing reactors aren't designed to contain a nuclear accident as a whole, so that the environment would be unaffected. Your language implied that existing reactors had that capability, because you reduced what's a whole array of potential safety problems to just the capability of the containment vessel to contain a molten core.
Re: (Score:3)
I didn't claim otherwise.
Let's review...
in order to build safe containment vessel floors that can hold an ugly puddle of radioactive sludge.
So we did build such containment vessels? Then why did the Fukushima accident happen at all?
Floors are generally not considered "safe" based on their ability to contain an explosion, and per the subject of discussion, the only criteria I am referring to is indeed the ability to mitigate one particular kind of failure mode. If we expect a single mechanism to protect against every possible failure happening at once, we must also avoid all useful definitions of the words "safe". It's a block of concrete we're talking about, not Superman.
Engineers have been doing failure analysis on nuc
Re: (Score:2)
Fukushima's containment vessel could (and did) contain the molten core... but not the hydrogen explosions that also occurred inside the reactor chamber because of the total coolant loss.
My language should imply that nuclear reactors are safe against the foreseen failure modes. At Fukushima Daiichi, it was not expected that all of the coolant systems would fail at once and that repairs would be hampered by the tsunami damage.
The hydrogen explosion could not happen in the reactor chamber. What happens is that the reactor overheats, the zircornium reacts with the water. The oxygen atom is ripped away from the water to form zircronium oxide. The left over hydrogen cannot explode inside the reactor vessel because the oxygen is gone. So it leaks out and is eventually ignited.
Question for everyone: does anyone know if Fukushima has the US style concrete containment buildings? The explosions I saw on tv were clearly of an indust
Re: (Score:3)
We don't understand the mechanics involved,
Sure we understand those "mechanics".
It is bottom line not different to smelting steel in a steel plant.
Re: (Score:3)
Re: (Score:2)
Wouldn't it more constructive to learn how to nullify radio activity?
We already know how. Keep nuking the atoms until they split into stable elements. The primary problems are that 1) each step isn't 100% reliable, and 2) some nasty, nasty things are created in the meantime.
Re: (Score:2)
Re:Great (Score:4, Funny)
That's very smug and glib, but your attitude is like saying that trains and cars are a waste of time because we'll eventually invent airplanes, and we can stick with horses until then.
Re: (Score:2)
Re:Great (Score:5, Funny)
Re: (Score:2)
And, it should be noted, they want to find out in controlled conditions with sufficient protective equipment in a facility explicitly configured for this kind of situation. This is science.
Hopefully the researchers have purchased a sufficient quantity of GI Joe figurines and toy tanks to deal with the inevitable tiny Godzilla they will create.
Re:Great (Score:5, Informative)
You calculate the maximum amount of energy you could get out of the reaction and make sure that whatever you're using to contain it can contain that much. It's not as though there's infinite energy in uranium.
Re:Great (Score:5, Insightful)
Good luck with that. IDB Reference Characteristics of LWR Nuclear Fuel Assemblies from the 1996 Integrated Database Report (copied from Nuclear Tourist [nucleartourist.com]) mentions a fuel rod assembly containing 185 kg uranium. In contrast, Little Boy which destroyed Hiroshima contained 64 kg uranium, and that was certainly not a 100% efficient fission reaction.
It is not realistic to design nuclear power plants to withstand the maximum energy you could get out of the reaction. That would kill off the nuclear industry.
Feel free to start discussing whether it is realistic to get all the energy out of the 185 kg uranium. You can argue that it is less highly enriched than bombs, and that it is entirely unlikely that uranium which is mostly U-238 is going to suddenly decide to fission. I completely agree, but then we are no longer protecting against the maximum energy that could get released.
Re: (Score:2)
Ah sorry, I misread the comment. For this particular test, they can of course create such a protected environment. If nothing else, do it like a nuclear bomb test deep underground.
Once in a while I wish it was possible to delete posts...
Re: (Score:2)
Now what I do not know is which has more heat load: a brand new fuel rod running full bore for a few days, or an old fuel rod full of radio isotopes, but only running at half capacity due to the waste products. I'd guess the new one
Re: (Score:2)
Well a very logical approach.
But in relation to a containment vessel the amount of energy is "infinite". Halftimes around a few thousand to a few million years.
In other words: the uranium in a reactor will "burn" for years. In case of a melt down that means it stays molten for years.
Lets make a simple example.
The "bottle" in which we melt the uranium is made of "something" like steel or lets say fro sake of argument "lead". (Lead means low melting point, so we can argue better).
Uranium is very heavy, so if
Re: (Score:2)
What causes the meltdown is actually the waste products of the reaction. The waste products are radiologically and thermally hot. If not cooled they cause the fuel rods to melt. The molten mass will go downwards absorbing
Re: (Score:2)
You kind of answered your own rant there. The physics behind nuclear fission reactions are well understood in terms of the worst case scenario for a run away reaction and the greatest possible magnitude of heat and other high-energy products for a given input of fissionable material.
There is no question that a controlled environment can be created
Re: (Score:3)
Reaction rates are fairly well understood, as are the characteristics of the radiation itself, so it's fairly straightforward to build a containment vessel that can hold the whole experiment. As I understand it, what's not really well known is how the fuel itself behaves in a meltdown, because they are (fortunately) so rare. Apart from "everything melts and settles in a puddle at the bottom", we don't know how quickly it melts, how that affects reaction rates (though we know it doesn't explode like a nuclea
Re: (Score:2)
The same might have been said before Chernobyl 1986. A power plant is supposedly a controlled environment, and the people there certainly thought they knew what they were doing...
I'm not knockin' the Japanese for wanting to conduct this test. I agree that it is a test that should be conducted (well, should have been conducted, decades ago), and they'll probably do it properly. Doing it with a single fuel rod, rather than an en
Re: (Score:2)
A power plant is supposedly a controlled environment, and the people there certainly thought they knew what they were doing...
Yeah, like maintaining their equipment regularly [heraldsun.com.au], am I right? ;-)
Re: (Score:2)
You realize Japan is a sovereign nation, right?
Re: (Score:2)
Not really. They haven't assembled their nukes yet. Realpolitik definition of 'sovereign' for the 21st century.
Re: (Score:2)
More like warmongering definition.
Re: (Score:2)
What could possibly go worngg?
FTFY
WTF? (Score:3, Funny)
Re: (Score:2)
Fortunately the odds of a reactor in Japan “melting down to China” are even lower than they are in the general ameri-centric case. Or at least they would be if odds could go negative.
We all know what's going to happen... (Score:3)
Can't wait for this mini meltdown to lead to its inevitable ultimate conclusion: MiniGodzilla!
Re: (Score:3, Funny)
Re: (Score:2)
AND... Fire-beathing, of course!
Great with the ladies: "Come Yumiko, let me light your cigarette with... (dramatic pause) my Mini-Godzilla!"
Re: (Score:2)
http://godzilla.wikia.com/wiki/Minya [wikia.com]
your favorite monster sucks (Score:5, Funny)
Re: (Score:2)
I believe you mean Minilla:
http://godzilla.wikia.com/wiki/Minya [wikia.com]
Having watched Godzilla vs. SpaceGodzilla last night, I feel obligated to remind you that it may also be Little Godzilla: http://godzilla.wikia.com/wiki/Godzilla_Junior [wikia.com]
Good Idea (Score:4, Insightful)
It seems so obvious to me now, having seen the idea in print. This is not the sort of thing that is easy to analyze. A test is really a good way to understand the phenomenon. The paradigm where engineers attempt to make sure it never happens has its limits. Looking at what happens during the failure will allow engineers to develop meaningful "defense in depth" measures.
Regards,
Jason C. Wells
Re:Good Idea (Score:5, Insightful)
The paradigm where engineers attempt to make sure it never happens has its limits. Looking at what happens during the failure will allow engineers to develop meaningful "defense in depth" measures.
That was understood decades ago, and has been SOP for that long in other safety critical applications like aircraft. The fact that it wasn't done before this is extreme negligence.
Re: (Score:3)
The paradigm where engineers attempt to make sure it never happens has its limits. Looking at what happens during the failure will allow engineers to develop meaningful "defense in depth" measures.
That was understood decades ago, and has been SOP for that long in other safety critical applications like aircraft. The fact that it wasn't done before this is extreme negligence.
To test a meltdown scenario is to admit that it is possible. This is not something that big power ever wanted to do, until it happened of course.
Re: (Score:2)
I don't think "big power" ever claimed a melt down was impossible.
What they claimed is that it would be kept 'contained' in the 'containment vessel'
In other words it would not get into ground water etc.
Re:Good Idea (Score:5, Interesting)
I'm curious how much they'll be able to infer, though. Nuclear reactors (and reactions) are viciously non-linear. If you make it too small, you'll get no (self-sustaining) reaction at all. From that point up, the nuclear reaction scales with volume, thermal transfer probably scales with surface area, and other material properties and deformations will scale anything from linear to fourth power (at least).
So trying to infer anything about full-scale reactors from this is going to rely on a lot of modelling to tell you how the results will be transformed into real-world performance. Since it's that model that you're trying to investigate, there are lots of potential pitfalls.
Re: (Score:2)
Re: (Score:3)
If they're doing what I think they're doing and modelling the early stages of a meltdown when individual rods are overheating, then the nonlinearity shouldn't be an issue. The fuel rods in a reactor are, at that stage, reasonably independent of one another. It won't tell you much about what happens when the fuel all melts and starts pooling at the bottom of the reactor of course.
Re:Good Idea (Score:5, Funny)
It won't tell you much about what happens when the fuel all melts and starts pooling at the bottom of the reactor of course
They already did that experiment, but it was poorly instrumented.
Re: (Score:2)
Independent in what sense? As in, individually there is no self-sustaining reaction and no meltdown, but put them together and they produce enough heat and radiation to melt?
I know that's asked sarcastically, but I'm genuinely interested in what way the fuel rods behave independently of each other that would be interesting.
Re: (Score:2)
until the rods reach the "puddle at the bottom of the reactor"stage they can be modeled seperately (sort of maybe)
Re: (Score:2)
I was thinking more like "the rod's basically just a unit experiencing a certain neutron flux from the rest of the reactor and is at a certain temperature" but you're right, it's not a reasonably independent state.
Re: (Score:2)
I'm curious how much they'll be able to infer, though. Nuclear reactors (and reactions) are viciously non-linear. If you make it too small, you'll get no (self-sustaining) reaction at all.
This is not "let's melt down a core and we'll learn all about meltdowns." They are probably looking for a few specific data points to help their modeling.
I thought that experiment was already underway (Score:2, Funny)
Just give it a little time folks. You will have your answer just like the rest of the world, only sooner.
Environmental impact? (Score:3)
Are they going to do this in already contaminated areas, or are they going to potentially screw up some new place?
It's not unreasonable to want to know more from a scientific standpoint, but hopefully someone is asking "what if this goes worse than expected?"
Re:Environmental impact? (Score:5, Funny)
Being a major industrialised nation with a nuclear power program, Japan has no nuclear research facilities so they're going to do it in downtown Tokyo.
Re: (Score:2)
Being a major industrialised nation with a nuclear power program, Japan has no nuclear research facilities so they're going to do it in downtown Tokyo.
Wait, there's more to Japan than Tokyo?
You'd never guess it by watching half of their movies and TV shows.
Re: (Score:2)
It's ok, its not a long way to China from there
Re: (Score:2)
You jest, but a significant number of Tokyoites glow like they've already helped with some nuclear experiment.
really?! (Score:2)
Redundant? (Score:5, Insightful)
Test site suggestion (Score:2)
They need to make sure they do this somewhere where if it all goes wrong, nothing of value is lost, like maybe Croydon.
Re: (Score:2)
I was thinking Chernobyl. Nobody will notice a bit more.
Japan needs their reactors restarted.. (Score:4, Insightful)
The situation with the imports of coal and oil / gas is not sustainable.
Renewable sources are part of it, but they do not have the energy density for baseload required to run a modern society. Japan is a nation with limited resources. Their power options are limited. Import of power from neighbors isn't a great long term move for sovereignty.
This puts them between a rock and a hard place, so to speak. Mark my words though, those reactors will be fired up, because they need to be. They should build more.
The scale of the amount of energy consumed by modern civilization is head-spinning. Nuclear is our only real option. Existing technologies should be deployed, and new ones researched. No politician in the west has the balls to do that, so we're going to burn every drop of oil instead, largely because nobody ever looks at the numbers and amount of energy required. (I however, did.)
Thankfully, China may save us.
I just hope the nuclear option picked isn't the one with the warheads. That will fix the problem too. There is some quality black humor and irony there.
Re: (Score:2)
Unfortunately free markets roll downhill, and while nuclear isn't as far to climb as solar or wind, it's still uphill.
Re: (Score:2)
I agree with xtal that one or the other of the "nuclear options" is not unlikely. But I doubt that nuclear in its existing implementation is a solution, in that the more existing-style plants there are, the more accidents there will be, the more public resistance there will be, and the more likely the plants will be permanently shut down.
What is needed, and I'm not saying it's about to happen, is to rearrange economies so that energy is priced at or higher than its real cost to the environment. I don't kn
Re: (Score:2)
Renewable sources are part of it, but they do not have the energy density for baseload required to run a modern society.
Hint: read up what 'baseload' means.
http://www.thefreedictionary.com/base+load [thefreedictionary.com]
http://en.wikipedia.org/wiki/Base_load_power_plant [wikipedia.org]
Every plant is 'baseload able'. And it certainly has nothing to do with "energy density"
Nuclear is our only real option Sure, because a GW made nuclear is so superior to a GW made with wind or wave or solar.
Re: (Score:2)
Mark my words though, those reactors will be fired up, because they need to be. They should build more.
Bad idea, did you learn nothing from Fukishama? Japan is one of the most earthquake-prone places on Earth, and places prone to earthquakes are terrible places to site a nuke. It would be worse than a nuke sited on the San Andreas fault in California; that's just madness. Japan simply is a bad place for nukes, they're stuck with whatever green energy they can extract and the rest will have to be carbon. No
woo! Gilbert Home Physics Kit! (Score:2)
first, they have three meltdowns because they can't get things right in the face of a storm. now, the Japanese seek a meltdown just... because. those Ninjas have the curiosity of a 3 year old...
Isn't "controlled meltdown" an oxymoron? (Score:2)
If it's controlled, it's not really a meltdown, is it?
Re: (Score:2)
what part of "meltdown" don't you understand, or where do you pull an implicit 'uncontrolled' from?
Re: (Score:2)
You're confusing the nuclear engineering word "meltdown" with what it has come to mean in standard speech. In nuclear engineering, a meltdown occurs when the fuel reacts with enough heat to melt itself. Once your fuel is melted you have much fewer options to bring the reactions under control because you no longer control the geometry of the situation, you can't just insert control rods or even inject a neutron absorber.
Better Idea (Score:2)
Re: (Score:2)
nuclear power designs that can't melt down to matter what. Plenty of them.
Such as? No sarcasm there - I'm interested. MSR's have always seemed great, but unfortunately we've lost 40 years of time in which they could have been developed. Pebble beds have proven to be troublesome for other reasons.
Re: (Score:2)
nuclear power designs that can't melt down to matter what. Plenty of them.
Such as? No sarcasm there - I'm interested. MSR's have always seemed great, but unfortunately we've lost 40 years of time in which they could have been developed. Pebble beds have proven to be troublesome for other reasons.
MSR: Molten salt reactor? The one with the fuel chemically mixed with the salt? While interesting, I was never really a fan of that one. If you mean molten sodium, interesting, but kind of reactive. One I liked was a molten lead reactor. Easy to use coolent (if you can imagine using lead as a coolent). Self shielding (Its lead). High boiling point (compared to water), so low pressure primary system.
Use of thorium as a fuel instead of uranium. Because it emits 1.3 neutrons as opposed to uranium's 2,
Destructive testing.. better get it right (Score:2)
When considering fissionable materials they better get their destructive testing planning right the first time. I don't think they'll get another chance to repeat it. Much like the NASA/FAA crashing the Boeing 707 (720) in 1984 [wikipedia.org] to anti-misting agent in the fuel.. Unfortunately the plane didn't land as they had planned but ultimately it showed that the anti-misting agent didn't work but because of smoke, they estimated that only about 23%-25% of the 113 passengers would have survived.
As a result of analysis of the crash, the FAA instituted new flammability standards for seat cushions which required the use of fire-blocking layers, resulting in seats which performed better than those in the test. It also implemented a standard requiring floor proximity lighting to be mechanically fastened, due to the apparent detachment of two types of adhesive-fastened emergency lights during the impact. Federal aviation regulations for flight data recorder sampling rates for pitch, roll and acceleration were found to be insufficient.
So out of a somewhat
Didn't this already happen once before? (Score:2)
Re: (Score:3)
You're misremembering Chernobyl I think. They disabled various safety systems in order to perform some tests that did not strictly require that those systems be disabled. It was never their intention to allow the reactor to enter an unsafe state, though. And in this instance, they're not working on a living reactor.
Re: (Score:2)
English translation: prompt neutron critical. Reactors need neutrons to keep going. There are two kinds, prompt and thermal (slow). Reactors are controlled by taking neutrons out of the mix using mechanical means (control rods, slow) or chemical means (boron in the water,slower). Both assume that the reaction is dependent on thermal n
Hasn't this experiment been done before? (Score:2)
It certainly sounds useful - if for no other reason than because we likely have much better detection equipment (and hence should get much better data) than we likely did the last time something like this was done.
clearly needed (Score:2)
This is the premise (Score:2)
of, what, 8 dozen anime stories?
Fukushima overblown ! (Score:3)
The nuclear accident at Fukushima has been greatly overblown.
My family owns a condo in the city mentioned in Pandora's Promise (Guarapari-ES-Brazil), where a Geiger counter reads 20 micro sievert/second, while a half mile away from Fukushima Daichi plant it reads about 4 micro sievert/second these days. That spot isn't isolated, it's in a beach right in the downtown area, people have been sunbathing right there for generations. hundreds of thousands of people flock every summer to the beaches there.
There has been studies and studies trying to find a pattern of elevated cancer in that city. There's none !
The real problem isn't radiation per se. It's the leak of radioactive materials (that in turn produce radiation), mostly Cesium.
With the containment areas and everything, you'd need to actually ingest that material in order to get sick (in large enough quantities).
People mix up the hydrogen gas explosions (which is not radioactive), trying to make the case that it is.
The interesting fact is should the plant operators decided to keep it going, the accident would have been prevented.
Radiation is everywhere. Our body produces radiation from Potassium and other elements that have naturally radioactive isotopes in small concentrations.
It's possible in the days right after the accident it was dangerous, but the risk now is beyond tiny considering the area they relocated people from.
Re:sure (Score:5, Funny)
Re: (Score:3)
That sounds like a worst case scenario to me, at least in the scope of a single experiment. Rinse, repeat, SCIENCE!!!!
Didn't we do this years ago? (Score:2)
I know we had unplanned criticality accidents that melted fuel; The US and USSR should have tons of this kind of data.
Shit, ORNL had liquid metal reactors.
Seems like one had to be shut down before it exploded... U233 is a strange beast, apparently; it separates from the liquid metal coolant in globs, lol.
Alvin Weinberg talked about some of the stuff in his books; like burning a whole rail car of uranium to see what happens...
Re: (Score:2)
What have you not done?
Damn you! Damn you to hell!
Re: (Score:2)
Alas.. nobody remembers the Gargantua movie as well as the ToHo Frankenstein movie. [cinemassacre.com] Those were much better than any of the Godzilla flicks. We have monsters eating humans, when did Godzilla or any of his other frenemies do that?!?
Re: (Score:2)
Yes, but they didn't create that disaster on purpose. The scientists want a disaster that they created. Probably to gain entrence to the evil league of evil.
Re: (Score:2)
guess that means we can blame chernobyl and fukushima on the damn environmentalists
Re: (Score:2)
Loss of Fluid Test at National Reactor Testing Station (now Idaho National Laboratory) tried in the late 60s early 70s, but environmentalists got it blocked.
Cite? Some people blame environmentalists for everything including ingrown toenails. Did they also halt research on MSR's? Also, the anti-nuke part of environmentalism didn't really get started until TMI in 1979.
Re: (Score:3)
Re: (Score:2)