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Spontaneous Fission In Fukushima Daiichi Unit 2
Kyusaku Natsume writes "Tokyo Electric Power Co. said Wednesday that some of the melted fuel in reactor 2 at the Fukushima No. 1 nuclear plant may have triggered a brief criticality event. Tsuyoshi Misawa, a reactor physics and engineering professor at Kyoto University's Research Reactor Institute, said that if Tepco's data are correct, 'it's clear that the detection (of xenon-133 and -135) comes from nuclear fission.' Tepco spokesman Junichi Matsumoto said the test results suggest that either small-scale fission occurred in the melted fuel, or conditions to trigger criticality were temporarily met for some other reason. He said the same thing could also happen at reactors 1 and 3. But because the reactor's temperature and pressure level have not changed, the fission would not have been large-scale, Matsumoto said, adding that it would not thwart Tepco's schedule for achieving a cold shutdown at the reactors. In response, boric acid water was injected again on November 2. On the plus side, the concentration of radioactive materials in the air is low enough that workers inside some areas of Fukushima Daiichi workers soon will not have to use full face masks."
Obviously it's fake, we all know that after shutdown there CAN'T be uncontrolled fission going on. It's physically impossible, you dumb hippies!
Heaven forbid a moth would land on that fissle material...
Heaven forbid a moth would land on that fissle material...
Rather a good thing that (so far) radiation tends to kill things, rather than mutate them like good ol' fiction suggested for 70, or more years.
but all it takes is once ...
A feeling of having made the same mistake before: Deja Foobar
From Mainichi Daily News
Tokyo Electric Power Co. said Thursday the detection of radioactive xenon at its stricken Fukushima Daiichi power plant, indicating recent nuclear fission, was not the result of a sustained nuclear chain reaction known as a criticality, as feared, but a case of "spontaneous" fission.
make imaginary.friends COUNT=100 VISIBLE=false
Am I the only one getting tired of all this nuclear talk when we are ignoring the real Godzilla threat?
You mean, like *shudder* a sequel to the American version?
the horror! the horror!
A feeling of having made the same mistake before: Deja Foobar
I was a proponent of expanding nuclear fission electricity generation until Fukushima. Fission is a zero-carbon system and cheap at massive scale. However, my enthusiasm also assumed that the industry was regulated and transparent enough to be safe. Clearly it is not. The bigger nail in the coffin for me, however, is that the first month or more of issues with Fukushima were clouded with lies from the utility that runs the plant and from the Japanese government itself. Why should we ever trust anything the utilities say about nuclear safety ever again? They don't have the moral integrity to handle the responsibility of running a safe nuclear fission industry.
I still hold out hope for the safe cold fusion dreams. It may not be a rational hope but it would be awesome.
Colder water increases the chance of a criticality. Colder water is denser, therefore a better neutron moderator. As the temperature in the core drops, it probably crossed the threshold for a (briefly) sustained reaction, which probably then melted or reformed into a shape no longer capable of sustaining the reaction. As the shape and condition of the fuel is currently a complete unknown, this could happen again at any time until all the way down to room temperature. /former US Navy reactor operator
Down at the bottom of Reactor 1, they have a melted core. It's not surprising that they have a criticality event once in a while. Nobody seems to have a clue how to get in there, remove the core bit by bit, and transport the mess in small pieces to some disposal location. TEPCO is saying that in 10 years, they might be able to start on that. Meanwhile, they have to continuously remove about 2MW of heat or things get worse.
One bright spot in this is that the plant is built on bedrock, and the containment vessel seems to have held. It needs to hold for another decade or two.
One of the best inventions for a train was its braking system.
You have to apply energy to *prevent* a train car from braking.
This prevents run-away cars.
A successful nuclear reactor would have something similar
where you have to apply energy to keep the coolant at bay.
i.e. The core is at the bottom of the ocean and energy
is spent by the reactor to keep ocean water from rushing in.
I'm half expecting Godzilla to emerge from off shore and stomp the rest of the plant to bits.
Truth may be the first casualty of war, but it seems to be bound up and stuffed into a file cabinet in a disused lavatory in the basement of a building with a sign "Beware the leopard" on the door, when there's a disaster and a business involved.
It's so quaint when people are surprised that the nuclear industry lies to the public about the risks involved, or that the government is almost always complicit in the perpetration of those lies. The truth about nuclear energy, they way it is typically delivered (as cheaply as possible), is that it is staggeringly dangerous. Incidents are, happily, fairly rare, but they are catastrophic when they do occur. That truth is bad for business if it is dealt with honestly, by anyone, in the public square. So yeah, duh... They are going to lie about it, always.
As a former navy nuclear enlisted personnel; I can tell you that reactors operate at criticality all the time. The mere definition of critical is when all the thermal neutrons born from fission go on to cause more fission reactions. Critical = steady state. 'Prompt critical' or 'supercritical' is when its critical without the contribution of thermal (delayed) neutrons.
Every single reactor startup, we calculate exactly what rod height we expect to reach when the reactor goes critical. Once we are critical we then allow steam demand and thermal coolant temperature to drive reactor power output. higher temps are less dense thereby thermalising fewer neutrons lowering reactor power. If steam demand or load increases coolant temperature subsequently lowers making the coolant more dense in turn thermalising more neutrons increasing reactor output. Its all driven back to steady state. This is commonly referred to as a negative reactivity coefficient. Critical = steady state and Steady state is a good thing.
This article confuses me a great deal, and IAANP (grad student). They say "one hundred thousandth of a becquerel per cubic centimeter of xenon-133 and xenon-135 was detected in gas samples.", that means one decay per second in every 1/10 of a cubic meter. This is a very low rate. U-238 undergoes spontaneous fission in about 1 in 10^5 radioactive decays whether it is in a reactor or not,and about 1% of those fissions produces a Xe-135 (either directly, or after decay of one of its parents like I-135). If I do a back of the envelope calculation, I find that for 10 tons (a guess) of U-238 sitting there being nice, about 100,000 Xe-135 will be produced every second. Thus, unless the air volume they are sampling from is much larger than 10,000 cubic meters, this sounds like what I would expect WITHOUT criticality.
Am I missing something here?
Don't Bogart the fish sticks
> People need to keep in mind that Life causes Death 100% of the time, You can take that to the bank!
So far, for humans, it's only about 90% of the time. At least 10% of the humans ever alive are still alive.
I love Mondays. On a Monday, anything is possible.
Actually, the field mice around Chernobyl have a much higher rate of mutation including a 300% increase in fertility rates compared to those outside the exclusion zone which more than makes up for the slightly increased morbidity rate. It was one of the more interesting tidbits in a recent PBS show on research in the exclusion zone.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
The sources I find by googling state that no thorium reactor has ever performed to commercial power production requirements, significant operational disadvantages have not yet been overcome (particularly in the fuel-processing stages) and that development mostly ceased 50 years ago because in practice it's so far been even less cost-effective than uranium and plutonium fission plants.
However, research is ongoing, especially in countries with large thorium deposits. Perhaps someday soon it will be possible to build a truly effective commercial thorium reactor. It's almost as likely as commercial fusion plants and much more likely than "zero point energy" plants.
I keep hearing of complaints about TEPCO misinformation etc. Reading the IAEA and NISA reports has seemed fine to me, where is all this disinformation coming from?
http://en.wikipedia.org/wiki/Timeline_of_the_Fukushima_I_nuclear_accidents#March
They denied the meltdown for months. They denied the leaks of radioactive material, they denied there was a risk from tsunamis, they just lied about everything for as long as they could.
You can't take the sky from me...
Hold on...
You're saying that two fledgling industries (wind and solar) have had a higher death rate per MWHr than an industry who has been around for years, and have many employees who have never even been near the outer shell of the reactor?
Ya, I found your reference, since you kinda forgot to post it.
http://nextbigfuture.com/2011/03/deaths-per-twh-by-energy-source.html.
Now you need to look at *how* they came up with those numbers.
First, they're measuring the rate per TWh. So I'd guess that they're estimated that 2.28TWh of solar have been produced world wide by rooftop facilities (you forgot to mention *ROOFTOP*. Like, any schmuck with a ladder who buys a solar panel). So if a single person died in a way related to that solar panel, in that 2.28TWh, that makes it so dangerous.
A more appropriate scale would have been deaths per thousand man hours, directly involved in the power generation facility. A separate number could be correlated deaths.
Come on everyone, you know this song! Sing along!
Correlation does not equal causation.
Your citation is not talking about power generation facility accidents.
For anything but nuclear, they are including environmental, public health, and even global warming. ya. The victims of hurricanes, tsunamis, forest fires, droughts.. You get the idea. They're also considering ozone, coal dust, power plant emissions. If someone dies from a respiratory related illness anywhere near a fossil fuel plant, they died because of it. I'd be willing to bet that they even included people getting hit by freight trains transporting coal, and accidents with oil tanker ships. (ya, ya, both get carried by both, I'm just making a point, not a documentary). That's every person who may have died because of something related to fossil fuel power generation since the first coal plant was built in 1926. I couldn't find a date of the first oil powered plant, but I know they've existed since at least the 1930's.
For nuclear, they are considering nuclear accidents. There have been a handful of accidents since the 1950's. The memorable accidents have caused wide spread destruction and loss of life. And of course, the accident in the Soviet Union was seriously downplayed.
But lets be fair. For hydroelectric, they were only able to pad their numbers by 171,000, when the Banquio Dam broke. A dam that showed evidence of damage just after it was built. That they knew would fail. And finally did fail. Did they include Hiroshima and Nagasaki as nuclear accidents? How about the American troops and civilians who were exposed to radiation during the first hundred or so nuclear tests. Nah, that wouldn't be fair. If you're going to count gross neglect as a cause of death, you'd damned well include intentional manslaughter in it.
So, who wins? I don't know, and I don't have the time to do a comprehensive examination of every incident at every power generation facility world wide since ... well, it doesn't matter when, because I
Serious? Seriousness is well above my pay grade.
Did you bother looking for any? Because I didn't have any trouble finding dozens of such reports after ten seconds of research.
Which really didn't surprise me, since I remember reading them in most of the major newspapers and online news feeds.
The Fukushima 50 (actually around 280 volunteers, I believe) knowingly went into the exclusion zone prepared to die. Are you going to pretend none of them got injured, or that their injuries somehow were not really important? These people have asked to be anonymous, and not to be bothered by the press (and so far they haven't been) but they have knowingly set their limit for radiation to 250 millisieverts - five times the maximum allowed in US plants, twelve times the max allowed in France, and more than twice the dose at which an increase in cancer risk is evident.
"It's hard to believe anyone could have the impudence to distort the truth so infamously."
Look, now I Godwinned the thread. I hope you're happy.