Slashdot Mirror
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."
I love it when they fix stuff.
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.
A feeling of having made the same mistake before: Deja Foobar
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!
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
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.
"workers soon will not have to use full face masks." => More propaganda
However, they will HAVE to wear LEAD SUITS => PRICELESS
Yours In Hiroshima,
Kilgore Trout.
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
So there was spontaneous fissioning still going on in these reactors, yet not enough of it to contribute to the heating of the core. I apologize to whoever claimed this was going on. I however don't apologize for downplaying it, because we now see it wasn't a significant.
Don't get down on nuclear. Thorium is the future. We have enough supply of it to replace the entire world's energy needs, and the salt based solution is the safest there is. It does not require the reinforced meltdown containment of traditional nuclear.
If any nuclear power could be called safe, Thorium is it. Or LFTR, specifically.
https://plus.google.com/u/1/107403602702342125509/posts/VFLzb7rzByx - All about Thorium and the WH.gov petition link.
I8-D
I fully agree and can relate.
I just wanted to add that it was interesting timing for this announcement, as it came right after the first reactivation of a Japanese reactor since the Fukushima accident.
Sdelat' Ameriku velikoy Snova!
Thorium is not safe. It needs insane quantities of sodium, which will disperse in the air as soon as the first fire happens. Also it needs chemical reprocessing 24/365 together with each reactor, which pollutes, and is highly dangerous.
>> Nuclear power has caused fewer deaths per TWh
Absolute lies. This takes in account 30 deaths for Tchernobyl while there were ca. 1 million.
It does not take in account the health of million of people affected by chemical and radiological pollution in countries like gabon. It does not take in account the future deaths resulting from leaking fuel storage, which is inevitable on the long run. (leaking, spreading, and deaths are all inevitable).
aaaaaaa
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.
Call me when they detect nuclear fusion.
This was basically the worst natural disaster that could happen to it, short of getting hit by an asteroid. On top of that, there were problems with planned backups (like having the wrong kind of generator on hand). Also, it was using old technology as you noted. For all that, nobody died.
Sounds pretty safe to me. Was there damage and contamination? Yes. Can we do better in the future? Hell yes. However over all this sounds pretty good.
Life is not a no-risk game. As you accurately point out, other power technologies cause deaths too. We need to stop being so scared of nuclear radiation just because it is invisible and look at it from a practical standpoint.
Yes, nuclear power will cause deaths sometimes. Get over it. Unless it causes a high number, it isn't a problem. We do not live in a safe world.
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.
No worries, this is all perfectly safe. Or so I've been told on slashdot.
That's been tried. One GE design had huge blocks of ice with boron as an emergency cooling system. Sequoyah Nuclear Generating Station in Tennessee uses that technology. It's not considered a good idea any more. There's a finite supply of coolant, but the waste heat from the reactor keeps on coming.
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
http://youtu.be/N2vzotsvvkw
Thorium reactors would address your concerns. The plants become self regulating - reaction stops itself if/when needed. That, and the actual thorium elements are a) more common than uranium, and b) generate much less waste. Lots of videos on YouTube explaining the details, but the link above is a good introduction. It also explains the differences from the current Uranium based reactors.
WE CAN STILL MEASURE RADIOACTIVITY AT HIROSHIMA! THE OLDEST NUCLEAR EVENT IN HISTORY!
NO NUKES! NOT NOW! NOT EVER!
I'm pretty sure they dropped a test bomb long before it ever made it to Japan... that *might* be older than the first drop of a weaponized bomb. Because no one takes a brand new weapon to battle without making sure it works, first!
Sorry, error. The spontaneous fission branch isn't 10^-5, it's 10^-5%, so decrease my result by a factor of 100.
Don't Bogart the fish sticks
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.
Okay, I'll play ball. Go snuff out the sun. Go on. Go do it. I'm waiting...
You could measure radioactivity anywhere on earth. The earth is radioactive. In all likelyhood the only reason we're here alive is a natural reactor running in the earth's core right now.
Take my basement in the US midwest. We had a radioactivity problem there, so now we have a radon system. What's your solution for me? Don't build a house, live in the trees like a monkey? The Uranium that's producing the radon has been in the soil for eons, it isn't the byproduct of any of the bombs or accidents (the three biggies are quite a bit younger than our house).
While we're at it, why don't you go measure radioactivity released by coal plants. What you find might surprise you. Then again I suspect the thought of uranium in your soil might surprise you too.
Slashdot Patriotism: We Support our Dupes!
While I do have concerns about nuclear power, I have to say that your post comes across sounding more like a raving lunatic than someone who has a logical, rational argument against nuclear power, and therefore, you are unlikely to win anyone over to your point of view with your rant. I'll list some of the more obvious objections here:
Nuclear technology must be abolished and destroyed, and anyone possessing it must be put to death for the greater good of mankind.
Groan. You do realize that once the genie has been let out of the bottle, you can't just put it back in, right? The knowledge has been released, and if you try to obliterate that knowledge, all you are going to do is drive it underground. Even if you *could* convince every country in the world to do as you suggest -- and just to be clear, you won't -- that means the only people to still have nuclear technology are the very people you DON'T want possessing it.
...Hiroshima, Nagasaki, Several atolls in the Pacific... How many more places must be contaminated before we admit defeat? WE CAN STILL MEASURE RADIOACTIVITY AT HIROSHIMA!
Yeah...so what's your point? You may still be able to measure the radioactivity at Hiroshima and Nagasaki, but those are currently thriving, populated cities teeming with normal, healthy people. You may be able to measure some amount of residual radiation there, but obviously it isn't causing any significant health effects. I saw an article within the last year or two claiming that life was even returning to the Chernobyl area much quicker than scientists expected. There were some definite genetic anomalies there so I wouldn't recommend moving the family there yet, but animal life was thriving nonetheless. IIRC, the scientists studying the site claimed that life was actually more diverse near Chernobyl than in the surrounding areas because of the lack of human activity there...despite the increased radiation levels.
[HIROSHIMA] THE OLDEST NUCLEAR EVENT IN HISTORY!
Ummm...may I humbly suggest you check your facts before spouting things that are just patently untrue? Hiroshima was the second nuclear explosion. The first was near Alamagordo, New Mexico, USA, one month before Hiroshima. The first sustained nuclear chain reaction occurred in a lab three years earlier in Chicago. And nuclear fission was first demonstrated in Germany seven years before Hiroshima (source: http://inventors.about.com/od/timelines/tp/nuclear.01.htm, found in about 30 seconds via Google).
I'm not saying that nuclear doesn't have its problems and that we should immediately rip out all coal, oil and natural gas power plants so that we can replace them with Fukushima Daiichi plants across the world. But really, dude...at least try to make a reasoned argument against nuclear power instead of just "screaming" hysterically.
MCSE? No, sir...I don't do Windows. Yes, I am an idealist. What's your point?
No one knows if the containment vessel has been breached. Most likely it has and the fuel is actually sitting on that bedrock. Which was why they had all that water pouring back into the ocean..
Lies, lies, lies and more lies. Anyone with a HS diploma should have know fission occurred when neutrons were observed in the atmosphere, days following this event.
Hiroshima tidied up nicely and is a thriving city.
Worry about something that kills tens of millions of people, such as tobacco, instead.
"This post is an artistic work of fiction and falsehood. Only a fool would take anything posted here as fact."
>> Of course since you can't make bombs from the by products
I don't believe this "no proliferation risk" that the nuclear industry is pretending. Of course, the uranium the fuel contains is unsuitable. Of course it does not generate Pu as is. BUT. but it generates neutrons. So you simply add a "blanket" of U238 (very easy to get, US trowed a lot onto Lybia in the last months). The only thing you have to do is NOT to mix your breeder with the core. Any engineer can come with many easy ways to do this, and to exchange the blanket often to get better bomb material. What do you get from that ? Pu239.
aaaaaaa
Everyone knows that nuclear fission is a natural event
much like global warming. Nothing to fear.
Regarding the 1975 Dam catastrophe... Wikipedia is entirely too polite on the Chinese government's culpability in the disaster, and what happened to hydrologist Chen Xing, who warned that the dam's design was inadequate, recommending 12 sluice gates instead of the 5 implemented.
For his criticism, he was over-ridden by party officials and exiled to the western provinces.
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.
aaaaactually...
The Little Boy was never tested before it was used in combat.
Perhaps you are thinkng of the Fat Man which was dropped on Nagasaki, which was tested first as The Gadget at White Sands.
SJW n. One who posts facts.
Recent news is that India has committed to the development of a commercial scale thorium reactor, with a target date for completion of 2020.
Will
The cascade failure of hydroelectric dams doesn't have a radioactive half-life of 100,000 years. There's the difference.
Crap your pants and its just crappy pants that can be cleaned up in the washing machine. Crap radioactive isotopes out your ass with a radioactive half-life of 100,000 years and tell me its the same thing.
The Indian design of thorium reactor is a pressurised-water fission reactor like most uranium reactors around the world except it is fuelled with a small amount of highly-enriched uranium (HEU) and possibly some plutonium to provide enough neutron flux to "burn" the thorium fuel. The HEU at 20% is a lot closer to bomb-grade than regular pressurised-water fuel enrichment (about 3-4%). India is not a signatory to the Nuclear Non-proliferation Treaty (NPT) hence not covered by the IAEA so these reactors would be ideal for any country wishing to divert uranium and plutonium into weapons programmes.
Either way, the Trinity bombing test predated both Hiroshima and Nagasaki by almost a month. So it is the oldest nuclear event in history.
Yes, India is believed to contain at least 25% of the world's thorium resources, so it makes sense for them to work on exploiting them.
Similarly, the USA has vast acreage under the plow, vast unfarmed prairies, and large deserts so it makes sense for us to work on sustainable carbon-neutral biofuels.
India also has a troublesome nuclear power right next door, and thus is (probably/unfortunately/sadly) interested in the bomb-making potential of nuclear fission technologies.
The USA has enough bombs already that we can pretty easily keep our arsenals full for the foreseeable future.
When did we stop considering the Big Bang a nuclear event?
This entire conversational thread works OK for me just as it stands, though.