People....people, people please. Listen. There will be no atomic explosion.

[Paradoxical]

I admit that what I initially said about the Fukushima distaster was WILDLY inaccurate. This accident has outpaced any personal conception I previously had of nuclear accidents. But this was not due to a technical misunderstanding of the mechanics behind nuclear physics. My inaccuracies were a product of grossly overestimating the safety systems.

With that being said, there is no way that an actual nuclear explosion can occur either in the core of the reactor or the spent fuel pools.

A power excursion is indeed a criticality accident. And there is the possibility of an actual nuclear power excursion occurring. And that may produce a large explosion. But that is not the same as a nuclear explosion.

There will be no giant nuclear mushroom clouds. There may be an explosion. But it will not be due to nuclear detonation.

The difference between the energy yield of the two events is massive.

[LAGC]

1. I'm guilty of underestimating the scope of this situation as well.

I really thought they'd have a handle on things by now, but the news keeps getting worse.

I still think the benefits of nuclear power outweigh the potential cons though, especially considering how old those Japanese reactors are and how improved newer reactors are.

I'm sure there will be even more safe-guards built into new nuclear plants going forward.

[Paradoxical]

3. I can no longer support nuclear energy after this accident.

[marions ghost]

24. thank you

:thumbsup:

What was that about the "Chicken Littles"? We chickens got severely tarred and feathered.

But thanks for admitting that your higher expectations and faith in the industry have not been fulfilled.

The more like you that turn away from nuclear towards better alternatives, the greater is the possibility that it can be stopped at this point. People like you--people who have lost faith--are key to that happening. Very important.

[Kalun D]

9. Yeah

that's why the nuclear power industry is allowed to write the rules it's governed by here in the states.

there's not going to be ANY new nuclear plants in the USA, and Germany, and Switzerland, and more than likely many other countries.

if one of the most technologically advanced countries (Japan) is having this much trouble where does that leave the rest of us?

[Paradoxical]

10. The reactor design at Fukushima is terrible.

Like, I made some assumptions before I ever viewed the design of the reactor and reactor building. And those were bad assumptions.

I also believe the reactor design is fairly popular throughout the world.

[RegieRocker]

31. Hind sight is always 20 / 20. All designs are dangerous according to

murphys law.

[Jamastiene]

42. There is a nuclear power plant near where I live that is built the same way.

We have had earthquakes here too, but not nearly as strong. That doesn't mean we cannot have a strong one. We just haven't yet.

[JuniperLea]

47. I'll check back with you once the cancers start appearing next year...

eom

[villager]

2. It would still lead to a massive release of additional radiation, however...

n/t

[Electric Monk]

4. Reassured is something I don't feel, fwiw.

Thanks for trying, kid.

I thought I knew it all when I was 18 too, fwiw.

[Paradoxical]

5. Do you believe that 2+2=4?

[Vinnie From Indy]

6. A nuclear explosion would require an entirely different mechanism

The danger is fire or steam that would propel radioactive material into the atmosphere.

[Kalun D]

7. Actually

a non nuclear explosion of a reactor core is worse than a nuclear bomb, just compare Chernobyl with Hiroshima/Nagasaki.

the force of the explosion is not what I'm talking about, it's the nuclear contamination

It could even be worse than Chernobyl if a fissioning core melts through all containment to the water table.

[Paradoxical]

8. Yes, radioactive contamination may be worse.

As the blast is not clean like an actual nuclear detonation.

But the energy of the blast will not be in any way similar to an actual nuclear detonation.

I keep thinking that people are picturing a giant explosion like a nuclear bomb. That is simply not going to happen.

[Kalun D]

11. There is No Maybe

Chernobyl was worse, much more long term radioactivity. The force of the explosion is irrelevant the area is evacuated except for the workers.

[Paradoxical]

12. I'm talking relative. I'm not denying Chernobyl was worse.

I'm saying that the radioactive release from the Fukushima disaster may exceed Chernobyl. That doesn't mean it will.

[malaise]

33. You know that

HOW?

[Kalun D]

45. Thread

I'm talking compared to Hiroshima Nagasaki, not Fukushima

Chernobyl has more long term radioactivity contamination

[CJvR]

23. Hardly surprising...

...an A-bomb contains a few kg of radioactives, a reactor several tons.

[pa28]

13. OK, I remember your post from a few weeks ago 'let's talk about nuclear reactors'

Maybe that was not the exact title but it was something along that line. You posted a nice OP when events proved you wrong which deserves some credit but how can you authoritatively say what will happen now when no controls are left and events are now nothing more than a live experiment?

It's true that there will never be a mushroom cloud "atomic explosion" but I sometimes wonder about the possibility of an atomic "fizzle". I'm certainly no expert and my layman's mind imagines one critical mass falling on another critical mass creating a small detonation that spreads material into the environment. Maybe you can explain why this is impossible.

I saw a documentary on Chernobyl and the engineers on the scene were worried about such a possibility when they were examining the melted mass in the basement of the reactor building. Maybe they were wrong.

Here's another story with commentary from an engineer concerned about the same thing. Maybe he's wrong too.

http://www.dcbureau.org/201103141303/Natural-Resources-News-Service/fission-criticality-in-cooling-ponds-threaten-explosion-at-fukushima.html

Once again. No mushroom cloud but I'm not convinced a criticality detonation is impossible. I've looked into this a bit and perhaps you can assist.

[Paradoxical]

15. The difference between an excursion and a detonation is significant.

Both are the result of criticality. But that is really where the similarities end.

A power excursion is the rapid increase of the reaction. This heats the mass causing it to expand in volume. Which ends the reaction.


A nuclear explosion is essentially a complete burn. It is designed to confine the material within a given area in order to facilitate the reaction.

What's important is the difference in energy yield.


Fizzle is partial detonation. When proper pressure is not reached, the yield is significantly decreased. But there will likely still be a massive explosion.

[bananas]

17. Is this the one: "We need to have a serious discussion on nuclear reactors"

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=439x620088

Amazing how many wrong things in that post:
- containment domes several meters thick
- there will be no explosion.
- even if there was, the containment dome would stop the material from reaching the open air
- etc etc etc

It was all misinformed happy talk.

[bananas]

14. It's "unlikely" but possible for a small nuclear detonation equivalent to a tactical nuke

It happened at Chernobyl.
It's "unlikely" but we've seen so many "unlikelys" already.
It won't be a large explosion like Hiroshima.
It would be big enough to blow apart what's left of the building.

http://en.wikipedia.org/wiki/Chernobyl_disaster

A second, more powerful explosion occurred about two or three seconds after the first; evidence indicates that the second explosion resulted from a nuclear excursion.
...
However, the ratio of xenon radioisotopes released during the event provides compelling evidence that the second explosion was a nuclear power transient. This nuclear transient released ~0.01 kiloton of TNT equivalent (40 GJ) of energy; the analysis indicates that the nuclear excursion was limited to a small portion of the core.

For all intents and purposes, that was a nuclear explosion.
A "nuclear transient" which releases as much energy as a small tactical nuke is a nuclear explosion.
0.01 kiloton = 10 ton, which is equivalent to a small tactical nuke:

http://en.wikipedia.org/wiki/Davy_Crockett_%28nuclear_device%29

The M-388 round used a version of the W54 warhead, a very small sub-kiloton fission device. The Mk-54 weighed about 51 lb (23 kg), with a selectable yield equivalent to 10 or 20 tons of TNT (very close to the minimum practical size and yield for a fission warhead).

http://en.wikipedia.org/wiki/Prompt_critical

Large-scale (production) nuclear reactors are susceptible to prompt criticality accidents when a large amount of reactivity is added to a core, such as during the movement of control rods. Alternate mechanisms include the loss of negative reactivity, such as when hot, borated coolant water is replaced with cold, pure water in the reactor core.<1> Historically, all such accidents have been caused by control rod movements. The rapid uncontrollable increase in reactor activity in prompt critical conditions may irreparably damage the primary containment of the reactor, namely the fuel cladding. A breach in the primary containment may be further exacerbated by a failure of the secondary, tertiary, and subsequent containment, which in a typical reactor plant might include the reactor vessel, reactor plant piping, various shielding materials that surround the reactor, and finally the reactor building. Nuclear reactors are designed to make prompt criticality as unlikely as possible, while utilizing multiple layers of containment as a precaution against the release of radioactive fission products should a breach occur as a result of a reactor accident.

[Paradoxical]

16. Dude, you're still wrong no matter how many times you post that.

Like I already said, criticality does not necessitate nuclear detonation.

[bananas]

18. A "nuclear transient" which releases as much energy as a small tactical nuke is a nuclear explosion.

Tell us again about the containment domes several meters thick at the Japanese plant.

[Paradoxical]

19. "Small tactical nuke" - .01 kilotons? Yeah that's 10 tons of TNT.

A tiny explosion when compared to even the primitive bombs dropped on Japan. Which were roughly 21,000 tons a piece.

Astronomical difference in power output. And not only that, there is a real functional difference between distribution of energy released in different types such as blast or gamma radiation.

[bananas]

20. That's why they're called "mini-nukes" or "small tactical nukes"

They are still atomic explosions.
There are no "ifs", "ands" or "buts" about it.
Tell us again about the containment domes several meters thick.

edit to add: there were even "backpack nukes" http://en.wikipedia.org/wiki/Backpack_nuke

[Paradoxical]

21. Mini-nukes are nuclear explosions. A power excursion is not.

One involves intentional confinement of material to increase the speed and strength of reaction.

The other is accidental and the reaction is stopped as soon as the material is heated and expands in volume.

[kristopher]

25. The public understands the difference twixt thermonuclear bombs and China Syndrome Dirty Bombs

Your OP is overtly an attempt to clear up a misconception that few possess. A "mushroom cloud" does not necessarily evidence a thermonuclear explosion - it is characteristic of any large explosion. Every discussion I've seen is focused on the China Syndrome possibility, well known as a dirty bomb steam explosion.

It would be good to settle on terms and address "nuclear transient" directly, please, so that people aren't confused. Your response keeps sliding into "power excursion". I know you have a valid reason for that but the act of change isn't helping your somewhat tattered credibility since it looks like you are deliberately altering the parameters of what is being discussed and continuing to soft sell the dangers associated with the situation.

You might try making your case that the sudden massive release of energy you are referring to isn't the same as full criticality in a thorough, professional, descriptive presentation. It would be the proper thing to do, but I don't think it would create the effect you wish to foster.

[CJvR]

39. I used to think that.

But after running into people who thought depleted uranium was a radiological weapon and was made from used reactor fuel my confidence in people's understanding of nuclear issues isn't what it used to be.

[bananas]

44. A fuel-air explosion isn't always intentional - but it's still an explosion

Just because it's not intentional doesn't mean it isn't an explosion.
Just because it's not confined doesn't mean it isn't an explosion.
An accidental flour mill explosion is still an explosion.
It's accidental and the reaction is stopped as soon as the material is heated and expands in volume.
It's still an explosion.

http://en.wikipedia.org/wiki/Thermobaric_weapon

Thermobaric explosives apply the principles underlying accidental unconfined vapor cloud explosions (UVCE), which include those from dispersions of flammable dusts and droplets.<2> In previous times they were most often encountered in flour mills and their storage containers, and later in coal mines, but now most commonly in discharged oil tankers and refineries, the most recent being at Buncefield in the UK where the blast wave woke people 150 kilometres (93 mi) from its centre.<3>

[Recursion]

40. There was no nuclear explosion at Chernobyl

Two people being wrong doesn't make a post right.

[themadstork]

62. No there wasn't. There was NO nuclear detonation at Chernobyl.

At this point your constant reposting of this crap is basically disinformation. If you won't acknowledge the difference between a criticality accident and nuclear detonation then you should step out of these threads and stop spreading fear.

[CJvR]

22. Now now...

...dont go and spoil a perfectly good global hysteria & panic attack with such boring things as facts.

As for A-Bombs going off in nuclear reactors the closest thing you can get to that is what happened in Chernobyl's graphite moderated reactors.

[kristopher]

26. You don't seen to realize it but the "hysteria" line is totally worn out.

[CJvR]

35. Oh...

...I agree that Fukushima have thrown us a few surprises, mainly huge hydrogen blasts and spent fuel pool issues. But it isn't a Strangelovian doomsday device despite all the screwups, misfortune and stupidity.

[JohnnyRingo]

27. When white hot matter hits ground water, as it will do if left unchecked....

it will explode much like if one throws molten solder in a bucket of water. The solder will turn the water into steam at such a fast rate it will fling the solder and water in all directions. If that solder is radioactive, it becomes a "dirty" bomb on a smaller scale that Fukushima.

There is no option but to stop the reaction before it gets to that point. Even if people have to die doing it.

The Japanese know this.

[sendero]

28. Keep lowering the bar..

.. of course there won't be an atomic explosion. A steam/hydrogen explosion will do a BETTER job of disseminating isotopes anyway. And that is not only possible, it is very possible.

[muriel_volestrangler]

29. There's a another thread claiming there may already have been an 'atomic explosion'

Thanks to an Alex Jones interview. Yes, DUers are taking Infowars as a reasonable source on this. The bar was lowered by others.

[Javaman]

30. alex jones is a halfwit. nt

[Aerows]

57. Hey, Aggie

I love how you keep attempting to discredit every bit of evidence that leads to the line of thought that this is a major catastrophe.

It *IS* a catastrophe, the public is being mislead as to the gravity of the situation, and no, you can't sit back and downplay this like it is nothing. I understand the urge to do so if you are a person that works in the industry, but that doesn't serve humanity or the public.

I am not anti-nuke, I am vociferously anti-bullshit. I'm just as pissed when I get lied to about nuclear energy as I am about anything else I get lied to about, and continuing to soft sell it and PR the consequences over are not going to make me less pissed off.

Let's hear the ugly truth and go from there, because there is a time for reality to sink in so that we can deal with it.

[muriel_volestrangler]

59. I have no idea why you're calling me 'Aggie'

All I'm doing it trying to get things accurate - 'the ugly truth', if you will. That, inevitably, involves pointing out the Alex Jones is an idiot conspiracy theorist who makes his living suggesting all kinds of secret goings-on that have no basis in reality.

At no point have I suggested 'this is nothing'. But saying there were atomic explosions at Fukushima won't get us anywhere. Telling people it's worse than it is will just spread fear.

[Art_from_Ark]

38. Hydrogen explosions have already happened

Here's MIT's explanation about them, shortly after their occurrence:

http://mitnse.com/2011/03/15/explanation-of-hydrogen-explosions-at-units-1-and-3/

After the March 15 explosion, radiation levels rose dramatically here 100 miles south of the reactors, rising to 6-7 times normal background levels in the course of a few hours. But the levels dropped fairly quickly after that:

[Odin2005]

32. This catastrophe has really brought out the kooks.

[Bonobo]

41. Odin dost spake the truth! nt

[Odin2005]

43. Thanks! I find it unseemly to the victims the amount of BS pouring out from this.

I keep hearing fools saying that crops here in the US will be made dangerous to eat from radiation and other such nonsense. Just because some of the radiation has blown over to here does not mean it will increase the amount of radioactivity substantially over natural background levels from the carbon-14, potassium 40, and radon in the environment.

Now for the folks in Japan it's a different matter, they are REALLY screwed! :-(

[Art_from_Ark]

61. It's the people in Fukushima and, to a lesser extent, northern Ibaraki

who will pay the highest price for this nuclear disaster.

The 30km combined mandatory/recommended evacuation zone right now covers about 1/10 the area of Fukushima Prefecture (think of it as covering 1/10 the land area of Connecticut). They are talking of expanding that. The largest city on the cusp of that zone is Iwaki, which has a population of more than 350,000. Imagine trying to evacuate all those people.

The disaster has already severely affected food products from the area-- no one wants to buy Fukushima food products, and Ibaraki farm products are also suffering, even though the only Ibaraki farm product that has recently not passed radiation tests is spinach (according to the Ibaraki Shimbun newspaper). Of course, the fishing industry is also damaged, as are the supporting industries. Many roads are still in poor condition, and an earthquake earlier this week re-damaged part of an expressway that serves Iwaki. So those folks up in Iwaki and surrounding area are the ones who face the greatest nuclear-related risk at this time.

[KittyWampus]

34. So it could be a dirty bomb- which would spread radiation.

Just not as high into the atmosphere.

[Urban Prairie]

36. So are there any computer-simulated models of what would happen

if hundreds of tons of super-hot molten radioactive slag comprised of the nuclear fuel, silicon and cement burns down and hits the water table?

Or the fact that all four reactors might all suffer the same fate?

It certainly appears that at least two of the four reactors' spent fuel storage pools have been destroyed, especially from HD images taken by satellite of the roofless Reactor #3.

In order to someday "bury" all four, I expect that the roofs of reactors #1 and #4 will need to be removed, and three of the four may need to have a portion of each of their four walls knocked down perhaps halfway to ensure a "proper" burial of their contents...

Somehow.

[spanone]

37. perhaps you are still wildly inaccurate

[JuniperLea]

48. +1

[JuniperLea]

46. There will be a garden variety explosion...

when that hot core hits the water table... and it will spew radiation far and wide... same outcome eventually, just a different mechanism.

[flamingdem]

49. You are moving the bar, but it's not convincing

They're not out of the woods at Fukushima, almost anything cant still happen including explosions.

A dirty bomb type explosion is still possible.

[flamingdem]

50. Plus, you still haven't reformed using the bait of "atomic exposions" and "mushroom clouds"

Show us a link were a reader was pushing the mushroom cloud nuclear blast theory please

[ikri]

51. That would probably be

This thread (now moved to the dungeon) - Breaking : Water near boiling point at Fukushima #4 spent fuel pool + atomic explosions possible

[flamingdem]

52. The 9/11 forum?

That post contained a lot of great links and solid data.

Was it the one fringe link that caused the reclassification?

[Urban Prairie]

53. It would be more like a volcanic effect, IMO.

But who really knows how much volume, for what distance, and with what amount of force any irradiated "ejecta" in the form of steam, ash, and molten slag would be spread and propelled?

If an "eruption" or eruptions were to occur AFTER the four reactors are buried, the built-up pressure due to super-heated and radioactive steam could become enormous, causing a much more powerful explosion and eruption.

I hope that TEPCO can cool each of these reactors' contents to the point where they cannot become super-hot again, but that could take months, if not years?

[Aerows]

54. Good to see people owning up

to the fact that this situation is out of hand, and we just cannot trust the information we are getting, nor can we trust government reaction to a nuclear incident.

I'm not against nuclear energy, per se, but my faith in leadership's ability to deal with a catastrophe is nil at this point.

They are freaking clueless and helpless to stop what is a disaster. That's what makes nuclear energy so dangerous, yet so seductive as an energy source.

[divvy]

55. VERY Small scale may have already happened

The fuel heats up and the pressure builds UNDER the cladding. It will eventually relieve itself. Pieces of fuel rod were blown (some say 1 mile) into the air at Fukushima. Large fragments were found between the reactor buindings







Google SL-1

More pictures of the SL-1 reactor explosion here:

http://www.google.com/images?q=SL-1+reactor&oe=UTF-8&hl=en&client=safari&um=1&ie=UTF-8&source=univ&sa=X&ei=cDOZTavPHsGM0QG0uITxCw&ved=0CDgQsAQ&biw=980&bih=1208

[Keith Bee]

56. Uh.....

...I didn't ever think there would be one. :shrug:

[ljm2002]

58. "But this was not due to a technical misunderstanding"...

..."of the mechanics behind nuclear physics."

So? Good for you for understanding nuclear physics, but you were still wrong, and pretty forceful with your pronouncements. I don't claim much technical understanding of the mechanics behind nuclear physics (some, but not much). Yet I knew the potential for disaster from the moment the plant was reported as damaged.

People with a wonderful grasp of theory can be very arrogant. I am not directing this at you personally, nor am I trying to demean those who have a grasp of theoretical physics. I admire that greatly. I also applaud you for being able to admit you were wrong. But very bright people often seem to believe that because they are smarter than almost everyone else, in the theoretical realm, they must therefore be right more often than everyone else, in other realms as well.

Wrong.

"In theory, theory and reality are the same; in reality, they're different." (--me)

Theory will never encompass reality with all of its messiness and variables that we cannot control. That is why I believe we should not be playing with nuclear power: we can control it just fine, as long as everything goes along smoothly. It is indeed a triumph of theoretical physics and practical engineering. But then along come external realities -- things like materials stress, terrorists, human error, natural disaster, the depredations of time, the politics of renewing nuclear plant licenses after their built-in lifetime has expired -- to name just a few messy aspects of reality that are not necessarily amenable to tidy theoretical analyses. So I do not blindly trust the judgment of theoreticians, however brilliant, to properly assess the risks to the rest of us, especially when the risks are as high and as long-lived as they are with nuclear materials.

[girl gone mad]

60. I was able to make some fairly accurate assessments...

because I took the time to look at the actual evidence and read the actual scientific data available relating to loss of cooling accidents at boiling water reactors, while others who were very loudly proclaiming their scientific genius were satisfied to simply deride anyone who doubted the happy talk as being "hysterical" and uneducated.

I put up with a lot of insults from the know-it-all crowd, but I was right. The situation was far more dangerous than officials were letting on. Cooling was not sufficient. Fuel rods were damaged. Melting, fragmentation and re-criticalities did occur.

Some people have earned credibility here, others have lost it. Maybe you can learn a lesson. Hippie punching is not a viable alternative to actual scientific inquiry.

[themadstork]

63. Do you have links for the recriticalities?

I keep wondering if this happened and can't find anything.