How would you fix Fukushima? 4

[Windward]

I would start by locking up the TEPCO officials who have been in charge of the response to this monumental disaster. They have been lying and procrastinating and refusing to recognize the danger from the start.

It will take trillions of dollars to stop this thing from getting worse, possibly terminal for life as we know it. How would you do it?

 

[JayMaechtlen]

The NBC news link above did specify that the radiation was Beta.
They said that the higher levels were noted after using an instrument that was capable of the higher readings.

It seems a bit odd that the level would be that high, unless the contents of the tank were highly radioactive - unless the tank was weeping and depositing contaminants on the outer surface?

As far as "fixing" Fukushima - looks like there are multiple problems, and not any quick solutions.

another link

Link

Jay Maechtlen

http://www.laserpubs.com/techcomm

 

[TGS4]

Ah yes - I did see that the NBC news article, in the final line, did indicate that the radiation was beta. So, ingesting the leaked water directly may not be wise, but standing next to it with a decent haz-mat suit is fine. I still don't see enough information to justify

...There is enough technical information about the accident to show that it is a deadly threat to life on the planet...

 

[Windward]

Here is the first part of the article "The Crisis at Fukushima 4 Demands a Global Take-Over" by Harvey Wasserman, and a quote which appears near the end of the article. I urge everyone to read it and sign the petition which the article presents:

"September 20, 2013 "Information Clearing House - We are now within two months of what may be humankind’s most dangerous moment since the Cuban Missile Crisis.

There is no excuse for not acting. All the resources our species can muster must be focussed on the fuel pool at Fukushima Unit 4.

Fukushima’s owner, Tokyo Electric (Tepco), says that within as few as 60 days it may begin trying to remove more than 1300 spent fuel rods from a badly damaged pool perched 100 feet in the air. The pool rests on a badly damaged building that is tilting, sinking and could easily come down in the next earthquake, if not on its own.

Some 400 tons of fuel in that pool could spew out more than 15,000 times as much radiation as was released at Hiroshima.

The one thing certain about this crisis is that Tepco does not have the scientific, engineering or financial resources to handle it. Nor does the Japanese government. The situation demands a coordinated worldwide effort of the best scientists and engineers our species can muster.

Why is this so serious?...

Former Ambassador Mitsuhei Murata says full-scale releases from Fukushima “would destroy the world environment and our civilization. This is not rocket science, nor does it connect to the pugilistic debate over nuclear power plants. This is an issue of human survival."

http://www.informationclearinghouse.info/article36293.htm

 

[davefitz]

Without hard data on the amount of radionucliedes released , most of the claims of imminent health threats appear to be hysterical and similar to the "chicken little " claims of the "sky is falling". Perhaps the reason that no data is being released is to prevent credibility being given to the dire warnings.

In any case, after Chernobyl the mfrs of water cooled reactors vociferously claimed that their designs could not possible cause the type of damage that the russian RBMK graphite moderated reactors are capable of. Such mfrs are very quiet now, and industry groups are actually recommending that no public discussion be given to the issues raised by Fukishima. Likewise, immediately prior to the TMI accident the MIT Rasmussen study claimed such an accident could not occur more frequently than once per 100,000 yrs.

It brings to mind the way manual rug-makers of the far east deliberately weave an error into each rug, to remind them that every action made by a human involves an error, without exception.

"Nobody expects the Spanish Inquisition! "

 

[Windward]

good one, davefitz. According to the long and detailed Wikipedia article "Radiation effects from the Fukushima Daiichi nuclear disaster", it seems that no authorities on the subject are very alarmed yet about the long term effects of the initial and continuing contamination. But the article does not discuss the probability that three of the cores have melted into the ground. I don't believe anyone has any good idea how to deal with this problem, or how bad it could be.

The greatest danger otherwise is the spent fuel rods in the pool at Unit 4. TEPCO and the Japanese government, with the help as reported today of the French and maybe the Russians, intend to start removing them in November. The potential for a catastrophe during this operation cannot be dismissed:

"...A lot depends on what blows up, if anything. If only Unit 4 blows up, Japan is at risk, including Tokyo, and the nuclear dust will pass across the Pacific to the U.S. People on the West Coast will be warned to keep their windows closed for a while.

If the whole facility blows up, one scientist is talking about moving her family to the southern hemisphere. From the article quoted above:

Chernobyl’s first 1986 fallout reached California within ten days. Fukushima’s in 2011 arrived in less than a week. A new fuel fire at Unit 4 would pour out a continuous stream of lethal radioactive poisons for centuries..."

http://www.truth-out.org/news/item/...e-radiation-of-hiroshima-create-85-chernobyls

I wonder whether it would be possible and effective to build a large structure under the spent fuel pool at Unit 4, to anchor it in place against any earthquake, ground liquifaction, tsunami or other threat from nature. Then the fuel rods could be left in place with cooling as needed, instead of risking the enormous danger of removing them.

 

[MikeHalloran]

Building a structure under a dump, without first removing and storing the dump, seems, um, ambitious. ... and if you can remove and store the dump, you don't need the structure.

Could we find enough able- bodied and suitably skilled terminal cancer victims to do either? ... in exchange for an uncontrolled but free radiation 'treatment'?







Mike Halloran
Pembroke Pines, FL, USA

 

[TGS4]

Please explain how one of these cores could "blow up".

 

[Duwe6]

"Please explain how one of these cores could "blow up". " Hopefully, that was a facetious question !??!

Totally impossible - not improbable - impossible. Civilian nuke fuel is about 3.5% enriched. It is theoretically possible [per some DOE 'leaks'] to make a nuclear fission device - bomb - out of 80% enriched fuel. But that takes a sophisticated design that they are NOT releasing.

A uranium bomb can be made 'gun-type' like Hiroshima's "Little Boy', as uranium metal can be exposed to air and moisture. Plutonium requires 'implosion' to reach critical mass, using layered explosives fired with incredibilly precise timing. It required the invention of thyratrons for the switching and a special blasting cap.

So there is not the necessary minimum concentration. And there is not the necessary geometry of assembly. Nor is there the extreme speed of attaining the required geometry. Totally impossible for three different reasons.

 

[cloa]

Nuclear cores are actually at critical mass. There is no requirement for any that for a uncontrolled nuclear fission. Note they have control rods in a normal nuclear reactor- expressly to stop nuclear explosions. Don't confuse nuclear weapons with uncontrolled fission reactions. They have those device and implosives so they cause a nuclear explosion exactly when they want in a reliable manner.

Plutonium and uranium don't any of that to cause uncontrolled nuclear explosions- lump enough of it together depending on its surroundings(its a factor in the critical mass) and it will have an uncontrolled nuclear explosion- albet a rather small one.

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[TGS4]

Duwe6 - you and I may understand that it was a facetious question, but I wanted to know if Windward really truly understands that. I completely agree with you. cloa confuses uncontrolled fission with "blow up", which is akin to an explosion - and terminology like that raises the specter of nuclear weapons. That's intentional, though not technically correct.

It's the same as confusing a birthday sparkler burning brightly and vigorous with a BLEVE or a TNT explosion, and even that difference with deflegration.

If you really think that that the nuclear volume in a fee reactor cores, if somehow made into a "dust" and instantly ejected into the air were going to be the end of life on this planet, then you really haven't been paying attention to both history and math. You are aware that from 1945 until recently, there have been a large number of above-ground nuclear bomb tests (including two that weren't tests...) - the total mass of fissile material is likely orders if magnitude greater than what exists at Dai'ichi. And last I checked, life on this planet was doing just fine, thank you very much.

Now, cloa does have point that there is a such thing as critical mass, and that is the reason for control rods. However, the real concept that you need to understand is critical density. Suppose that the critical mass of fissile uranium is 2kg (example only). You can only get a sustained reaction if it has a rather high density - suppose it is 10,000 kg/m^3. All of these reactors are actually designed so that the critical density is barely achieved. And in the unlikely, but as we have seen not impossible, scenario of a meltdown, they are designed to dissipate the molten fissile material so that it is no longer at the critical density.

So, as Duwe6 said, no explosion, not even a detonation, deflegration, or even a conflagration. As a matter of physics, it just can't. Trying to say otherwise is fearmongering.

 

[JayMaechtlen]

The phrase "fuel fire" was used-
Is graphite used in those reactors? If not, exactly what would be combustible?


Jay Maechtlen

http://www.laserpubs.com/techcomm

 

[MikeHalloran]

Uranium metal, like magnesium and titanium, requires fanatical housekeeping around machining operations, because when finely divided, as in chips and grinder swarf, it is extremely easy to ignite and burns strongly in air. I'm guessing there may be some uranium metal in the fuel.

Mike Halloran
Pembroke Pines, FL, USA

 

[Duwe6]

Zirconium is used to make the jacket for fuel rods. And it burns like magnesium.

Just like everything else at Fuku -- if it is kept wet, there is no problem. They ran out of water, less than 100 yards/meters from the ocean!

 

[cloa]

"All of these reactors are actually designed so that the critical density is barely achieved."- refers to one rod (multiple rods are kept separate by their design) in good shape - not a lot of debris from several rods- they were not designed for this upset situation- it was designed to avoid ever getting in this situation- there was a water pressure release valve that none of the onsite personnel even knew about. They don't uranium

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[TGS4]

Actually - these things were indeed designed for this worst case scenario. That worst case scenario is that there is a complete melt-down of the fuel rods, and the molten fuel gathers in a molten lump at the bottom the reactor vessel. It will quickly "burn/melt" through the reactor pressure vessel and fall to the concrete containment vessel. There, the bottom is shaped to NOT have the molten fuel sit together in a lump, but to be spread out - spread out sufficiently so as to be below the critical density.

Yup - burning (as in rapid oxidation of the zirconium cases would be pretty bad - but the uranium itself won't burn because it's in the uranium-oxide form (already burnt...). Furthermore, the uranium oxide itself won't even melt because it's melting point is so ridiculously high, it stays as a powder.

Worst case scenario of a zirconium fire would be the release equivalent to a "dirty bomb", which, while locally bad, it still far less radiation than an above-ground nuclear test, of which this planet has been exposed to likely over 500... And survived...

 

[MikeHalloran]

Thank you TGS4 for correcting my misunderstanding of which metal might possibly be burning.

I'm curious now about whether the shaped(?) concrete bottom of the containment vessel actually did spread out the detritus that fell on it.


Mike Halloran
Pembroke Pines, FL, USA

 

[TGS4]

I am curious, too. Numerous simulations show that it should, this would be the validation of the simulations. I suppose that this may depend on the damage to the concrete secondary containment from the beyond-design-basis earthquake.

 

[davefitz]

I am not too certain of the details, but the above discussions related to a 3.5% enriched uranium fueled reactor core is not totally relevant to the main issue at fukushima- the major issue seems to be the stored fuel pool, and a mixed fuel ( uranium /plutonium) was apparently used. It is not clear if the concrete foundation of that pool was designed to prevent agglomerating past critical mass.

"Whom the gods would destroy, they first make mad "

 

[TGS4]

Certainly, the short-term wet storage pools losing water is a concern. I would be very doubtful that a complete water loss event would result in a run-away reaction. But, I'm not a nuclear physicist, just an engineer. Definitely losing water in a storage pool is a credible failure scenario - if that hasn't been accounted for (and based on what I have seen from my dealings in the nuclear power world I have no doubt that it would), I would he very surprised. I feel quite confident that there are contingencies in place to deal with that - even if it means just tossing the damn storage canisters in the ocean...

 

[cloa]

TGS4- Doesn't that involve the big assumption that the fuel rods become totally molten after zirconium induced hydrogen explosion- the estimated melting point is 2800C-much hotter than the chemical explosion (furnace/jet engine/magma temperatures). More likely Fukushima has a pile of hot stripped fuel rods whether there is effective water or just air cooling- its simply never going to get that hot. The rods are seriously heavy- 2/3 ton so not slightly to easily shift around- even a powerful earthquake would need considerable sideways motion to be a problem- more of problem is human/robot accident in removal.

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