Thursday, November 10, 2011

#Fukushima I Nuke Plant Reactor 4: TEPCO Says Explosion on 4th Floor Air Duct

from the hydrogen gas that came from Reactor 3 when they did the vent of Reactor 3. TEPCO says in the handout for the press on November 10 that the gas, instead of going up the exhaust stack (oh no here we go again, the stack...) into the air, went to Reactor 4's air duct on the 4th floor.

To prove their case, TEPCO released the photographs on November 10 taken on the 3rd, 4th, and 5th floors of Reactor 4 on November 8. The heaviest damage is on the 4th floor with totally destroyed and disfigured air duct pipes. The rebar of the floor of the 5th floor is lifted upwards, while the floor of the 4th floor is pushed downward. It seems plausible enough that an explosion (there may be more than one, judging by the number of "fires" that Reactor had on March 15 and 16) took place on the 4th floor.

Photographs taken inside Reactor 4 before were rather neat and orderly. But this set of photographs shows the inside to be just as badly destroyed as Reactor 3. Or for that matter, as the top floor of Reactor 1 as seen in the video I posted before.

5th floor: Rebar blown to vertical position

5th floor: Rebar of the floor lifted upward

5th floor: Floor lifted upward

4th floor: Wreckage of air duct

4th floor: Wreckage of air duct, on the floor

4th floor: Floor pushed downward (could be seismic damage?)

3rd floor: Wreckage of air duct

For the complete set of photos, go to TEPCO's "Photos for Press" page, here.

The sequence of the explosive events in Reactors 3 and 4 is this, then:

  1. TEPCO did the vent of Reactor 3 at 9:20AM on March 13. The hydrogen gas supposed to have flowed into Reactor 4 through the air duct, to the 4th floor.

  2. Reactor 3 blew up at 11:01AM on March 14. The duct connecting Reactor 3 to the exhaust stack (shared by Reactors 3 and 4) was destroyed in the explosion and disconnected from the stack.

  3. After nearly 2 days after the hydrogen gas from Reactor 3, as the result of the vent, had filled the air duct on the 4th floor of Reactor 4, Reactor 4 had a hydrogen explosion at 6:12AM on March 15.

The problems I have are these:

  • Why did the hydrogen gas from Reactor 3 go to Reactor 4 to begin with, instead of out to the stack and into the atmosphere?

  • Why didn't Reactor 4 blow up when Reactor 3 did, if it was filled with hydrogen gas? Instead, it waited another day till it finally blew.

It does look like a hydrogen explosion, as I don't see any evidence of high temperature. The Spent Fuel Pool of Reactor 4 looks pretty much intact.

Any insight, readers?


evendine said...

Would be really interesting to find an architectural engineer who could calculate the forces involved in the creation of this level of damage (given the thickness of reinforced concrete, strength of materials, etc).

As has been pointed out before (by Arnie G and others) there is evidence that prompt criticality rather than hydrogen being the cause of the explosions. The detonation resulting fropm PC produces a highly energetic supersonic shock-wave, whilst hydrogen explosions essentially burn and are much less energetic.

This issue is critical to reactor safety globally. The photos look to me as though the damage has been created by a detonation wave.

In the 2nd image '...5th floor: Floor lifted upward...' you can actually see the spherical shape of the shock-wave. It may be possible to triangulate backwards to find the centre of the sphere and therefore the ignition point of the explosion, for example.

An explosives expert's opinion would be really useful...

arevamirpal::laprimavera said...

@evendine, I agree. Structural engineer, building demolition expert, or military expert (missile or nuke bombs..).

So far, I haven't read articles or posts by these people if they ever look at the wreckage of Fukushima.

Anonymous said...


Alas, TEPCO has yet to publish a fairy tale related to facts... This theater has more to with diversion from the three shaky molten reactors burping and continuously releasing deadly fallout than a authentic desire to find out.

Reactors 3&4 have one common stack; after-xplosion pics show how reactor 3 connection into it has vanished. Why no info given if it has been repaired like in Reactor 1? See above. Timing is crucial, not given. See above.

Reactors 2,3,4 have also other extra single pipes connecting to the southern 4barrel stack. Only pipes 2&3 from (plutonium?) reactors go through some kind of filter bldg, while no.4 pipe goes directly into the stack. Why this story does hide these basic structural issues? See above.

Alas, I have made clear illustrations of this papal organ structure on my stacky-dirt irradiation revealing website.
Enjoy at

Each stack is 3 meter diameter, 140m high. A single truck drive through size barrel causes a huge draft by itself. Single stack is continuously ‘pumping’ air into the jet stream per year. Fukushima six reactors have 7 of theses ‘pumps’ sucking 24/7 Fukuvitamins for the global village - 7billion human lungs & environment. Unhindered, from the molten, open reactors...

Inhale. Wonder why.

Reactor three xplosionS: see the linky how it went.

Btw AREVA. You asked about the Stacks. It was YOU, not me.

But wait, more to come. Here is the reason behind this all irradiating nuke uranium water boiler madness: AlGoReal sea level hoax - here this papal pancake debunked - factual youtube video: beach has escaped 100km during last 500 years. Continues Where? Find out...


Anonymous said...

At least three things are true, 1) 3 and 4 have not been connected to a stack via a duct for quite some time now, 2) corium melts piping and 3) the troll in the hot seat is trying to backpedal, Edano-like, on his "still functional and pumping stack" theory.

Anonymous said...

"Btw AREVA. You asked about the Stacks. It was YOU, not me."

You didn't have to answer.

Anonymous said...

Alas, Trolls Cant.

But of course, u may start to offer insight whatsitlike beteween your legs. Again. And Again ... nothing else, cuse there isnt anybody home up there. No facts, never. Which could see that nothin at all was asked from there.

Anonymous said...

Statement of A rto L auri, fmr (=whistleblower), Olkilu0t0 Nuclear Engineer
A THEORY OF FUKUSHIMA - incl Reactor No.1.

Anonymous said...

Stacks are said to need power to operate - they had no power after all the issues, right?

Anonymous said...

IAEA has just published news of high Iodine-131 levels in Central Europe 11.11.2011 15:06

Steve From Virginia said...

First of all, what happened in reactor 4 will largely be a mystery and emphasis on sequence is a distraction from real issue which is removing spent fuel from all the reactor pools ASAP.

The reason for the mystery is because nobody knows what exactly was inside reactor 4 March 14-15. Tepco is being disingenuous as usual.

Explosion in unit 3 was videotaped. If the two buildings were connected some of the unit 3 explosion would have emerged from unit 4 building.

Tepco has never acknowledged that it 'forgot' (neglected) SPF #4 during the emergency and let it boil to near empty. Any hydrogen would have come from exposed fuel rods oxidizing zirconium in presence of steam.

Paint didn't burn off walls which would be signature of the thermobaric hydrogen blast.

Tepco originally blamed fuel tank for diesel generator for fire and 'damage'.

The absence of a video of a fiery blast suggests a steam explosion. There would have been steam overpressure from melting fuel hitting water in the bottom of the SF pool.


Structural damage is consistent w/ earthquake in a poorly designed and constructed building.

Crumpled sheet metal is consistent with steam blast.

Anonymous said...

Statement of A rto L auri, fmr (=whistleblower), Olkilu0t0 Nuclear Engineer
A THEORY OF FUKUSHIMA - incl Reactor No.1.

Arto Lauri is not a nuke engineer, you flaming liar, he's a former electrician who worked at a nuke plant and has been labeled as schizophrenic even by the anti-nukes. His facts, oops, I mean "factys" are the enemy of truth. He couldn't see a blown up stack-duct even if it hit him square in the head.

Anonymous said...


Ach so. Our troll hit again. Head into cement floor... Arto can prove himself what he is. Reader may check his backround from Facebook and Youtube.

Do Nuke Power Plants Really give schizophrenics first class security clearings - like Arto?

Oh boy, no wonder Fukushima was built & xploded. With other 500 doubledecker beach bombs uranium steam-age mills... Hmm. Agreed. Theyre all factless papal schizos, just like you...


Anonymous said...

Arto Lauri has a degree in nuclear physics from Facebook and Youtube?

Arto Lauri doesn't have first class security clearing anywhere--he was fired from his electrician's job long ago when he first started displaying his schizophrenia.

Anonymous said...



"Nuclear physics" - invented by instant expervert.

Exclusively for the reader: Facebook and Youtube are info relaying internet applications, some bits there even containing some terriblese facts. The troll has been denied access by the handler.

But hey, now youre being funny while sober. Just keep trousers on.


Anonymous said...

"Do Nuke Power Plants Really give schizophrenics first class security clearings - like Arto?"

A stupid question that is self-answering. Just look at what is happening at Fukushima Daiichi. You bet they let pathologically lying schizophreniacs have first class security in nuke plants, they run the places! Arto Lauri just happened to be too retarded(one can just imagine how retarded compared to the rest of them), so they fired him.

Anonymous said...

"But of course, u may start to offer insight whatsitlike beteween your legs."


"But hey, now youre being funny while sober. Just keep trousers on."

You come in here self righteously lecturing us about your KJV bible and yet you are spamming us with your alternative lifestyle! This is not a virtual closet, this is a Japanese-nuke-disaster blog. Go away, for God's sake.

Anonymous said...


Arto was so 'retarded' that he against all death threats reported how 0lkilu0t0 was dumping Tritium into the Baltic Sea. Common practice by all you wise men ... as the Tritium content is 125Bq/m3 compared to North Sea 4Bq/m3.

Yes, real schizo by your nukelubed std. Let facts flow through the terriblese Yotube of Facebook...


Whatever, I regard highly anyone who doesnt care about the nukelubed fatwas - like AREVA does - and stands against your handlers.

Anonymous said...

.troll's squirming because he was wrong, wrong, wrong about the stacks.

Anonymous said...


Plutonium Radiation Plumes -view from Reactor 1 Stack; one second extended, color VFXEextra -filter enhanced clip from the original TEPCOtheater performance. Fresh video, published 60 minutes ago.

Based on TEPCO video shown here at


See how the Plumes, now full with the meltdown corium effluents, shoot continously into the sky:


Anonymous said...

"See how the Plumes, now full with the meltdown corium effluents, shoot continously into the sky:"

What, you mean not through a stack?

Aren't Plutonium Radiation Plumes the same crap as Betatorches?

Anonymous said...

You are Swedish???

Anonymous said...


FYI: Seven 3m (diameter) Fuku Stacks pumping effluents in the sky are all G.E. inventions, theyre now japanese...

Plume clearly visible on the video - after filtering.

Every NPP has one stack capable of releasing tritium etc effluents (described detailly in NRC documents) up to m3 per year.

Now Fukushima is above all cause its three meltdown ruins effluent content is thick as ever...

Take a copy of the video as long as it exists...


evendine said...


I don't think the level and type of damage shown in figs 1 & 2 could have been caused by a steam explosion - not enough energy intensity. Cracks are much more likely to be caused by seismic events (rather than what we see in the images) given their low frequency...

Take a look at this image from US nuclear weapon structural tests of a bank vault. The shape of the rebar looks rather familiar :0)

Another thing I've noticed in the images is the contradictions in what TEPCO claim about this image:

Its a view looking down into the reactor well on level 5, TEPCO claim that the square wire mesh being bowed out suggests the explosion was in the ducting behind it.

The 'Elephant in the room' is the fact that the railings around the edge have clearly been powerfully blown +away+ from the centre of the reactor well!

Another oddity is that TEPCO's mesh appears free of the white material which has been sprayed over everything in the area. Why, when the white material was clearly applied after the explosion?

Anonymous said...

"The 'Elephant in the room' is the fact that the railings around the edge have clearly been powerfully blown +away+ from the centre of the reactor well! "

Well, nice Elephant. Good makeup, glorious coreography...

Anonymous said...

Used to be a interesting blog. Now, unfortunately, its just become a vehicle for batshit crazy posters.

Anonymous said...

There's just one batshit crazy poster (a.k.a. Finnish/Swedish troll) and what you are witnessing is him blowing his stack and having a meltdown because he was proven wrong. He's about as subtle as a tarantula on a piece of Angel Food cake in the pangs of a death throe.

Anonymous said...

yes the tinfoil is getting thicker by the day, you may want to consider a bit of filtering, laprimavera.

Anyway, here's my two cents, fwiw:
1. a blast is a blast, doesn't matter what made it happen, it still "feels" the same
2. what we have here looks like 3-4 psi of overpressure.

-bruce said...

2 or 3 psi over pressure?
non-sense; floors are load rated at kg/ft squared in the 100s of kgs.
it looks like a detonation for sure.

Anonymous said...

Sad to see that people, without fail, eventually post aggressive, defensive and offensive personal comments. I would remove the comment form altogether and let them scratch each other's eyes out elsewhere.

evendine said...

Where did my earlier post disappear to? Someone above quoted part of it, so I'm not imagining I posted it!?!

Anonymous said...

I would remove the comment form altogether and let them scratch each other's eyes out elsewhere.

Thanks for that non aggressive, non defensive and non offensive advice.:-(

Anonymous said...

can't wait for reporters to visit, looking forward to their insight.

Atomfritz said...

Now they release these images eight (!) months after the accident.

Regarding the floor damage seen on the 6th picture I do not believe that this was earthquake damage. The force needed for this damage really needs explosives.

In fact this picture reminds me of german WW II bunkers demolished after war, using LOTS of high explosive.

For example, some of the larger bunkers (flak towers) of about the size of a Fukushima reactor building needed more than one hundred tonnes of TNT just to produce cracks in the outer walls (thickness 3.5 to 5 meters of reinforced concrete). The first demolition attempts with about 20 tonnes of TNT only produced cracks in the floors (reinforced concrete, minimum thickness 50 cm) so they had to pile up even more explosives for the next attempts to just have the floors destroyed.

I really doubt that there would have been more damage than popped-out doors and windows if the reactor buildings were as massive as a bunker.

Atomfritz said...

One of the main criticisms about piling reactors on one site is that the meshing/sharing of technical infrastructure between the reactors produces the danger of side effects from one to another reactor.

This has been true in Chernobyl where after the accident of #4 the #3 had to be un-meshed from the destroyed #4 with much effort.

Apparently even the sharing of off-gas conduits is dangerous, as this (officially) produced a chain-reaction of reactor buildings popping open as happened in Fukushima.

Imagine eight reactors like at Kashiwazaki-Kariwa going out of control just because of one single point of failure.

This is the reason why in Germany even the few reactor sites with more than one reactor don't share infrastructure between different reactors (except the switchyard) so that the chance of one failing reactor putting down the others is minimized.

Looking at the other images of the Tepco photo collection I got stuck at this image: , titled "Wire mesh, inlet of the air-conditioning at Spent Fuel Pool was bent to the reverse direction".

To me this wire mesh doesn't look like rebar, but more than sort of fishing net to avoid big objects falling into the spent fuel pool.

But there is more on this photo that I never read of.
There seems to be sort of ponton float in the pool now. Why, I ask myself. Maybe this is a measure to avoid even more stuff falling into the pool.

This appears to be a good idea at first thought, but at second thought I doubt this is really a good idea.
If the feedwater piping fails or the pool begins to crack open and leak, Tepco will have to resort to Putzmeister concrete truck watering. And if this happens, this "ponton cover" could have its own bad implications.

Did Tepco report on this ponton anywhere?

Atomfritz said...

Here you can see a german video of the demolition of a flak tower (with english subtitles). Note how violently doors and windows pop out, but the building in total remains more intact than a Fukushima reactor building...

Anonymous said...

Atomfritz, the construction methods are very different. The outer shell of the Fukushima reactors is made of light wire-reinforced concrete panels hanging on a ferroconcrete frame, basically what you would find in any factory building made in the past 50 years.

The Flak towers were monolithic concrete structures reinforced with steel beams (yes, beams, big H profile things), rebar AND steel wire mesh, built to resist big bombs going off in the immediate vicinity. Repeatedly.

In fact, the Flak towers are so well built that they are still standing - taking them out of action was done by blasting their internals only because demolishing them outright was deemed too difficult - and it's not like Allied sappers and engineers at the end of WWII lacked experience, explosives or demolition hardware.

In sum, it takes much less boom to harm a Fukushima-style building than to bring down a Flakturm.

Anonymous said...

"Why did the hydrogen gas from Reactor 3 go to Reactor 4 to begin with, instead of out to the stack and into the atmosphere?"

Just because H is lighter than air, doesn't mean it will go up a stack and out. It would if there was free convective movement in the ducts and stack, but that's very unlikely to be the case. Gates would be closed, etc. H gas movement would be via small leaks in gates, from pressurised side to lower pressure. In this case the H will just displace air, but can't really convect.

Likewise, there'd have been closed gates all through the system, so where the H went would be determined by leaky seals and gates, not the 'normal' route of gas being deliberately, fan-driven, vented up the stack.
So it's quite conceivable that H gas could have worked its way from unit 3 to unit 4. (Please don't take this as implying I believe a word TEPCO says. Just that this particular story is feasible. For once.)

"Why didn't Reactor 4 blow up when Reactor 3 did, if it was filled with hydrogen gas? Instead, it waited another day till it finally blew."

This too is feasible. Hydrogen (like any explosive gas) is only explosive when mixed with air/oxygen within a certain ratio range. This range is bounded by the LEL (lower explosive limit) and UEL (upper explosive limit.) It's possible that the H leaking through ducts from #3 to #4 was concentrated enough to be non-explosive, ie not even flammable. Not enough oxygen for the H to burn.
So, H gas being produced in #3 somewhere, getting into the ducts in concentrated (and possibly pressured) form, but also leaking into the interior of #3 in a concentration able to detonate. So unit #3 has a H-air explosion, which moves stuff around in the SFP enough to trigger (milliseconds later) a prompt criticality.
Meanwhile, the explosion blows away the ducts leading from #3 to the stack via conducted shockwave, but the ducts going on to #4 contain such concentrated hydrogen that they don't explode. And the shockwave isn't enough to take them out either.

Time passes. The concentrated hydrogen that got into the #4 ducts diffuses through leaks into the volume of the #4 building, while air also gets back into the ducts. Likely also the #4 SFP water level goes down, exposes rods, and more hydrogen is released here. Result is a building with a variety of different concentrations of hydrogen in different areas, including the ductwork. Then a spark somewhere (or the SFP burning rods) triggers the hydrogen explosion. The detonation wave travels via complex paths, through different floors and ductwork.

TerraHertz (part 1 of 2)

Anonymous said...

The floors blown up and down, and the outer wall panels blown out, are clearly the result of distributed overpressure, and lots of it. As for the explosion being 'in the ducts' like TEPCO says... bullshit. SOME of the explosion was in SOME of the ducts. But take 111110_06.jpg - those duct remnants have been crushed INWARDS. And in photo #7, those are duct remnants fallen from directly above (photo#6) so there's no way they were ducts being blown to pieces by internal overpressure. They got crushed and mangled, then fell down. Also, the contained volume of the ductwork (if that's where all the hydrogen was) isn't enough to provide overpressure sufficient to blow the walls and floors to bits like that. Had to be the entire building air volume involved. Just more so on some floors than others, hence differential pushes up and down on floors.

"It does look like a hydrogen explosion, as I don't see any evidence of high temperature. The Spent Fuel Pool of Reactor 4 looks pretty much intact."

To be more precise, anything that involved THICK reinforced concrete beams and plates survived, while thinner planes (roof, wall panels, some floors) didn't. The SFP and reactor containment are thick.
Note that people making comparisons to WWII concrete bunkers are wasting everyone's time. Those things are many feet thick. Fukushima reactor building walls and some floors are only few inches thick. Stupid design, but there you go.

What a pity no one seems to have been videoing the building when it blew. I can't recall, was the #4 explosion at night?

TerraHertz (part 2 of 2)

Anonymous said...

Hey, I just noticed. In photo #7, foreground just to R of center, there's an overpressure-crushed five gallon oil drum. From the symmetry of the crush, it looks like it must have been empty, or nearly empty. Safe to assume it had the cap on.
From the amount of crush, it shouldn't be hard to work out the approximate amount of overpressure. To me it looks like less than +1 atmosphere (from my experience playing with crushing metal cans by applying vacuum to them.)

That some of the outer wall panels stayed on #4, had suggested to me it wasn't a very big explosion.
What luck the #4 SFP didn't do the same prompt criticality trick as #3 SFP. (And I still say the #3 SFP was THREE prompt criticalities in quick succession. Not just one as A.G says.)


Anonymous said...


- The Reactor 4 was empty 3/2011. Earlier the TEPCO's had managed to drop a huge steel part into it, had to 'service = dig it out. Smbdy here posted an album containing detailed pics.

- Some of the Reactor turbine hall structures [intentionally kept secret] are one meter thick reinforced cement. Reactor has (partial?) 1-2m thickness. This is seen from engineering drawings from 0lkilu0t0 which is similar. The purpose of these walls is somewhat long story on channel radiation, never publicized in English before.

- Typical NPP radiates 48 various kinds of radiation - while only four are measured. Some can be stopped by a sheet of paper, while some with thick walls and some just irradiate surroundings unhindered blowing through any structure. The irradiation effect is such that some particle flow can be detected across/through the globe. Super-Kamiokande, CERN /Meyrin Neutrino Factory / Large Hadron Collider detector is being planned into mid Finland - the Chief scientist laments the NPP interference and boasts how the best place is 1.5km deep mine... The plan is to shoot eVolt myon beam 2200km through the earth for fun - creating an irradiated 'tube' from Swizerland to Finland - like earlier accelerators to places like Gran Sasso Italy, Homestake US, etcetc. Here is a illustrative entertainment 2minute clip for the willing:

- The dirty secret of J-Parc (10 megawatt accelerator shooting myon beams to Kamiokande mountain detector across Japan) is just next beside Daichii NPP - is to create the destructive myon pulses without power transmission loss... Go look at its website archives and see how immense systems these mad scientist have build, with its 27 steer able 'ports' to shoot energy beams anywhere and create havoc across the globe - places like Haiti... More on the mentioned issues here:


Anonymous said...

"Imagine eight reactors like at Kashiwazaki-Kariwa going out of control just because of one single point of failure."
November 11, 2011 10:35 PM

Shutdwon since 3/2011. Very likely one or more reactors in meltdown. There was similar smokey (meltdown?) news like from Daini Reactor 2. Would explain lots of mystery rad 'findings'...

evendine said...

The reactor blueprints show that the building is very substantial:

The lower walls (several of which were destroyed in the explosion) range from 1 to 1.5 m thick. The floors range from 0.5m to > 2m thick. Nothing but a supersonic blast pressure wave from a +DETONATION+ could blow holes in pre-stressed concrete as observed.

Hydrogen does not detonate, it burns. What then caused the detonation? There is only one possible explanation - given the un-fuelled status of the reactor - prompt criticality in the fuel pond, perhaps caused by a hydrogen explosion temporarily compressing fuel material into a critical mass (as has been suggested for the explosion in reactor #3 by Arnie G and others).

The explosion clearly happened somewhere on level 4, as it's roof was deformed upwards and floors beneath were deformed downwards, which fits with this view.

Anonymous said...

Good bldg info, thks.

The Fukushima Project; news site

Anonymous said...

The lower walls of the reactor building are not made of pre-stressed concrete. Only the PCV is pre-stressed.

Hydrogen does detonate. In fact, ALMOST ANYTHING that burns can detonate (even feathers if you make them into a fine enough powder).

Where do you get such ideas?

Atomfritz said...

@ anon 4:45 and TerraHertz

Thank you for the good explanations.

I never understood why the pro-nuclearists were so irresponsibly optimistic to build nuclear plants in light industrial structures like any harmless industry building.

In fact I wanted to point out that things with high potential danger like reactors and turbine halls deserve to be protected with an adequate protective outer containment shell, like a flak tower.

The newest reactor buildings in Europe, be it WWER-1000 or EPR type, have domes with wall thicknesses of almost 2 meters. These are designed to withstand hydrogen explosions, bazookas, jumbo jet crashes etc.

IMHO it's criminal to put reactors in normal light industrial buildings.

For example, in 1978 concrete plates of the turbine hall building of Balakovo NPP fell down, setting the turbine building ablaze. In a heroic improvisation effort the workers managed to prevent reactor meltdown, irradiating many people heavily.
Other NPPs in "industrial buildings" show similar problems. Bellona published photos from the Leningrad NPP where the buildings had to be reinforced with additional supports to prevent it crashing down. (sorry, I don't find the link atm, as Bellona recently reordered its web site)

So it's imho very important not only to look at the reactor building itself.

@ anon 4:10

evendine is somewhat right, hydrogen burns. ;-)
It's oxyhydrogen that detonates. The detonation speed of 2.8 km/sec makes its destructivity.
But I think we can exclude a fuel pool prompt criticality, as we have seen the pictures of the fuel in the pool. If there were a prompt criticality explosion, it for sure would look less orderly.
In the Chernobyl NPP the peak power of the reactor before the explosion was, according to the estimates I read, in the magnitude of a hundred gigawatts, and so there probably the explosion was a mixture of nuclear, steam hammer and oxyhydrogen explosion. I think we can be very happy such didn't occur at Fukushima.

evendine said...

@Anon 11:34

Yep - it seems you're right about hydrogen / oxygen mixtures being capable of detonation. As I said originally: 'An explosives expert's opinion would be really useful' (I'm not one)

I suppose it would be possible to calculate the maximum energy available within the relevant building volumes, since we have the plans of the building (given H/O gas mix at optimum) and to calculate the required energy (given a detonation wave) to cause the damage observed.

Some experience of such scenarios might be more useful. Sounds like a complex calculation...

Strikes me that the although a detonation wave may be +possible+ as a result of a H/O reaction, the energy density would be orders of magnitude lower than those caused by detonation of a HE liquid or solid compound. A prompt criticality would produce energy densities orders of magnitude grater than HE too, i imagine.

It's also interesting to consider the probability of 'burn-off' of of hydrogen produced by the violently exothermic (1200 degC+) zircalloy reaction that is said to have produced it in this case. Once it has mixed with enough oxygen, at such a temperature, given it's very low minimum ignition energy (1/10th that of petrol) - surely it would simply burn away?

evendine said...

(didn't see your post until i'd posted mine)
:0) Aha! (re: H/O detonations)

BTW: one assumption you're making about the state of the #4 fuel pool is that TEPCO have actually allowed us to see +real+ pictures of it. I wouldn't trust them as far as I could throw a nuclear reactor ;0)

Anonymous said...

I think you're looking at the results of a steam explosion, largely.
The commenter who stated the lack of charring from hydrogen has a point.

"The 'Elephant in the room' is the fact that the railings around the edge have clearly been powerfully blown +away+ from the centre of the reactor well! "
A little, but not by much.

"ducts .. got crushed and mangled, then fell down. "
The ducts show signs of flailing about, like a pennant in the breeze. Hydrogen combusting fed back in the ducts repeatedly (fast) to produce the flailing.

As Atomfritz said, the detonation speed is what distinguishes hydrogen.

And don't underestimate the power of steam produced by a superheated object.
Videos of steam explosions in volcanoes speak of its power.

Freezing water expands well enough to crack rock, and confined steam destroys rock effortlessly.
Earthquake damage? Couldn't have happened there. :)


I think most would agree with that.
Not just let reporters visit, identify the nuclides.

Anonymous said...

evendine said...

BTW: one assumption you're making about the state of the #4 fuel pool is that TEPCO have actually allowed us to see +real+ pictures of it. I wouldn't trust them as far as I could throw a nuclear reactor ;0)

The whole story is a eight month Hollywood err TEPCOwood stage.

The same staging goes on with the recent carefully selected 'journalist's' visit and 'reporting'. Their pictures show that - oops no cameras ... correction: the TEPCO handout pictures show that ... hmm. enjoy Bang Bang wild west.

Anonymous said...

@ evendine

If we do not trust the photos and video, we may as well be discussing if it was an excess of magical ponies that made it blow up.

The risks involved in faking footage would be enormous. I can believe that TEPCO are suppressing information (they've done it before), but distorting/fabricating? No.

Anonymous said...

@ evendine
read this
for a cogent discussion of hydrogen and SFPs

What Mr. Genn Saji says there about the #3 SPF also applies to #4 (in spades, even, because #4 was ignored in the first few days, so it almost certainly started to boil at some point).

Anonymous said...

"but distorting/fabricating? No."

LOL. -->they've done it before ... yes truly, over and over. This dicussion is part of the program.

When free access is closed, handouts are totally screened. Here seen one of their latest Theatrics -failures, a 2.5 sec leak...


Whatever, be MSM-happy and inhale.

evendine said...

@Anon 3:20:

Ok, so if i've understood Saji correctly, the suggestion is that it was radiolysis that generated the hydrogen in the #4 SFP, not a zicalloy reaction (with it's very high associated temps) and approx 38kg-H2 (850 m3) of gas dissolved in the pool water was released en-mass when the water approached boiling point and drove the gas out of suspension.

Useful to have some numbers - thanks for that...

I suppose the question is - would such a release of that quantity of H2 be likely to lead to a hydroxy mixture capable of detonation and would such a detonation have sufficient energy density to create the devastation observed?

To get some idea, if we calculate the combustible mass of the H/O mixture, assuming perfect conditions of 2:1 ratio, relative atomic mass of O being 16x that of H we get:

38 + (38 x 16/2) = 342 Kg

As a comparator, would 342 Kg of TNT be capable of creating the level of destruction observed?

What is the likelihood of reaching anything like perfect hydroxy mixture before igniting? Pretty low, I would have thought, given the number of possible ignition sources and hydrogen's very low minimum ignition energy...

Anonymous said...

"I suppose the question is ..... mixture capable of detonation and would such a detonation have sufficient energy density to create the devastation observed?"

Do the calculations with Methane ... seeps from known reserves 1km below, known to naturally cause xplosions. Why would that be here, now?

Plutonium MOX channel radiation(s) has been burning the base rock porous allowing such seepage after quake.

(s) = Multiple 'types'.

Anonymous said...

There's a very detailed analysis of the #4 explosion cause here:
Fukushima Daiichi NPS Disaster Timeline
Relevant part starts on page 33.

I'm now convinced the #4 SFP water level never got low enough to expose the fuel rods. Thanks for one tiny mercy in a world of pain.


Anonymous said...

350 kg of TNT would be indeed just about enough to cause the damage observed, if it were properly distributed.

But 1 kg of H2/O2 stoichiometric mix is roughly equivalent to 8 kg of TNT. 300-something kg of H2 would be quite enough, thank you very much, even under less than ideal conditions.

I'm very angry with those who keep mumbling about huge criticality excursions, for this exact reason (I'm looking at you, mr. Gundersen!).

People just can't seem to wrap their heads around explosions and what they can really do. I blame Hollywood.

When you grow up watching puffs of burning naphta chase action heroes around, you come to think you can outrun a shock front in real life and walk away unharmed from bomb blasts if only you avoid getting shrapnelled somehow.

evendine said...

@TeraHetz - thanks for the link. Will check that out...

@Anon 2:45:

The problem is, it seems that detonation will only occur when the H/O mix is close to 2:1.

It's clear that some kind of detonation did occur, but +highly unlikely+ that it was caused by hydrogen from whatever source, given that the hydrogen in the building was exposed to so many possible ignition sources and hydrogen's very low minimum ignition energy.

In other words, any hydrogen in the building would have burned off long before it reached the 2:1 mix required to cause detonation...

So, what caused the detonation!?

Anonymous said...

4% in air can already go bang. 8% is firmly in detonation territory iirc.

There are "recombinators" (I think they are called) in such plants, to burn off hydrogen - but they were not working, or not installed for some reason.

In the absence of electricity, I'd say that, on the contrary, an ignition source is pretty hard to come by. Maybe something metallic fell? Some klutz tried to turn on the lights?

I find the lack of video and/or first-hand reports of the actual explosion(s?) at #4 very, very disturbing.

evendine said...

@Anon: 7:46:

Actually H needs to reach 18.6% in air in order to be capable of detonation - two thirds of the way to the 29% ideal hydroxy mixture, according to this:

So between 4% and 18.5% it will burn rather than detonate and needs very little energy input do so, for example: 0.02mJ at 10% air concentration.

If we assume for a moment that the cause of the explosion +was+ hydrogen - why didn't the energy source that supposedly caused the detonation cause a deflagration beforehand?

I agree with you on the lack of video point - seems highly suspicious...

Anonymous said...

subsonic flame fronts can go supersonic if the flow is accelerated in some way, such as by choking (walls, a constriction in a pipe), or even a meeting a different blast.

evendine said...

#1 did what would be expected from a hydrogen explosion - namely the gas rose to the roof of the building and exploded, blowing the roof off. Hydrogen is the most buoyant of gases and rises at circa 60km/hr (16m/s), so if it had any path to the reactor hall, any gas in the building would have reached the roof in a few seconds. This must include almost every part of the building, apart from the PV and containment. #1's side-walls are virtually intact.

So why are the +basement+ walls and so many side-wall panels of #3 and 4 so badly damaged? Remember they were built from reinforced concrete 1-1.5m thick?

Why is the general level of damage orders of magnitude worse at #3 and 4?

Anonymous said...

As you point out, 12:14, the results are quite different and puts extra focus on assumptions.

" +highly unlikely+ " can't really be stated when these buildings were seriously compromised by the quake.

Recall the description of the onsite inspectors' experience of the buildings' interiors right after the quake.
They fled because they feared their lives were in danger, immediate danger.

Part of the job of inspector is to be able to do an immediate assessment of systems, in this case.
They fled.

evendine said...

:Anon 2:52:

I think it's standard practice in earthquake zones to leave the building immediately - to avoid falling objects and structures, but these building are extremely strong...

It's interesting to be able to compare the outcomes in different structures of the same basic type with the same function in the same location. An unusual opportunity from the analytical standpoint.

Surely it can be deduced that whatever happened in #1 was different to what happened in #3 and 4...

Anonymous said...

What happened in #1 was necessarily different, as it is an older and smaller reactor.

Anonymous said...

....onsite inspectors' experience of the buildings' interiors right after the quake.They fled because they feared their lives were in danger, immediate danger."

And died. If the question is about the four IAEA inspectors...

Why did they have to die? Maybe saw smtg naughty.

evendine said...

@Anon: 1:16:

...older smaller and more weakly constructed, so why was the outcome less severe by orders of magnitude?

Anonymous said...

"And died. If the question is about the four IAEA inspectors...

Why did they have to die? Maybe saw smtg naughty."

Sucked up a stack, were they? First their clothes, then them.

Anonymous said...

yes #3 was categorically different than 1.
The key point is that once these reactors began to meltdown any subsequent events were in direct contempt of normal reactor systems, systems you must assume were entirely disrupted.
The two that did explode probably had both steam and hydrogen explosions, and 3 had quite a bit more occurring.

what is this about the 4 IAEA inspectors dying afterwards?
A link of some sort is required to seriously consider it.
I haven't heard of these 4 before, and I've missed little on this Fuku stuff.

Anonymous said...

"4 IAEA inspectors dying "

Don't even try to understand as it is the Finn/Swede troll again. It must be another one of his sorry ass attempts at sarcasm and enlightenment. Epic fail as usual.

Anonymous said...

I suspected it was him and was apprehensively awaiting his attempt to link Josef Stalin to the IAEA inspectors.

evendine said...

@anon 10:33:

I do assume disruption of all systems, but my point is that that the collection of reactors were operating as parallel systems, essentially i.e. sharing the same context.

It seems to me that this provides an unusual opportunity for comparison, in that we can effectively remove certain factors as being contributory, since they apply to other reactors in the group...

evendine said...

I know this a purely voluntary interrogation ;0), but:

#1 was older, smaller and more weakly constructed, so why was the outcome (compared to #3 and 4) less severe by orders of magnitude?

Anonymous said...

Anon 1:17 PM, it might still happen.

Anonymous said...

"this provides an unusual opportunity for comparison, in that we can effectively remove certain factors as being contributory "

The impression I have with hydrogen transport and explosion is that it's a little harder to say definitively where precisely it occurred than we'd like.
2 of the 3 explosions had a large lateral component and lacked the dark mushroom cloud of #3.
I'm not sure if pure steam explosions would have had that much of a lateral reach, speaks of hydrogen, mixed most likely. Don't really see any indicator that says only this type or that type occurred.
Rods melting at that temp., how could they not produce steam explosions.

#3 was the only one loaded with MOX. The degree of verticality and speed with which it reached that height speak of something boosting it.
As Gunderson said, it was nuclear.
And as Busby said, Chernobyl was also partially a nuclear explosion.

Ivan said...

"Chernobyl was also partially a nuclear explosion."

Technically Chernobyl did not constitute nuclear explosion, but reactivity excursion of nuclear materials from core.

Anonymous said...

@ evendine

In fact reactor 1 actually caused the most damage as the explosion made conditions on site take a radical turn for the worse, severely affecting work on the other two.

It is not useful to make direct comparisons. The accident causes are the same, but the paths taken afterwards are wildly different.

It is, otoh, useful to think about how commonalities in design and shared equipment (vent stacks, control rooms, power lines, access roads etc etc) contributed to this awful outcome.

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