Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Nullpunkt]

Hmmm . . .

The northeast corner of Bldg 4 is odd, for sure. I don't believe it was the whole roof that lifted -- maybe the northeast corner might have had that effect. But if so, why?! What happened in the northeast corner of that building.

@liamdavis:

Maybe you could lend your expertise here, sir. Also, can you comment on your assessment of the possibility that the concussion and shock wave from the Bldg 3 explosion might have done structural damage to the northeast corner of Bldg 4 that wasn't readily visible from the outside. Perhaps after the blast at Bldg 3, the northeast corner of Bldg 4 was simply the weakest link.

From the picture you attached I think nothing from inside the building has damaged the roof. Something has landed on top of the roof. It hit not directly from overhead, more a bit from the side, so it bend over the wall.
If you take a closer look to the object it is partly above the roof skeleton and the main part stamped into the building construction.

Where did you find this picture? I could not find any other images of this part of the building.

 

[TCups]

From the picture you attached I think nothing from inside the building has damaged the roof. Something has landed on top of the roof. It hit not directly from overhead, more a bit from the side, so it bend over the wall.
If you take a closer look to the object it is partly above the roof skeleton and the main part stamped into the building construction.

Where did you find this picture? I could not find any other images of this part of the building.

Here:

http://cryptome.org/eyeball/daiichi-npp/daiichi-photos.htm

 

[Jorge Stolfi]

How this is possible ? Unit 4 core location is 5C more than SFP, how empty core can be so hot ?[/PLAIN]

Unit #4's SFP is almost completely covered by the fuel handling machine that crashed into it. Then there are roof beams etc. above it. So it is possible that the infrared image is seeing the water in the reactor, but not that in the SFP.

 

[elektrownik]

And my new image of #4:
[PLAIN]http://img535.imageshack.us/img535/3165/gggss.png

 

[Jorge Stolfi]

IN the last three NISA releases (98, 99, 100) they started giving two CAMS readings for the drywell (A,B) and two for the suppression torus (A,B), instead of one.

For units #2 and #3, the previous single readings match closely the new (A) readings. Fine.

For unit #1, however, neither (A) nor (B) match the previous single readings. However, the previous readings would match the new (A) readings multiplied by 10. Specifically, the readings given as 1.07×10⁰, 1.00×10⁰ and 9.92×10^-1 Sv/h should be multiplied by 10.

The CAMS readings are given in exponential notation. My guess is that TEPCO made a mistake in the exponent of the S/C readings for unit #1, either in the last three releases or in all the previosu ones. I caught a couple of such mistakes before, so that is not out of the question. Moreover, it is almost certain that they produce each fax sheet by editing the previous one. (There is a spurious hyphen in front of a temperature reading that looks like a minus sign; it has been there forever.)

I will keep TEPCO's values in my next plot, until the issue is clarified.

 

[TCups]

Unit #4's SFP is almost completely covered by the fuel handling machine that crashed into it. Then there are roof beams etc. above it. So it is possible that the infrared image is seeing the water in the reactor, but not that in the SFP.

The verbiage "crashed into" may be a bit strong, given the current video of SFP 4 and the almost intact FHM

 

[cphoenix]

1. The explosions had enough force to pull the water from the cooling pond (spent fuel pool)?

At Building 3, yes. It is probable that the explosion was steam, and the steam was the vaporized water leaving the cooling pool.

Building 3 seems to have soot on it.

Also, wasn't there a fireball in the building 3 explosion video?

When you talk of vaporized water leaving the cooling pool, that sounds like my theory of low pressure high volume steam explosion. But I thought that fit building 4 a lot better than building 3.

At Building 4, it is not known with certainty, but it is possible and perhaps probable. The spent and un-spent fuel in the pool would have to be partially uncovered to become damaged and to then produce the hydrogen gas. It was hydrogen gas that most likely caused the explosion in Building 4.

Why do you say there was hydrogen gas in building 4? There was damage below-decks in building 4, where hydrogen would not have gone. Also, a hydrogen explosion would probably have done a lot more symmetrical damage to the building, knocking off all the top row of panels.

Chris

 

[Jorge Stolfi]

The verbiage "crashed into" may be a bit strong, given the current video of SFP 4 and the almost intact FHM

But my impression is that the FHM is much lower than it should be, and part of it is below the main (top) floor, i.e. inside the pool. Is that right?

 

[TCups]

From the picture you attached I think nothing from inside the building has damaged the roof. Something has landed on top of the roof. It hit not directly from overhead, more a bit from the side, so it bend over the wall.
If you take a closer look to the object it is partly above the roof skeleton and the main part stamped into the building construction.

Where did you find this picture? I could not find any other images of this part of the building.

Well whaddya know . . .
Nullpunkt may be right. The damage to the northeast corner of Bldg 4 does look like an impact from something that fell on it. That would explain the north wall collapsing inward, except . . . what fell on it? If it is something from the explosion at Bldg 3, it must have had one long "hang time", or there was another explosion we missed. I guess you don't look for something if you don't think it could have happened.

@|Fred

Your the skeptic, Fred. What do you think? Does a falling object pass the "|Fred Test"?

 

[TCups]

But my impression is that the FHM is much lower than it should be, and part of it is below the main (top) floor, i.e. inside the pool. Is that right?

I am not sure that is right, but I don't know. Heck, I am not sure now that I "know"anything about any of these events.

 

[TCups]

Building 3 seems to have soot on it.

Also, wasn't there a fireball in the building 3 explosion video?

When you talk of vaporized water leaving the cooling pool, that sounds like my theory of low pressure high volume steam explosion. But I thought that fit building 4 a lot better than building 3.



Why do you say there was hydrogen gas in building 4? There was damage below-decks in building 4, where hydrogen would not have gone. Also, a hydrogen explosion would probably have done a lot more symmetrical damage to the building, knocking off all the top row of panels.

Chris

I retract my earlier statement, sir. I cannot say with any reasonable degree of certainty that I know what specifically caused any of the explosions except perhaps for Building 1, and only that because it occurred in immediate temporal proximity to venting of hydrogen gas from the containment.

 

[|Fred]

But my impression is that the FHM is much lower than it should be, and part of it is below the main (top) floor, i.e. inside the pool. Is that right?

Personal estimate is about 2m bellow where it should be, It derailed into really

 

[TCups]

Personal estimate is about 2m bellow where it should be, It derailed into really

OK, but I meant what do you think about something having fallen into the northeast corner of the roof of Building 4?

 

[etudiant]

Is there any logical explanation for TEPCOs concern about the structural stability of the reactor 4 SFP?
A hydrogen explosion in the SPF would have left the support structure unscathed and there was no fuel lower down to do damage.
So that leaves only the reactor 3 explosion as a suspect. One part of that explosion did seem very horizontal and looked to impinge on the reactor 4 building.
There has not been any good explanation of this, which preceded the roof blowing off.
Can anyone provide insight?

 

[Jorge Stolfi]

I have updated my plots of the #1--#3 reactor variables to TEPCO-NISA release 100 (dated 2011-04-18 15:00).

http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/Main.html"

I had to change the format of my files to accommodate the new readings that have been provided in the recent releases (and the 3-digit NISA release numbers! Perhaps I should plan already for 4 digits...) The new data include the drywell and torus temperatures, and the alternative "B" readings for drywell and torus CAMS. I have also provided space for the alternative ("A" or "B") readings of water level and core pressure; these have been available for some time, but I had entered only one of them until now. Over the next few days I hope to add the past readings of these alternate measurements.

Beware that the CAMS readings for unit #1 suppression chamber may be wrong by a factr of 10, as noted in my previous post.

 

[NUCENG]

I've been looking for the photo evidence of a second explosion at unit 3 and haven't found anything conclusive, yet. But I have some other information that tends to bring more doubt of a big hydrogen explosion in the Unit 4 SFP.

Some here have expressed a lot of doubt about TEPCO's information. Since I am using their data, not everyone will agree.

They have described damage to fuel in the Unit 4 SFP as minor. Their samples indicated concentrations of I-131 at 220 Bq/cm^3 and Cs-137 at 93 Bq/cm^3. I took the conservative assumprion that the core just offloaded was the only contributor yo that radioactivity. assumed only a release of 5% for gap release. In a volume of the size of the SFP absent any dilution, but accounting for 30 days of decay would produce activities for CS and I in the range of 1E6 Bq/cm^3. You would have to feed and bleed for a full turnover of SFP volume 16 or 17 times to reach the measured concentrations. If their sample is correct, fuel damage was minor as they claim.

 

[TCups]

I've been looking for the photo evidence of a second explosion at unit 3 and haven't found anything conclusive, yet. But I have some other information that tends to bring more doubt of a big hydrogen explosion in the Unit 4 SFP.

Some here have expressed a lot of doubt about TEPCO's information. Since I am using their data, not everyone will agree.

They have described damage to fuel in the Unit 4 SFP as minor. Their samples indicated concentrations of I-131 at 220 Bq/cm^3 and Cs-137 at 93 Bq/cm^3. I took the conservative assumprion that the core just offloaded was the only contributor yo that radioactivity. assumed only a release of 5% for gap release. In a volume of the size of the SFP absent any dilution, but accounting for 30 days of decay would produce activities for CS and I in the range of 1E6 Bq/cm^3. You would have to feed and bleed for a full turnover of SFP volume 16 or 17 times to reach the measured concentrations. If their sample is correct, fuel damage was minor as they claim.

Yes, but doesn't TEPCO also report the damage at Bldg 4 as a "hydrogen explosion"?

 

[MadderDoc]

Well whaddya know . . .
Nullpunkt may be right. The damage to the northeast corner of Bldg 4 does look like an impact from something that fell on it. That would explain the north wall collapsing inward, except . . . what fell on it? <..>

Isn't the simple answer: Parts of the roof.

There must have been an explosion inside the building, including in the upper floor, everyone would agree. Both the walls, and the roof must have been affected by that explosion. The wall pillars and panels must have been pushed outward by it, the roof however must have been blown upwards.

So, in the moment after the explosion we have had a weakened pillar and wallpanels structure still standing below, and -- 100s of tons of roof in the air some distance above it.

What goes up must come down, so the roof did, and some of it incidentally on top of the north wall. And since the wall had already been buckled outward by the explosion, the next powerful hit from above could leave it only even more collapsed, and even further pushed outward.

 

[NUCENG]

Yes, but doesn't TEPCO also report the damage at Bldg 4 as a "hydrogen explosion"?

Yes, in their initial reports they called it hydrogen.


Here was their first release:

Press Release (Mar 15,2011)
Damage to the Unit 4 Nuclear Reactor Building at Fukushima Dai-ichi Nuclear Power Station


At approximately 6:00am, a loud explosion was heard from within the
power station. Afterwards, it was confirmed that the 4th floor rooftop
area of the Unit 4 Nuclear Reactor Building had sustained damage.

World Nuclear News :

17MARCH
The explosion at unit 4 is thought to have been from a build-up of hydrogen in the area near the used nuclear fuel pond. It severely damaged the building, as well as that of adjacent unit 3, with which it shares a central control room.

So they were saying that there was some simultaneous damage to both Unit 3 and Unit 4.

But now the damage to fuel in the SFP on Unit 4 does not seem to support that scenario.

It keeps bringing me back to a second explosion in Unit 3.

I can't prove it, but I haven't seen anything that fits better.

 

[elektrownik]

What about this strange idea ?
[PLAIN]http://img864.imageshack.us/img864/770/7d39a2e665024e3f8856f31.jpg

 

[TCups]

RE: MECHANISM OF DAMAGE TO BLDG 4 (AND PROBABLY BLDG 3 ALSO)

Nullpunkt has it right. A careful look at the reasonably intact roof of Bldg 1 and the girder structure of Bldg 4 shows that the roof is in "patchwork" square segments that vary slightly in their shades of gray. The same patchwork is present on the north surface of the portion of the roof that fell into Bldg 4. Looking carefully, I believe an explosion (perhaps steam?) over the SFP 4 could have neatly peeled the roof off the building like the lid off a sardine can. Once the south end of the roof was lifted sufficiently high, the north end slid into the top of the building like a giant knife. It looks like a large slab of the roof was involved. A small portion of the roof has also impacted over the southeast corner of Bldg 4 doing structural damage there as well.

And PS: There is a second green crane or some type of machine inside the service floor of the north end of Bldg 4 clearly seen through the second open panel from the right.

And that said, I think all of the damage at Bldg 3 has to be re-assessed in terms of not the FHM going ballistic (perhaps portions did, perhaps not), but instead, the entire roof itself slicing down in a similar fashion on the north end of Bldg 3 as well.

Good call Nulpunkt!

 

[clancy688]

Um, there's something I just spotted about Unit 4...

Sat-Image of March 16th, Unit 4 is already destroyed but the roof is still covered:

http://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichi2_march16_2011_dg.jpg

Sat-Image of March 17th, the cover on Unit 4s roof is gone:

http://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichirec_march17_2011_dg.jpg

 

[GJBRKS]

Um, there's something I just spotted about Unit 4...

Sat-Image of March 16th, Unit 4 is already destroyed but the roof is still covered:

http://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichi2_march16_2011_dg.jpg

Sat-Image of March 17th, the cover on Unit 4s roof is gone:

http://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichirec_march17_2011_dg.jpg

(Very OT , but if you would have seen just this picture 1 year ago without further info ,you would not have believed this could happen...I'm still amazed ...)

 

[bytepirate]

Yes, in their initial reports they called it hydrogen.


Here was their first release:

Press Release (Mar 15,2011)
Damage to the Unit 4 Nuclear Reactor Building at Fukushima Dai-ichi Nuclear Power Station


At approximately 6:00am, a loud explosion was heard from within the
power station. Afterwards, it was confirmed that the 4th floor rooftop
area of the Unit 4 Nuclear Reactor Building had sustained damage.

World Nuclear News :

17MARCH
The explosion at unit 4 is thought to have been from a build-up of hydrogen in the area near the used nuclear fuel pond. It severely damaged the building, as well as that of adjacent unit 3, with which it shares a central control room.

So they were saying that there was some simultaneous damage to both Unit 3 and Unit 4.

But now the damage to fuel in the SFP on Unit 4 does not seem to support that scenario.

It keeps bringing me back to a second explosion in Unit 3.

I can't prove it, but I haven't seen anything that fits better.

something else is very hard to explain:
if the hydrogen was produced by a zircaloy reaction, this means the assemblies must have been exposed to the air. right?
but there was no water added to the pool until 4 days after the explosion.
actually, they put big efforts to spray water on the #3 SFP, before they started with #4.

questions to be answered (find my answers in {}):
- was fuel in #4 exposed? {no}
- if not: could enough hydrogen have been produced (radiation decomposition, steam)? {no}
- if yes: why was the fuel covered after the explosion (why did TEPCO obviously did not worry about exposed fuel, + #4 was [only] INES 3 rated after the explosion [weak evidence though]) {i have posted a thesis on this before, but it is too weird to be true}

if the reason for the destruction of #4 was *not* hydrogen:
- could #4 has been damaged by an explosion in #3? {no}
- as no damage to #4 has been observed: was there a second explosion in #3? {no}
- if yes, what kind of explosion in #3 could have an impact on #4 as observed (must have been very directed, no damage to #2...)? {no}
- what else could have exploded in #4? {nothing}

if all my answers are correct, unit 4 has not exploded at all...

 

[clancy688]

if all my answers are correct, unit 4 has not exploded at all...

In conclusion, since 200 pages we have only found evidence / clues why Unit 4 couldn't have exploded, and not a single one to support a big explosion.
And yet, Unit 4 is totally in ruins. It's truly a mystery... ^^;

 

[TCups]

(Very OT , but if you would have seen just this picture 1 year ago without further info ,you would not have believed this could happen...I'm still amazed ...)

Odd lighting, for sure, and really poor resolution, but I believe the damage was already done. The photos are at different angles (about 45 deg vs 90 deg overhead), but I believe I can see the larger pieces of debris on the roof (small arrows), the X structure of the roof girders (rectangle), the inward bowing of the north wall, and the odd angle at the northeast corner (long arrow), even so.

 

[Jorge Stolfi]

Isn't the simple answer: Parts of the roof..

Checking some pics:

http://cryptome.org/eyeball/daiichi-npp/pict10.jpg
http://cryptome.org/eyeball/daiichi-npp/pict12.jpg
http://cryptome.org/eyeball/daiichi-npp/pict13.jpg
http://cryptome.org/eyeball/daiichi-npp/pict46.jpg

Your explanation seems to be the only viable one if there was no late explosion in #3. However, I understand that the roof truss of #4 (still largely intact) was covered with narrow sheet metal strips (plenty of them around, some of them still in place) and then with a layer of tar/concrete. Your theory seems to require a continuous layer of thick sheet metal (or something that looks very much like it), covering at least a large fraction of the roof. There seems to be no such layer in unit #3 or its debris.

The object in question seems quite heavy and hard, since it bent several thick steel beams without itself shattering or crumpling. Would a concrete sheet behave that way? It also seems to have a couple of shallow grooves or ridges parallel to its topmost edge.

It could be an exploded boiler or tank from the lower level of #3, perhaps? Or a piece of #3's drywell dome?

On the other hand, I can believe that such a large piece of debris, falling sideways onto the roof truss, could have pulled the steel beams down, and they in turn could have pulled the concrete beam inwards.

 

[Jorge Stolfi]

Sat-Image of March 16th, Unit 4 is already destroyed but the roof is still covered:
http://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichi2_march16_2011_dg.jpg

I think that the roof is already gone in this picture, but the roof's metal skeleton looks like a continuous cover because of the low elevation of the camera and low image resolution,

EDIT: ON second look, I am not so sure. It does seem that the roof tarmac is still there, but the mysterious "metal sheet" is already stuck into it.

EDIT2: On third look, it may be an illusion allright. In http://cryptome.org/eyeball/daiichi-npp/pict10.jpg" , taken with the same camera angle, the truss beams are closely spaced and cover the roof completely. With low resolution it would seem a continuous roof.

 

[TCups]

Checking some pics:

http://cryptome.org/eyeball/daiichi-npp/pict10.jpg
http://cryptome.org/eyeball/daiichi-npp/pict12.jpg
http://cryptome.org/eyeball/daiichi-npp/pict13.jpg
http://cryptome.org/eyeball/daiichi-npp/pict46.jpg

Your explanation seems to be the only viable one if there was no late explosion in #3. However, I understand that the roof truss of #4 (still largely intact) was covered with narrow sheet metal strips (plenty of them around, some of them still in place) and then with a layer of tar/concrete. Your theory seems to require a continuous layer of thick sheet metal (or something that looks very much like it), covering at least a large fraction of the roof. There seems to be no such layer in unit #3 or its debris.

The object in question seems quite heavy and hard, since it bent several thick steel beams without itself shattering or crumpling. Would a concrete sheet behave that way? It also seems to have a couple of shallow grooves or ridges parallel to its topmost edge.

It could be an exploded boiler or tank from the lower level of #3, perhaps? Or a piece of #3's drywell dome?

On the other hand, I can believe that such a large piece of debris, falling sideways onto the roof truss, could have pulled the steel beams down, and they in turn could have pulled the concrete beam inwards.

The object is heavy -- yes, hard -- no. Isn't the flat roofing structure of most commercial roofs is something like corrugated metal with a thick layer of tar and pea gravel sprayed onto the metal substrate to form a heavy, watertight roof slab? Someone here must know commercial roofing, but I am betting the roof was fairly flexible, but heavy. And if the mass of the whole roof were lifted, peeled upwards largely intact and put in motion by a pressure wave from the explosion and then gravity, then that slab of roofing would have plenty enough mass and kinetic energy to do some serious damage IMO.

 

[cphoenix]

something else is very hard to explain:

("If it was hydrogen" edited out by cphoenix)

if the reason for the destruction of #4 was *not* hydrogen:
- could #4 has been damaged by an explosion in #3? {no}
- as no damage to #4 has been observed: was there a second explosion in #3? {no}
- if yes, what kind of explosion in #3 could have an impact on #4 as observed (must have been very directed, no damage to #2...)? {no}
- what else could have exploded in #4? {nothing}

if all my answers are correct, unit 4 has not exploded at all...

I've already explained how something could have exploded in #4. The water in the spent fuel pool could have had up to 1/10 kiloton of explosive force, simply from being superheated under 2 atm of pressure - the pressure under 40 feet of water. 1E10 grams in the pool, 4 J/g/C, 25 C over 1-atm boiling point... once you do the math, it's clear that if even a small fraction of the pool's volume were unable to cool by convection, the resulting burp of steam could easily take out the building.

BTW, my alias is looking more cryptic to me all the time, and that wasn't my intention. I'm Chris Phoenix, and my email is my alias at gmail.com. Nice to meet you all.