Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[OnlyOneTruth]

Hope this hasn't been posted before: http://www.tepco.co.jp/nu/f1-np/intro/outline/outline-j.html" from TEPCO after you pipe it through a translator.

 

[|Fred]

I'll start a new attempt to raise awareness for an annotated picture posted before:

most annotation were speculation made early and were proven wrong

- Big steam pipe is located close to unit 3 (perspective error) and was destroyed in U3 explosion
- The actual concrete panel corresponding to the hole has been blown outward from U4
- every time some one see some red bleeding due to compression they think it's glowing , I'm also seen report of UFO at fukushima based on dust making some picture out of foucus..
- There is no evidence that the roof melted, other visual rules out melting imo, and suggest cut and bent
-I don't think there was any robots at the time

 

[Borek]

could I conclude that at least part of the fuel core has melted through the pressure vessel into the drywell of reactor 3 ?

From what I understand if that will happen we will see different isotopes around the plant.

 

[MadderDoc]

I'll start a new attempt to raise awareness for an annotated picture posted before:

The annotation characterizes the curved deformation as damage from heat. Isn't that plausible? Do we have any reliable information on the sequence of events in No4 (fire before/after explosion)<..>

I don't think that is a plausible damage from heat.

Allow me to draw your attention to a possible suspect at the foot of the building (see attachment). It is found at the scene of the crime, in a plausible position after an assumed hammering of unit 4's north side. It appears to be a boiler tank or something of that sort, about 10 meters long, about 3 meter in diameter. It appears to have been blasted. And, perhapos significantly, it appears to be lying on top of pieces of unit 3's roof construction.

 

[PietKuip]

and now tepco held press point in English ...
http://www.ustream.tv/recorded/14088840

It seems they want to fill the drywell with water, to cover and cool the reactor pressure vessel.

Why would one do that? The steel is so thick that it cannot conduct that much heat. Is it cracked open? Tepco said that they had to guess the RPV water level.

And they said that at this moment they did not believe that there was an ongoing criticality at reactor 1. Mumbling something about neutron measurements.

The journalists did not seem very well prepared.

 

[elektrownik]

From what I understand if that will happen we will see different isotopes around the plant.

We will not see any isotopes until tepco will give us data about them, they give us now only I and Cs...

 

[TCups]

I'll start a new attempt to raise awareness for an annotated picture posted before:

The annotation characterizes the curved deformation as damage from heat. Isn't that plausible? Do we have any reliable information on the sequence of events in No4 (fire before/after explosion)

@TCups, you posted the picture, You remember where you got it?

I remember the picture well. I can't source it. I think it was a Reuters picture and its original annotations were only the red Japanese characters.

The English annotations added were my own observations and speculations at the time, most of which have subsequently proved to be wrong (as |Fred has noted).

 

[jmelson]

It has been suggested elsewhere that the fuel rods could have been protected effectively against failure by a thin gold coating, to protect the zirconium cladding from oxidation.
Is this valid even if the fuel rods overheat substantially because of lack of cooling?
Obviously the gold coating could fail once the temperature reaches the melting point of gold, but a very thin coating might well remain intact even if above melting.
Any studies or references would be very much appreciated.

Gold platings are quite effective at preventing oxidation, but are also fragile, especially when there is gas and corrosive things like Iodine present. So, the gold might work great at modest temperatures, but when stuff gets hot, I think the plating would start to flake and shed pretty rapidly. Obviously you couldn't afford a really heavy gold plating.

Jon

 

[TCups]

I don't think that is a plausible damage from heat.

Allow me to draw your attention to a possible suspect at the foot of the building (see attachment). It is found at the scene of the crime, in a plausible position after an assumed hammering of unit 4's north side. It appears to be a boiler tank or something of that sort, about 10 meters long, about 3 meter in diameter. It appears to have been blasted. And, perhapos significantly, it appears to be lying on top of pieces of unit 3's roof construction.

Astute observation. The tank is on top of ground debris, but that doesn't necessarily confirm it came from Bldg 4. But the path of debris from the hole in the side of Bldg 4 plus the impact damage to the north side of the smaller building structure and the final resting place would be consistent with the tank being a projectile.

These hi-res views weren't available when the causes of the damage from the initial north face photograph of Bldg 4 was posted.

 

[Cire]

REGARDING THE INTERNAL BALLISTICS OF EXPLOSIONS IN CONFINED SPACES

I cannot speak with authority about hydrogen gas + oxygen explosions, but I can speak with authority about reloading ammunition with various gunpowders and primers so, for what its worth, consider this:

Propellants are tricky in their burn characteristics. Propellants like double-base propellants or those found in rockets (Ammonia perchlorate / HTPB) have burn rates that are much more sensitive to pressure then a simple H2 + O2 reaction is.

For reference here is a power plant that exploded due to a CH4 leak.. Note the damage in the photo is not too different then what we see at fukushima.

[PLAIN]http://img854.imageshack.us/img854/144/boom.jpg

 

[Jorge Stolfi]

Can anyone look on new nisa report and write here what think about new data ? They add values from many sensors: http://www.meti.go.jp/press/2011/04/20110417002/20110417002-2.pdf

I see that they added two temperature sensors in the suppression chamber, which so far agree quite well: #1 = 54C, #2 = 77C, #3 = 44C.

They also added another CAMS reading for the drywell, the (B) reading: These are quite different from the (A) readings: #1 = ?(A,B), #2 = 26.00(A) 29.50(B), #3 = 15.90(A) 12.10(B), all Sv/h.

They also added another CAMS reading for the suppression torus, the (B) reading, also very different from (A): #1 = 1.07(A) 667(B), #2 = 0.60(A) 121.00(B), #3 = 0.60(A) 56.20(B), also in Sv/h

I believe there is a typo in release 97, the #1 drywell CAMS reading "1.07×10⁰ Sv/h" should be 1.07×10¹.

In that same sheet, the #3 drywell CAMS reading "2.00×10¹ Sv/h" may be a typo; from the adjacent values it should be around 1.6×10¹

I am waiting for the next release (99) to update my plots.

 

[Jorge Stolfi]

I am waiting for the next release (99) to update my plots.

It seems there was only one release on apr/17 so I have updated the plots anyway.
I have also added pressure x temperature plots for the core (for whatever they are worth).
All the best.
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/Main.html

 

[cphoenix]

cphoenix: Dunno. It just seems to me that the 2-bar steam from the SPF would blow off the roof (and the walls) on top first, and would not blow off anything else. Sure, sure, intuitions might be wrong, but I really don't think 2-bar overpressure would blow through the floor after blowing the roof off. Keep in mind that there's tons and tons of air in the way of this 2-bar overpressure. Intuitions might be wrong but they're better than no mental 'simulation' at all.
Also i really don't think water would superheat on the bottom without being convection stirred. I've no idea how stupidly those spent fuel pools are designed, but even with all due disrespect for the industry that has control rods fall out during maintenance, I don't think spent fuel pool wouldn't be able to convection-stir itself.

I agree that the water would not blow through a solid floor. And I agree that an undamaged pool would probably convection-stir itself.

If something flat fell into the pool, so that it lay on top of the fuel racks, it could easily suppress convection. Either an aftershock or the building 3 explosion might have knocked stuff into the pool. I assume the fuel racks are more like a bundle of pipes than like an open lattice, so any pipe you closed the top of would superheat. You wouldn't have to cover the whole pool or rack area. Whatever fraction you covered, that's what fraction of 100 tons of steam you'd get.

I completely agree about the tons of air in the way of the overpressure. That's why I think some of the water might have stayed superheated and liquid long enough to run or spray belowdecks. I'm picturing a closed room on the outer edge of the building. Suddenly a few hundred pounds of superheated water sprays in through a vent shaft. The pressure in the room goes up to 5 or 10 PSI over atmospheric. Now there's 100 tons of force pushing on the wall. Pop!

Meanwhile, up above, the steam bows out one wall, blows out some panels, lifts the roof, then escapes, leaving the roof to drape itself softly over the floor. The moving air and steam knock things off shelves and scatters them over the floor. Some bigger things are thrown around by having a thousand-ton water cannon shot at them.

From outside the building, it's hard to tell what happened. There's no BOOM, just a giant gurgle and hiss, and some cracking sounds from the crumbling concrete. The building puffs steam, which quickly dissipates. There's no residual smoke. And in five seconds, the building has gone from intact to destroyed.

Edit/afterthought: Does anyone have pictures of conventional power plants destroyed by a boiler explosion? The boiler would be hotter, of course, but the overall effects might be similar. I'll start with these... http://machinetec.blogspot.com/2010/11/safty.html

 

[rowmag]

Btw: New sensor data from R3. Radiation now at 253 Sv/h. Noone can tell me the core is still closed if this value is real.

Maybe I am looking at a different source, but the value of 253 looks to be the temperature of the R3 pressure vessel bellows seal in degrees C. The R3 drywell radiation readings are 15.9 Sv/h and 21.1 Sv/h, as of 6:00 on 4/17:

http://www.meti.go.jp/press/2011/04/20110417002/20110417002-2.pdf

 

[MadderDoc]

Astute observation. The tank is on top of ground debris, but that doesn't necessarily confirm it came from Bldg 4. But the path of debris from the hole in the side of Bldg 4 plus the impact damage to the north side of the smaller building structure and the final resting place would be consistent with the tank being a projectile.

These hi-res views weren't available when the causes of the damage from the initial north face photograph of Bldg 4 was posted.

However, in defence of the suspect object, it would seem evidenced from a Digitalglobe satellite photo taken on March 12th (detail attached) in which the object can be seen lying in it's present position, that this object has absolute nothing to do with any of the later events in unit 3 and 4. Oh well.

 

[MadderDoc]

I remember the picture well. I can't source it. I think it was a Reuters picture and its original annotations were only the red Japanese characters.
<..>

The picture is a Tepco handout, a detail from a photo depicting all 4 reactors. There is a link to both photos close to the bottom of this page:
http://www.tepco.co.jp/en/news/110311/index-e.html

 

[gmax137]

It seems they want to fill the drywell with water, to cover and cool the reactor pressure vessel.

Why would one do that? The steel is so thick that it cannot conduct that much heat. Is it cracked open? ...

How thick is the containment vessel? And what's the temperature difference across it (inside to outside)? I'd guess that the thickness of the steel doesn't matter much relative to the (probably low) heat transfer coefficients at the inner & outer surfaces.

 

[rowmag]

They seem to include the temperatures for cores A and B Suppression chambers and drywel.

Drywell chamber temperatures are separated between RPV and HVH ,
I think RVP is the outside temperature of the reactor pressure vessel extending into the drywell.

The full legend is "RPV bellows seal."
The other one is "HVH return."
(Wherever those two locations are.)

Reactor 3 RPV temperature within the drywell seems highest with a temperature of 253.2 C ,
which is higher than the RPV bottomhead temp itself , suggesting what ??
An amount of molten core within the drywell ?

This actually resolves a little mystery that was puzzling me a couple of days ago. There was a report on the asahi.com website on the 15th that the internal temperature at Reactor 3 had been rising, from 170 degrees on 4/12, to 200 degrees on 4/13, and 250 degrees on 4/14. The article said it was possible the sensor was reporting incorrect values due to earthquake damage, but the fact that the temperature was rising was certain. Cause unknown, but they planned to try changing the water injection rate.

http://www.asahi.com/special/10005/TKY201104140523.html

However, no other news agency reported this, and I didn't see any such temperatures in the METI data sheets, so I wondered if this was somehow a mistaken report. Now it seems that it was indeed a correct report, based on not-publically-released readings. Presumably, the temperatures in the article were measured at the RPV bellows seal.

 

[Jorge Stolfi]

I have been looking at the pressure-presure and pressure-temerature plots made from TEPCO's faxed data:
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/Main.html

Just to get the ball rolling, here are my interpretations

Reactor #1

I have no pressure data for #1 before the RPV got depressurized, and no plottable data pair before the #1 explosion.

Between March 13 and 15, shorly after the explosion (69 to 107 hours; red dots), core pressure PC and drywell pressure PD both decreased exponentially, keeping an almost perfect relation PD = 1.56*(PC - 80). Note that PD was higher than PC at this time. One mechanism I can think of that could explain this behavior is if gas or liquid was flowing from the drywell into the RPV and from there to the outside, by relatively narrow channels.

Another possibility is that the drywell was flooded to a level above the RPV's bottom but below the RPV's internal water level, and both vessels were airtight except for a leak in the bottom of the RPV, allowing water to flow from the DW into the RPV as the pressure in the latter fell.

During this time the torus and drywell were at exactly the same pressure. That presumably argues against he drywell being flooded at the time.

Between March 16 and 18 I have no drywell pressure data for unit #1.

Between March 18 and March 22 (180 to 290 hours; brown and green dots) pressures were stable, PC = 270 kPA, PD = 180 kPA. From March 23 to 24 (290 to 320 hours; light blue dots) both began to increase slowly, roughly preserving the diference PC = PD + 100 kPa. Perhaps the water level in the core was now 10 m higher than in the drywell, and the difference was maintained somehow.

Through all that time (March 18 to 24) the pressure in the drywell was almost exactly 20 kPa higher than in the torus. Perhaps the drywell's pressure sensor was under 2 m o water at that time?

By March 24 the drywell and torus pressures were close to their design limits. On March 24 (320 hours on; beginning of dark blue dots) the drywell pressure was apparently vented . Curiously, at first the core pressure PC too decreased slightly, suggesting again a narrow leak beween the two containers. But this "leak" apparently got plugged, so that PC continued to increase in the following days while PD remained constant at 370 kPa. There were two other drywell release events on March 29 (to 210 kPa) and March 31 (to 150 kPa); again PC decreased slightly as well during the releases, then kept on increasing.

From March 24 to April 7 the torus pressure was rigorously equal to the drywell pressure, suggesting that there was a connection between them.

Something again happened on April 07 (nitrogen injection?) The drywell pressure increased from 150 kPa to 200 kPa then remained stable until today (April 17). On that day PC fell momentarily then recovered and continued its steady increase.

On april 7 the torus pressure PS had a smaller increase and stabilized at 20 kPa below PD. Perhaps the connection between DW and SC was closed? Or the DW pressure sensor again got submerged in 2 m of water?

I will save my "analysis" of plots for #2 and #3 for later.

 

[MJRacer]

I have been looking at the pressure-pressure and pressure-temperature plots made from TEPCO's faxed data:
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/Main.html

Just to get the ball rolling, here are my interpretations

Reactor #1

I have no pressure data for #1 before the RPV got depressurized, and no plottable data pair before the #1 explosion.

Between March 13 and 15, shorly after the explosion (69 to 107 hours; red dots), core pressure PC and drywell pressure PD both decreased exponentially, keeping an almost perfect relation PD = 1.56*(PC - 80). Note that PD was higher than PC at this time. One mechanism I can think of that could explain this behavior is if gas or liquid was flowing from the drywell into the RPV and from there to the outside, by relatively narrow channels. (underline added)(snip)

Please refer to my post:

It might be helpful to review this document: (http://cryptome.org/0003/daiichi-assess.pdf)

Selected quotes that probably apply to all 3 units:

Recirculation pump seals have likely failed.

Vessel temperature readings are likely metal temperature which lags actual conditions.

Low level release path: fuel damaged, reactor coolant system potentially breached at recirculation pump seals, primary containment damaged resulting in low level release.

Might recirc pump seal failure agree with your analysis?

 

[rowmag]

So whence cometh the damage to Unit #4 exterior? There appears to be photography showing Unit 4 intact after Unit #3 exploded. But look at Unit 3 in those pictures. There is concrete slab siding on the ground floor and two floors of open concrete support beams and girders. In the pictures showing Unit 4 damaged the seems to be another floor missing from Unit 3. The damage to Unit 4 is bent away from unit 3. Is it possible there was a second explosion at Unit 3 that caused the damage to Unit 4?

I think the following image argues against this admittedly intriguing idea:
http://livedoor.2.blogimg.jp/dqnplus/imgs/6/d/6dffb5e9.jpg

That was on 3/14, after #3 blew up but before #4 did.
The damage to building #3 seems largely complete at this point already.
#4 has no visible damage yet.

Zoom in of the above:

Compare with the next day, after whatever had happened to #4:
[URL]http://www.tepco.co.jp/en/news/110311/images/110316_1f_chijou_1.jpg[/URL]

They look about the same to me...

 

[Ches]

Hello, I've been lurking here for the last month. I was happy to find a place where people actually knew what they were talking about. For that, thank you.

I found a Tepco press site with images and videos, some that I have not yet seen on any other sites.
http://www.tepco.co.jp/en/news/110311/

I found the "Sampling in Spent Fuel Pool of Unit 4" video very interesting. I was surprised it is in such good shape, at least to my "not-a-scientist" eyes.
http://www.tepco.co.jp/en/news/110311/images/110414_1f_1.zip

If you have already seen these, I apologize and I will go back to my lurking.

 

[MiceAndMen]

Are there any good options (i.e. free) for uploading large images to the web? I have some more Oyster Creek drawings, but they are very large. I uploaded a couple to photobucket but they have a size limit that makes the result useless.

These are both originally 5088 x 3296 pixels at 72 dpi. I've played with resizing in photoshop and saving with different jpeg quality compression ratios, but none come out clear enough to show any details.

http://i1223.photobucket.com/albums/dd509/MiceAndMen1/Oyster Creek/OysterCreekDwgRB.jpg
http://i1223.photobucket.com/albums/dd509/MiceAndMen1/Oyster Creek/OysterCreekDwgRefuelLevel.jpg

I suppose the best solution is to post the URLs to the original PDFs. I'll have to find them first, but I'll post them when I do.

 

[MiceAndMen]

For those looking to pin down the location of the camera that captured the explosion of Unit 3, I used a program called Global Mapper (an excellent piece of software) to get a 3D idea of the topography surrounding the plant. Global Mapper let me download ASTER elevation data for the area. I coupled that with a topographic map I found on a Harvard website, and used Global Mapper to drape the topographic map over the top of the 3D elevation data. I drew a line from the corner of the Unit 3 reactor building through the vent stack that it was lined up with in the explosion video, and extended that line out to 16 km. Global Mapper has an additional function (one of many) that generates an elevation profile along that line.

Source data from ASTER
http://asterweb.jpl.nasa.gov/

Topo map from Harvard (Fukushima base map at the bottom of the page)
http://cegrp.cga.harvard.edu/japan/?q=category/tags/topography&page=1

The topo map was originally made in 1970, although there is a notation on the side of the map that says the air information is correct through October of 1980. There's also a disclaimer that some of the data might not be completely accurate. Nevertheless, there are multiple aerial obstructions noted at the Fukushima Daiichi site. One gives the height above ground as 82 meters, and the other as 131 meters. I'm not sure how to correlate that information with the vent stacks we've seen in all the pictures.

 

[MiceAndMen]

Gah! A 3-file attachment limit to posts... OK, here is the 3D pic I generated with Global Mapper and its associated elevation profile out to about 5 km. Note the high spot is about 65 meters, and that is lower than either stack height listed on the topographic map.

 

[MiceAndMen]

Here is a similar set of pics but going out to a distance of 16 km from the plant.

Has anyone tried to contact NHK or some other Japanese media outlet to ask the direct question of where the camera was situated at the time Unit 3 exploded?

 

[drdodge]

if anyones interested

latest drone photos here

http://www.cryptome.org/

dr dodge

 

[AntonL]

Are there any good options (i.e. free) for uploading large images to the web? I have some more Oyster Creek drawings, but they are very large. I uploaded a couple to photobucket but they have a size limit that makes the result useless.

http://min.us/"

 

[rowmag]

Here is a similar set of pics but going out to a distance of 16 km from the plant.

Has anyone tried to contact NHK or some other Japanese media outlet to ask the direct question of where the camera was situated at the time Unit 3 exploded?

No, but I recall them saying that the cameras were located beyond the evacuation zone, which at the time of the #3 blast was 20 km in radius. So might want to try extending your search to at least 20 km from the plant.

 

[MiceAndMen]

http://min.us/"

Thanks AntonL!

Oyster Creek Reactor Building General Arrangement (approx. 1 MB)
http://i.min.us/ikukv6.jpg

Oyster Creek Reactor Building Refueling Level (approx. 5 MB)
http://i.min.us/ikum3E.jpg

The second pic shows a lot of little details, such as the height of the 4 reactor cavity shield plug slabs being 7 feet (2.13 meters). Note that the differences between the Oyster Creek plant and the Fukushima reactors are quite possibly non-trivial. It would be really nice if TEPCO would release a set of drawings but I don't think that's going to happen.

I'll find the URLs for the PDFs I have of the Oyster Creek drawings. There are 4 PDF files totalling about 23 MB. Hmmm... now that I think about it, there are no direct PDF download URLs, you'll have to navigate an NRC website to get to them. I'll post how to do that tomorrow.

I spent more than a few hours searching for reactor building blueprints on the NRC site, and the ones for Oyster Creek are the only ones I could find. Others haven't been scanned into PDF form yet, and still others are, I think, not publicly available at all. That's too bad because I believe the closest reactors in the US to the Fukushima Daiichi ones are the ones at Vermont Yankee and (now closed) Millstone I.

 

[AtomicWombat]

I don't think that is a plausible damage from heat.

Allow me to draw your attention to a possible suspect at the foot of the building (see attachment). It is found at the scene of the crime, in a plausible position after an assumed hammering of unit 4's north side. It appears to be a boiler tank or something of that sort, about 10 meters long, about 3 meter in diameter. It appears to have been blasted. And, perhapos significantly, it appears to be lying on top of pieces of unit 3's roof construction.

I think that's a crane.

 

[liamdavis]

It seems that the explosions at each plant would leave distinct evidence as to its nature. A shattering (high velocity) explosion should leave some sharp ragged edges on the concrete structure. Where as propellant (low velocity) damage should show erosion.

Water turning to steam expands about 1728 times in volume. It starts out with no velocity and accelerates. The speed it obtains between its point of origin and the building walls would give it an energy impulse upon impact similar to an explosion. However, between being water and being steam at full expansion, it would behave much like a fluid. If a significant quantity of water flashed to steam and had only expanded to 2-400 times its volume at the time it initially pushed the wall panels out then it would leave the marks of a (debris laden) fluid eroding the remaining concrete structure.

Hi-res close-up pictures of the remaining vertical supports and the underside of horizontal structure should bring clarity to which event happened at which buildings. This would make the reconstruction of events more focused and productive.
liam

 

[HowlerMonkey]

I wonder if the reason for the higher temperature at the bottom of #3 is the cool water is being injected at the top and the heated water is leaking past the sensor out the bottom?

 

[GJBRKS]

I wonder if the reason for the higher temperature at the bottom of #3 is the cool water is being injected at the top and the heated water is leaking past the sensor out the bottom?

At 252 Celsius and low pressure that water is not liquid water anymore.
Steam will not attain this temperature without external heating

 

[AtomicWombat]

@TCups, you posted the picture, You remember where you got it?

I got it from a news site, and TCups annotated it.

It was the first picture released by TEPCO.

 

[|Fred]

I think that's a crane.

Are you referring to the yellow trucks ?

 

[NUCENG]

I don't think it'd matter noticeably that it'd take away neutrons, if the coating is very thin (e.g. a few micrometers), but a significant fraction of it would still turn into mercury, so you'd get some sort of gold-mercury amalgam. I really don't know if it would even remain there at all. Plus the mercury tends to have corrosive effect. edit: plus, perhaps, electrochemical corrosion as well, if any of gold flakes off.

That is the point. With its relatively large cross section, if you put a thin layer of gold in the area of highest neutron flux in the reactor, it won't be there very long.

 

[NUCENG]

We will not see any isotopes until tepco will give us data about them, they give us now only I and Cs...

One of the clues would be another huge release of iodine. That hasn't happened from their data. Slow increases in iodine would potentially indicate reevolution of iodine gas due to pH in pools becoming acidic. A sudden huge release would occur from interaction with concrete releasing a whole new set of chemicals.

 

[NUCENG]

I think the following image argues against this admittedly intriguing idea:
http://livedoor.2.blogimg.jp/dqnplus/imgs/6/d/6dffb5e9.jpg
That was on 3/14, after #3 blew up but before #4 did.
The damage to building #3 seems largely complete at this point already.
#4 has no visible damage yet.

Zoom in of the above:

Compare with the next day, after whatever had happened to #4:
[URL]http://www.tepco.co.jp/en/news/110311/images/110316_1f_chijou_1.jpg[/URL]

They look about the same to me...

Lacking explanation for internal hydrogen explosions in Unit 4 due to TEPCO reports of conditions in the fuel pool of Unit 4, there are two possibilities: internal explosion from another souce, or external exposion.

My experience with BWRs including refueling outages is that there is no internal source that could justify the kind of damage I see. Acetylene is used for cutting, but in small tanks brought to each work site. Most welding is arc welding. There are lubricants, but not in confined containers that could develop the kinds of forces evident in the damage.

I agree there are pictures showing the damage to Unit 4 was after the explosion of unit 3. But there seem to be significant differences between those picture of unit 3 and pictures taken after unit 4 showed damage. The early pictures show parts of the third and fourth floors still standing on Unit 3. Current pictures show only 2nd and part of 3rd floors.

My focus was the area at the wall of unit 4 which appears to be bent inwards. That is my evidence of the direction of force. I'm looking for a set of photos of unit 3 that can prove the timeline, but so far have problems with confirmed times for the photos.

 

[clancy688]

Packbot(s) entered into reactor buildings 1 & 3, after opening some of the doors connecting with the turbine buildings. Measurement results are expected to be released on April 18th or later : http://www.jiji.com/jc/c?g=soc_30&k=2011041700293

http://english.kyodonews.jp/news/2011/04/86132.html

Radiation levels are at 10-49 mSv/h in Unit 1 and 28-57 mSv/h in Unit 3. Why are they not checking Unit 2?

As far as I know, the only difference between Unit 2 and the other Units is, that Unit 2s secondary containment has been flooded. Does that mean that they send these robots into the secondary containments of Units 1 and 3? And then do these radiation levels imply, that there the RPV has not been breached? (Aside from ruptured valves and such)

 

[AtomicWombat]

Allow me to draw your attention to a possible suspect at the foot of the building (see attachment). It is found at the scene of the crime, in a plausible position after an assumed hammering of unit 4's north side. It appears to be a boiler tank or something of that sort, about 10 meters long, about 3 meter in diameter. It appears to have been blasted. And, perhapos significantly, it appears to be lying on top of pieces of unit 3's roof construction.

I think that's a crane.

Are you referring to the yellow trucks ?

I think what MadderDoc is pointing to (thumbnail) is one of these cranes.

 

[razzz]

The way I'm picturing the cores and cooling is that there are leaks so whatever water level that can be maintained is the same level the rods will melt down to even if they have to flood the whole basement to get the water level constant. In the meantime, fluctuating water levels cause fuel to react to the environment besides the constant bleeding of contaminated water while waiting for a cool down(s).

From a previous posted link http://canteach.candu.org/library/20044507.pdf" which is in .pdf format, the author notes steam is a better coolant but when nitrogen is injected (to displace hydrogen) it causes core temperature to rise. This is the same paper that tries to cover all possible angles during a nuke accident but in hindsight omits seawater ramifications when used as coolant.

Also, how can you stop the contaminated seawater from entering and contaminating the ground water table as the ocean permeates the shoreline esp. during tidal movements?

 

[|Fred]

The early pictures show parts of the third and fourth floors still standing on Unit 3. Current pictures show only 2nd and part of 3rd floors.

I do not agree with this statement , I do not see the missing part you are referring to, could you please point them out


AtomicWombat, crane as is crane truck or as in crane equipment from the Nuk Building ? I think I missread you you were speaking of crane truck but since so far we were talking about crane equipment..

 

[Samy24]

http://english.kyodonews.jp/news/2011/04/86132.html

Radiation levels are at 10-49 mSv/h in Unit 1 and 28-57 mSv/h in Unit 3. Why are they not checking Unit 2?

As far as I know, the only difference between Unit 2 and the other Units is, that Unit 2s secondary containment has been flooded. Does that mean that they send these robots into the secondary containments of Units 1 and 3? And then do these radiation levels imply, that there the RPV has not been breached? (Aside from ruptured valves and such)

You can not trust any of the readings/reports. Because it's TEPCO and the press most of the time do not know what they are writing about.

The same website reports 270 mSv at the gateway to Unit 1. That implies that the radiation is higher inside the gateway than inside the reactor building. Make your conclusions please.

http://www3.nhk.or.jp/daily/english/18_03.html"

 

[elektrownik]

http://english.kyodonews.jp/news/2011/04/86132.html

Radiation levels are at 10-49 mSv/h in Unit 1 and 28-57 mSv/h in Unit 3. Why are they not checking Unit 2?

As far as I know, the only difference between Unit 2 and the other Units is, that Unit 2s secondary containment has been flooded. Does that mean that they send these robots into the secondary containments of Units 1 and 3? And then do these radiation levels imply, that there the RPV has not been breached? (Aside from ruptured valves and such)

I think that they don't check s/c yet... also there is some error in translation, from picture and tepco news I think that they send 2 robots to #3 building, and nothing yet to #1..

 

[AtomicWombat]

AtomicWombat, crane as is crane truck or as in crane equipment from the Nuk Building ? I think I missread you you were speaking of crane truck but since so far we were talking about crane equipment..

Sorry I meant truck mounted cranes. I'm pretty sure they were there before the explosion in unit 3.

 

[Krikkosnack]

Yes, but that height gives us only information about initial speed - we don't know mass, so we can't tell anything about amount of energy. And if I remember correctly the idea of OP was to calculate mass from this data - and this is simply impossible. It is not an accident that in the simplest approach - mgh=mv²/2 - mass cancels out

Magnificent, you are a kind of genius. I would never have got there!
I simply said that I wanted to estimate its mass if we were able to calculate the energy involved during the explosion as I know the height at which these items have gone up. If you do not want to contribute, you are not required to do so..

 

[DSamsom]

Apparantly NISA announced that the reactor builing No 4 is now flooded in 5 meters of water. Anyone to explain this? Do they mean the SFP?

 

[TCups]

It seems that the explosions at each plant would leave distinct evidence as to its nature. A shattering (high velocity) explosion should leave some sharp ragged edges on the concrete structure. Where as propellant (low velocity) damage should show erosion.

Water turning to steam expands about 1728 times in volume. It starts out with no velocity and accelerates. The speed it obtains between its point of origin and the building walls would give it an energy impulse upon impact similar to an explosion. However, between being water and being steam at full expansion, it would behave much like a fluid. If a significant quantity of water flashed to steam and had only expanded to 2-400 times its volume at the time it initially pushed the wall panels out then it would leave the marks of a (debris laden) fluid eroding the remaining concrete structure.

Hi-res close-up pictures of the remaining vertical supports and the underside of horizontal structure should bring clarity to which event happened at which buildings. This would make the reconstruction of events more focused and productive.
liam

@liamdavis:
Thank you very much for that information. Very much looking forward to your analysis and what you can tell us about the various events at each of the buildings!

It is hard to escape the conclusion that water flashing to steam occurred at Bldg 3 and that the source of the explosion in Bldg 4 had to ultimately be the spent and un-spent fuel in the SFP.

Thanks AntonL!

Oyster Creek Reactor Building General Arrangement (approx. 1 MB)
http://i.min.us/ikukv6.jpg

Oyster Creek Reactor Building Refueling Level (approx. 5 MB)
http://i.min.us/ikum3E.jpg

The second pic shows a lot of little details, such as the height of the 4 reactor cavity shield plug slabs being 7 feet (2.13 meters). Note that the differences between the Oyster Creek plant and the Fukushima reactors are quite possibly non-trivial. It would be really nice if TEPCO would release a set of drawings but I don't think that's going to happen.

I'll find the URLs for the PDFs I have of the Oyster Creek drawings. There are 4 PDF files totalling about 23 MB. Hmmm... now that I think about it, there are no direct PDF download URLs, you'll have to navigate an NRC website to get to them. I'll post how to do that tomorrow.

I spent more than a few hours searching for reactor building blueprints on the NRC site, and the ones for Oyster Creek are the only ones I could find. Others haven't been scanned into PDF form yet, and still others are, I think, not publicly available at all. That's too bad because I believe the closest reactors in the US to the Fukushima Daiichi ones are the ones at Vermont Yankee and (now closed) Millstone I.

@MiceAndMen:

Thank you also for the detailed drawings of the reactors. The last in particular gives some excellent details on the "likely" construction of the upper containment including the shield plugs (which as it turns out) are clad in carbon steel -- at least at the Oyster Creek facility.

As above, flashing of water to steam seems at least to me to be what occurred in part at Unit 3. It also seems likely that the initiating event was an explosion occurring in the primary containment. How to get from "A" to "B" is a question that I don't think has been answered fully.

As for Unit 4, the shattered upper mast of the FHM seems to indicate a violent event in the SFP with lots of energy transferred to the mast, but perhaps not so much damage to the remainder of the FHM. And additional plans detailing what might have been directly behind the blown out panels at the north and south face of Bldg 4 would be most interesting.

@all:
Coming at the explosion in the lower building, here's a hypothetical question for someone who knows reactors:
In the myriad of pipes, tanks and accessories hooked up to the RPV and primary containment and housed outside of the RPV and primary containment, in the lower building (other than the torus suppression pool), are there any of them that might explode as a direct result from over-pressure, steam or hydrogen accumulation inside the primary containment or RPV?

 

[artax]

if anyones interested

latest drone photos here

http://www.cryptome.org/

dr dodge

Nice one!

not read the last 20 pages but there's a good situation update here:-

http://cryptome.org/0003/daiichi-assess.pdf

I know there are translation problems, but I just love the way they say "unit one is relatively stable"!

Relatively! ... to what!