Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[razzz]

Should there not be more recognition of the role of the salt in the reactors?
There were estimates for the volume of salt left behind in the reactors from the emergency cooling, it was appreciable relative to the overall RPV volume.
So is it possible the fuel pellets freed up by the loss of the cladding would not collect at the bottom of the reactor, but rather be caught in the salt, like raisins in a cake. That would prevent the fuel from coalescing and overheating, which might explain the low temperature at the bottom of reactor 1.
Is this a plausible possibility or is there some obvious fact that makes this an invalid idea?

A drop of seawater, in trace elements, contains every mineral known to man and high heat just brings the elements out of suspension so I haven't seen any studies on seawater reactions when used as a coolant in nuclear plumbing let alone interactions with nuclear fuels. Maybe the noted glowing was phosphorescence i.e. luminescence of living organisms.

 

[sp2]

Originally Posted by sp2
That was definitely not a function of wind.

Wind was clearly blowing to the SE at that point.

Steam (presumably) was spewing straight out of #3, sideways, toward the north, and then getting blown by the wind out to sea, towards the SE.

I feel that you are ruling out weather phenomenon too definitively here. Failure to take into account a range of weather phenomenon has caused repeated wild speculation over the last week, based on live feed images. There is now a danger that if something really does change, we may miss it because we are so used to these false stories caused by live feed images.

As you can see, people are mostly not too surprised to hear of stuff coming from the north end of the building. Perhaps it would be helpful for you to review a video that was shot early on, and shows an area where this stuff is likely to be coming from:

http://www.youtube.com/user/modchannel

Check out the above at around 3:08, 3:23 and 3:48 for a view of what was escaping from the north side in the past.

Steve--

You seem to have some difficulty with the distinction between 'observation' and 'wild speculation.' My post was an example of the former, and had nothing whatsoever to do with the latter. I very simply reported what I saw, and how it compared with what I had previously seen.
It sounds like many others' observations corroborated mine.

There have indeed been many examples of hyperbole and misinterpretation here.
This was not one of them.

Perhaps it would be helpful for you to review the definitions of those words, before carelessly throwing around labels like 'wild speculation' and 'false stories.'

You have a great weekend.

 

[westfield]

Please search the thread - it is not clear (at least to some) whether the sound is really part of the recording and whether it was not added from some other source.

I'll have a stab at making it clear. Been lurking for a few weeks but this audio discussion has driven me spare and caused me to unlurk.

Take it from a career audio professional and\or look at the evidence below, it's not in any way the sound of unit #3 exploding. To me, a glance at the waveforms is enough to see it's a cut up effects track assembled from a 3 or 4 samples with some tweaks with effects and dynamics.

There are SO many things to speculate about, this audio track shouldn't be one of them. It's fake.

edit : should I have just linked the image or is embeddeding it ok here?

 

[sp2]

I'll have a stab at making it clear. Been lurking for a few weeks but this audio discussion has driven me spare and caused me to unlurk.

Take it from a career audio professional and\or look at the evidence below, it's not in any way the sound of unit #3 exploding. To me, a glance at the waveforms is enough to see it's a cut up effects track assembled from a 3 or 4 samples with some tweaks with effects and dynamics.

There are SO many things to speculate about, this audio track shouldn't be one of them. It's fake.

http://i1185.photobucket.com/albums/z360/fukuwest/misc/fukuu3audiobullgarbage.jpg

edit : should I have just linked the image or is embeddeding it ok here?

Wow. Thanks, that's great stuff.

I have to say, I'm *not* an audio engineer (or anything close to one), but that's what I thought from the first time I heard that tape.

It sounded utterly bogus. Like the same 'boom' repeated three times with the same interval. (Not to mention that it was instantly obvious it had been tampered with to cut out what should've been a very long delay --which called it into question right off the bat.)

I really couldn't understand why intelligent guys seemed to be taking it so seriously, and spending so much time on it.

Thanks for elucidating.

 

[AntonL]

It looks like TEPCO is moving forward with it's plan to cover Unit 1 in a steel frame covered with polyethelene sheets.

to be followed by a concrete structure

[PLAIN]http://k.min.us/inx8Me.JPG

extracted from
http://www.tepco.co.jp/nu/fukushima-np/f1/images/f12np-gaiyou_4.pdf

the English version will become available later today or tomorrow
http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/f12np-gaiyou_e_4.pdf

this document also discusses the Areva plant (page 12)
and how Unit 2 is proposed to be cooled (pages 3-5)

Earlier and future version of these documents can be viewed by changing the last digit of the file name.

 

[AntonL]

I really couldn't understand why intelligent guys seemed to be taking it so seriously, and spending so much time on it..

intelligent guys will investigate every lead and only stop a particular direction when that direction is proven false.

 

[|Fred]

looking at this
zoom on poor quality video, seem conclusive with the fact that the multiple event "orange explosion and "vertical" movement were closer in there time line that I initially suspected.

I believe I see the birth of "mushroom" cloud sucking in the orange explosion.
There is also some kind of bright effect just behind the tower that is impossible do identity

 

[GJBRKS]

looking at this
zoom on poor quality video, seem conclusive with the fact that the multiple event "orange explosion and "vertical" movement were closer in there time line that I initially suspected.

I believe I see the birth of "mushroom" cloud sucking in the orange explosion.
There is also some kind of bright effect just behind the tower that is impossible do identity

It's getting clear to me that an initial hydrogen burst cracked and depressurized the RPV or containment , followed by the ' emptying' of RPV and/or containment , the 'sucking ' effect produced by the rapid upward movement of gasses

 

[MadderDoc]

The ground level floor is the area where the scram headers are located. Below ground level is the torus room and corner rooms where RHR and Core Spray system pumps are located. In BWR4s the HPCI and RCIC systems may also be on this level. There is a mezzanine level in the corner rooms that may be what is being referenced.

I'd rather not speculate whether that may be the case. Tepco has used the expression 'second basement floor' in connection with the release of a series of photos showing workers standing in full protective gear including boots in a feet of water in what appears to be a long corridor. According to the captions the workers have been photographed in the second basement floor of unit 1.

 

[NUCENG]

Link is fixed. It should be .html, rather than .htm

Thanks Astronuc. Must have cut off the l using copy and paste.

 

[PietKuip]

I'll have a stab at making it clear. Been lurking for a few weeks but this audio discussion has driven me spare and caused me to unlurk.

Take it from a career audio professional and\or look at the evidence below, it's not in any way the sound of unit #3 exploding. To me, a glance at the waveforms is enough to see it's a cut up effects track assembled from a 3 or 4 samples with some tweaks with effects and dynamics.

There are SO many things to speculate about, this audio track shouldn't be one of them. It's fake.

Thank you.

I have been looking around for infrasound recordings by seismic monitoring systems in Japan, but I could not find any. Maybe someone who reads Japanese could find some microbarograph recording somewhere?

 

[Azby]

to be followed by a concrete structure

[PLAIN]http://k.min.us/inx8Me.JPG

extracted from
http://www.tepco.co.jp/nu/fukushima-np/f1/images/f12np-gaiyou_4.pdf

the English version will become available later today or tomorrow
http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/f12np-gaiyou_e_4.pdf

this document also discusses the Areva plant (page 12)
and how Unit 2 is proposed to be cooled (pages 3-5)

Earlier and future version of these documents can be viewed by changing the last digit of the file name.

Thanks for finding that, Anton. The timeline shown on P2 is pretty vague, but it looks like 3-6 months from June to complete the polyethlyene "cover," and then work on the concrete "container" starts, beginning with "final design." I'd guesstimate that a concrete structure of that size would take the better part of a year.

 

[Calvadosser]

looking at this
zoom on poor quality video, seem conclusive with the fact that the multiple event "orange explosion and "vertical" movement were closer in there time line that I initially suspected.

I believe I see the birth of "mushroom" cloud sucking in the orange explosion.
There is also some kind of bright effect just behind the tower that is impossible do identity

It looks as if the orange explosion is sucked back but I think this is probably an illusion.

I think that what really happens is that the glowing orange mass of gas/debris cools as it expands and ceases to radiate visible orange light. The outermost area cools quickest, so it gives the appearance of the orange area retreating.

Films of some nuclear test explosions show this effect - the orange fireball ceases to glow and becomes a dark-coloured mushroom as it expands (though on a slower timescale than the Fukushima explosion).

 

[MadderDoc]

looking at this
zoom on poor quality video, seem conclusive with the fact that the multiple event "orange explosion and "vertical" movement were closer in there time line that I initially suspected.

I believe I see the birth of "mushroom" cloud sucking in the orange explosion.

I agree with your observation regarding the briefness of the temporal separation of the two phenomena, and the apparent sucking effect.

There is also some kind of bright effect just behind the tower that is impossible do identity

I am not sure what you are looking at there, but this could be it. During the development of the fire phenomenon, one sees light from the fire being reflected from those parts of the vertical structure elements of the exhaust stack which have a free line of sight to the fire, as well as to the observer. This forms a curious pattern of light changing in tune with the development of the flame, and the development of smoke interfering with the line of sight from the tower to the flame.

 

[NUCENG]

It looks like TEPCO is moving forward with it's plan to cover Unit 1 in a steel frame covered with polyethelene sheets. This news item doesn't give an expected date of completion, but I seem to recall September being bandied about previously.

http://www3.nhk.or.jp/daily/english/14_02.html
http://english.kyodonews.jp/photos/2011/05/90962.html

Also a news item reporting that the NISA says there's (probably?) no need to fill unit 1 RPV with water.

http://www3.nhk.or.jp/daily/english/13_26.html

I understand their intent is to stop the offsite releases, but how thick would it have to be to survive typhoon winds or wind driven debris impacts?

 

[Cire]

It's getting clear to me that an initial hydrogen burst cracked and depressurized the RPV or containment , followed by the ' emptying' of RPV and/or containment , the 'sucking ' effect produced by the rapid upward movement of gasses

It's highly unlikely you could over-pressurize the RPV. The support plumbing would fail first and the RPV would depressurize. You don't design the system such that your pressure vessel is what pops first.

Not to mention the dozen or so relief valves installed on the RPV to prevent this from happening.

 

[Borek]

edit : should I have just linked the image or is embeddeding it ok here?

Embedding is OK, if you can resize it a little bit (just trim the white on the left/right, picture is too wide now and can break forum formatting for some; in general we assume 800 px is a max width) it will be perfect. Contact me by PM if you have any troubles with resizing or reposting.

What you wrote about mono/stereo is interesting. I guess plotting the difference between L/R channels should show that's really the case - I would expect it to be flat for mono and not-flat for stereo (plus minus compression artifacts).

 

[AntonL]

I understand their intent is to stop the offsite releases, but how thick would it have to be to survive typhoon winds or wind driven debris impacts?

They may use modern Kevlar reinforced fabrics.

And not to forget the wind loading of the structure, the weakest point will be the roof as it is shallow pitched to reliably shed rain water. If the wind direction is across the two slopes it will generate aerodynamic lift, like a wing, and possibly be the first mode of failure even before typhoon like wind speeds are reached.

And how they are going to work on the roof is beyond me if it is too hot for helicopters to overfly the open SFP

 

[NUCENG]

They may use modern Kevlar reinforced fabrics.

And not to forget the wind loading of the structure, the weakest point will be the roof as it is shallow pitched to reliably shed rain water. If the wind direction is across the two slopes it will generate aerodynamic lift, like a wing, and possibly be the first mode of failure even before typhoon like wind speeds are reached.

Thanks, I guess we'll see as they move forward.

 

[zapperzero]

Hey wait a minute. I thought a Chernobyl-like sarcophagus was not being contemplated. Any word on digging to bedrock to contain water pollution?
EDIT: Having perused the document, it seems they plan on patching up a torus which is cracked.

 

[swl]

I understand their intent is to stop the offsite releases, but how thick would it have to be to survive typhoon winds or wind driven debris impacts?

I don't think you understand. Here in Japan, the first thing the government does after a crime is to erect a a temporary shelter of blue vinyl to protect the crime scene from prying eyes and photographers. You know; they want to stop the offsite releases (of information). They may need to get some duct tape out after the typhoon, but it's hard to take pictures in the heavy wind and rain anyway, so no big loss.

I don't imagine their blue vinyl enclosure will do us much good for containment of radiation when they've already lost containment inside multiple layers of high tech alloys and steel reinforced concrete. And how is the tent going to stop the water from flowing out into the ground water and ocean?

 

[MadderDoc]

GJBRKS wrote:

It's getting clear to me that an initial hydrogen burst cracked and depressurized the RPV or containment , followed by the ' emptying' of RPV and/or containment , the 'sucking ' effect produced by the rapid upward movement of gasses

It's highly unlikely you could over-pressurize the RPV. The support plumbing would fail first and the RPV would depressurize. You don't design the system such that your pressure vessel is what pops first.

Not to mention the dozen or so relief valves installed on the RPV to prevent this from happening.

Based on the available data of the reactor parameters, the combined system of RPV and support plumbing of unit 3 failed already on March 13th (between 9:10 and 9:25 the RPV pressure dropped abruptly from 7.3 MPa to 0.45 MPA, while drywell pressure increased from 0.46 to 0.53 MPa.) This would seem to imply that the dozen or so preventive relief valves you mention, failed too.

Consequently, on March 14th, the day of the explosion, the RPV and the PCV were no longer sharply separated volumes, and a depressurizing of the PCV at that stage would also lead to a depressurizing of the RPV . The data available up to and after the explosion indicates a depressurizing of both vessels in connection with the explosion of no less than 0.1 MPa.

 

[elektrownik]

They injecting 14,5m3/h to unit 3 now but temperatures going up not down...

 

[GJBRKS]

It's highly unlikely you could over-pressurize the RPV. The support plumbing would fail first and the RPV would depressurize. You don't design the system such that your pressure vessel is what pops first.

Not to mention the dozen or so relief valves installed on the RPV to prevent this from happening.

I said nothing about over-pressurization.

I talked about sudden depressurization and resulting volume expansion

The RPV was known to handle at least 70 atm

 

[yakiniku]

A couple of WSPEEDI forecasts have been released by MEXT (24th and 25th March, towards the bottom of the page):

http://www.mext.go.jp/a_menu/saigaijohou/syousai/1305747.htm

The more interesting link is for the 25th March which contains estimated accumulated iodine 131.

http://www.mext.go.jp/component/a_menu/other/detail/__icsFiles/afieldfile/2011/05/10/1305799_0325.pdf

 

[Jorge Stolfi]

These roof panels that are long and narrow and overlapping or interlocking when attached to the joists and ribbing that make up the roof ...

You seem to be referring to a layer of ribbed sheet metal (aluminum?) strips that sits over the steel framework. Those strips look like bits of white fettucini in the aerial photos (some 8 meters long and less than 1 meter wide), and are scattered all over the place. a few of them are still attached to the steel frame of #4.

Above that sheet metal layer there seems to be a dark grey layer of concrete and/or tarmac. In the best photos of #4 one can see some ribbing on it too, possibly a negative cast of the ribbing on the metal sheets. That layer presumably is reinforced with rebar or wire mesh, because in #4 a chunk some 15-20 meters across was thrown up in the air, then sliced though the steel beams next to the north wall, and is still hanging there in one piece.

Unit 4 looks like the blast (type??) came from the lower floors so didn't disengage the entire roof like a 'normal' hydrogen explosion would and even forced the parapet and its associated pivoting wall inward during the blast just pushing or sliding the roof section that remained inward until it folded the framework.

In #4 the entire concrete/tamac layer and almost all the metal sheets of the roof were blasted away. Part of the explosion indeed appears to have occurred in the 4th floor (below the service floor), but the only communications between those floors are the elevator shaft and four narrow stairwells at the corners. That is quite enough for the H2 to flow between floors, but hardly enough to transmit the explosion with such a force. Moreover the service floor slab of #4 does not appear to have been breached or even cracked (unlike that of #3).

I still cannot quite understand what hapened to the top of the north wall of #4. Its exterior paint seems to have been scraped down, and its top edge was pushed southwards (i.e. inwards) by several meters. I thought about the middle parts of the pillars being pushed out by the explosion and causing the tops to pivot inwards; but there does not seem to be anything in that location that could have served as the pivot, and I cannot see how the explosion could have pushed the middle of the pillars out without also pushing the top.

My best theory so far is that the slab of concrete/tarmac on the roof, after being lifted by the explosion, behaved like an airfoil and fell diagonally rather than straight down (as a playing card will do if you drop it at an angle). Part of it hit the roof steelwork near the north wall; after slicing thhrough the roof beams it crashed into the north pillars near the middle, breaking them at that height and pushing them out. The other part of the slab fell over the top edge of the wall; being tilted, it slid northwards and down over that edge, leaving the scrape marks and pushing the edge down but southwards. This chunk of the roof slab should now be lying among the rubble and ruined buildings at the feet of the north wall.

Since buildings #3 and #4 seem to be very similar, I would expect the roof of #3 to behave in a similar way. Namely the concrete/tarmac layer probably was lifted as one or more large "flakes", rather than pulverized. (However the explosion of #3 was more forceful and so the flakes may have been smaller than the mega-flake of #4.) Once in the air, those broad but thin flakes may fall obliquely rather than straightdown due to aerodynamic effects. Does this match the observations?

 

[|Fred]

Hey wait a minute. I thought a Chernobyl-like sarcophagus was not being contemplated. Any word on digging to bedrock to contain water pollution?
EDIT: Having perused the document, it seems they plan on patching up a torus which is cracked.

If they believe cooling it no longer achievable, I make sens to fast forward to options that were on hold because they interferes with cooling. Retrospectively it could look like 2 months wasted, and I'm sure the expert who believed the core melted to the bottom within the first few hours/days will make a point underlining that.

 

[GJBRKS]

They injecting 14,5m3/h to unit 3 now but temperatures going up not down...

I'm not sure about the dimensions of the RPV ,

but if I assume a height of 21 meter and diameter of 7 meter ,

(http://www.jnes-elearning.org/contents/bk/JNESeL-BK-004.pdf )

and a resulting total decay heat of 7 Mw ,

(http://mitnse.com/2011/03/16/what-is-decay-heat/ )

then an evenly spread of this heat energy around the surface would result in 15100 W/m^2

Which is equivalent to a blackbody temperature of 445 Celsius .

(http://www.wolframalpha.com/input/?i=15100+watts+per+square+meter&lk=1)

So without other cooling a homogenous conduction within such an RPV would not exceed

an outside surface temperature above 445 degrees celsius.

(http://www.tepco.co.jp/nu/fukushima-np/f1/images/032_1F3_05141200.pdf)

(EDITED for change of estimated decay heat for unit 1 to unit 3 )

In the case of unit 1 with a smaller estimated decay heat production of 4.5 Mw this would be 370 degrees Celsius

 

[zapperzero]

So without other cooling a homogenous conduction within such an RPV would not exceed

an outside surface temperature above 370 degrees celsius.

(http://www.tepco.co.jp/nu/fukushima-np/f1/images/032_1F3_05141200.pdf)

Okay. Now, to fill the RPV with something that will distribute the heat from the core, which is pooled on the bottom, evenly along the whole inner surface. Oh, wait...

 

[AntonL]

I'm not sure about the dimensions of the RPV ,

but if I assume a height of 21 meter and diameter of 7 meter ,

(http://www.jnes-elearning.org/contents/bk/JNESeL-BK-004.pdf )

and a resulting total decay heat of 7 Mw ,

(http://mitnse.com/2011/03/16/what-is-decay-heat/ )

then an evenly spread of this heat energy around the surface would result in 15100 W/m^2

Which is equivalent to a blackbody temperature of 445 Celsius .

(http://www.wolframalpha.com/input/?i=15100+watts+per+square+meter&lk=1)

So without other cooling a homogenous conduction within such an RPV would not exceed

an outside surface temperature above 445 degrees celsius.

(http://www.tepco.co.jp/nu/fukushima-np/f1/images/032_1F3_05141200.pdf)

(EDITED for change of estimated decay heat for unit 1 to unit 3 )

In the case of unit 1 with a smaller estimated decay heat production of 4.5 Mw this would be 370 degrees Celsius

Interesting analysis, however I think your decay heat load is too high, it would be around 2.7MW today (https://www.physicsforums.com/showpost.php?p=3242513&postcount=3526")

 

[jim hardy]

Based on the available data of the reactor parameters, the combined system of RPV and support plumbing of unit 3 failed already on March 13th (between 9:10 and 9:25 the RPV pressure dropped abruptly from 7.3 MPa to 0.45 MPA, while drywell pressure increased from 0.46 to 0.53 MPa.) This would seem to imply that the dozen or so preventive relief valves you mention, failed too.

Consequently, on March 14th, the day of the explosion, the RPV and the PCV were no longer sharply separated volumes, and a depressurizing of the PCV at that stage would also lead to a depressurizing of the RPV . The data available up to and after the explosion indicates a depressurizing of both vessels in connection with the explosion of no less than 0.1 MPa.

do not the plant logs show they manually opened those relief valves on 13th to depressurize?
That is part of US industry mitigation strategy to lower reactor temperature, hence lower heat into drywell . I was under impression from some press releases that they had got high level direction to do so.
Drywell needs to be kept below 350F or so for two reasons
so electrical penetrations don't melt their polymer seals and leak,,
and metal skin doesn't expand from heat enough to buckle and develop cracks.

So opening them makes RPV and Drywell two connected volumes.

Those WONDERFUL plots that Jorge Stolfi put up show it quite clearly,
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/Main.html
select unit 3 Pc X Pd and you see the horizontal line slightly below middle is the depressurization. After that the red and yellow dots show drywell and core remained coupled but offset for a few days. (but core lower than DW by 1/2 atm? instrument error maybe, 1/2 atm on a 100 atm gage isn't bad) .
they got closer in green dots then decoupled.


Are instructions posted anyplace how to imbed pictures and quotes? as you see i am not having much luck.

Have you guys studying the columns seen this picture?
http://www.flickr.com/photos/xtcbz/5705961026/in/photostream/
moderator feel free to imbed if you like, it saves casual readers from having to log in so often.

 

[Borek]

Are instructions posted anyplace how to imbed pictures and quotes? as you see i am not having much luck.

Check your PM box (Private Messages link in the bottom right corner).

 

[MadderDoc]

<..>
In the case of unit 1 with a smaller estimated decay heat production of 4.5 Mw this would be 370 degrees Celsius

I am not familiar with this sort of calculation. It appears to be saying that a blackbody heated from within has a maximum surface temperature which can be calculated with no regards to the energetics of its environment. This seems counter-intuitive. Assuming the temperature of its environment is 370^o, equal to the surface temperature of the RPV then no net heat transfer between the two can occur. On the assumption that the RPV can be no warmer than it already is, while seeing that heat energy is still produced on its the inside, one is led to ask: what happens to that energy?

 

[GJBRKS]

Interesting analysis, however I think your decay heat load is too high, it would be around 2.7MW today (https://www.physicsforums.com/showpost.php?p=3242513&postcount=3526")

I took that figure from an MIT calculation specifically aimed at Fukushima I reactors 2 and 3.

It extrapolates to after 1 year of 11th of March

http://mitnse.com/2011/03/16/what-is-decay-heat/

They address one caveat : Their calculations assume an infinite prior operational time which
would upscale the results slightly , but I doubt that it would correct downwards that much to 2.7MW

However , using your 2.7 MW and this time including the top and bottom ends of the cylinder , it would result in an upper flux of 5600 W/m^2

http://www.wolframalpha.com/input/?i=2.7+MW+%2F+%28%2821+m+*+7+m+*+pi%29%2B%282+*+pi+*+%283.5+m+^+2%29%29%29

Equivalent to 287 degrees Celsius for reactors 2 and 3

 

[GJBRKS]

I am not familiar with this sort of calculation. It appears to be saying that a blackbody heated from within has a maximum surface temperature which can be calculated with no regards to the energetics of its environment. This seems counter-intuitive. Assuming the temperature of its environment is 370^o, equal to the surface temperature of the RPV then no net heat transfer between the two can occur. On the assumption that the RPV can be no warmer than it already is, while seeing that heat energy is still produced on its the inside, one is led to ask: what happens to that energy?

The calculations do not concern themselves with the environmental temperatures.
The named temperatures are above those of the environment.

But that would be a correction of less than 10% , I'm assuming it could be +- more than 10% considering that these are estimates.

And i don't think an evenly distribution of the heat is likely

 

[AntonL]

I wanted to study the initial explosion of unit 3 to check if anything new can be found, I have no further insight to what has been said.

However, I make available the http://k.min.us/illbHq.zip" s of the first 1.5 seconds in 40mS increments (25 frames/second)

The only strange thing is the apparent contraction and as some have said bulging of unit 3 just before the explosion, compare frames 000ms and 040ms,

The contraction I attribute to a mpeg compression or sharpening artifact, but why the west wall should suddenly reflect less light - possibly already starting to crumble or shake as a reaction of what is happening inside.

 

[jim hardy]

"""It's highly unlikely you could over-pressurize the RPV. The support plumbing would fail first and the RPV would depressurize. You don't design the system such that your pressure vessel is what pops first.

Not to mention the dozen or so relief valves installed on the RPV to prevent this from happening. """

Smaller pipes are usually more pressure tolerant than big vessels because of their smaller area.

i believe what happens when you exceed the capacity of the safety valves is the head bolts stretch opening a gap under it and steam blows out sideways.

It's an easy calculation,
Force up = pressure X area of head
maximum force the bolts can hold down is
Force down = area of bolts X yield strength of bolt material

to get area of bolts you need the number of them and their diameter.

yield strength - i saw 125000 psi someplace which sounds reasonable for exotic bolt steel. Here's a reference,
http://www.americanfastener.com/technical/grade_markings_steel.asp
go down to A490 grade near bottom of chart it's 120,000 psi

When the up and down forces equal the head will lift.
Fup = pi/4 X (diameter of head)^2 X Pressure
Fdown = pi/4 X ((diameter of bolts)^2 X (number of bolts) X (yield strength of bolts)

at lift,
Fup/Fdown = 1 = pressure X ((diameter of head)^2 / ((diameter of bolts)^2 X (number of them) X yield strength of bolts)

solve by USWAG method: (Un Scientific Wild A** Guess)
Head = 16 ft diameter, 30 tons USWAG
Bolts = 3 inch and sixty of them USWAG but looks right from ppictures
Bolt yield= 120,000 yield SWAG, not U because it's referenced

When pressure makes Fup/Fdown = 1 head lifts.

1 = Press X ( 16ft X 12 in/ft )^2) / (3in^2 X 60 X120,000 psi)

1= Press X (568.9E-6)

Press = 1/0.0005689 = 1758 psi
A real mechanical engineer would adjust for weight of head by adding weight/area of head,
say 60,000 lbs / (28,953 sq in) = 2 more psi,, bumps it up to 1760 psi.
1760 psi isn't very much pressure for good pipe.

I checked my units and think i did that right.
But it's only back of envelope calc using guesses so don't take it as real.
Somebody knows how many bolts there really are and the actual vessel head diameter.

That's how i'd design a vessel, make its headbolts be the safety valve of last resort.

old jim

 

[MadderDoc]

re unit 3

do not the plant logs show they manually opened those relief valves on 13th to depressurize?

I have no access to the plant logs, only notes I took of press releases at the time of the events, and of observations of the webcam.
Here are excerpts, just what I find may be relevant to your question:

March 12th
11:00 Preparing to implement a measure to reduce the D/W pressure (i.e. venting)

March 13th
08:41 Venting procedure finished
08:56 Radiation at site boundary exceeds limits
09:10-09:25 Large drop of RPV pressure, with increase of DW pressure
10:00 webcam shows vent from unit 3 exhaust stack
13:00 webcam shows vent from unit 3 exhaust stack
14:00 webcam shows vent from unit 3 exhaust stack
14:00 Sea water injection is being attempted followed by boric acid injection
14:00 Safety relief valve has been opened manually

March 14th:
05:00 Water level that has been held at about -2.3 m relative to fuel top goes downscale
06:00 DW and SC pressure goes above design max limits
07:00 Water level comes back within scale, but only at -3.0 m relative to fuel
08:00 Water level indicators erratic or water level unstable
11:01 Explosion

 

[TCups]

Based on the available data of the reactor parameters, the combined system of RPV and support plumbing of unit 3 failed already on March 13th (between 9:10 and 9:25 the RPV pressure dropped abruptly from 7.3 MPa to 0.45 MPA, while drywell pressure increased from 0.46 to 0.53 MPa.) This would seem to imply that the dozen or so preventive relief valves you mention, failed too.

Consequently, on March 14th, the day of the explosion, the RPV and the PCV were no longer sharply separated volumes, and a depressurizing of the PCV at that stage would also lead to a depressurizing of the RPV . The data available up to and after the explosion indicates a depressurizing of both vessels in connection with the explosion of no less than 0.1 MPa.

Or, might it simply imply that the pressure relief valves were bypassed, as by damage and subsequent rupture of one of the connecting feed lines, especially the high pressure steam lines near the top of the RPV? Would that not produce the same observations?

It has been reported that lateral forces of the quake exceeded the design limits of Unit 3.

 

[jim hardy]

""The only strange thing is the apparent contraction and as some have said bulging of unit 3 just before the explosion, compare frames 000ms and 040ms, """

i have speculated whether there might have been a near invisible hydrogen flame already leaving the building at those first instants, it distorted the image while the flying debris took a few milliseconds to accelerate from rest.

warn me when i approach the line, guys.

 

[jim hardy]

Maddrr Doc neither do i have access to logs and may be having a senior moment.
Here's some notes about venting unit 1, i could be remembering wrong unit.

>>>>>>>
Anger rose as TEPCO dithered

TEPCO began preparations for opening the valves around 7 p.m. on March 11. Pressure inside the No. 1 reactor was particularly high.

"Soon, the reactor won't be able to withstand the pressure," said an official of the accident headquarters at the plant, which was keeping in touch with TEPCO's head office via video phone. "We have to vent the pressure immediately."

"Pressure inside the containment vessel of the No. 1 reactor has gone up dramatically," the agency told Banri Kaieda, economy, trade and industry minister, at 12:45 a.m. on March 12. In fact, it had reached 1.5 times the designed maximum, meaning the condition of the reactor was critical.

"To get things under control, we have to pour water into the reactors and then vent the steam that is generated," Haruki Madarame, chairman of the Cabinet Office's Nuclear Safety Commission, told Kaieda.

At 1:30 a.m. on March 12, Kan, Kaieda and Madarame gathered at the crisis management center in the basement of the Prime Minister's Office.

The three urged TEPCO officials to vent the steam as soon as possible. But TEPCO officials said there was no way of opening the valves because there was no power supply.

Exasperated, Kaieda called the utility's head office in Tokyo and the accident headquarters at the plant every hour, pressuring them to open the valves immediately.

TEPCO workers tried to open the valves by manually overriding the automatic system, but struggled to make progress because they had to work in darkness.

At dawn, pressure inside the No. 1 reactor was more than twice the designed maximum.

Eventually, at 6:50 a.m., the government ordered the utility to open the valves under the Nuclear Reactor Regulation Law.

When Kan visited the accident site shortly after 7 a.m. and found TEPCO had not opened the valves yet, he reprimanded company officials. The officials replied they would like to have another hour to make a decision on what to do.

Kan blew his stack.

"Now's not the time to make such lackadaisical comments!" the prime minister told the TEPCO officials.

Yet even still, the utility spent three more hours discussing the matter before finally opening the valves at 10:17 a.m.

Five hours after that, a hydrogen explosion occurred at the No. 1 reactor, blowing apart its outer building.

via Yomiuri



source http://www.houseofjapan.com/local/tepco-tardy-on-plant-emergency

 

[MadderDoc]

<..>
The contraction I attribute to a mpeg compression or sharpening artifact, but why the west wall should suddenly reflect less light - possibly already starting to crumble or shake as a reaction of what is happening inside.

If you can attribute the contraction to artefacts why not go the full Monty and attribute the lessening of reflection from the west wall to artefacts too? Using the 'artefacts' card, nothing in a video should really be inexplicable :-)

No seriously. You should establish for yourself a baseline looking at a series of frames before 000ms. How much bulging and contracting do you see there, how does it look when nothing is ongoing in the building, how much can it all wobble due to artefacts?

I think you will not likely find a contraction similar to the one you see in frame 040ms in any frames before frame 000ms. If that is so, then what you see is an aberration in relation to your baseline and therefore unlikely an artefact. It is the real thing, something is really changing. Same goes for what you see on the west wall.

(You may consider using another video source, the one you have been using appears to have been recompressed resulting in loss of information)

 

[AntonL]

Tepco admit to the possibility that all primary containment vessels of all reactors are leaking.
[URL]http://www.asahi.com/national/update/0514/images/TKY201105140388.jpg[/URL]
english article: http://www.asahi.com/english/TKY201105130192.html
japanese article: http://www.asahi.com/national/update/0514/TKY201105140387.html
which also talks of that the cooling plan for Unit 1 will most likely be abandoned.
3000Tons of water is missing from the unit 1 containment, possibly in the torus basement and also leaked into the ground water.

Also here is the english article of the leaked 100 page report http://www.asahi.com/english/TKY201105130370.html

 

[rowmag]

Tepco admit to the possibility that all primary containment vessels of all reactors are leaking.
[URL]http://www.asahi.com/national/update/0514/images/TKY201105140388.jpg[/URL]
english article: http://www.asahi.com/english/TKY201105130192.html
japanese article: http://www.asahi.com/national/update/0514/TKY201105140387.html
which also talks of that the cooling plan for Unit 1 will most likely be abandoned.
3000Tons of water is missing from the unit 1 containment, possibly in the torus basement and also leaked into the ground water.

Also here is the english article of the leaked 100 page report http://www.asahi.com/english/TKY201105130370.html

English version says 3000 tons of water missing, Japanese version says 3000 tons of water found in basement.

So what now? Fill the basement with cement?

 

[robinson]

I don't think it's speculation to say this is the biggest nuclear mess mankind has ever faced.

 

[swl]

""The only strange thing is the apparent contraction and as some have said bulging of unit 3 just before the explosion, compare frames 000ms and 040ms, """

My opinions:

The building was not contracting. The upper containment walls are beginning to expand in the "0" frame. I can see that the dark roof outline has not moved down, but the white color of the wall does appear to have moved down at the upper edge.

As has been noted, H.264 compression uses inter-picture prediction over as many as 16 frames. This codec is intended to provide very high data compression while maintaining reasonable -motion- picture quality. When set up for streaming video, like on youtube, the data is optimized for a motion picture where you view each frame for 1/25th of a second. It can not be relied upon to provide fidelity of an individual frame for still analysis.

In addition to being subjected to H.264 conversiom, avi conversion, and pray tell what else, the quality of the master was almost certainly of poor quality with low resolution, poor contrast and atmospheric distortion.

Question: Having done my bast to discredit the reliability of the video, does it look to any of you like the ignition point might have been outside the upper southwest corner?

 

[AntonL]

re unit 3


I have no access to the plant logs, only notes I took of press releases at the time of the events, and of observations of the webcam.
Here are excerpts, just what I find may be relevant to your question:

March 12th
11:00 Preparing to implement a measure to reduce the D/W pressure (i.e. venting)

March 13th
08:41 Venting procedure finished
08:56 Radiation at site boundary exceeds limits
09:10-09:25 Large drop of RPV pressure, with increase of DW pressure
10:00 webcam shows vent from unit 3 exhaust stack
13:00 webcam shows vent from unit 3 exhaust stack
14:00 webcam shows vent from unit 3 exhaust stack
14:00 Sea water injection is being attempted followed by boric acid injection
14:00 Safety relief valve has been opened manually

March 14th:
05:00 Water level that has been held at about -2.3 m relative to fuel top goes downscale
06:00 DW and SC pressure goes above design max limits
07:00 Water level comes back within scale, but only at -3.0 m relative to fuel
08:00 Water level indicators erratic or water level unstable
11:01 Explosion

Extracted from NISA status report for Unit 3 http://www.nisa.meti.go.jp/english/files/en20110513-1-2.pdf

March 11th 15:42 Report based on the Article 10 (Total loss of A/C power)
March 13th 05:10 Occurrence of the Article 15 event (Inability of water injection of the Emergency
Core Cooling System)
March 13th 08:41 Started to vent.
March 13th 13:12 Started to inject seawater and borated water to the Reactor Core.
March 14th 05:20 Started to vent.
March 14th 07:44 Occurrence of the Article 15 event (Unusual rise of the pressure in PCV)
March 14th 11:01 Sound of explosion
March 16th around 08:30 White smoke generated.

 

[AntonL]

I don't think it's speculation to say this is the biggest nuclear mess mankind has ever faced.

yes you a right, Chernobyl vaporized their core and spread it over a large area, Fukushima are dissolving their core and burying it in their ground water.

 

[turi]

re unit 3
[...]
March 14th:
05:00 Water level that has been held at about -2.3 m relative to fuel top goes downscale
06:00 DW and SC pressure goes above design max limits
07:00 Water level comes back within scale, but only at -3.0 m relative to fuel
08:00 Water level indicators erratic or water level unstable
[...]

Does anyone here know how those water level sensors work? What could cause them to give erronous info (instead of simply appear offscale or stuck)? If the newly attempted measurements at unit 1 are to be believed the two sensors there showed erronous info for quite some time. Also interesting might be that they both showed more or less the same values. How do two of those sensors go awry in the same way?

 

[MadderDoc]

The calculations do not concern themselves with the environmental temperatures.

No, and that's what strikes me as odd. It is as if this RPV is suspended in empty space at absolute zero- Otherwise I cannot see how one can avoid involving a term representing the temperature of the environment. A blackbody is something that would absorb all radiation incident on it, if I understand that term? It would seem to have to emit that amount of energy again plus the internally produced heat in order to reach an equilibrium temperature. I think.