Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Dmytry]

Well agree with you (found skimmer illustrated in http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110418e5.pdf" from Tepco). Do you mean skimmer level does not give SFP level ?

Where is the water in the skimmer surge tank going? Why are they releasing this water? Does not matter, but just curious.

Dunno. Maybe they pumped water out of skimmer surge tank for some reason, so that if they pour too much water it overflows into skimmer surge tank. Or maybe it got damaged by quake+explosion+aftershocks.

 

[Rive]

The fission energy per Bq of I-131 is then 1.1E-3 J
http://www.wolframalpha.com/input/?i=(((8.0252+days)/ln(2))/second)*(6.9E9+eV)

100KW of fission, for 1 day, makes 7.8E12 Bq of I-131.
http://www.wolframalpha.com/input/?i=(100kw*1+day)/((((8.0252+days)/ln(2))/second)*(6.9E9+eV))

edit: note, noscript strips parens out of the url. The final formula is:
(100kw*1 day)/((((8.0252 days)/ln(2))/second)*(6.9E9 eV))

you guys do the concentrations and volumes, it's late night here. I didn't check my sources, so beware.

Thanks - it'll be useful

 

[elektrownik]

Leaks of radioactive materials from fuel rods have been suspected at a nuclear power plant in Tsuruga, the Fukui prefectural government said Monday, citing a rise in density of the toxic substances in coolant water. [...]

According to Japan Atomic, 4.2 becquerels of iodine-133 and 3,900 becquerels of xenon gas were detected per cubic centimeter Monday, up from 2.1 and 5.2 becquerels, respectively, during previous measurements conducted last Tuesday.

Radiation leaks from fuel rods suspected” at Japan’s Tsuruga nuclear plant — Radioactive Xenon up 75,000%

Any ide what this could mean ?

 

[~kujala~]

I just made an insight, I don't know if there is any truthness in it, probably not.

TEPCO says SFP 4 is contaminated because they have sprayed contaminated seawater there.

We also know that SFP 2 is propably high-level contaminated.

So perhaps what TEPCO is saying about SFP 4 is true. Wouldn't this same apply to SFP 2?

The theory is that seawater sprayed to SFP 4 has been taken in front of unit 4 whereas seawater used to cool SFP 2 has been taken in front of unit 2.

And because the highest level of radiation in seawater is in front of unit 2 we would also see the highest level of radiation in SFP 2.

This would be called recycling... The high-level leakages from the reactor number 2 to the sea would be seen all around the Fukushima plant.

 

[|Fred]

On the high resolution pictures that were taken a while back we can see the truck and fire hose taking watter from what will be known after as contaminated trench. So what they are suggesting is not so far fetched and could actually by a true full explanation.

 

[Astronuc]

Any ide what this could mean ?

I don't know the details, but whenever there is a failure of a fuel rod(s) in a reactor, there is a spike in the Xe and Kr in the coolant (usually classified as a Xe spike). Normally the longer lived Xe-133 increases then settles down. One can measure the Xe-138/Xe-133 and/or Xe-135/Xe-133 to determine if the leak is tight (low ratio) or open (high ratio).

If it is one or a few failures, this is not unusual, although it is undesirable.

The cause of cladding breach could be debris (e.g., small pieces of wire) fretting, grid-to-rod fretting, or perhaps a faulty weld. More details would be necessary to understand the significance.

 

[TCups]

Nice side by side video on youtube of #1 and #3 explosion

http://www.youtube.com/watch?v=1Q3ljfLvHww"

Very impressive to see the difference in shape and power.

If you look at the frame by frame version of #3 explosion,
you can clearly see the fireball, followed by the implosion and catapult shot.

http://www.youtube.com/watch?v=9PHQ3IJHJbw"

It seems to me, that the implosion/explosion also has impact on structure of building #4.
Could be the reason for the curved damage seen on the left side of the building #4, after it blow up.

I, for one, have never been able to "clearly see" the implosion of Bldg 3. If an explanation of the mechanism for an implosion following the initial fireball was given, I guess I missed it. By "implosion", is it meant that some type of negative pressure developed with sufficient force to suck the building inward? What exactly is implied by "implosion" and what inference as to the nature of the explosion can be drawn if in fact implosion occurred?

 

[PietKuip]

What would be most helpful is a sticky that has, without additional interpretation, and indexed as appropriate (including location, date and time), links and graphics (with original source and copyright data) of ...

One could do that: a thread where each of the regulars has their own few postings that they try to hold up to date.

Another possibility is a wiki. There is http://fukushimafaq.wikispaces.com/ and http://fukushima.wikispaces.com/

 

[Rive]

At the Original Foto, the Truck in Unit4 is not to see, the Door is closed.

Two frame from the previously linked 'Tour' video (04.22.) are attached: one is about the door of U3, one is about the door of U4.

It's interesting, that while U3 is more damaged than U4, the tunnel of U3 looks more intact.

U4: Is it possible that the door was opened and the truck was pushed out by the explosion?

PS.: U4.: actually, I could not find the door on the pictures, even on the aerial photos...

 

[MadderDoc]

Two frame from the previously linked 'Tour' video <..>

Those a very fine looking frames. I've been looking for a good version of this particular 'Tour' video unsuccessfully for a while, and would be grateful for a repost of the link.

 

[Rive]

Originally it was posted https://www.physicsforums.com/showpost.php?p=3274193&postcount=5352".

Link:

A different version (more cuts, less real footage, but less subtitles):

Used software: DownloadHelper extension for Firefox, Mp4Cam2AVI, AVIDemux.

 

[RealWing]

Interesting comment in the TEPCO status reports on Daiini - that 'Residual heat removal system (A) was disabled due to the earthquake." Only RHR (B) systems are operating. This comment was made for all 4 reactors.

I would have assumed that both A and B trains of the RHR system would have been qualified to the Design Basis Earthquake, so it appears that it may not have been adequately designed for a DBE?? That would not bode well for the other TEPCO plants - that are running today.

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110502e9.pdf

 

[Dmytry]

Interesting comment in the TEPCO status reports on Daiini - that 'Residual heat removal system (A) was disabled due to the earthquake." Only RHR (B) systems are operating. This comment was made for all 4 reactors.

I would have assumed that both A and B trains of the RHR system would have been qualified to the Design Basis Earthquake, so it appears that it may not have been adequately designed for a DBE?? That would not bode well for the other TEPCO plants - that are running today.

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110502e9.pdf

Ya. Everyone's been making up as a fact everywhere that the reactor withstood the quake, whereas the fact was that they made it up out of thin air.

 

[DSamsom]

Would be too coincidental for the hourly webcam to register an explosion of some kind. And the no-wind (see ocean) situation is probably a better explanation for this odd shaped plume. Still, what is happening on the most recent webcampicture ?

http://www.tepco.co.jp/nu/f1-np/camera/index-j.html

 

[Caniche]

Would be too coincidental for the hourly webcam to register an explosion of some kind. And the no-wind (see ocean) situation is probably a better explanation for this odd shaped plume. Still, what is happening on the most recent webcampicture ?

http://www.tepco.co.jp/nu/f1-np/camera/index-j.html

You see all those nice green reassuring pine trees in the foreground? I'll bet you a dime to a dollar that they'll be crispy brown in twelve months. Pine trees is like that

 

[MiceAndMen]

Sorry to be running so far behind -- PF seems to be having server problems that coincide with my reading time.

What would be most helpful is a sticky that has, without additional interpretation, and indexed as appropriate (including location, date and time), links and graphics (with original source and copyright data) of:

1) technical drawings and diagrams of the physical plan at Fukushima

2) photos and videos of Fukushima

3) relevant tables, graphs & charts (ie, of radiation measurements, RPV and SFP parameters, etc.)

4) links to related articles

Going forward, perhaps posters could include such appropriate links and attachments, not only in their posts, but also appended to the appropriate sticky.

This thread is an amazing source. It deserves to be indexed and footnoted and perhaps, technically edited to better organize and categorize the content. I predict it will be a long-lasting source for technical and historical research.

In the aftermath of the Columbia Space Shuttle accident in 2003, some people worked on a "Columbia Loss FAQ" for quite a while. Unfortunately it's offline now, but copies are still available through archive.org.

HTML version: http://replay.web.archive.org/20050212050722/http://www.io.com/~o_m/columbia_loss_faq_x.html

Text version: http://replay.web.archive.org/20050307183230/http://www.io.com/~o_m/columbia_loss_faq.html

Maybe those can be used to get an idea of one possible way to consolidate information in one place. A lot of what we get by way of media stories on the web is sure to disappear off the internet over time.

 

[ElliotLake]

In the aftermath of the Columbia Space Shuttle accident in 2003, some people worked on a "Columbia Loss FAQ" for quite a while. Unfortunately it's offline now, but copies are still available through archive.org.

HTML version: http://replay.web.archive.org/20050212050722/http://www.io.com/~o_m/columbia_loss_faq_x.html

Text version: http://replay.web.archive.org/20050307183230/http://www.io.com/~o_m/columbia_loss_faq.html

Maybe those can be used to get an idea of one possible way to consolidate information in one place. A lot of what we get by way of media stories on the web is sure to disappear off the internet over time.

Things are already disappearing, and access as well; Kyodo news for instance has trimmed accessibility. There is software to add wikis to sites, perhaps this forum's host has such a capability?

 

[mikefj40]

From NHK: "The Japanese government is about to begin releasing data projecting the spread of radiation from the Fukushima Daiichi nuclear plant that it initially withheld for fear of causing panic.

The data in question is in a computer system called SPEEDI that predicts the spread of radioactive substances based on actual radiation measurements at various locations and weather conditions.

A joint task force of the government and Tokyo Electric Power Company says about 5,000 undisclosed bits of data will be released from Tuesday.

The information will be carried on the websites of the science ministry, the Nuclear and Industrial Safety Agency, and the Nuclear Safety Commission.
The secretary-general of the joint task force and prime the minister's advisor, Goshi Hosono, apologized for the delay in releasing the data."

http://www3.nhk.or.jp/daily/english/02_32.html?play

 

[Ms Music]

Someone told me the other day that pieces of fuel had been found a few miles (or kilometers) from Dai ichi. Is this confirmed? Or bogus?

 

[georgiworld]

From NHK: "The Japanese government is about to begin releasing data projecting the spread of radiation from the Fukushima Daiichi nuclear plant that it initially withheld for fear of causing panic.The data in question is in a computer system called SPEEDI that predicts the spread of radioactive substances based on actual radiation measurements at various locations and weather conditions.

A joint task force of the government and Tokyo Electric Power Company says about 5,000 undisclosed bits of data will be released from Tuesday.

The information will be carried on the websites of the science ministry, the Nuclear and Industrial Safety Agency, and the Nuclear Safety Commission.
The secretary-general of the joint task force and prime the minister's advisor, Goshi Hosono, apologized for the delay in releasing the data."

http://www3.nhk.or.jp/daily/english/02_32.html?play

I have refrained from condeming both the government and Tepco but this has changed everything.
These numbers must be horrifying to people who understand their significance.
This ongoing catastrophe is being managed by the eternal wisdom of Japanese bureaucrats.

The Bridge over the River Kwai. Be happy in your work!

They are willfully withholding vital information from the world!
Who do they think they are?

They do this, just as Japanese physicians hide the truth from their terminal patients because they believe the patients is better off not knowing the truth. Aside from the fact that they are demonstratively wrong regarding health, they are are giving themselves god-powers.

This was beautifully illustrated in the Kurosawa film, Ikiru where a middle aged bureaucrat has terminal cancer and is lied to by his physician.
http://www.imdb.com/title/tt0044741/usercomments?filter=best

They don't have the right to do this to a patient and they don't have the right to do this to our planet.

Can't we just call this a world's problem and not a Japanese one.

Can someone figure out what to do? Can't we creat some world agency with unlimited resources?

 

[Cainnech]

http://youtu.be/kO0flpwmjJI

More on 77-year-old Michio Ishikawa of the Japan Nuclear Technology Institute on the situation at Fukushima I Nuke Plant, as he appeared on Asahi TV on April 29. [...]

To whom it may be of interest, two articles by Michio Ishikawa written on March 15, 2011 and April 11, 2011.

http://www.gengikyo.jp/english/shokai/Tohoku_Jishin/article_20110318.html
http://www.gengikyo.jp/english/shokai/Tohoku_Jishin/article_20110413.htm

 

[mikefj40]

These numbers must be horrifying to people who understand their significance.

They haven't released anything yet and when they do the numbers will be significant to those closest to the site. Being old enough to live through weapons testing in the '50's and '60's I'm not all that concerned, even though I live in California. This is not that big of a deal for those of us 5000 miles away.

Interesting graph of worldwide radiation dosage from '45 - '10 http://www.nytimes.com/imagepages/2011/05/03/science/03radiation_graphic.html?ref=science from today's NYT article "Drumbeat of Nuclear Fallout Fear Doesn’t Resound With Experts" http://www.nytimes.com/2011/05/03/science/03radiation.html?ref=radiation

Before I get too far afield for this thread let me just say that the best thing about everyone's contribution to this thread is the absence of fear-mongering and an overwhelming desire to understand what's happening in an information-poor environment. I'm reserving judgment until the numbers are published and those that know much more than me make sense of it.

 

[|Fred]

Someone told me the other day that pieces of fuel had been found a few miles (or kilometers) from Dai ichi. Is this confirmed? Or bogus?

You'll find the answer a few pages back... it was suggested as a possibility as of some reading could have indicated that.. This speculation made in an US report ... Some people reading the report translated that as a fact. Point is we don't know for sure.

I have refrained from condeming both the government and Tepco but this has changed everything.These numbers must be horrifying to people who understand their significance. This ongoing catastrophe is being managed by the eternal wisdom of Japanese bureaucrats.

The people who followed from day one knew that http://www.bousai.ne.jp/eng/ was really not updated for the important areas: Fukushima prefecture etc.. it was (still is) "under survey".. Today they are saying that this will finally have it up to date..

I would say that people concerned did not wait for that :they is several others webs sites to get the info from...and there has been since almost day 1..

 

[mikefj40]

Today they are saying that this will finally have it up to date..

Fred, thanks for the link. Looks like they posted new monitoring data today (5/2) for Fukushima http://www.mext.go.jp/english/incident/1303962.htm and Miyagi http://www.pref.miyagi.jp/kokusai/en/accidents_fukushima_nuclear.htm (I'm going to miss those oysters...).

It looks like they aren't filling in the historical blanks and just starting with current readings. I'd like to see data for isotopes other than "radioactive iodine" and "radioactive cesium" too.

 

[default.user]

To whom it may be of interest, two articles by Michio Ishikawa written on March 15, 2011 and April 11, 2011.

http://www.gengikyo.jp/english/shokai/Tohoku_Jishin/article_20110318.html
http://www.gengikyo.jp/english/shokai/Tohoku_Jishin/article_20110413.htm

1.he forgot to mention the criticality.
Through them, the corium is open again.
water penetrates into the corium.
the opening is large enough, it can cause a steam explosion.
2. why the corium is inside the water? why it is not at the bottom of the vessel?
have you seen his pictures too.
not vote because several factors.

 

[Astronuc]

Someone told me the other day that pieces of fuel had been found a few miles (or kilometers) from Dai ichi. Is this confirmed? Or bogus?

I don't believe that is correct. The SFP of unit 4 looks more or less intact, and there is not large opening in the cores of Units 1 or 3, and the roof of unit 2 remains intact.

The roof of unit 1 looks like it collapsed onto the reactor service building floor.
http://www.tepco.co.jp/en/news/110311/images/110415_1f_3_1.jpg

Roof of unit 3 is covered by debris.
http://www.tepco.co.jp/en/news/110311/images/110415_1f_3_4.jpg

For fuel to escape from the core, the large cement plug would have to be removed, as would the drywell cap, the reactor vessel head, the steam dryer and the steam separator. There is no clear path for the fuel to be ejected from the cores.

I also don't believe that any fuel rods are found outside of the containment area. I suspect steel reinforcement rods were mistakenly identified as fuel rods.

 

[TCups]

I don't believe that is correct. The SFP of unit 4 looks more or less intact, and there is not large opening in the cores of Units 1 or 3, and the roof of unit 2 remains intact.

The roof of unit 1 looks like it collapsed onto the reactor service building floor.
http://www.tepco.co.jp/en/news/110311/images/110415_1f_3_1.jpg

Roof of unit 3 is covered by debris.
http://www.tepco.co.jp/en/news/110311/images/110415_1f_3_4.jpg

For fuel to escape from the core, the large cement plug would have to be removed, as would the drywell cap, the reactor vessel head, the steam dryer and the steam separator. There is no clear path for the fuel to be ejected from the cores.

I also don't believe that any fuel rods are found outside of the containment area. I suspect steel reinforcement rods were mistakenly identified as fuel rods.

@Astronuc:

What type(s) of scattered debris following a hydrogen explosion might have a 900 mSv/hr activity? It would seem to me something from the SFP of Unit 3 would be at the top of the suspect list, but perhaps not so. Your opinion? Thanks.

 

[Arizonan]

The Gunderson video from fairewinds.com, April 25 I think. Gunderson is a nuclear engineer. From his analysis of the data, he suspects the fuel storage pond at #3 reactor blew up in the explosion, accounting for the high levels reported in some surrounding debris, such as 1 Sv emanating from a chunk of concrete. I don't have the exact date of the video to hand, but could find it if anyone interested.

According to the IAEA charts, containment vessel breaches are suspected at 2 out of 3 reactors; TEPCO has admitted partial meltdowns at all three; increasing amounts of I-131 indicate some criticality somewhere, either intermittent or ongoing. Anyone have a solution?

And how would 334,000 Bq/kg get into the evaporated sewage sludge? (Today's Fukushima news.)

I don't believe that is correct. The SFP of unit 4 looks more or less intact, and there is not large opening in the cores of Units 1 or 3, and the roof of unit 2 remains intact.

The roof of unit 1 looks like it collapsed onto the reactor service building floor.
http://www.tepco.co.jp/en/news/110311/images/110415_1f_3_1.jpg

Roof of unit 3 is covered by debris.
http://www.tepco.co.jp/en/news/110311/images/110415_1f_3_4.jpg

For fuel to escape from the core, the large cement plug would have to be removed, as would the drywell cap, the reactor vessel head, the steam dryer and the steam separator. There is no clear path for the fuel to be ejected from the cores.

I also don't believe that any fuel rods are found outside of the containment area. I suspect steel reinforcement rods were mistakenly identified as fuel rods.

 

[AntonL]

flooding reactor 1 leaves tepco puzzled and cooling rate back to 6m³/h

http://mdn.mainichi.jp/mdnnews/news/20110502p2a00m0na012000c.html

 

[rowmag]

From NHK: "The Japanese government is about to begin releasing data projecting the spread of radiation from the Fukushima Daiichi nuclear plant that it initially withheld for fear of causing panic.

The data in question is in a computer system called SPEEDI that predicts the spread of radioactive substances based on actual radiation measurements at various locations and weather conditions.

Looks like SPEEDI stuff is going here:
http://www.nsc.go.jp/mext_speedi/index.html

Estimated integrated effective doses from 3/12 to 4/24:
-->Infant (1-year olds) internal (thyroid) exposure to iodine: http://www.nsc.go.jp/mext_speedi/0312-0424_in.pdf

-->Adult external exposure from I-131, I-132, Cs-137 and Cs-134: http://www.nsc.go.jp/mext_speedi/0312-0424_ex.pdf
(10 mSv is the shelter-indoors level, per notation arrow)

Hourly wind-borne spread plots here:
http://www.nsc.go.jp/mext_speedi/past.html
(Could be helpful for answering questions such as why a spike showed up at such and such a place at a certain time.)

 

[AntonL]

http://mdn.mainichi.jp/mdnnews/news/20110501p2g00m0dm005000c.html"

Japan will have to get used to Western satire, next I presume they will claim the Hollywood rights

they already protested regarding below cartoon published 21 April in the Herald Tribune
http://english.kyodonews.jp/photos/assets/201104/0422023.jpg
fortunately they are not that fanatical and and respond by issuing a fatwa.

 

[Jorge Stolfi]

Roof of unit 3 is covered by debris.
http://www.tepco.co.jp/en/news/110311/images/110415_1f_3_4.jpg

Looking at the damage to #3 and the explosion, I suspect that the roof frame was lifted to some extent and then fell back more or less in place. The pillars on the N, W, and S sides were torn away, and all but two of its attachment points on the E side were broken too. So I think that the roof frame pivoted on the E side like the lid of a sardine can, by some unknown angle, during the explosion That would have left a path for some items to be thrown from the service floor on higher trajectories, hence to greater distances.

However that may be irrelevant. To my eyes, the bright flash seen at the start of the explosion apparently occurred in the SFP region, and blasted through the S wall (so that we could see it) before the damage had time to spread rest of the building. The flash rules out a steam explosion. Could a hydrogen explosion behave that way? (I would expect a flameless explosion affecting the entire building at the same time, like that of #1.)

Guesses are cheap, so I would guess a mini nuclear explosion in the SFP -- the flash -- that ignited the hydrogen. Unlikely?

(PS. An overdue grant report has prevented me from updating my NISA plots since release 114. Right when some action is happening, darn. I'll catch up on Wednesday, hopefully...)

 

[MiceAndMen]

flooding reactor 1 leaves tepco puzzled and cooling rate back to 6m³/h

http://mdn.mainichi.jp/mdnnews/news/20110502p2a00m0na012000c.html

From the article,

Officials said the water level inside the reactor's pressure vessel remained almost unchanged -- at about 1.6 meters above the top of the fuel rods -- when the amount of water was temporarily increased. With water pumped into the pressure vessel leaking out, workers estimate that the water level inside the containment vessel stands at about 6 meters, but they do not know the exact level.

Things like this are part of the reason why they don't release more information such as engineering drawings of the plant and reactors. If they did release such information we would know in about 10 minutes, and that would make them look bad. I sincerely hope the desire of most Japanese people is to act responsibly and not be slaves to their cultural need to save face. I think portrayals in the media of Japanese nuclear experts, TEPCO chiefs and government officials depicting them as clowns are not far away, and would not be far from the truth.

 

[|Fred]

The Gunderson video from fairewinds.com,. From his analysis of the data,

As I said , he is referring to a US report that say that one could speculate that , and M.Gunderson, make it a hard fact, multiplying the range by 2. I provided a proper analysis with link to the material last week. Point is it a assessment base on a theory he elaborated not based on had fact.
I now question the rigor of his analysis and his will to correct him self. I already challenged his alleged Spent fuell rack theory a while back when he explained solely based on a shady low resolution video that the fuel rack of the pool 4 were sticking out the pool . Without his experience proper photo analysis was rather pointing to his alleged rack being part of the Crane. This was confirm later but he never retracted.

So If I value the insight Gunderson can provide, I won't for granted. And to be honest the cumulative contradictory contribution of this thread is for me more trustworthy.


********

Thank you rowmag , was the evac zone / order to take iodine made in accordance to the data now released ?

 

[rowmag]

Thank you rowmag , was the evac zone / order to take iodine made in accordance to the data now released ?

The evacuation zones were decided based on similar plots, but not sure whether exactly these ones. These plots show the estimated exposures received so far, and the evacuation zones were, I believe, based on projections of exposures expected over the next year. (Not sure how those were calculated, whether they extrapolated from present estimated ground contamination patterns, or whether they did something fancier, such as using SPEEDI with typical wind patterns over the course of a typical year, and some assumption about ongoing emissions...)

Anyway, there have been several such maps shown, and they all have the general features of one big pseudopod going up to the North-West, and a smaller one down to the South-West, but they differ in various details after that. The people living in the northwest pseudopod (beyond the circular zone that is already under evacuation orders), in the towns of Iitatemura and surrounding areas, have been told to evacuate by the end of this month. The people in the southwest pseudopod (in the town of Iwaki) have not, if I recall correctly.

I don't think any orders to take potassium iodide have been issued, by the way, just evacuation orders.

 

[MadderDoc]

Someone told me the other day that pieces of fuel had been found a few miles (or kilometers) from Dai ichi. Is this confirmed?

It has not been confirmed by any primary source that I know of, but perhaps indicated by a secondary source. If you was practically able to track the information you got back to where it came from etcetera, I'd expect the trail to lead you to a NRC report from March 26th. According to this report neutron sources have been found up to 1 mile away from the reactors. In the context of the NRC report, 'neutron sources' would be understood as another way of saying 'something from the fuel', and NRC would be understood as talking not from thin air, but from information available to it, and originating, in the eyes of the NRC, from a primary source.

Or bogus?

The bit 'a few miles', I think can be dismissed as bogus. No credible source I know of has talked about anything from fuel being found at that distance.

It is implausible that the events in unit 1, 2, or 4 could have been the source of ejection of fuel fragments for anything even coming close to a km or a mile.

As regards unit 3, I think the jury is still out. I think it is beyond discussion that some material from unit 3 -- I am talking here in general terms, not particularly or necessarily about material from fuel -- was ejected to distances up to the 1 km range by the events in unit 3. Should this ejection have encomprised material from fuel, it would have to be material from the spent fuel pool, or from the core. What was once the service floor of unit 3 is a mess, and we know preciously little about its conditions. Personally I find it implausible if the events in unit 3 did not eject material from fuel.

 

[MadderDoc]

Looking at the damage to #3<..> To my eyes, the bright flash seen at the start of the explosion apparently occurred in the SFP region, and blasted through the S wall (so that we could see it) before the damage had time to spread rest of the building. The flash rules out a steam explosion. Could a hydrogen explosion behave that way? (I would expect a flameless explosion affecting the entire building at the same time, like that of #1.)

It is clear from the video, that the explosion in unit 1 was not a flameless explosion. The explosion was however quite brief, compared to the flame/fire phenomena seen during the unit 3 explosion, the briefness consistent with its being a hydrogen detonation.

Unit 3 otoh, put on display fire/flame phenomena lasting for at least 0.4 seconds during the inital phase of the explosion. And after the explosion, in the remains of unit 3 we see evidence that intense heat has been present during the explosion for long enough to melt and burn away steel and concrete structures. The long durance of the flame phenomena, and the presence of such destructive intense heat, seem to me quite inconsistent with the explosions being (only) a hydrogen explosion.

 

[zapperzero]

Data acquisition system ERSS failed, delaying evacuation:
http://www.thehindu.com/news/international/article1987882.ece

TEPCO lied about Fukushima Dai-ni being in cold shutdown (but maybe we knew that already? we really need a timeline):
http://af.reuters.com/article/energyOilNews/idAFL3E7FL2HE20110421

 

[zapperzero]

Live webcam of Dai-ichi. Lots of fog atm:

http://www.youtube.com/user/tbsnewsi?feature=feedlss#p/l/-ZPYlazljME

 

[Rive]

... in the remains of unit 3 we see evidence that intense heat has been present during the explosion for long enough to melt and burn away steel and concrete structures.

Can you please give me some links to this part of the topic?

Just one more guess about the explosion of U3:
- Boom one: I think the initial explosion was a hydrogen explosion above the service floor, with minor damages on structures below the floor: this part was similar with the explosion of U4. The differences from the U1 explosion were because the upper building of U1 is steel, not concrete. At this point the pillars of the upper building were gone on the south and north wall.

- Boom two: my guess is that this part was a originated from the lower building, somewhere on the north side. Maybe because of a hydrogen release from a torus-failure, like in U2, ignited by the first explosion. (There was that PDF not so long ago about GE MK1 simulated failures). This explosion ripped the northwest corner of the building, with a strong NW and upward momentum, with a lot of debris, some of them contaminated. At this point the pillars on the west side were gone.

- Boom three: with the pillars gone the overhead crane fall down and pushed the FHM (did anybody managed to find that damned FHM of U3? It's not on the top of SFP, not on the top of equipment pool, but these parts are mostly intact, so after two weeks of pixel-hunting of every available footage and pic I see no other place for it than below the crane) through the upper concrete plug of the containment and released a lot of really hot steam, maybe with some hydrogen, maybe ignited on free air.

Any ideas, comments on this sequence?

 

[jlduh]

Some questions from this article:
http://mdn.mainichi.jp/mdnnews/news/20110502p2a00m0na012000c.html

1)

Furthermore, when workers increased the amount of water pumped into the containment vessel, pressure inside the vessel fell, threatening a hydrogen explosion. As a result, workers had to once again reduce the amount of water. When pressure inside the containment vessel falls to a level near regular atmospheric pressure, oxygen can enter the container from outside and react with hydrogen inside to produce an explosion.

Could somebody explains me why pressure inside the RPV is dropping when injected water volume increases from 6 to 14 M3/h, whereas it seems there is no increase in the water level inside the RPV which stays at around 1,6 meters below the the top of fuel rods (i would say maybe: below what was the top of fuel rods as they are probably gone since a long time and relocated lower into the reactor in the water). To me it doesn't make sense.

2) second question related to this extract: why do they consider that if pressure falls inside the RPV towards a value close to 1 atm, there could be oxygen coming from the outside, IF THE CONTAINMENT IS NOT DAMAGED? I know that Tepco said once it could be damaged (and i think what they say here with oxygen is confirming this hypothesis) but as they said almost everything and its contrary on many subjects if you look back, this part of the explanation is a little bit fuzzy to me...

3) other question from this extract:

On May 1 TEPCO announced that it had pumped about 120 tons of water from the turbine building of the No. 6 reactor into a makeshift tank. The level of accumulated water, totaling roughly 4,900 tons, stands at about 2 meters. Its level of radioactivity is thought to be relatively low.

Ok so we have now 4900 tons of water, or 2 meters of water, inside the turbine building of N°6 reactor...

So again what are the hypothesis for this water, if we believe Tepco statement that there is no internal link from the reactor on this one (i saw some graphics on this thread which showed data that could contradict this, with level inside RPV going up and down at regular intervals, and same thing with temps. But?). A) This could be water left from the flooding of the tsunami, but it would not increase along the time; so there must be a continuous flow, right? B) Did the water level of the water table under the Daichi plant moved upward with the tsunami and so there is part of the basement which is now under the water table surface?

But personnaly, i cannot fully remove from the scope the hypothesis of an internal leakage of this reactor (which is cooled by the internal cooling system, instead of external open loop "cooling" (low efficiency) on the n°1 to 3). The radioactivity of this water is "thought to be relatively low" doesn't tell you more, right?

 

[elektrownik]

#3 RPV is 205C now, why ?
also only 1,6m water in #1 SFP

 

[Borek]

These numbers must be horrifying to people who understand their significance.

Quite the opposite - they can be horrifying to those who DON'T understand their significance, so they were not release to not start the panic.

I am not saying that's the case, just pointing out you are jumping to conclusions.

Things like this are part of the reason why they don't release more information such as engineering drawings of the plant and reactors. If they did release such information we would know in about 10 minutes

Don't underestimate them, don't overestimate yourself.

 

[zapperzero]

Some questions from this article:
http://mdn.mainichi.jp/mdnnews/news/20110502p2a00m0na012000c.html

1) Could somebody explains me why pressure inside the RPV is dropping when injected water volume increases

2) second question related to this extract: why do they consider that if pressure falls inside the RPV towards a value close to 1 atm, there could be oxygen coming from the outside, IF THE CONTAINMENT IS NOT DAMAGED?

1. Water inside RPV gets less hot. Steam production drops. Pressure drops. Oops.
2. The containment IS damaged, obviously, or else they would have filled it many times over with all the water they've been pumping in.

The hole(s) in the RPV _must_ be somewhere below water level or else they would have atmospheric pressure above it. I do not believe in hairline cracks in the RPV above water level not getting worse after a month.

So, what mechanism is left, that would allow air from the outside, but only when pressure drops below atmospheric? Well... sounds like a check valve, no? Something that right now is being held shut by pressure inside the RPV, but which would hang open if that pressure went away.

I think there is a big hole or a number of smaller holes on the bottom of the RPV. The drywell ("bulb") is thus flooded and the water drains out of it into the basements and steams into the atmosphere through one or more holes (pipes, instrumentation, wiring, end-cap even, maybe). These are probably a bit above the level at which water in the RPV is (the steam in the RPV is pushing down, but not by much).

The good news is that in this scenario fuel is submerged and being reasonably cooled all the way down, including whatever portion of it may have dropped on the drywell floor. The semi-bad news is the water is leaching all sorts of nastyness out.

 

[MadderDoc]

#3 RPV is 205C now, why ?
also only 1,6m water in #1 SFP

Where do you see this data, elektrownik?

 

[elektrownik]

Where do you see this data, elektrownik?

Here: http://www.meti.go.jp/press/2011/05/20110503001/20110503001-3.pdf (last page)

 

[jlduh]

Well, if i look at some data from speedi system, in the North west of Daichi some readings are around 20 to 37 micro SV/h, which is 175 mSv/year to 320 mSv/year if we assume a constant dose, less if we assume some future decay of course, depending on which isotopes is responsible for these values.

http://www.mext.go.jp/component/english/__icsFiles/afieldfile/2011/05/02/1305674_050219.pdf

But note that these values are the ones the 2nd of May so decay of I-131 from early deposits has already happened, and the values are still high. So either these values are from isotopes with much lower decay time (Cs for example) or there has been ongoing deposits.

Again, these values are just radiation data per h, and not real absorbed doses, which again can involved much more complex phenomenon of concentration through ingestion, inhalation depending of what people do, touch, eat, and drink. Alpha and betas doses then have to complete the picture of gamma doses for a complete full understanding of the health effects.

Does the speedi system gives some "projection" of absorbed doses by the way -if somebody found it?

Just a remark: at the end of the pdf there is a page with chart showing comparison between various absorbed doses. Just note that these doses are in microSV/year, so it would be fair to make it easy for people -who are not experts in nuclear matters- reading this page to express the values and the chart in the same unit, don't you think? One french frie is one part of a potato, so it make it strange and useless to compare the two.

Also, i find always a little bit tendancious to just mention that for example Guaripari levels in Brazil are 10 Msv/year (and even higher on the beach sands, but ok let 's say very few are spending one full year on the beach!), without precising that more studies tend to show that the population there (or in other places with high "natural" levels) have higher cancers rates than average:

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B7581-4FJT8MK-13&_user=10&_coverDate=02/28/2005&_rdoc=1&_fmt=high&_orig=gateway&_origin=gateway&_sort=d&_docanchor=&view=c&_searchStrId=1738762424&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=907ad049822bb6f73609384f1368d09b&searchtype=a

http://rpd.oxfordjournals.org/content/early/2010/08/05/rpd.ncq187.abstract

More research has still to be done on this matter i think.

For a long time radon has not been a concern, but now with more an more research it is known to be a serious factor in some areas in France for example.

Explaining that something is not dangerous because it is "natural" is a weak argument. Asbestos is also natural, oil is also natural, and it can be very dangerous depending on where it is in the body of a living organism!

 

[jlduh]

Where do you see this data, elektrownik?

I read 116°C and 135°C for the RPV temps. NO?

EDIT: ok i see the 205°C in the last page. But i don't know what is this specific temp (maybe someone who reads japanese?) as on the sketches of the reactors the two temps indicated are 116 and 135°C...

It is indicated related to RPV but it is also in a "D/W" (dry well) line, so i don't know what it is actually?

 

[Samy24]

#3 RPV is 205C now, why ?
also only 1,6m water in #1 SFP

As I have learned the "skimmer level" is not the water level in the SFP
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110418e5.pdf"

The temperature is rising since the last days, but is still lower than the highest readings in the past. So maybe it does not explode by now ;)

 

[Samy24]

I read 116°C and 135°C for the RPV temps. NO?

EDIT: ok i see the 205°C in the last page. But i don't know what is this specific temp (maybe someone who reads japanese?) as on the sketches of the reactors the two temps indicated are 116 and 135°C...

The 205°C is "RPV bellows seal"