Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Gilles]

Sorry, I come here only from time to time (plus jet lag ..) and I may have missed part of the discussion, but it seems that interesting observations can be done on these graphs

http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/v8/Main.html

Obviously explosions happened after the sudden decrease of pressure in React 2 and 3, and most likely 1, probably to the voluntary depressurizing to allow water to flow in the reactor - releasing a huge amount of steam and hydrogen that had been produced very early after the failure of cooling systems. Then in R1 and 3, temperature remained very high (300 or 400 °C) whereas the pressure was only a few bars -indicating that places where temperatures were measured were out of water, and overheated by fuel rods much hotter than the boiling point at this pressure. Probable oxidation and maybe fusion have occurred continuously then. Can it be that the vessels were totally dry at this time ? R2 was steadily around atmospheric pressure and 100 °C - probably boiling water covering the fuel. Around the 20th of March a significative decrease of temperature occured. Is it due to the arrival of fresh water in the vessel - although no variation of water level was recorded, but may be they're measured in the confinement around the vessel - or may be to the melting of upper parts of fuel rods that gathered in the liquid phase, solidifying here ? A new rise of temperature in R2 these last days is worrying - does it mean that water is again very low ?

 

[rmattila]

Thank you Nuceng and Cire for those anwsers, you mention that the drywell (primary containment in concrete if I'm not mistaken) Has been flooded. I've seen this "idea" on the paper written by or for Areva.
But I haven't seen any statement , indications or explanation by the Japanese authorities or tepco that they did so ...
Is is a standard procedure ? how did they get some water there and when..


Early on TEPCO reports indicated that they were injecting seawater into the reactor pressure vessel. My Bad. I misremembered reading that they had been performing containment flood. However looking at the TEPCO updates since 11 March, I cannot confirm that. So my speculation of a steam explosion was invalid. However if melt-throu does occur, the interaction with containment concrete will be revealed by the activation and release of concrete materials.

I will do better job of checking my WAGs.

As far as I have followed the situation, in the early JAIF raports it was mentioned that water injection to core at all units was continuing, water injection to unit 1 containment vessel was "done", and to units 2-3 "to be decided".

In later JAIF reports, up until March 21, water injection to containment vessels 1 and 3 was reported to be "continuing (Seawater)", and for unit 2 "to be decided". On March 22, they changed the status to "confirming" on units 1 and 3 and "to be decided (Seawater)" on unit 2. On the latest releases, the status on units 1 and 3 containment vessel is stated as "to be confirmed".

Based on that mixed information, I'm not sure if anyone outside Tepco has an accurate idea whether water has so far been injected to any of the containment vessels on purpose. It seems that there has been a constant confusion of the terms "reactor pressure vessel" and "containment", with different combinations such as "core containment vessel" etc. being seen in different reports.

 

[AntonL]

Based on that mixed information, I'm not sure if anyone outside Tepco has an accurate idea whether water has so far been injected to any of the containment vessels on purpose. It seems that there has been a constant confusion of the terms "reactor pressure vessel" and "containment", with different combinations such as "core containment vessel" etc. being seen in different reports.

Assuming that heat generated in reactor is only from residual heat from the decay of the isotopes, I have observed that water volume injected is 200% to 400% of water required to boil that heat away.

This leads me to conclude that the indicated flow rates are the combination of
1) Water injection into reactor vessel
2) Water spray in PCV to condense some of the steam generated

that could explain the huge amount of water now being leaked/released into the basements.

According to pressure readings released
reactor vessel: Unit 1 OK as >.3MPa_g high pressure Unit 2 & 3 breached zero and even negative

Primary Containment Vessel - all units OK as high pressure

leads me to believe a controlled discharge of water from PCV into the basement area - naughty naughty especially with below report from two days ago:

Edano said he has received a report that the radioactive substances are assumed to be either condensed steam from the reactor containment vessel or radioactive substances diluted by the water released into those facilities as part of cooling efforts

"released into those facilities as part of cooling effort"
What does that mean !
Surely they know the consequences !

 

[|Fred]

You are in deed right "Water injection to Containment Vessel" is mentioned on the JAIF reports
http://www.jaif.or.jp/english/news_index.php

What is a bit misleading is that the status change from "done" to "confirm" to "to de decided" to "confirming" to "to be confirmed" etc.. in a confusing order as the status is present without logical link to past action like "to be confirmed" rather than "resuming to be confirmed"

 

[|Fred]

Analyse of the day
http://www.meti.go.jp/press/20110330002/20110330002-5.pdf
http://www.meti.go.jp/press/20110330002/20110330002-4.pdf

140La 8.1 10^-2 Bq/cm^3 .. 1.6 days half life ..
132Te 1.8 Bq/cm^3 ...
129Te 21 Bq/cm^3
129mTe 4.1Bq/cm^3
110mAg 3.6 10^-2 BQ/cm^3 They specify a half life of 250 days for this element , what deos "m" stand for Silver 110 half life is suppose to be a few seconds?

 

[havemercy]

According to french IRSN yesterday' release, the people in charge have put sand bags and concrete to prevent the water to flow from the Trench to the ocean :


http://www.irsn.fr/FR/Actualites_pr...Seisme-Japon_Point-situation-29032011-12h.pdf

 

[AntonL]

Analyse of the day
http://www.meti.go.jp/press/20110330002/20110330002-5.pdf
http://www.meti.go.jp/press/20110330002/20110330002-4.pdf

140La 8.1 10^-2 Bq/cm^3 .. 1.6 days half life ..
132Te 1.8 Bq/cm^3 ...
129Te 21 Bq/cm^3
129?Te 4.1Bq/cm^3

As asked earlier:
Tc-99m 6 hour half life -

 

[|Fred]

I think you asked or hoped Tc-99m was a mistake / measuring error.
now we have multiple measuring error, It could indicate that the probability of them not being error, increased.

Quick summary

If we have a reactor core vessel breached immersed into a concrete containment vessel filled with watter but leaking.. where do we go from there ?

If currently off line cooling system managed to be switched on , do we have simultaion of cooling a breached core vessel

If we can not provide additional cooling to the core vessel what are the options ?


I'm reading this 15 years old paper http://www.oecd-nea.org/nsd/docs/1994/csni-r1994-6.pdf .. might provide awnsers

 

[AntonL]

They specify a half life of 250 days for this element , what deos "m" stand for Silver 110 half life is suppose to be a few seconds?

m stands for "metastable". What that means for your isotope is another whole question. Check out http://en.wikipedia.org/wiki/Metastable

Some energetic states of an atomic nucleus (having distinct spatial mass, charge, spin, isospin distributions) are much longer-lived than others (nuclear isomers of the same isotope).

 

[jlduh]

Don't know who is this guy Michio Kaku but even if he is saying what he says in a very dramatic manner (theatral speaking), i have the unclear but deep feeling since some time now that what he is talking about, about this kind of domino effect, cannot just been forgotten or expelled from minds. We saw that every time there is an evolution where more radioactivity is released, this creates huge problems for workers to stay around and continue their work: there has been several evacuations, and with the news about the (very) contaminated water in the basements, this delays even more the process to put in place a cooling process using installed equipment (not to say that it may also just annihilates any possibility to do it this way, and also to get close to the reactor or pressure vessel from the bottom).

So the point is that any worsening of the release of radioactivity (by air through breaches, or by huge amount of water now) pushes a little bit further, meter by meter,the volume around the installations into which worker cannot enter (at least for no more than a given short time) to do the work. This is the big problem with nuclear accidents i think: the source is at the core but it generates more and more repulsive contaminants that creates a problem (increased distance) to attack the problem... at the core! I think it specific to nuclear accident like that, for example a fire even huge, like in Russian forests, is destroying it's own fuel (once it is burnt, it stops) and so the battle is always at the peripheral lines which can be approached to some extent (it is also very meteo dependent ,if rain comes it helps). I see a very different scenario in case of nuclear accidents like this one.

So i think at this point, nobody can for sure reject the idea that IF radiations worsens (gradually or suddenly with for example an other explosion), then the safe or let's say bearable limit (for humans) around the cores will be expanded, the no man's land volume around them will increase and what is saying is that then, this can be an on going process implying that human made operation (including cooling of reactors) could not been done at some point.

Then the domino effect is "possible":from "reactors" to "pools on reactors", then to "common pool on site", then to the "two other reactors on site", then why not two the "second Daini plant which is 12 miles south"?

Every time some human presence is required to maintain one part of the installation "functionning", and that this man cannot stay there because of increased radiation, then this is a possible problem. Except if everything is fully automatic and continue to work without damage (?) or if bio-robots (sacrified men like at Tchernobyl?) are an option in this case?

What I'm just saying is that even if this guy is putting it in words that are a little bit too dramatic to be scientific, totally true, what he is saying cannot just be refuted like that, except if we someone can show that this domino game is NOT possible.

So let's demonstrate it's not possible?

 

[Gilles]

Analyse of the day
http://www.meti.go.jp/press/20110330002/20110330002-5.pdf
http://www.meti.go.jp/press/20110330002/20110330002-4.pdf

140La 8.1 10^-2 Bq/cm^3 .. 1.6 days half life ..
132Te 1.8 Bq/cm^3 ...
129Te 21 Bq/cm^3
129mTe 4.1Bq/cm^3
110mAg 3.6 10^-2 BQ/cm^3 They specify a half life of 250 days for this element , what deos "m" stand for Silver 110 half life is suppose to be a few seconds?

yes, m stands for metastable - excited but somewhat stable nuclear spin states. What I don't know is if the half-life is given for beta decay only or for the some of all decay modes including transition to the stable Ag110 ?

and Tc-99m is produced by the decay of Mo-99, which has a longer half-life of 66 hours - however it should have fairly disappeared if no fission had occurred for 20 days = 480 hours. Looks pretty hot inside.

 

[DrDu]

and again Tc-99m 6 hour half life is detected - I hope measuring error

What's the problem with Tc-99m having 6 hour half life?

 

[jlduh]

Hummmm, is this guy (TEPCO chairman) actually living on another planet?

He added that the No.1 through 4 reactors would eventually have to be shut down for good.

http://www3.nhk.or.jp/daily/english/30_28.html

Does it mean that he had still some hopes that they could be restarted? Damn, if they only could be shut down FOR GOOD, that would be the best news from 2 weeks, especially for the workers on site...

These kinds of "understatements and distortions" of reality bother me and make me feel very angry to say the least. How can we trust people with this kind of language, really?

Ok i know we're getting political. But HE started! Sorry.

 

[jlduh]

Achille's heel revisited...

Kaieda urges safety steps at other nuclear plants

Japan's industry minister has urged power companies across the country to secure emergency energy sources for their nuclear power stations.

Banri Kaieda told reporters on Wednesday that the accident at the Fukushima Daiichi plant was due to a failure to secure emergency electricity and a loss of cooling systems at the reactors.

Kaieda urged utility companies to secure mobile generators as a source of emergency power that can safely cool nuclear reactors, and to ensure water-supply routes for fire engines.

He demanded that the companies confirm emergency steps and conduct drills within a month, or stop operating their nuclear power plants.

Kaieda added that putting an immediate end to operations at nuclear power plants is out of the question, because Japan relies on them for about 30 percent of its electricity.

NHK has learned that 90 percent of the 15 nuclear power stations nationwide, excluding the 2 quake-hit plants in Fukushima, have decided to introduce new emergency power generators, including mobile generators.

Some utilities have already conducted simulations for cooling procedures based on a scenario in which emergency generators have failed to work at their nuclear reactors.
Wednesday, March 30, 2011 16:57 +0900 (JST)

http://www3.nhk.or.jp/daily/english/30_27.html

 

[AntonL]

Hummmm, is this guy (TEPCO chairman) actually living on another planet?

He added that the No.1 through 4 reactors would eventually have to be shut down for good.

http://www3.nhk.or.jp/daily/english/30_28.html

Does it mean that he had still some hopes that they could be restarted? Damn, if they only could be shut down FOR GOOD, that would be the best news from 2 weeks, especially for the workers on site...

These kinds of "understatements and distortions" of reality bother me and make me feel very angry to say the least. How can we trust people with this kind of language, really?

Ok i know we're getting political. But HE started! Sorry.

Please see this in context - even talking to reporters this is an announcement to Tepco share holders which he has to do sometime as responsibility to the shareholders and stock exchange regulations, normal business practice and not because he only realized it today. It also makes decision making for the accident manager easier - no economic pressure to preserve

 

[|Fred]

Depending of the translation he allegedly said that the plant would be decommissioned.. but I guess you never miss an occasion to jump on guns with preconceives opinions based shady data..

Meanwhile I manage to find some other photos from plant released today by A.P.
3 attached and 6 inlined

and some more

 

[wasteinc]

fred , even decommissioned would be the understatement of the decade

We have a huge accident in progress,
we have possible fission continuing (we still can't make out how the "mistake" on the I-134 and the other isotopes came to be)
we have radioactivity around the plant that reaches Chernobylian proportion even though they are trying to hide it ( >1000mSv/h ?)
we have at least one FSP damaged by a falling crane in reactor 3 (hats off to our perceptive radiologist)

and the only thing saving the japanese inland until now is the wind (as the austrian meteorological department reports every day).

I understand it is important to focus on the physics of this event in this forum, but I sometimes tend to think that some people here are more focused than TEPCO is the last weeks. (their "ill" chairman to begin with)

 

[artax]

Excellent photographs Fred, shame the res. isn't higher but still there's a lot to see!
I'm sure Tcups will be scrutinising these like I will when I get some time!

 

[TCups]

Depending of the translation he allegedly said that the plant would be decommissioned.. but I guess you never miss an occasion to jump on guns with preconceives opinions based shady data..

Meanwhile I manage to find some other photos from plant released today by A.P.
3 attached and 6 inlined

and some more

Even the strength of the blast at Unit 3 did not blow out every single wall panel of the floor below the top (reactor access) floor. And the top floor (the top two tiers of columns) is where hydrogen was most likely to accumulate. Not only did the explosion at unit 4 take out every panel on the east and west side of the building of the floor below the reactor access floor (ie, at the same level as the SFP), it also appears to have taken out one south side panel a floor below the SFP (ie, two floors below the reactor access floor) and also, it did much less damage to the roof beam superstructure than did the blast at Unit 3, and it left the north wall of the top floor partially collapsed inward, and it left at least two panels on the east and west sides of the top floor intact. Compare, carefully, the east, west, and south elevation views.

http://nimg.sulekha.com/business/original700/aerial-2011-3-30-1-11-12.jpg

http://nimg.sulekha.com/business/original700/aerial-2011-3-30-0-20-7.jpg

http://nimg.sulekha.com/business/original700/japan-earthquake-2011-3-30-0-50-12.jpg

Great new photos. Lots to ponder.

 

[artax]

So it looks like the blast at unit 4 was much lower down in the building than that of unit three with unit 1 being initiated in the roofspace?
Very revealing images these.
Anyone know if there's video footage of the unit 4 blast?
a few more images here,

http://www.dailymail.co.uk/news/art...huge-amounts-claims-battle-lost.html?ITO=1490

and finally they're using drones, so original images will be far superior.
It looks like there are a lot of manhole covers open, either blown off during the explosion or possibly removed after for measurements of radiation.
But as they are only around unit 4 I suspect blown off during explosion.

 

[timeasterday]

It seems like something is blurred out on just about every photo of reactor 3. Weird - must be just steam at an odd angle.

 

[curious11]

It seems like something is blurred out on just about every photo of reactor 3. Weird - must be just steam at an odd angle.

Reminds me of the blur effect in the Ringu films!

Well spotted, it's a strange looking effect indeed. Unlikely to be steam as it's in the same form in all views shot at different times...

Does it line up with the hotspot in the IR image released previously?

/edit on quick inspection it does indeed line up with the large white spot in the IR. One wonders how far above the temp at white that area actually is.

 

[|Fred]

I forgot to give the full mandatoty credit
In this March 24, 2011 aerial photo taken by a small unmanned drone and released by AIR PHOTO SERVICE, Unit 4, left, and Unit 3 of the crippled Fukushima Dai-ichi nuclear power plant are seen in Okumamachi, Fukushima prefecture, northern Japan. (AP Photo/AIR PHOTO SERVICE)

Here is the picture of the drone

As previously mentioned Japanese officials do have picture taken with a military class drone with resolution allowing to read plates on the car..

Ps: they waited 6 days to release the picture as far as I understand

 

[jlduh]

Well, when you say that Tepco chairman is also talking to shareholders, maybe you are right, but again as a citizen, this way of saying things in its first intervention since the very beginning, and just before apologizing by this typical japanese move of inclination of the body in front of the press, creates a strange feeling in my body. Maybe this inclination is for the shareholders in fact, who knows?

And even if this is for the shareholders AND the victims, i find problematic to put on the same level at the same time the shareholders and the victims. If he wants to give a message to shareholders, he can use private means, send mails or letters, pay some adds in the relevant newspaper, or give an economic press conference. The mix up of these things of various importance is kind of strange to me as i said.

 

[artax]

Reminds me of the blur effect in the Ringu films!

Well spotted, it's a strange looking effect indeed. Unlikely to be steam as it's in the same form in all views shot at different times...

Does it line up with the hotspot in the IR image released previously?

/edit on quick inspection it does indeed line up with the large white spot in the IR. One wonders how far above the temp at white that area actually is.

If it's where the hole is to the south of centre in the roof of the building I'm pretty sure it's where the projectile like lump of heavy (concrete) blew upwards in the video and just pierced through the steel girders. this is where some of the steam is emanating.
Hope we can get full res images!
In fact looking at the 2 trails of debris on the roof of the turbine building (one with hole in it) the two lines of debris are almost parallel, suggesting that the explosion came from two sources, or it had two escape routes.
After re-examining... they do converge (Using the white lines at the very edge of turbine building) but to the north side of the building, not where the blurred area is, and the hole.

 

[AntonL]

It seems like something is blurred out on just about every photo of reactor 3. Weird - must be just steam at an odd angle.

steam over water of SFP

 

[AntonL]

So they were moving fuel in/out of reactor building 4

Check the truck in the tunnel

 

[jensjakob]

This is a very nice picture, since it show the number of panels above the work-floor (and the SFP surface).

Now back to the other analysis of the SPF and blowout.

 

[Astronuc]

Depending of the translation he allegedly said that the plant would be decommissioned.. but I guess you never miss an occasion to jump on guns with preconceives opinions based shady data..

Meanwhile I manage to find some other photos from plant released today by A.P.
3 attached and 6 inlined

and some more

Nice. If those service tunnels are on the same end as the SFPs, then all 4 units, 1-4 have the SFPs on the south side of the building and the equipment storage pool is on the north. The fuel handling machines would have been parked at the south end of the spent fuel pools, and unit 4s refueling could have been over the SFP. If there was fuel debris from SFP, it then should be coming out the south face of the buildings.

 

[curious11]

steam over water of SFP

I think the blurriness is caused more by the fact the debris is slumped into the water. It definitely appears more of a blur than a fade although it could just be down to the low resolution of the images.