Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[robinson]

The brief history of this disaster is replete with avoiding all kinds of data, or at least avoiding sharing it with others. It's no surprise little is known, and speculations are rampant. Real data, modern measuring instruments, the internet, all kinds of things would improve knowledge at will.

 

[jim hardy]

Fuel cask drop. Like a drydock for fuel assembly shipping casks. With all due respect to TCups, his contention that there was a separate small pool for the processing of fuel for shipping, was incorrect. I miss TCups' contributions nonetheless.

might that be the same structure that's sticking up above operating deck on unit 3 at 2:17 in this drone video? or am i seeing crane superstructure?
http://link.brightcove.com/services...E6wO3LtfIeoh6Zb7QdQVJE3mcx&bctid=921494038001

or http://bcove.me/dqtotqon takes one same place.
would put up a frame-grab if i had that skill.

 

[joewein]

might that be the same structure that's sticking up above operating deck on unit 3 at 2:17 in this drone video? or am i seeing crane superstructure?
http://link.brightcove.com/services...E6wO3LtfIeoh6Zb7QdQVJE3mcx&bctid=921494038001

or http://bcove.me/dqtotqon takes one same place.

It's also http://www.youtube.com/watch?v=dV0lRkbMAZM&feature=related", which I find more convenient for looking at still frames in Pause mode.

At 2:17 I just see a view of the east side of the building, with no particularly interesting details.

Did you mean to link to a different video, since this one shows a flyby of unit 4, not unit 3: For example, the reactor cap has been lifted off, with the bolts undone. At 2:49 you see one of the exterior wall segments standing behind the reactor cap.

In unit 3 shots you can usually barely see anything of the 5th floor because it's all covered under rubble. No walls were left standing above that floor level, even the frame collapsed everywhere but the west side.

 

[ernal_student]

I am sorry that on account of having been away I have been unable to help with translation of news reports, etc., lately. I just caught up on the more recent posts and noticed the debate concerning water pollution. Below are excerpts from a recent post that I find particullarly noteworthy (please correct me if I edited this statement in an inappropriate manner).

Concerning Chernobyl:

The Chernobyl number was calculated only for airborne releases. With the (in)famous IAEO iodine conversion method (the conversion factors they used can only be applied for airborne releases btw).

And, concerning Fukushima:

The official, often quoted number, will, even in the future, most likely only contain airborne released. Since the airborne release is finished, the real value of this number won't go up.

Note: the writer modified this later to the equivalent of "the value won't go up significantly".

Fukushima continued:

Water contamination is an entirely different thing. For example there's 140.000 TBq each of C134 and C137 loose in the basements. That's each twice the the size of the Chernobyl airborne release and half of a Chernobyl core's worth of C.
[...]
But water contamination DOESN'T count in official release numbers. Remember this.

I would like to have a second opinion on the assertion that "water contamination DOESN'T count in official release numbers", since it sounds preposterous to me, to say the least. Who is it who officially sanctions such blatant misrepresentation of the facts?

Thank you in advance.

PS: To avoid misunderstanding: I am not attacking the person who posted this; I want to confirm the information. Thank you.

 

[Borek]

I would like to have a second opinion on the assertion that "water contamination DOESN'T count in official release numbers", since it sounds preposterous to me, to say the least. Who is it who officially sanctions such blatant misrepresentation of the facts?

The way I read it contaminated water that is still contained in the buildings is - technically - not released, so there is no reason to count it as contamination outside of the NPP. TEPCO is purifying this water, so there is a chance it will be never released.

At least that's the plan. Wish them luck.

 

[tsutsuji]

[URL]http://www.tepco.co.jp/en/news/110311/images/110703_1t.jpg[/URL]
http://www.tepco.co.jp/en/news/110311/images/110703_1.jpg & http://sankei.jp.msn.com/region/news/110703/fks11070314050002-n1.htm : A hose carrying sea water for cooling at unit 5 had a crack and transformed itself into a fountain. It is only sea water, so there is no radiation. Without cooling the reactor temperature at unit 5 rises by 2.5°C per hour from the initial 41°C at 8 AM. It will reach 100°C within 22 hours, but Tepco is confident it can change the hose by that time.

http://mdn.mainichi.jp/mdnnews/news/20110703p2g00m0dm023000c.html Tepco has announced that the cooling of unit 5 has been resumed.　http://www3.nhk.or.jp/news/html/20110703/t10013939101000.html When cooling was resumed at 1:40 PM, the reactor temperature had reached 47.7°C. Tepco sees the movement of the hose caused by the tides as the probable cause for the crack. Tepco is going to study solutions to prevent the same problem from occurring again.

http://mainichi.jp/select/weathernews/news/20110703ddm001040074000c.html As of 2 July 5 PM the quantity of decontaminated water produced by the water treatment facility had reached 11,170 m³, of which 3580 m³ are desalinated.

http://www.dailyindia.com/show/448693.php The brand new air cooling system at unit 3's spent fuel pool is working fine with a 40 °C temperature in the pool.

 

[clancy688]

Note: the writer modified this later to the equivalent of "the value won't go up significantly".

And even that I modified to "Ups, my statement may have been bogus" - since the official report shows us that there were BIG C137-releases (10% of the whole number) even three weeks after the tsunam.

Regarding the "only airborne releases count":

Let's take a look at the first INES classification (which were also taken as the official release numbers and since then updated): http://www.nisa.meti.go.jp/english/files/en20110412-4.pdf
The first page states

"Nuclear and Industrial Safety Agency (NISA) estimated the total amount of discharged radioactive materials from the reactors of Fukushima Dai-ichi NPS to the air"

Further let's take a look at the INES manual:
http://www-pub.iaea.org/mtcd/publications/pdf/ines-2009_web.pdf
On page 15 it says the following:

Two methods are given for assessing the radiological significance of a
release, depending on the origin of the release and hence the most appropriate
assumptions for assessing the equivalence of releases. If there is an atmospheric
release from a nuclear facility, such as a reactor or fuel cycle facility, Table 2
gives conversion factors for radiological equivalence to
131
I that should be used.
The actual activity of the isotope released should be multiplied by the factor
given in Table 2 and then compared with the values given in the definition of
each level. If several isotopes are released, the equivalent value for each should
be calculated and then summed (see examples 5–7). The derivation of these
factors is explained in Appendix I.
If the release occurs during the transport of radioactive material or from
the use of radiation sources, D2
values should be used. The D values are a level
of activity above which a source is considered to be ‘dangerous’ and has a
significant potential to cause severe deterministic effects if not managed safely
and securely. The D2
value is “the activity of a radionuclide in a source that, if
uncontrolled and dispersed, might result in an emergency that could reasonably
be expected to cause severe deterministic health effects” [5]. Appendix III lists
D2
values for a range of isotopes.

So, where's the problem now? The problem is that NSC, NISA, the government, etc. want everybody to understand the situation. Which includes laymen. You can't give laymen a table of released fission products and expect them to grasp how serious the release now was - since there are isotopes (like Xenon) which have minor impact and others (like Strontium) which are very dangerous.
It would be best to present the public ONE number - the higher the number, the bigger the environmental concern. That's easy to understand, for nearly everybody. For that purpose IAEO invented the I131-conversion. Take the whole release, convert it into one number. That's by no means a measure to cover up big accidents. It's an honest effort in making radiological consequences understandable for the greater public.
But now there's a problem with that iodine conversion. Apparently, the IAEO guys thought that there's only ONE major release path - the aerial release. There's no conversion chart for releases to the sea, only one for airborne releases. And so they only count the airborne numbers...

 

[ernal_student]

The way I read it contaminated water that is still contained in the buildings is - technically - not released, so there is no reason to count it as contamination outside of the NPP

OK, I understand that part. (^^) But some contaminated water has been released by TEPCO into the ocean, some water has run into the ocean on its own, some has seeped into the ground and more is expected to seep into the ground.

Is this not what the disucssion about building underground walls, etc., has been about?
Also the suggestion that solving the ground water contamination problem can wait until later. Why should such contamination not be accounted for? I feel confused.

TEPCO is purifying this water, so there is a chance it will be never released.
At least that's the plan. Wish them luck.

Yes, we all hope they will succeed.

 

[ernal_student]

Apparently, the IAEO guys thought that there's only ONE major release path - the aerial release. There's no conversion chart for releases to the sea, only one for airborne releases. And so they only count the airborne numbers...

I think I understand what you have explained. So if the people who use the IAEO number clearly explain that it is only a minimum value because it does not account for the water pollution, I would find that acceptable - otherwise it would be cheating.

 

[SteveElbows]

Looking at the latest reactor 3 first floor radiation survey, it seems that the robot vacuum cleaning mission did not achieve dramatic reduction in radiation levels:

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110703_01-e.pdf

 

[Joe Neubarth]

'Worriar' vacuum cleaning robot

Cleaning the floor of reactor unit 3

Hummmmmm? So soon, we will find out the status of the fuel rods in SFP3? I still think most of them are there, perhaps in a degraded state. Arnie thinks most of them are gone. Arnie is a far smarter man then me, but I still think I am right.

 

[SteveElbows]

Hummmmmm? So soon, we will find out the status of the fuel rods in SFP3? I still think most of them are there, perhaps in a degraded state. Arnie thinks most of them are gone. Arnie is a far smarter man then me, but I still think I am right.

The cleaning was only to try to reduce the dose that workers will receive when they are installing things such as nitrogen injection equipment in the reactor 3 building, its got nothing to do with the fuel pool level of the building.

 

[Joe Neubarth]

The cleaning was only to try to reduce the dose that workers will receive when they are installing things such as nitrogen injection equipment in the reactor 3 building, its got nothing to do with the fuel pool level of the building.

Thanks for the info. Then, "DRAT!" There are so many theories out there and most of them could be discounted or cleaned up with some sort of survey of the total facility even if it has to be by robots. I think the fuel rods are still there. Some might be melted, but I have not signed on to the Prompt Criticality theory in the fuel pool.

I also think that microsecond later BIG explosion came out of the torus, but that can not be proven until we can shine a light down through the hole in the floor.

 

[Bioengineer01]

Simple, let's check the wind direction and then look for any reports of radiation increases in the region where any fallout should have gone. I may take a few days but will allow us to discard this as a no-event, or maintain it in our list of "inconsistencies" between observations and reported data.

Not sure if anybody followed up on this, but I do see a peak that could be associated with this event, that we discarded as a non-event. Food for thought. Oh, the video that looked like an accident was happening with flashes that looked like fires and explosions and we dismissed as fog and light effects of trucks coming occurred in June 14th.

 

[Bioengineer01]

...I am willing to bet based on running this type of level of complexity projects that the expected date is somewhere after end of June and June 15th was shortest possible date if NOTHING went wrong (something that only a PR or an administrator could think). ...

How well did I do in predicting the actual project completion date? Did I get it right? :)

 

[jim hardy]

It's also http://www.youtube.com/watch?v=dV0lRkbMAZM&feature=related", which I find more convenient for looking at still frames in Pause mode.

At 2:17 I just see a view of the east side of the building, with no particularly interesting details.

Did you mean to link to a different video, since this one shows a flyby of unit 4, not unit 3: For example, the reactor cap has been lifted off, with the bolts undone. At 2:49 you see one of the exterior wall segments standing behind the reactor cap.
...

indeed, that's the video i meant to link and indeed it looks like same one on your youtube link.
http://www.youtube.com/watch?v=dV0lRkbMAZM&feature=related

And yes it's a fly-around of unit 4. Photos of unit 3 deck seem to be held close by Tepco.
At 2:17 unit 3 is in the background, looking toward north-nortwest. Make it fullscreen and pause, its top floor is indeed cluttered with roof beams atop bigger beams. This is the only view i remember seeing that gives a decent look from that elevation. And it's not great.



Trying to get a feel for whether the operating deck got steam cleaned from center out,
and whether the darkening of beams is from heat charring the paint or from deposited soot while the black smoke was coming out.

as others have suggested i think TPTB avoid pictures of unit 3 deck so i try to look at them all. Highest resolution picture is that one of the back of IAEA hardhats looking at it from corner opposite this one.

old jim

 

[Atomfritz]

[URL]http://www.tepco.co.jp/en/news/110311/images/110703_1t.jpg[/URL]
http://www.tepco.co.jp/en/news/110311/images/110703_1.jpg & http://sankei.jp.msn.com/region/news/110703/fks11070314050002-n1.htm : A hose carrying sea water for cooling at unit 5 had a crack and transformed itself into a fountain. It is only sea water, so there is no radiation.

This confuses me.
Do they really expect a makeshift cooling bypass made of plastic tubes for the broken intake pump to last that long?
The text in the linked article suggests so...

(Btw, tsutsuji-san thank you for keeping up with news from Japan!)

Trying to get a feel for whether the operating deck got steam cleaned from center out, and whether the darkening of beams is from heat charring the paint or from deposited soot while the black smoke was coming out.

as others have suggested i think TPTB avoid pictures of unit 3 deck so i try to look at them all. Highest resolution picture is that one of the back of IAEA hardhats looking at it from corner opposite this one.

And this pic was taken long time after explosions. That time the explosion site already looked quite "clean" compared to earlier, less detailed images/videos.
And indeed, not only small debris seems to have been wiped off, larger pieces also. Sometimes I had the feeling that they also may have used the Putzmeister guns for "cleaning" the remains of the roof/top floor.
Maybe this even would make sense, as this would prevent dry dusty debris being eroded and taken away by wind?

And, they seem to be more eager to vacuum the lower floors than to find out what is going on the floors above.

Remember this is sort of a battlefield.
I find it very strange that they didn't attempt to send reconnaissance troops to the higher floors to find out the situation there.
Wouldn't the valuable insights justify to make a recon crew load up 50mSv at one rush?

I really do not understand this. Some other questions are disturbing me also.
Maybe they already did reconnaissance long time ago, just avoiding mentioning the results in the public?
Maybe they entertain us with nice sunny pool pictures from #4 to distract our attention from the other reactors?

And then, wouldn't it be more sensible to find a path that can be paravented with lead walls to make a safe route to the roofs, so they can be cleaned up?
The radiation on the roof floor could be very low, maybe in the order of 1 mSv like on #4 except some (probably lead paravent shieldable) hot spots.
So a worker could work there for more than one, two months before filling up the allowable 250mSv.
Imagine how fast this could be done if thousand workers would work in shifts...

Maybe the accident site would already have been cleaned up if the s**t had happened in the Soviet Union where people are not so panicky about radiation?

 

[Bioengineer01]

I think I understand what you have explained. So if the people who use the IAEO number clearly explain that it is only a minimum value because it does not account for the water pollution, I would find that acceptable - otherwise it would be cheating.

A friend that does PR for a living once told me that PR is the business of telling the truth in a way that people understand what you want them to understand and that rarely coincides with the truth. I have found the release estimates highly misleading all along. Especially if you look at their history from March 12th and on. The scandal that broke out in England about accident information news management may help us understand exactly how this happened.

 

[etudiant]

This confuses me.
Do they really expect a makeshift cooling bypass made of plastic tubes for the broken intake pump to last that long?
The text in the linked article suggests so...

(Btw, tsutsuji-san thank you for keeping up with news from Japan!)



... And then, wouldn't it be more sensible to find a path that can be paravented with lead walls to make a safe route to the roofs, so they can be cleaned up?
The radiation on the roof floor could be very low, maybe in the order of 1 mSv like on #4 except some (probably lead paravent shieldable) hot spots.
So a worker could work there for more than one, two months before filling up the allowable 250mSv.
Imagine how fast this could be done if thousand workers would work in shifts...

Maybe the accident site would already have been cleaned up if the s**t had happened in the Soviet Union where people are not so panicky about radiation?

My impression is that TEPCO is planning to do nothing to the reactor buildings until the covers are in place,
perhaps because they are concerned that the dust from the contaminated structure would be impossible to control. It is not even clear that there is any practical way to do more than neutralize the site with some sort of permanent entombment as the ultimate outcome.

 

[joewein]

It is not even clear that there is any practical way to do more than neutralize the site with some sort of permanent entombment as the ultimate outcome.

It doesn't have to be permanent. You could build a concrete tomb, but with an air lock for future access. It all depends on how long we're prepared to wait, how far robot technology will advance in the meantime and how much it's going to cost.

Eventually robots will be able to do the job, provided there is funding for them. There is really no point in sending in people *now* more than absolutely necessary, if perhaps in 5 or 10 years robots will be available that can do the cleanup work, about whose accumulated mSv doses you don't have to worry as with human workers.

The trouble is, some tasks (such as preventing hydrogen explosions by injecting inert nitrogen) are absolutely necessary to keep the site stable over a number of years. There is no alternative to getting them done now.

The part I don't understand about the nitrogen injections in unit 3 is this: Weren't they able to inject nitrogen in unit 1 *before* they sent in the first crews? They seemed to be able to use existing pipes from the turbine hall to the reactor core. What's different about unit 3? Did those pipes get destroyed in the hydrogen blast?

If the containments are at atmospheric pressure and are assumed to be leaky, presumably any nitrogen injected will displace whatever atmosphere is currently in the containment. Any guesses what this will do to radiation levels inside the reactor building? Seems to me that they need to do both injection and filtered venting.

 

[robinson]

If another large earthquake happens, as well as massive tsunamis, all bets may be off.

 

[etudiant]

If another large earthquake happens, as well as massive tsunamis, all bets may be off.

Absolutely correct.
However, was there not historical records that indicate these size quakes have roughly a thousand year interval between them? So hopefully there is some time before the strains build up enough for another.

 

[Joe Neubarth]

Absolutely correct.
However, was there not historical records that indicate these size quakes have roughly a thousand year interval between them? So hopefully there is some time before the strains build up enough for another.

Remember the quake at Fukushima was far less than the quake out in the Pacific Ocean that created the tsunami. We did not see a 9.0 quake in Japan.

 

[nikkkom]

It is not even clear that there is any practical way to do more than neutralize the site with some sort of permanent entombment as the ultimate outcome.

It doesn't have to be permanent. You could build a concrete tomb, but with an air lock for future access. It all depends on how long we're prepared to wait, how far robot technology will advance in the meantime and how much it's going to cost.

It is not even clear that there is any practical NEED to do more than neutralize the site with some sort of permanent entombment as the ultimate outcome.

What exactly can you possibly want to achieve by cleaning up the site to "green grass" state?

Even after thermal output will fall to levels which can be dealt with air cooling, central parts of these ruins will contain HIGHLY radioactive corium and residue from evaporated highly radioactive water.

This stuff, even if removed, needs to be stored somewhere; and after it is removed, steel and concrete of reactor pit will be radioactive anyway. If you'd want to dismantle the site, you'd need to remove and store them too, as medium-level waste, for many decades.

IOW: dismantling F1 ruins will definitely have astronomical cost, will possibly require some people to absorb a few more rems, and will still require storage for the radwaste.

The better idea, then, is to threat F1 as *the* storage for its radwaste. Total dismantling is not necessary. After 6-12 more months, remove top part of the buildings. Install heap pipes and radiators for heat conduction from ruined reactor cores and their passive air cooling. Fill reactor pit and torus with concrete. Remove fuel from SFPs. Possibly use Fukushima-1 in the future as the dry cask storage site - it will be slightly radioactive anyway for the next 100+ years, people won't live closer than about 5 km to it.

 

[Sorai]

Hello everyone, I just registered. I am not familiar with the format so sorry in advance for any blunder.

Not sure if anybody followed up on this, but I do see a peak that could be associated with this event, that we discarded as a non-event. Food for thought. Oh, the video that looked like an accident was happening with flashes that looked like fires and explosions and we dismissed as fog and light effects of trucks coming occurred in June 14th.

Here is a link to the Japanese Meteorological Agency, with past data from Maebashi City, about 10 Km away from Takasaki City where the CTBTO monitoring station is located:

http://www.data.jma.go.jp/obd/stats/etrn/view/daily_s1.php?prec_no=42&prec_ch=%8CQ%94n%8C%A7&block_no=47624&block_ch=%91O%8B%B4&year=2011&month=6&day=14&elm=daily&view="

And here is a link to the PDF with the data from CTBTO in Takasaki:

http://www.cpdnp.jp/pdf/110701Takasaki_report_Jun25.pdf"

Both links are in Japanese, but hopefully some google translate in the case of the JMA data may be good enough and the CTBTO chart can be consulted without any knowledge of Japanese, I think.

From what I have seen, the peak in June 11 corresponds to rainy weather, 15 mm accumulated during the day, which is the maximum registered during the whole month. The wind direction data seems to be only for the maximum registered, but during June 10 it was South-East and for June 11-12 it was North-West.

 

[joewein]

Do they really expect a makeshift cooling bypass made of plastic tubes for the broken intake pump to last that long?

Perhaps their attention focused so much on Fukushima 1, units 1-4 that unit 5 and 6 (and perhaps Fukushima 2) don't get as much attention as they still deserve. "Cold shutdown" is not a state that you once achieve but that has to be actively maintained.

Units 5 and 6 survived because one of the diesels at unit 6 was air cooled, so losing the sea water pumps didn't kill it. Other than that single diesel, units 5 and 6 still depend on either the grid or truck-mounted generators. I have not heard anything about moves to replace the dead diesels.

The plastic pipe incident shows that the sea water pumps still haven't been restored. The whole "cold shutdown" setup for units 5 and 6 seems very temporary still.

And this pic was taken long time after explosions. That time the explosion site already looked quite "clean" compared to earlier, less detailed images/videos.
And indeed, not only small debris seems to have been wiped off, larger pieces also. Sometimes I had the feeling that they also may have used the Putzmeister guns for "cleaning" the remains of the roof/top floor.
Maybe this even would make sense, as this would prevent dry dusty debris being eroded and taken away by wind?

I doubt they would want to wash contaminated dust onto the surrounding of the reactor building. Unit 3 was the most serious source of scattered highly active debris, because of its unique combination of a large explosion and large amount of radioactivity leaked. Unit 1 had a milder explosion and a lot less radioactivity. Unit 2 had somewhat more radioactive release but a largely intact building. Unit 4 had a smaller explosion and the least amount of radioactive contamination. Removing hotspots of several hundreds of mSv/h was very important for being able to get any work done near unit 3.

And, they seem to be more eager to vacuum the lower floors than to find out what is going on the floors above.

That's because they don't have to go upstairs right now to get the nitrogen injection going, which is their first priority. The heat exchanger for the unit 3 SFP is already hooked up working, which was the primary reason to go upstairs in unit 4.

Maybe the accident site would already have been cleaned up if the s**t had happened in the Soviet Union where people are not so panicky about radiation?

Maybe it would, if you had volunteered ;-)

 

[joewein]

What exactly can you possibly want to achieve by cleaning up the site to "green grass" state?

Even after thermal output will fall to levels which can be dealt with air cooling, central parts of these ruins will contain HIGHLY radioactive corium and residue from evaporated highly radioactive water.

This stuff, even if removed, needs to be stored somewhere; and after it is removed, steel and concrete of reactor pit will be radioactive anyway. If you'd want to dismantle the site, you'd need to remove and store them too, as medium-level waste, for many decades.

IOW: dismantling F1 ruins will definitely have astronomical cost, will possibly require some people to absorb a few more rems, and will still require storage for the radwaste.

The better idea, then, is to threat F1 as *the* storage for its radwaste. Total dismantling is not necessary. After 6-12 more months, remove top part of the buildings. Install heap pipes and radiators for heat conduction from ruined reactor cores and their passive air cooling. Fill reactor pit and torus with concrete. Remove fuel from SFPs. Possibly use Fukushima-1 in the future as the dry cask storage site - it will be slightly radioactive anyway for the next 100+ years, people won't live closer than about 5 km to it.

I don't disagree with your suggestion of using F1 as a dry cask storage site, provided tsunami defenses are beefed up sufficiently first. However, I disagree with leaving the corium in there for longer than a number of decades. This kind of waste needs to be stored for millennia in geologically stable formations, not in a building on a tsunami-swept sea shore never intended to be used for more than 40 years that has already suffered a major accident.

I am not a geologist, but in my opinion the safest storage site for Japanese nuclear waste may not even be found in Japan, which gets 20% of the world's earthquakes (and for that reason alone probably should never have built nuclear power stations in first place). The final storage problem would be solved better through international cooperation. Some countries have more suitable formations than others and if something goes wrong, the radioactive plume will does not stop at national borders and 12 nautical mile zones, as we have found out with Chernobyl and the Fukushima disaster.

 

[tsutsuji]

http://www.asahi.com/national/jiji/JJT201107040042.html At 9 PM on 3 July, The flow of water injected into unit 1 began to slowly decrease from the 3.5 ton/hour flow, although the pump was running normally. At 8:13 AM on 4 July, the flow reached 3 ton/hour, causing an alarm to ring.

Viewing that the cause of the problem might be the presence of a foreign body blocking the water, Tepco temporarily pushed the flow of water to 7.5 ton/hour and this action was successful in achieving the restoration of a 3.8 ton/hour flow at 8:50 AM.

The foreign body is believed to have come from the filtrate water from the dam.

http://www.nikkei.com/news/headline...19490E2E6E2E2E18DE2E6E2E5E0E2E3E39F9FE2E2E2E2 As a consequence of the sea water PVC hose failure yesterday, Tepco plans to change every PVC hose by something stronger. Tepco has yet to check all the locations where these hoses are used, but this concerns mostly the piping between the water treatment facility and the reactors.

In order to prevent the megafloat from pitching, the water must be injected into different chambers to ensure some balance. For that reason, injection was stopped on 3 July while the injection location is being switched to another chamber. It will resume on 4 July afternoon. Did you know that while it is meant to be multi-purpose, the most famous purpose intended for the megafloat was to make an extension to Haneda airport, but it was refused in 2010?

Tepco is installing shields to protect workers from radiations in unit 3's reactor building. The purpose is to be able to start nitrogen injection on 8 July.

 

[NUCENG]

I originally posted this on the TEPCO Management and Government Performance Thread and the Other Political thread. It hasn't generated any discussion there. There was a lot of speculation early on about how much NRC knew. These references are interesting reading because it looks almost like we were as well informed as they were. Also of interest is how their different ideas and speculations mirrored what went on here.

For anyone interested in NRC contacts with Japan in the early days

FYI NRC has responded to FOIAs

FOIA/PA 11-0118, 0119, and 0120

http://www.nrc.gov/reading-rm/foia/japan-foia-info.html

Rough count is way over 1000 pp.

 

[benzyme]

Thanks for that, NUCENG. I was in the habit of checking that FOIA page from time to time, but after a couple months just assumed there would be some kind of "emergency" exception that prevented their release.