Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Dmytry]

Sorry to be a bore but can I bump this. No answers yet and it does seem critical. Do we posses reliable monitors? or is the interpretation of the data more of an art than a science?
(yes the source was ZAMG , but they have changed their data presentation recently so don't forget to add 16 zeros to any figure that appears as X t0 the power 16;-) )

its more of BS than science. Nobody knows. It was blown off to the ocean. There ought to be ranges, of the sort of 5..100 , aka 'nobody got a clue' . Think about it, how do you even estimate this? The outflow of radioactive steam/aerosols/ etc is not known, the radioactivity of it is not known, and the wind is blowing to the sea. The only thing you can do is - simulate the flow of materials by the wind, calculate the factors for monitoring stations on other side of ocean, and then divide the values from those stations by factors. Very inaccurate, but that is the only thing that can be done in this case. CTBTO does this, I believe. Everyone else can't know it at all. They have no data to estimate it from.

 

[|Fred]

@|Fred

This looks about right , point being where we think there was a hole there is concrete
this is a close up of the hole after the explosion .
[PLAIN]http://img12.imageshack.us/img12/17/snapshot20110425222647.jpg

 

[Bodge]

See, reactor 4 was in maintenance, there's no need for these sensors to work.
That you had to alter the url should tell you something.

I can see that the reading is unusual and doesn't fit with the known facts.

Maybe we have an 'unknown unknowns' situation?

Although I'm not sure how you could measure anything so 'hot'...

also, 5 and 6 show closer to 30 Sv/hr in the Drywell, but it fluctuates daily - is there a problem here?

 

[Bodge]

Supposed measurements, in Sv/hr

4/25 _ 4250
4/24 _ 4250
4/23 _ 4250
4/22 _ 4200
4/21 _ 4200
4/20 _ 4300
4/19 _ 4350
4/18 _ 4450
4/17 _ 4250
4/16 _ 4400
4/15 _ 4900
4/14 _ 4850
4/13 _ 4850
4/12 _ 4750
4/11 _ 4900
4/10 _ 5000
4/09 _ 4900
4/08 _ 4950
4/07 _ 4950
4/06 _ 4900
4/05 _ 4900
4/04 _ 5000

http://atmc.jp/plant/rad/?n=4

 

[triumph61]

There is something wrong with #4 sft, science many days there wasnt so big problem, they were injecting 60-70t per day and temperature was stable, now science few days temperature is very hight (80,70,90C) from unknown reason, and now they are injecting 200t of water per day, this is danger becouse building structure could be damaged, #4 sft is very heavy becouse there is so much fuel, ther was many aftershocks, mayby one of theme increase leak from sfp, we don't know...

I found a google spreadsheet. The Water Level on Unit 4 is display. If the Level is correct, i don´t know
https://spreadsheets0.google.com/cc...ZDbX39YK-iFb0Iw&hl=ja&authkey=CP6ewJkO#gid=35

 

[razzz]

A recent german documentation about Chernobyl and Fukushima:

@9:50 -

The German documentary shows that they are still working on Chernobyl with ongoing construction of an off-site huge rolling shield to be placed over ground zero.

 

[triumph61]

Do you want to see some fun info from Reactor 4?

http://atmc.jp/plant/rad/?n=4

5000 Sieverts / hour in the suppresion chamber.

Down to 4250 Sieverts / hour today

N.B. You must alter the site's url to find this info: reactor 4's data is not given a hyperlink.

It is not Sievert- it is mm
https://spreadsheets0.google.com/cc...DZDbX39YK-iFb0Iw&hl=ja&authkey=CP6ewJkO#gid=3

 

[biffvernon]

Chris Busby being as entertaining as ever:

http://www.youtube.com/watch?v=x-3Kf4JakWI&feature=channel_video_title

 

[ElliotLake]

This looks about right , point being where we think there was a hole there is concrete
this is a close up of the hole after the explosion .
[PLAIN]http://img12.imageshack.us/img12/17/snapshot20110425222647.jpg[/QUOTE]
Lurker with first question: how is it that the edge of the opening on right hand side is so very clean and sharp
--yet appears to have rebar curled back from it?
Or are those shadows from above, and a doorframe unmarred by the explosion?

 

[biffvernon]

This account of the 11th March contains a few useful bits of information gathered toghether.

http://www.bloomberg.com/news/2011-04-25/japan-s-terrifying-day-saw-unprecedented-exposed-fuel-rods.html

 

[MadderDoc]

To people drawing squares on the wall of Unit #4: beware that the floors inside do not have the same height.

The floors inside do probably not have the same height, however the upper three stock wall structural elements and with them the wall panels of the east wall of unit 4 do appear to me be of about the same stock-height and width.

The hole would be within the lower part of the structural element of the east wall, which I would call row3 column1. On the closeup produced by THawk of the lower part of this element (see attachment) it appears looking into it, that we have a horizontal floor structure somewhat elevated over the base of the wall element, confirming what you are saying.

Via the putative hole, according to my measuring stick one might be able to gain access to areas above as well as below that floor. And I reckon that would mean: gaining access to more or less the complete outside of the thick concrete walls surrounding the -- presumably stainless steel lined -- spent fuel pool inside.

The 3nd floor is level with the roof of the building in front, and its ceiling is very low, just matching the height of the "hole". In the post-explosion pics, the "hole" is all but hidden behind a pile of rubble from the façade. the 4rd floor is slightly taller, the two rows of panels on the service floor (5th) taller still.http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/povray/blueprint/un3_building_cut_N_2.png

Edit: fixed the floors above (3rd and 4th)

Thanks for the caveats, Jorge. I believe you must be speaking from the drawings of unit 3. in which the upper three floors from the top have heights of 7.90 m, 7.90 m, and 7.62 m. We can't be certain that unit 4 is quite the same, but so far I've not spotted any significant difference.

 

[jlduh]

Very interesting article Biffvernon. Concerning the generators, some details are given and assumptions already discussed here confirmed: most of them were in the BASEMENTS.

http://www.bloomberg.com/news/2011-04-25/japan-s-terrifying-day-saw-unprecedented-exposed-fuel-rods.html

“Most are located in generator rooms in basement 1 of the turbine buildings,” Arai said, pointing to a diagram in a Tepco brochure of the Dai-Ichi plant. The turbine buildings holding eight of the generators are about 140 meters from the seafront, another two generators were on the ground floor behind reactor 4, which was offline for maintenance. Three others were in and around reactor 6, which was also offline.

But an other information is kind of interesting also:

Seawater flooded the basements of turbine buildings and other sites, disabling 12 of the 13 back-up generators and destroying electrical switching units. Salt water shorted electric circuitry, depriving the reactors of power for cooling and triggering a nuclear disaster that Tepco was forced to combat with fire hoses and makeshift pumps.

“The level of flooding differed by building, but it was as high as 1.5 meters in one turbine room,” said Hikaru Kuroda, chief of Tepco’s nuclear facility management group.

So if this is confirmed, and as i personally imagined it based on the layout out of this basements, that seawater actually flooded the basements of the turbine buildings. Which means that a certain volume of the water that has been reported on site (contaminated then, of course) was in fact from the tsunami.

This is important in my opinion because if this confirms to be true, then it means that the figures we got concerning the "highly contaminated water" in the basements, when it was reported, were probably in fact the result of a dilution of the cooling water leaking from the reactors(with even higher contamination levels I am my opinion) into uncontaminated seawater from the tsunami resting in the basement after the wave withdraw.

I'm not sure that this picture was clear for everybody so that's why i enlighten it. Do others share this analysis?

 

[NUCENG]

Great thread! Long time lurker and first post.

Nice hack! Why are #5 & #6 so high? (up and down)?

Great finding & explanation!

This is just one more anomaly for unit 4. The core was offloaded into the SFP. If the reactor cavity was drained for the core shroud replacement and the gates to the spent fuel pool failed or leaked contaminated water would have drained from the spent fuel pool into the RPV and reactor cavity. However if the refueling belows and manhole are intact the water should not have drained into the drywell proper. To get to the suppression pool, it has to be filling the drywell to the point it overflows down the Drywell to Torus vent pipes to the suppression pool. For the torus to be that hot we should be offscale high on site from the spent fuel pool.

 

[Caniche]

Just a very simple question regarding methodology .
At what point does existing fallout from tests/accidents become "background radiation"
How far has "background" radiation increased in the last 50 years ? (as opposed to "natural " background radiation ,which seems to be confused and combined.)

 

[WhoWee]

Lurker with first question: how is it that the edge of the opening on right hand side is so very clean and sharp
--yet appears to have rebar curled back from it?
Or are those shadows from above, and a doorframe unmarred by the explosion?

Some of the lines appear to be shadows.

 

[MiceAndMen]

That's a mighty fine catch you have there, mate. They come very handy. EW _and_ NS sections of unit 3! On leafing further through the Tepco documents, I find there's a schematic floorplan of the service floor of unit 3 on page 28 in this pdf (see also attachment below, with the schematic tentatively x/y scaled):

http://www.pref.fukushima.jp/nuclear/info/pdf_files/100805-6.pdf​

A very nice find! I think we have the MOX fuel experiment in Unit 3 to thank for many of those documents.

For anyone who wants to do some spelunking (potholing), the following page has links at the top (above the first 3 pictures of buildings) that lead to collections of PDFs relating to nuclear power in Fukushima Prefecture. Google's translation service helped me to navigate through much of it.

http://wwwcms.pref.fukushima.jp/pcp_portal/PortalServlet?DISPLAY_ID=DIRECT&NEXT_DISPLAY_ID=U000004&CONTENTS_ID=10739

 

[PietKuip]

Very interesting article Biffvernon. Concerning the generators, some details are given and assumptions already discussed here confirmed: most of them were in the BASEMENTS.

http://www.bloomberg.com/news/2011-04-25/japan-s-terrifying-day-saw-unprecedented-exposed-fuel-rods.html

Why do they put generators in the basements and spent fuel in the attic?

So if this is confirmed, and as i personally imagined it based on the layout out of this basements, that seawater actually flooded the basements of the turbine buildings. Which means that a certain volume of the water that has been reported on site (contaminated then, of course) was in fact from the tsunami.

This is important in my opinion because if this confirms to be true, then it means that the figures we got concerning the "highly contaminated water" in the basements, when it was reported, were probably in fact the result of a dilution of the cooling water leaking from the reactors(with even higher contamination levels I am my opinion) into uncontaminated seawater from the tsunami resting in the basement after the wave withdraw.

I'm not sure that this picture was clear for everybody so that's why i enlighten it. Do others share this analysis?

I agree. Those "puddles" were probably diluted. But it is difficult to guess by how much - a factor of 2 or a factor of 100?

 

[MadderDoc]

Lurker with first question: how is it that the edge of the opening on right hand side is so very clean and sharp
--yet appears to have rebar curled back from it?
Or are those shadows from above, and a doorframe unmarred by the explosion?

They are not shadows from above (see attachment with another zoom in).

I think what you see is just how the building is built: steel reinforced concrete pillars and vertical girders producing a skeleton of rectangular fields, and to this skeleton plastered to its outside, a layer of rebar reinforced concrete. In case of an internal explosion, this outer layer tends to be blown away and apart where it is not protected from the inside, by the pillar girder structure. Therefore I'd say the very clean and sharp right hand side (except for the rebar!) is not a doorframe, is just the right pillar of that rectangular field.

Anyway, the apparent hole we have been looking at does not extend as far as to the right pillar you are looking at. If there has initially been a doorframe at the right side of the hole, then surely it is now completely gone, blown away by the later explosion.

 

[PietKuip]

Just a very simple question regarding methodology .
At what point does existing fallout from tests/accidents become "background radiation"
How far has "background" radiation increased in the last 50 years ? (as opposed to "natural " background radiation ,which seems to be confused and combined.)

Total ionizing radiation is hardly higher than 50 years ago. The natural internal radiation is due to potassium-40 and carbon-14 (which actually has gone down because of burning fossil fuel).

But most other radioactive isotopes in the environment are man-made. Their natural level is essentially zero.

 

[jlduh]

At what point does existing fallout from tests/accidents become "background radiation"

very good question indeed... I asked it myself several times when i heard sentences like "this is lower than natural background" (sure you heard it already ;o))

Well, i guess that after a certain memory time, artificial can become natural...

Pietkuip, concerning "basement and attic" architecture, i think Joe Neubarth already got the right answer here: "APS" or Aboslute Pure Stupidity...

Back to my remark about very probable dilution by residual seawater from tsunami (which factor is the question) of the first flows of contaminated cooling water leaking from reactors into the basements: this is important to consider for the analysis of I-131 levels/decay because as the volumes are now being pumped to the waste facility, the new leaking water in the basement could very well exhibit higher contamination levels (or levels not properly decaying) just because the initial dilution by this resting seawater is no more acting of course. This could be an alternate and simple explanation to why the decaying is not showing as it should be, even without re-criticality...

Just an idea to keep in mind, maybe?

 

[Dmytry]

Why do they put generators in the basements and spent fuel in the attic?

Because the control rooms etc, power lines (to reactor from turbine hall) are on the bottom, and the fuel is taken out of reactor from the top? Looks like cheapest placement. A lot of extra machinery to get fuel to the bottom.

 

[Pheesh]

Total ionizing radiation is hardly higher than 50 years ago. The natural internal radiation is due to potassium-40 and carbon-14 (which actually has gone down because of burning fossil fuel).

But most other radioactive isotopes in the environment are man-made. Their natural level is essentially zero.

To add to this:
http://en.wikipedia.org/wiki/Low-background_steel

 

[Caniche]

.

But most other radioactive isotopes in the environment are man-made. Their natural level is essentially zero.

:) If only we could train those sheep to just eat the organic stuff

 

[MadderDoc]

This looks about right , point being where we think there was a hole there is concrete
this is a close up of the hole after the explosion .
[PLAIN]http://img12.imageshack.us/img12/17/snapshot20110425222647.jpg[/QUOTE]

I don't agree,
I admit that in this photo the thin yellow line with which I have indicated the position of the pre-explosion hole has been extended below the red line at the bottom, but I am painfully aware that's from _imagination_, I have seen no visuals indicating that the putative pre-explosion hole actually did extend below the lower boundary of the hole after the explosion.

Where I have _reason_ to think there may have been a hole before the explosion, there is now just a (larger) hole.

[URL]http://gyldengrisgaard.dk/fuku_docs/unit4preexplosionhole_ext.jpg[/URL]

 

[razzz]

From the closeup, they didn't even use small #3 rebar in this knockout panel, they used wire mesh (which is like smooth large wire, sometimes spot welded at intersections) probably preformed/preshaped, stood up, and secured/spaced on the forms before pouring concrete. That smooth faced vertical, looks typical when you look at enough of the remaining verticals also separated from their adjoining walls/panels. Remember the exterior blue and white clouded walls were meant to separate in an explosion and they did and were designed to not disturb the vertical and horizontal main-framing when they depart. If there was framing for a door or something else was going on, I'm sure we'll get that answer eventually.

Compared to Chernobyl, in the long run, you can see why it is important to stop uncontrolled groundwater intrusions from carrying off contamination or possibly interacting with what's ever left of the cores. Chernobyl is still threatened by groundwater seepage (maybe also rain water) finding the corium and causing reactions, this current disaster you might start worrying every time high tide occurs.

An attempt to build an underground perimeter watertight wall to bedrock encircling all 4 units wouldn't surprise me. From there you could build an enclosure to further isolate the units provided you get cool down and Unit 4 pool doesn't collapse and make the area unworkable.

 

[RealWing]

This account of the 11th March contains a few useful bits of information gathered toghether.

http://www.bloomberg.com/news/2011-04-25/japan-s-terrifying-day-saw-unprecedented-exposed-fuel-rods.html

Of particular interest is the comments about the radiation levels on site:

"On two occasions radiation levels at Dai-Ichi reached 1 sievert an hour" (100 R.hr)!
(I recall that they had to evacuate the site on 2 occasions - I now see why!)

"Linked by a hot line to Tepco headquarters in central Tokyo, the three-story, white bunker had extra-thick walls and two filtration systems designed to keep out radiation. It was to become their new home."

"When the No. 3 reactor housing exploded on the morning of March 14, levels inside the bunker jumped as much as 12-fold, he said, checking dates and times in a pocket diary."

So - what is the source for these very high levels? One possibility is from a quantity of spent fuel (from the SFP's) being blown into the air during the explosions? Another is from the large cloud of radioactive gasses? I hate to think it might be a criticality event - but maybe should add it to the list?

Other possibilities??

 

[mscharisma]

... So - what is the source for these very high levels? One possibility is from a quantity of spent fuel (from the SFP's) being blown into the air during the explosions? Another is from the large cloud of radioactive gasses? I hate to think it might be a criticality event - but maybe should add it to the list?

Other possibilities??

Was actually wondering: are any of you keeping a list of unresolved questions? You know, for example, cause of the explosion/fire in #4, isotopes on the highly radioactive concrete piece, source of radiation jump in bunker, etc? I'm thinking it might be useful given that some info get to us so much later, or can you still "connect the dots" even without such a list?

 

[WhoWee]

They are not shadows from above (see attachment with another zoom in).

I think what you see is just how the building is built: steel reinforced concrete pillars and vertical girders producing a skeleton of rectangular fields, and to this skeleton plastered to its outside, a layer of rebar reinforced concrete. In case of an internal explosion, this outer layer tends to be blown away and apart where it is not protected from the inside, by the pillar girder structure. Therefore I'd say the very clean and sharp right hand side (except for the rebar!) is not a doorframe, is just the right pillar of that rectangular field.

Anyway, the apparent hole we have been looking at does not extend as far as to the right pillar you are looking at. If there has initially been a doorframe at the right side of the hole, then surely it is now completely gone, blown away by the later explosion.

A few shadows are visible.

 

[NUCENG]

Was actually wondering: are any of you keeping a list of unresolved questions? You know, for example, cause of the explosion/fire in #4, isotopes on the highly radioactive concrete piece, source of radiation jump in bunker, etc? I'm thinking it might be useful given that some info get to us so much later, or can you still "connect the dots" even without such a list?

That's a good idea. I wonder if there is a way to do that so it is avilable for reference without searching through over 5000 posts. Maybe Borek or Astronuc can help us find a way to do it.

 

[Astronuc]

Was actually wondering: are any of you keeping a list of unresolved questions? You know, for example, cause of the explosion/fire in #4, isotopes on the highly radioactive concrete piece, source of radiation jump in bunker, etc? I'm thinking it might be useful given that some info get to us so much later, or can you still "connect the dots" even without such a list?

Ultimately it comes down to:

1. How much and what fuel was damaged, and to what extent, in units 1, 2 and 3?

2. How much and what fuel was damaged, and to what extent, in Unit 4 SFP?

3. What damage is there to the containment structures of units 1, 2, 3 and 4?

4. What damage is there to the RPVs, feedwater systems, and all related piping systems of Units 1, 2, 3 and 4?

We won't know the answers until 1) the fuel is removed, 2) the contaminated water is removed from the containments, and 3) the containments are decontaminated sufficiently to inspect with high resolution cameras, if not in person.