Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[TCups]

TCups,
Do you realize that is a view from the north - the opposite side from which you were previously suggesting the SFP was on.

@AtomicWombat

I stand corrected, sir. The detail picture originally provided as a screenshot and then annotated by me to show what I thought was the shaft, SFP, and something in the SFP is apparently WRONG. The screenshot I annotated matches the north end of the floor of Bldg 3, not the south end, so it cannot be as I annotated it. Sorry for the error. () The pool shown would have to be the equipment pool, not the SFP. I don't know if the equipment pool has a transfer chute and gate.

Post #1760 has been edited with the correction and the annotated photo I first posted there deleted.

 

[RealWing]

I believe we will eventually find that the diesel generator problem originated with the fuel supply. The fuel tanks are outside of the buildings on a concrete pad separate from the building itself. Five minutes of earthquake shaking independent of the building, with fuel sloshing and adding to the forces on the tank/foundation, would stress the fuel supply lines and connections. If the break happened low enough to draw in water it would result in damage to filters, injector pumps and injectors that would consume more time than the golden 8 hours .

A good summary, but I'll offer one correction concerning EDG fuel supplies. Seismically qualified emergency diesel power supplies means that not only is the DG qualified, but so is the building, all piping and electrical equipment etc in the building, all cabling routes into the plant - but also the outdoor fuel supply tanks and all piping and intrumentation needed post seimic event. All of this should have survived the quake.

Now the tsunami is a different issue. Some possible failure modes are:
- the water wave moved the outdoor tanks and sheared off the fuel lines.
- water entered the EDG buildings and damaged some of the equipment - most likely electrical.
The plant was clearly designed for a lower wave height, so I would expect that the designers did not make the buildings watertight.

 

[Reno Deano]

This may well be a naive reaction, but it seems to me that the obvious thing to do with the radioactively contaminated water in the turbine buildings is to pump it back into the reactors. Is there something wrong with that action? If/when they are able to re-establish core cooling, perhaps they could then work on dealing with the water contamination (salt, radioactive elements, etc) and leaks. But until then, why not reuse this water for the evaporative cooling?

Nice idea, but the reactors are now filled (level TEPCO wishes). Pumping the water back would mean removing water from the vessel (remember previous post: do not want the reactor vessel to go solid with water!), and putting it where?

 

[AtomicWombat]

What's the worst case scenario fix, vaporized the whole complex with a nuke?

That is the worst possible "solution". One of the best ways to increase the radiological impact of an atomic bomb is to use it against a nuclear plant, as nuclear plants generally have many times as much radioactive material than nuclear bombs. The radiation doesn't just disappear it turns into dust and vapour and then blows over the nearby landscape.

Or just post a no swimming sign in the Pacific Ocean...

If we could actually dissolve the whole thing in the Pacific Ocean people would hardly notice. The Pacific is so vast that the additional radioactivity would be tiny.

If not, time will be spent for the next couple of decades robotically cleaning up and that is after the situation stabilizes...

Yup, that's my guess. That's essentially what happened after TMI & Chernobyl, although with less emphasis on robots.

 

[Reno Deano]

How do you explain this?

Goldman Sachs Employees Told Not to Leave Japan
http://www.cnbc.com/id/42304574

Simple: Goldman Sachs is removing their gold in sacks to prevent neutron activation of it. The neutron beam story really scared them.

 

[AtomicWombat]

@AtomicWombat

I stand corrected, sir. The detail picture originally provided as a screenshot and then annotated by me to show what I thought was the shaft, SFP, and something in the SFP is apparently WRONG. The screenshot I annotated matches the north end of the floor of Bldg 3, not the south end, so it cannot be as I annotated it. Sorry for the error. ()

That's OK TCups. This is all pretty much a scientific exercise. We each propose hypotheses, offer evidence and then shoot each other down.

Gee I wish I had your screen-capture and picture posting skills. Mine are rudimentary. If I can't copy links I'm lost.

 

[M. Bachmeier]

so we are talking about the rods in the pool

M. Bachmeier,
Tepco did not provide data for the first 12h or so.. Mitsuhiko Tanaka pointed just like you did that the first 12h are crucial to understand what could have happen.. from the initial data he does figure a few thing
Reactor 1 Core vessel at t+12 is at 0.80Mpa donw from 7MPa , First reading of Containment Vessel is at 0.8Mpa (twice the design spec) up from 0.1MPA normal operating pressure.

That's kind of like making my point. Is there nobody on site (at the time) who could backtrack the data toward possible scenarios given their knowledge of the situation at the time. Besides, I'll bet my bottom dollar there was more to the initial data then is publicly known.

 

[Joe Neubarth]

As I understand it, not all the uranium in the fuel rods is 235, though the fuel is enriched to enhance that. Lots will be U 238, which by absorption of neutrons will convert to plutonium 239. So any fuel rods that have seen a lot of use should have a decent fraction of plutonium. So dispersed fuel from the spent fuel pools could elevate the levels of plutonium detected outside - not just the MOX fuel used in #3.

Astro and others, if I am way off base, please say so.

Five percent enrichment with 235.

 

[TCups]

That's OK TCups. This is all pretty much a scientific exercise. We each propose hypotheses, offer evidence and then shoot each other down.

Gee I wish I had your screen-capture and picture posting skills. Mine are rudimentary. If I can't copy links I'm lost.

Get yourself a Mac and it's very easy [Cmd]+ [Shift] +[4] gives a "+" cursor. Drag it over the screen and it takes a PNG snapshot of whatever is on the screen at that resolution. Then just add it as an attachment or drag the screenshot into Preview or Photoshop to annotate. I use Photoshop if I need to reset contrast, level or sharpen.

Only takes a few seconds. For example . . .

 

[AntonL]

here some basic facts to the cooling problem and amount of fuel on site

Unit 1
design 460 MWelect 1380MWtherm
400 Fuel elements in core and 292 in SFP
rest heat day 17 - 2.66MW reactor and about 60kW for pool

Unit 2
design 784 MWelect 2381MWtherm
548 Fuel elements in core and 587 in SFP
rest heat day 17 - 4.59MW reactor and about 400kW for pool

Unit 3
design 784 MWelect 2381MWtherm
548 Fuel elements in core (6% MOX since August 2010) and 541 in SFP (?% MOX)
rest heat day 17 - 4.59MW reactor and about 200kW for pool

Unit 4
design 784 MWelect 2381MWtherm
0 Fuel elements in core and 1331spent +200unused in SFP
rest heat day 17 - 0MW reactor and about 2000kW for pool

Total 14.5MW of cooling required

rest heat assuming 100% load at time of accident
in about 2 months the rest heat would be 50% of above
1MW will boil away 1.41 m3/h of water at temperature of 30 degree

Total 14.5MW of cooling required that is 20.5 m3/hour without overflow and spillage--------------------------------------
under control

Unit 5
design 784 MWelect 2381MWtherm
548 Fuel elements in core and 946 in SFP
rest heat day 17 - 4.59MW reactor and about 700kW for pool

Unit 6
design 1100 MWelect 3293MWtherm
764 Fuel elements in core and 876 in SFP
rest heat day 17 - 6.35MW reactor and about 600kW for pool

 

[AntonL]

Regarding the MOX fuel, I doubt that there is any in the SFP of reactor 3.

Thus any Pu measurements indicate a leakage from unit 3 reactor is this a correct assumption?

Third Japanese reactor to load MOX
10 August 2010
Tokyo Electric Power Company's (Tepco's) Fukushima I unit 3 is set to become the third Japanese nuclear reactor to load mixed oxide (MOX) fuel after receiving approval from the governor of Fukushima Prefecture, Yukei Sato. The unit follows Kyushu Electric's Genkai 3, which started using MOX fuel in November 2009, and Shikoku's Ikata 3, which was loaded with some MOX fuel in March 2010. According to the Denki Shimbun, the 760 MWe boiling water reactor will be loaded with MOX fuel by 21 August and the unit will restart in late September. Japan's Nuclear and Industrial Safety Agency has so far approved the use of MOX fuel in ten reactors, but utilities must also secure approval from prefectural governments before they can go ahead and use the fuel, which contains plutonium recovered from spent nuclear fuel.

 

[ailog]

I have followed this thread and the situation in Japan but am uncertain of what's happening currently. Here are some GENERAL observations and some questions. Please comment to help my understanding.

1. There is presently no coolant circulation whatsoever in any of the reactors 1 thru 4? The rush to get electrical power back on was to no avail because coolant pumps/piping and electrical equipment and controls were damaged beyond repair. Which means that if the emerg. generators had survived they most probably wouldn't have mattered (wrt circulating coolant).

2. Currently the affected reactors are filled with seawater? If the seawater is not circulated and cooled somehow, how does this help the reactor core? Just distributes the core heat? Steam is being made and periodically vented to reduce pressure?

3. If boron is a good moderator, would pumping a slurry of boron into the reactors help?

 

[M. Bachmeier]

Has anyone looked at the potential leaks from the mounts of the dry-well caps 1-3?

I'm sure I've come across more than one reference to effective seating of the cap on older Mark I reactors.

Without guile, is this the primary leak of contaminants?

 

[Joe Neubarth]

I have followed this thread and the situation in Japan but am uncertain of what's happening currently. Here are some GENERAL observations and some questions. Please comment to help my understanding.

1. There is presently no coolant circulation whatsoever in any of the reactors 1 thru 4? The rush to get electrical power back on was to no avail because coolant pumps/piping and electrical equipment and controls were damaged beyond repair. Which means that if the emerg. generators had survived they most probably wouldn't have mattered (wrt circulating coolant).

2. Currently the affected reactors are filled with seawater? If the seawater is not circulated and cooled somehow, how does this help the reactor core? Just distributes the core heat? Steam is being made and periodically vented to reduce pressure?

3. If boron is a good moderator, would pumping a slurry of boron into the reactors help?

1.Once cool enough a massive quantity of water can keep the Reactor Fuel from heating up. The question is where is it?

2. Pressure?

3. Until we find out where the fuel is, Boron in ample quantities to meet water standards is necessary. The control rods with most of the boron in them may still be standing tall. Just because the Zirconium and the Uranium flowed down to the bottom of the reactor does not mean the Control rods did. If they did melt in conjunction with the reactor melt down, the Boron would have dissolved in solution. As they were pumping sea water in by the ton, they probably seriously diluted the amount of boron in the reactor even though they are said to have injected boron at the end of the sea water injection. The sea water injection by itself could have led to limited criticality and reheating of the forming Uranium Lava sufficiently to burn through the bottom of the reactor vessel. I suspect that they made a bad situation far worse. Now that the water has accumulated in many diverse places it has a dilute solution of boron in it, but we do not know for certain where the Uranium fuel is.

 

[razzz]

Press Release (Mar 29,2011)
Plant Status of Fukushima Daini Nuclear Power Station (as of 9:00 am March 29th)[No update from the last release issued at 9:00 pm, March 28th]

Unit Status
1 · Reactor cold shutdown, stable water level, offsite power is
available.
· No reactor coolant is leaked to the reactor containment vessel.
· Maintain average water temperature below 100°C in the Pressure
Suppression Chamber.
2 · Reactor cold shutdown, stable water level, offsite power is
available.
· No reactor coolant is leaked to the reactor containment vessel.
· Maintain average water temperature below 100°C in the Pressure
Suppression Chamber.
3 · Reactor cold shutdown, stable water level, offsite power is
available.
· No reactor coolant is leaked to the reactor containment vessel.
· Maintain average water temperature below 100°C in the Pressure
Suppression Chamber.
4 · Reactor cold shutdown, stable water level, offsite power is
available.
· No reactor coolant is leaked to the reactor containment vessel.
· Maintain average water temperature below 100°C in the Pressure
Suppression Chamber.
Other N.A.

...Have a nice day...

 

[AntonL]

IAEA presentations available here http://www.slideshare.net/iaea/

 

[AntonL]

@AtomicWombat

I stand corrected, sir. The detail picture originally provided as a screenshot and then annotated by me to show what I thought was the shaft, SFP, and something in the SFP is apparently WRONG. The screenshot I annotated matches the north end of the floor of Bldg 3, not the south end, so it cannot be as I annotated it. Sorry for the error. () The pool shown would have to be the equipment pool, not the SFP. I don't know if the equipment pool has a transfer chute and gate.

Post #1760 has been edited with the correction and the annotated photo I first posted there deleted.

https://www.physicsforums.com/attachment.php?attachmentid=33668&d=1301364476

As the SFP is on the south side of the reactor, the steam escaping on the north side (follow link above) could indicate that the containment is breached and steam is not from a boiling SFP pool.

 

[AntonL]

[URL]http://www.asahi.com/national/update/0329/images/TKY201103290240.jpg[/URL]

[URL]http://www.asahi.com/national/update/0329/images/TKY201103290255.jpg[/URL]

The plan is to pump water in outside tunnel/trench into suppression water storage tanks marked by 2 blue dots south of unit 4. Total 6800m3 storage is available in those two tanks but 2800m3 are already stored - so 4000m3 can be pumped from the tunnel/trenches into those tanks.

The table list the maximum volume of the tunnel/trenches before overflowing, but we can see that they are about to overflow by the levels given.

 

[shogun338]

Has anyone looked at the potential leaks from the mounts of the dry-well caps 1-3?

I'm sure I've come across more than one reference to effective seating of the cap on older Mark I reactors.

Without guile, is this the primary leak of contaminants?

This is a good link about the seal that may be leaking a lot of this water around the area. http://allthingsnuclear.org/post/3964225685/possible-source-of-leaks-at-spent-fuel-pools-at This happened at plant Hatch in Georgia back in 1986 and they lost over 140000 gallons of water from the spent fuel pool . Don't trust TEPCO to tell the truth because when this happened at Hatch they told everyone that only 5000 gallons leaked. I live very close to Plant Hatch and fish around it all the time on the Altamaha River .

 

[shogun338]

I have followed this thread and the situation in Japan but am uncertain of what's happening currently. Here are some GENERAL observations and some questions. Please comment to help my understanding.

1. There is presently no coolant circulation whatsoever in any of the reactors 1 thru 4? The rush to get electrical power back on was to no avail because coolant pumps/piping and electrical equipment and controls were damaged beyond repair. Which means that if the emerg. generators had survived they most probably wouldn't have mattered (wrt circulating coolant).

2. Currently the affected reactors are filled with seawater? If the seawater is not circulated and cooled somehow, how does this help the reactor core? Just distributes the core heat? Steam is being made and periodically vented to reduce pressure?

3. If boron is a good moderator, would pumping a slurry of boron into the reactors help?

USA has sent boron to Japan to pump into the reactors . Other countries are also sending it to Japan . http://www.liveleak.com/view?i=d35_1300513133

 

[Soafcom]

Here are a few more images of Reactor 3 from 2011-03-16:

 

[|Fred]

This is a picture of unit 4 showing S/W wall and S/E wall
in Green overlay the operating Floor, in blue the alleged Spebt Fuel Pull
In yellow overlay the floor bellow the operating floor, notice that on this unit 4 the blast seems to have occurred on that yellow floor as well. how do we make sens of that ?

ps: http://www.ustwrap.info/show/iwakamiyasumi
tepco Press conference just started

 

[AntonL]

notice that on this unit 4 the blast seems to have occurred on that yellow floor as well. how do we make sens of that ?[/url]
tepco Press conference just started

If you check all available photos and videos you will see that the fuel loading tunnel to the west of the building is also destroyed. Unit 4 was under maintenance so fire/blast doors, hatches etc would be open that in units 1-3 would have been shut tightly allowing the blast to propagate from roof to basement as is evident in the visual material

 

[shogun338]

This is a picture of unit 4 showing S/W wall and S/E wall
in Green overlay the operating Floor, in blue the alleged Spebt Fuel Pull
In yellow overlay the floor bellow the operating floor, notice that on this unit 4 the blast seems to have occurred on that yellow floor as well. how do we make sens of that ?

ps: http://www.ustwrap.info/show/iwakamiyasumi
tepco Press conference just started

When reactor #3 exploded it caused most of this damage to unit 4 from the reports I have read . Here is a link to the very large explosion at reactor #3 . Reactor #3 is also the reactor that was loaded with the MOX fuel .http://ireport.cnn.com/docs/DOC-573617

 

[AtomicWombat]

This is a picture of unit 4 showing S/W wall and S/E wall
in Green overlay the operating Floor, in blue the alleged Spebt Fuel Pull
In yellow overlay the floor bellow the operating floor, notice that on this unit 4 the blast seems to have occurred on that yellow floor as well. how do we make sens of that ?

Hi Fred,
This is the southern wall of this reactor building. There is an almost identical hole in the northern wall (see my attachment) that has what looked to me like a discharge of corium lava. It may be just melted insulation. I am still unsure. Based on the position of the fuel crane (northern wall), it seems that this melted mass is unlikely to be corium.

I can explain the holes in the opposing sides assuming they are adjacent to the equipment pool (on one side) and the SFP on the other. Hydrogen would accumulate over the SFP. Once it reached the explosion limit the explosion would be strongest there, presumably strong enough to blow out both the SFP containment and the exterior wall.

Reactor diagrams also show that adjacent to the equipment pool the exterior wall is the only barrier to the outside environment. So this would be a weak point.

I find it difficult to explain why so many panels below the operating floor on the east and west side also blew out, especially since hydrogen is a light gas and would not tend to settle deep in the building..

 

[Emreth]

When reactor #3 exploded it caused most of this damage to unit 4 from the reports I have read . Here is a link to the very large explosion at reactor #3 . Reactor #3 is also the reactor that was loaded with the MOX fuel .http://ireport.cnn.com/docs/DOC-573617

We've been over this here, there are images after explosion at unit 3 which shows no damage on unit 4.

 

[AtomicWombat]

Unit 4 was under maintenance so fire/blast doors, hatches etc would be open that in units 1-3 would have been shut tightly allowing the blast to propagate from roof to basement as is evident in the visual material

Seriously? I had no idea these procedures were in place in reactors. It's like a warship or submarine.

 

[jensjakob]

Areva sends 2 experts to Fukushima:
http://english.kyodonews.jp/news/2011/03/81681.html

 

[shogun338]

We've been over this here, there are images after explosion at unit 3 which shows no damage on unit 4.

Why would it explode if it was in shut down mode ? Where is the link to the pics and the explosion of #4 ? I can't find them .

 

[Emreth]

Why would it explode if it was in shut down mode ? Where is the link to the pics and the explosion of #4 ? I can't find them .

This is the image after explosion #3 before #4. I don't think we have an explosion video for #4. #4 had fresh fuel in SFP.
https://www.physicsforums.com/showpost.php?p=3197547&postcount=539

http://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichiov_march14_2011_dg.jpg

 

[|Fred]

When reactor #3 exploded it caused most of this damage to unit 4 from the reports I have read

Please stand corrected, as this statement is not true. see attachment.

This is the southern wall of this reactor building. There is an almost identical hole in the northern wall

Thank you, notice that this hole is located on the floor below the operating floor and notice the way and that the wall still standing on the North on the operating floor.

What doe not make sens to me is that the pool are open to the air and located south.
assuming the watter level droped the hydrogen would have populated the operating floor going up from the pool rather than seeking ways across concrete , if anything it could have some how populated the top of the reactor core vessel.

But the floor bellow the operating floor makes little if no sens ? is there a structure that runs bellow the OP floor North to South on the whole level and is connected to the pool?

 

[shogun338]

This is the image after explosion #3 before #4. I don't think we have an explosion video for #4. #4 had fresh fuel in SFP.
https://www.physicsforums.com/showpost.php?p=3197547&postcount=539

http://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichiov_march14_2011_dg.jpg

Thanks for the pics. I see what your saying now . So just the spent fuel pools leaking most of the water out causes hydrogen to build up in the buildings causing them to explode .

 

[Borek]

What i think is even if there is a catastrophic radiactivity, it will be held confidential for various reasons.

You can buy a radiometer for something like $300 and check the radiation level by yourself, no way contamination can be held confidential.

 

[TCups]

Please stand corrected, as this statement is not true. see attachment.

But the floor bellow the operating floor makes little if no sens ? is there a structure that runs bellow the OP floor North to South on the whole level and is connected to the pool?

Fred:
The link between the open holes on the north and south walls of Unit 4, one level below the top floor, would seem to be the open tops of the SFP on the south and the equipment pool on the north. A blast in the top floor would, transmit a hydraulic shock wave into the pools if they were full of water. If not full of water, then they would be directly connected by air space and still subject to direct damage from the blast.

Consider, though, that if there were still some water in the equipment pool on the north end of Bldg 4, and if the damage were from hydraulic transmission of the shock wave, then that "tongue" of material we initially saw hanging out, whatever it was, may have been carried out by the water that gushed out.

 

[TCups]

Hi Fred,
This is the southern wall of this reactor building. There is an almost identical hole in the northern wall (see my attachment) that has what looked to me like a discharge of corium lava. It may be just melted insulation. I am still unsure. Based on the position of the fuel crane (northern wall), it seems that this melted mass is unlikely to be corium.

I can explain the holes in the opposing sides assuming they are adjacent to the equipment pool (on one side) and the SFP on the other. Hydrogen would accumulate over the SFP. Once it reached the explosion limit the explosion would be strongest there, presumably strong enough to blow out both the SFP containment and the exterior wall.

Reactor diagrams also show that adjacent to the equipment pool the exterior wall is the only barrier to the outside environment. So this would be a weak point.

I find it difficult to explain why so many panels below the operating floor on the east and west side also blew out, especially since hydrogen is a light gas and would not tend to settle deep in the building..

AW:

The picture you attached:
https://www.physicsforums.com/attachment.php?attachmentid=33678&d=1301381377

ls the north wall, and the outward "flow" appearance may be the result of water that gushed through the hole after the blast.

Two things about this picture have always seemed incongruent, though.

1) if the damage to bldg 4 were from an internal blast strong enough to blow that side panel out, then why the heck does the top wall seem to fall inward, not outward?!

2) look at the full length of the vertical column on the NE corner. It is damaged and appears to me to have buckled inward from the concussion of the blast at Bldg 3, doesn't it?

Another question: why don't we have video of the blast at Bldg 4? Did it occur after dark?

Something strange happened at Bldg 4, and we don't have all he information.