Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[jlduh]

TCUPS:

The "stuff" in the SFP3 may be the fuel handling equipment on top of the rods.

Do you talk about what I identify on what looks like the cover of the pressure vessel?

To Justguessing: based on the position where it is on the picture, it cannot be -for sure- the part where there are "rings on the vessel". Because it would mean the vessel is heavily tilted towards the external wall, which i don't foresee based on the layout of the building...

http://www.netimago.com/image_184761.html

 

[83729780]

groundwater containing radioactive iodine 10,000 times the legal threshold . . . The contaminated groundwater was found from around the No. 1 reactor's turbine building

According to the government's nuclear safety agency, the radioactive iodine-131 at a concentration
of 4,385 times the maximum level permitted under law has been detected in a seawater sample
collected Wednesday afternoon near the plant, exceeding the previous high recorded the day before.

how can the levels in the open ocean be almost half as much as the levels in a puddle?

 

[Astronuc]

We've been taking some air samples here in Finland, with preliminary results suggesting Cs-134/137 activity ratios of the order of 1,05. Having no idea of what kind of core design they are using at Fukushima, we made some rough calculations of isotopic concentrations of "typical" BWR assembly at different void histories (see example below).

What we're hoping is to try to see, if it would be possible to estimate the extent of core damage based on isotopic ratios of nuclides from different samples. Like, if it would seem that the measured isotopic ratios correspond to the void history in the top of the core rather than the core average, or the burnup in the most powerful assemblies vs. core average etc.

I wonder if anybody else is doing anything similar, and if someone would have better information on the fuel/reload strategy used in the accident reactors.

Based on the attached and assuming 1/4-core reload for unit 1, it has 4 batches with 148 days of operation since 15-Oct-2010. The batch size could be more like 104 up to 120 or so. If it was 1/3 core reload, the batch size would be about 132 assemblies. But they have a low duty and CF. Outage was 25-Mar to 15-Oct.

Data for Unit 2 indicate a discharge of 116 assemblies, which would indiate ~1/5-core reload. Outage was 16-Sep to 15-Dec-2010, so it is 87 days into the current cycle.

Unit 3 data indicate a discharge of 148 assemblies. The outage was from 19-Jun to 25-Oct-2010, and it was 137 days into current cycle.

It's complicated because of the low availability and relatively low CF depending on the unit.

If one assumes about 10 GWd/tU assembly average burnup in each of 3 cycles and about 8 GWd/tU in the fourth, that would be in the ball park. One would have to pro-rate the current cycles.

 

[TCups]

TCUPS:

Do you talk about what I identify on what looks like the cover of the pressure vessel?

To Justguessing: based on the position where it is on the picture, it cannot be -for sure- the part where there are "rings on the vessel". Because it would mean the vessel is heavily tilted towards the external wall, which i don't foresee based on the layout of the building...

http://www.netimago.com/image_184761.html

I see what justguessing is referencing. Yes, if the top of the entire primary containment is in that location, the north west corner of the structure, then there is MASSIVE damage to and displacement of the primary containment, and I believe, a much different picture would have emerged regarding the core contents of Unit 3.

I cannot independently confirm that the crane fell on the adjacent building. One report I read said so. Certainly, it appears something heavy probably fell on it.

One of the north-south rails for the overhead crane can still be seen in the middle of the two tiers of the erect structural columns on the east side of bldg 3. In fact, it probably supported them and kept them upright after the blast(s). The other rail from the west side is still attached to the columns, which have fallen, en bloc, to the ground immediately adjacent to the west wall. The north side of the top floor has been demolished, consistent with a crane being blasted to the north or to the north wall collapsing and dumping the crane out the north side or some combination of those forces. I see "something" in the debris, but I am hard pressed to say it is the overhead crane. If it is, however, and if it straddles the middle of the building (which I doubt) then it would again seem to prove that the plug did not blast upward from the location of the top of the primary containment, IMO.

I do find it likely that the structure on the west side is the end of the overhead crane.

 

[razzz]

I come up with a minimum of 350 tons of uranium needed to load these 4 reactors not counting extra or excess rod assemblies in various states (new and/or used) stored in proximity i.e. Unit 1,2 and 3 spent fuel ponds or whatever other basement broom closets they might be stored in.

How much potential heat in 350 tons of uranium?

 

[Joe Neubarth]

The top right corner of the 10:12:11 image look like the rings of the vessel to me.

The scale of the actual reactor to that debris is way off by a magnitude of four or five.

 

[shadowncs]

Cut from aerial-2011-3-30-0-20-11.jpg - I think it clearly shows the round outline of PRV from unit 4, to the east side of the building.
Wouldn't it make sense to be in the same position in unit 3? Roughly where lots of steam is seen in the same picture over reactor 3
Shot is from March 20.

https://www.physicsforums.com/attachment.php?attachmentid=33804&stc=1&d=1301595313

https://www.physicsforums.com/attachment.php?attachmentid=33805&stc=1&d=1301595313

Edit: don't know how to thumbnail them

 

[razzz]

how can the levels in the open ocean be almost half as much as the levels in a puddle?

It's possible some of the core(s) found a way route to bedrock or their contamination did besides following the overflow channels leading to the sea.

 

[jlduh]

To shadowncs: Yes you are right and this has already been discussed in one of the numerous pages of the thread. The axis of the reactor is in the middle of the building from North to South axis, but it is not in the middle of its building in the East West axis: it is shifted toward the East, the sea and the turbine building.

I repost this drawing that i captured on NHK, it shows it pretty well: it is shifted because the east part of torus is in fact below the connection building which links the reactor building and the Turbine Building.

http://www.netimago.com/image_184770.html

The building N°3 was smoking at one time from two places: above the SFP on the south side, and above the reactor axis defined at the position you describe.

 

[jlduh]

Just for info: it seems the french IRSN is no more publishing any daily report... The last one is from 29 th of March!
http://www.irsn.fr/FR/Actualites_presse/Actualites/Pages/201103_situation_au_japon.aspx#1

WHY?

 

[jensjakob]

Gents,

Inspired by TCups and armed with the new images, I looked at #3, wondering about the possible fuelrods.

Please see attached image.

FR's could easily have been in the equipmentpool, at the NE corner.

A hydrogen explosion could have blasted towards NW.

Take a look at the arrow I drawed, review the pictures, and give me your thoughts.

The truth is out there

Jens Jakob

 

[DSamsom]

No Idea, How much has the pressure increased or how quickly is it rising, and where are they measuring it... the last I heard (Wiki) they thought 1,2 and 3 had cracks in the containment, or was it the pressure vessel I just read.
Anyone know how high the reactor buildings are...(were!) I want to work out how high that concrete went in the blast at number 3.

Here's the graph of reactor-parameters of Unit 1: http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/v3/plot-un1-full.png

Core pressure is now at its highest point since March 11th, >600 kPa. Not a level that a BWR pressure vessel is very used to.

 

[TCups]

THE CRANE DID NOT FALL ON THE ADJACENT BUILDING

The earlier report of damages that the crane had fallen from unit 3 are incorrect. I stand corrected and I am now convinced that I see the entire crane structure, under the roof girders, and over the area of the concrete plug of the primary containment of unit 3. Thanks for pointing that out.

http://i306.photobucket.com/albums/nn270/tcups/DrywellTorus.jpg

 

[Astronuc]

Here's the graph of reactor-parameters of Unit 1: http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/v3/plot-un1-full.png

Core pressure is now at its highest point since March 11th, >600 kPa. Not a level that a BWR pressure vessel is very used to.

The reactor pressure vessel (RPV) normally operates at an internal pressure of 1055 psia (7274 kPa) with 101 kPa outside! The containment is design to hold about 400 kPa, but should be capable of more.

The design pressure for the RPV is about 8.9 MPa = 8900 kPa, and the hydrostatic test pressure is about 1.3 times design or about 11.6 MPa (11600 kPa).


FYI - http://www.ansn-jp.org/jneslibrary/npp2.pdf

 

[hbjon]

I come up with a minimum of 350 tons of uranium needed to load these 4 reactors not counting extra or excess rod assemblies in various states (new and/or used) stored in proximity i.e. Unit 1,2 and 3 spent fuel ponds or whatever other basement broom closets they might be stored in.

How much potential heat in 350 tons of uranium?

That is more than you can shake your baseball bat at. I like to imagine those u235 atoms as miniature pitching machines stuck on high. The molecule h2o is the catchers mit.(boron is a bigger mit). If the ball beans the batter in the mellon, tempers heat up and everyone loses their cool.

 

[AntonL]

Here are the results of sub drain water samples - this really does not look good
Limit I-131 4E-2 ---> Thus Unit 1 x 10000 as https://www.physicsforums.com/showpost.php?p=3221378&postcount=2222"

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110331e18.pdf

 

[jlduh]

EDIT:

The design pressure for the RPV is about 8.9 MPa = 8900 kPa, and the hydrostatic test pressure is about 1.3 times design or about 11.6 MPa (11600 kPa).

oups you are right Astronuc, i mixed up also with the containement normal design pressure. Sorry.

To TCUPS and all: I confirm that what i identified in a previous post as something like the yellow cover of vessel of reactor n°3 doesn't fit further investigation; its size is to small by around 40% (compared to cover of reactor 4 that we see from the roof) and the other views don't confirm the round shape...

The top view seems to confirm as you say that the roof structure that stays in the middle on No3 is hold by what looks to be the crane, just above the reactor axis. So it would mean that:

1- the crane is still there
2- the plug and the covers are still there (but leaking around)

These Hi RES modify a little bit what what we were thinking.

 

[razzz]

Based on the attached and assuming 1/4-core reload for unit 1, it has 4 batches with 148 days of operation since 15-Oct-2010...

Mr. Astronuc, I had my socks and shoes off trying to figure the possible amount of uranium involved while you were posting your figures so I didn't see it. Now that I see it, your attachment more than doubles my amount of known uranium involved between the 4 reactors. I understand some fuel is in various stages of decay thus less potent and I by no means what to understand the inter-workings of a nuke plant but was just trying to get a idea of the energy that could be released esp. in case of fire.

Your pic with totals seems high. Do they really have that much stored in spent fuel ponds? Did Unit 4 actually have those amount of assemblies already loaded?...At least as far as you know.

 

[jensjakob]

So, that could be why radiation in the ocean just goes up and up.

This is IMHO the exits from the turbinebuilding where coolingwater normally exits.

There should be no movement there. But it looks a lot like there is a flow out of these 2 ports, and on the ocean surface a slight oily discoloring is visible.

 

[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

Your pic with totals seems high. Do they really have that much stored in spent fuel ponds? Did Unit 4 actually have those amount of assemblies already loaded?...At least as far as you know.

Unit 4 has 1331 in SFP plus 200 newly delivered brand new units - reactor is unloaded
I also included my earlier post which estimate the heat load

 

[timeasterday]

THE CRANE DID NOT FALL ON THE ADJACENT BUILDING

The earlier report of damages that the crane had fallen from unit 3 are incorrect. I stand corrected and I am now convinced that I see the entire crane structure, under the roof girders, and over the area of the concrete plug of the primary containment of unit 3. Thanks for pointing that out.

http://i306.photobucket.com/albums/nn270/tcups/DrywellTorus.jpg

Yep, that's what I was seeing too. You can also see the same crane in shots of #4.

 

[Ms Music]

I decided to take some time today to examine the flyby video, and the drone pictures posted. It appears to me that the area with the "shiny rebar" is on the north side of the northwest corner of reactor building 3. Am I correct? (starts after 45 seconds -to 60 seconds)

http://www.youtube.com/watch?v=z9fKtXDaQVc"

Which now seems to be completely empty of rebar?

http://cryptome.org/eyeball/daiichi-npp/pict7.jpg
[/url]

People had speculated this was fresh fuel, so I assumed it would have fallen out of 4. But now it appears it came from 3? Is there any reason fresh fuel would have been in the north west portion of 3?

I know this is all speculation, but I am very confused. If it was rebar, it should still be there... It appears it has been cleaned up.

If it WAS fresh fuel, is it a hazard to workers?

Sorry if this was gone over previously, I have a tough time keeping up with this VERY busy thread. Thankful for all the people here!

 

[rmattila]

If one assumes about 10 GWd/tU assembly average burnup in each of 3 cycles and about 8 GWd/tU in the fourth, that would be in the ball park. One would have to pro-rate the current cycles.

Calculating from the power density (400 assemblies and 1380 MWth for unit 1, 548 & 2381 for unit 2), and assuming 80 % capacity factor and 170 kg U weight per assembly, one would get 5.93 MWd/kgU of exposure per year for unit 1 and 7.47 MWd/kgU for units 2&3. The rest depends on the cycle length and reload batch size.

I made a quick spreadsheet for guesstimating the core average burnup in different reload schemes. It seems that the core average burnup at unit 1 would probably lie around 20 MWd/kgU, and probably somewhat lower for the units 2&3. Any additional info on the reload strategies (=maximum discharge burnup & cycle length) would help in obtaining a better estimate. (NB: That's just a quick example to give an idea, certainly not double-checked for errors and/or omissions!)

 

[Astronuc]

Mr. Astronuc, I had my socks and shoes off trying to figure the possible amount of uranium involved while you were posting your figures so I didn't see it. Now that I see it, your attachment more than doubles my amount of known uranium involved between the 4 reactors. I understand some fuel is in various stages of decay thus less potent and I by no means what to understand the inter-workings of a nuke plant but was just trying to get a idea of the energy that could be released esp. in case of fire.

Your pic with totals seems high. Do they really have that much stored in spent fuel ponds? Did Unit 4 actually have those amount of assemblies already loaded?...At least as far as you know.

I haven't verified those number yet, but they seem reasonable. Unit 1 would have the equivalent of about 3 batches in its SFP. That means they have offloaded some (oldest assemblies) to the common pool. Units 2 and 3 seem about right. I expect they have plans to offload some of the oldest fuel. Each pool probably has 3 to 4 batches of old fuel. The oldest batches would probably have been cooled down over about 3+ years.

Unit 4 did a full core offload for maintenance. They would then reinsert some fuel (2 or 3 batches) and add fresh fuel (some or all of the 200). If the unit is loading ~1/3 core, that's about 180 assemblies. They may have a policy of keeping some extras just in case. On the other hand, depending on capacity factor and cycle length, they could be doing reloads of up to 200 assemblies in Units 2, 3 and 4.

 

[razzz]

Unit 4 has 1331 in SFP plus 200 newly delivered brand new units - reactor is unloaded
I also included my earlier post which estimate the heat load

Thanks for that (again) AntonL. I'm sure you'll correct me if I'm wrong in the following...

Doesn't seem possible, now I come up with about 854 tons of uranium between the 3 reactors and 4 pools. And 'fuel elements' I take to mean 'assemblies' where 60 fuel rods makeup 1 assembly and one assembly contains an estimated .171 ton of uranium with 4995 assemblies in play or 299,640 individual fuel rods. Crazy.

I can see why the US sent specially trained Marines for population decontamination.

Nothing has blown up lately, which is about the only good thing.

 

[TCups]

I know this is all speculation, but I am very confused. If it was rebar, it should still be there... It appears it has been cleaned up.

If it WAS fresh fuel, is it a hazard to workers?

Sorry if this was gone over previously, I have a tough time keeping up with this VERY busy thread. Thankful for all the people here!

It still appears to be there, in the NW corner of Bldg 3

It is uncertain what the rod-like structures are.

It is unlikely spent fuel (or fresh fuel rods) would have been transferred to the equipment pool. The fuel handling machine does not go there and I don't think there is a transfer chute that would allow the fuel rods to be transferred under water to the equipment pool. The equipment pool contains the head of the pressure vessel when the reactor is shut down and the reactor pressure vessel is opened for refueling. Perhaps someone can confirm that statement.

 

[jensjakob]

Gents,

At some time we discussed how high the Tsunami had swept at Fukushima.

Looking at the hi.res images I found these tanks on the west-side of #4. See the pond around them? Full of water.

I checked with some of the early video from the plant, before water-spraying, and they are also full on those videos.

I vote for this as an indication that a pretty powerfull wave swept past all reactors.

Still searching for more signs in the images.

/Jens Jakob

 

[james14]

We have heard many times that the radiation coming from the standing water is > 1000 mSv / hr. So we don't know the actual levels, just that it's greater than the 1000. I believe some here have estimated this value to be wildly lower than the actual.

Lately there have been reports of this water being > 10,000 times the level of water normally in a reactor.

Would I be right therefore in assuming that the normal level of radiation levels of water in a reactor is approx 0.1 mSv / hr?

Basically I was wondering if the "levels > 10,000" was as limited a piece of information as the "> 1000 mSv/hr" one. Or, if we could perhaps work out an actual level of radiation from those figures of "> 10,000 times the normal level in a reactor"

 

[timeasterday]

I don't think this image has been posted before but seems to show refueling operations at one of the reactors.

 

[shadowncs]

Still searching for more signs in the images.

We can only speculate but look at aerial-2011-3-30-0-50-45.jpg from 20 March... if those are tsunami runups then we have an idea.