Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Borek]

blast that everybody has interpreted as a replica of 5.6 on Richter scale ?

On April 22 : According to RBC, the epicenter of the earthquake was located at a depth of 35.8 km at a distance of 74 km from the city of Fukushima, and only 22 km from the nuclear power plant "Fukushima-1. According to the US Geological Survey, tremors were recorded at 19:25 MSK.

No idea why you think these things are in any way related. Epicenter was 22 km from the plant, not under reactor building. Besides, there were many quakes in the area since the big one, why this particular one caught your attention?

 

[havemercy]

Because it is the nearest of the plant.

 

[elektrownik]

Because it is the nearest of the plant.

If there would be explosion which would generate 5.6 quake then you wouldn't see reactor buikdings anymore...

 

[clancy688]

In my opinion, ANY steam explosion that triggered a 5.6 magnitude quake would've been a boom that would give the Hiroshima bomb a run for its money...

 

[SteveElbows]

be patient guys my first try at photo well maybe second

Has this been posted?

found it at Cryptome..was taken March 16, and the deck looks a lot worse in later photos.
it's in the zipped file of full size photos and has this name: aerial-2011-3-18-14-50-0.jpg
(editing mine, with MS-Paint, which clobbers the resolution)

you can see the concrete cap not there but i can't tell for sure about the yellow thing on right. In the hi-res it's a maybe.

Would one who knew how to lighten be able to see down into that black hole and tell if yellow containment cap is there?

In my opinion this is one of the classic illusions from the early Fukushima pictures. I remember when I first saw it, it was briefly quite compelling because the apparent chasm was in roughly the right place. But subsequent photos and video destroy the illusion pretty well. See the problem is that with other footage we can get a glimpse of how much the crane & associated debris occupy this area, and we can see how the smoke/steam and lack of light in that part of the building create a range of shadowy unrealities in this part of the building. What looks like a nice well rounded hole appears to me to mostly be darkness and smoke, with perhaps a bit of crane and roof adding to the effect when seen from the angle that footage was taken at.

No footage has emerged that gives us a really clear idea of the exact state of things there, and no really compelling evidence has emerged from that zone, despite many people likely studying such footage a lot due to the frequent debates about whether any part of reactor 3 launched into the air. When combined with what other data tends indicate, lots of people are going to assume that nothing major launched from reactor 3, and it will now take some compelling evidence to convince a lot of people to reconsider this issue. I am not really expecting it to happen, but I'll be ready to eat my words if it does.

I remain very interested in the exact nature of containment damage at reactor 3, so I hope that one day we get a better look at the damaged areas. The closest I have got towards identifying any potential trouble, and getting a look at things I can actually identify at reactor 3 that arent badly obscured, was a picture I posted a while back. Taken from a helicopter video, it shows area where dryer storage pit/pool is joined to area above reactor, where removable concrete wall is in place. Image quality not clear enough to say with any certainty, but it is possible that we can just glimpse the very edge of one set of the semi-circular plugs that sit above the reactor. The only evidence for this in attached photo is thin black line, that may be slightly curved, in area to left of the emerging smoke. This is where top of the dryer pool concrete wall becomes part of the service level floor, and traveling further in that direction we would expect to find reactor plugs making up the next part of the floor. So perhaps this thin line is where the wall ends and the plugs begin. But because of where the crane & its supporting structure has fallen, we can only see a small portion of this service floor area, so I can't be sure of anything.

 

[Borek]

Because it is the nearest of the plant.

At 22 kilometers? Seismographic data are much better than that. If memory serves me well, places where underground nuclear tests were done were located with few hundred meters accuracy.

Edit: according to wikipedia, 5.6 is about 4 kT TNT, about one fourth of Hiroshima bomb, that would be hard to miss.

 

[Bandit127]

If there would be explosion which would generate 5.6 quake then you wouldn't see reactor buikdings anymore...

According to Wikipedia (sorry..) a 5.6 quake is equivalent to 3.8 kilotons of TNT.
http://en.wikipedia.org/wiki/Richter_magnitude_scale"

For a sense of scale - if I recall correctly from previous posts, the explosion of the Unit 3 building was expected to register about 2.2. (Working backwards from the table, I would estimate the equivalent would be about 30 kilogrammes of TNT).

Edit - Oops! Thanks Borek - I must type faster.

 

[havemercy]

Ok, then it is not possible. Thanks.

 

[jim hardy]

Jorge :
""I suppose that neutron absorption is the main factor preventing re-criticality. TEPCO has been using boron in the emergency cooling water; the effect should be like that of soot particles making smoke clouds black instead of white. Also the corium itself may (or may not) include neutron-absorbing material from the control rods.

Is this correct? ""

i'd say so. Without moderator or reflector the neutrons simply keep on going and leave the neighborhood. They can eventually emit an electron and so become a hydrogen nucleus(proton).

"To have fission one needs to have a significant fraction of the emitted neutrons slowed down and scattered back to the fissile material. If the fuel is immersed in a large amount of moderator, and there is no absorption, every neutron that leaves it will eventually be scattered back to it, by "drunkard's walk" statistics. (This is the same effect that makes sunlit clouds look white.) "
well as you said, not every neutron will make it back, some of the 'staggering drunks' fall by the wayside. It takes maybe a dozen collisions with a light nucleus like hydrogen to slow a neutron to the energy favorable for fission, maybe forty with something heavier like sodium. Remember energy in elastic collisions divides in some proportion to masses involved. Each collision stands a chance of inelastic absorbtion without fission so there's some loss by absorbtion.
You need to have about half the neutrons survive moderation to get critical.

Here's a link to a short course - you'll have no trouble with the slides. i may have posted it before, sorry, the senior moments sort of run together anymore.

http://www.if.uidaho.edu/~gunner/ME443-543/LectureNotes/ReactorPhysics.pdf

If the corium contains melted control rods it's probably safe. The addition of melted steel reactor parts could make it safe. The seawater salt is mildly absorbtive.
But its Russian Roulette.

btw i really liked your charts and bragged on them in another forum. Thanks!

old jim

 

[jim hardy]

Thank you Steve Elbows for posting this comment:
""No footage has emerged that gives us a really clear idea of the exact state of things there, and no really compelling evidence has emerged from that zone, despite many people likely studying such footage a lot due to the frequent debates about whether any part of reactor 3 launched into the air. When combined with what other data tends indicate, lots of people are going to assume that nothing major launched from reactor 3, and it will now take some compelling evidence to convince a lot of people to reconsider this issue. I am not really expecting it to happen, but I'll be ready to eat my words if it does...""

That is where I am too. It's an open but doubtful question and the absence of good photos does lend to conspiracy theory. I don't like conspiracy theory and have been looking to dispel it.

To that end i put a couple early photos over on scribd, not wanting to clutter this board with a long essay.
If you have fifteen minutes to kill, and promise to not accuse me here of fearmongering , i welcome your comment at this link, or about it here:
http://www.scribd.com/jim_hardy_9

It's an honest question. I want to rule some things out but the "optical illusions" keep on cropping up.
The link at scribd tells how to get the three high resolution photos you need to see what i see. It just won't show in the low res ones. I would post them if knew how to preserve the hi-res. One of them is from first ten seconds of that helicopter video and requires training your eye to look for it. I want to know if i am seeing what is not there.

i am working on a photobucket album but even photobucket destroys the resolution, you just got to go back to the source. and that's too much to ask of folks in a general audience.



So, happy surfing. Keep up the good work here fellows.

 

[SteveElbows]

That is where I am too. It's an open but doubtful question and the absence of good photos does lend to conspiracy theory. I don't like conspiracy theory and have been looking to dispel it.

To that end i put a couple early photos over on scribd, not wanting to clutter this board with a long essay.
If you have fifteen minutes to kill, and promise to not accuse me here of fearmongering , i welcome your comment at this link, or about it here:
http://www.scribd.com/jim_hardy_9

It's an honest question. I want to rule some things out but the "optical illusions" keep on cropping up.

Yikes! Trying to read your instructions for locating things of interest on the photos caused my brain to meltdown! And then I realized that the other 'feature of interest' you were pointing to is one I already gave my thoughts on for you here a while back.

Bottom line for me is that even the original resolution versions of these images are no way good enough to use to prove very much one way or another. People can stare at the images we've had for ages now as much as they want, I don't expect anything new and compelling to leap out (although its always possible I suppose). Dont get me wrong, I am interested in some of the things you have pointed out, but I've given up expecting to learn anything about them unless I get more footage, but we don't get much from these areas since march. I am not afraid to point out stuff in new images, such as the pile of 1000mSv rubble the other day, even when I am not at all sure what they are, nothing wrong with a bit of speculation, but I feel that most existing images have been done to death and little has been learnt.

 

[jim hardy]

Thanks Steve

i appreciate your honest assessment.

it is speculative.

jim

 

[jim hardy]

here's a generic refueling photo, shows top of vessel open with head bolts installed. Note circled walkway - vessel protrudes above refueling cavity floor and walkway presumably crosses vessel to containment flange. I think the outer green ring is the bolt circle for containment cap, perhaps NucEng or somebody with BWR experience can correct me.

never mind deck loop it's just a hose..
four white spots must be reflections of ceiling lights.

pls excuse if a repeat.

 

[GJBRKS]

here's a generic refueling photo, shows top of vessel open with head bolts installed. Note circled walkway - vessel protrudes above refueling cavity floor and walkway presumably crosses vessel to containment flange. I think the outer green ring is the bolt circle for containment cap, perhaps NucEng or somebody with BWR experience can correct me.

never mind deck loop it's just a hose..
four white spots must be reflections of ceiling lights.

pls excuse if a repeat.

Here is a close up from a T-Hawk video of the reactor 4 cap ,

[PLAIN]http://www.inkers.nl/uploads/reactor_cap.JPG

http://www.youtube.com/watch?v=AUx7lIUsogA"

 

[SteveElbows]

Note circled walkway - vessel protrudes above refueling cavity floor and walkway presumably crosses vessel to containment flange.

Fuel is moved along that channel, to and from the fuel pool, its not for humans to walk along. At least that's my understanding of it, I am no expert.

 

[Most Curious]

The "cattle chute" is to move fuel. Those are not bolts sticking up but studs. After reactor lid is installed they thread nuts on them, etc.

I presume a few studs are removed to facilitate fuel transfer and, of course, some for replacement if damaged or suspected of being defective. Big suckers - wonder how many foot-pounds??

 

[MadderDoc]

<..>It's an open but doubtful question and the absence of good photos does lend to conspiracy theory. I don't like conspiracy theory and have been looking to dispel it.

I think it is fair to say that the access to photos and videos have left some of us with unanswered questions now for months about the happenings at unit 3 during the last half of March 2011, questions which Tepco reasonably should be well-positioned to answer. Conspiracy may not be the right word, but it is an awkward situation indeed.

 

[MiceAndMen]

I think it is fair to say that the access to photos and videos have left some of us with unanswered questions now for months about the happenings at unit 3 during the last half of March 2011, questions which Tepco reasonably should be well-positioned to answer. Conspiracy may not be the right word, but it is an awkward situation indeed.

We should take up a collection to pay for another round of hires photos from the Air Photo Service guys. Their photo survey on March 24 was over two months ago and we haven't seen a whole lot of new pictures from the air since then.

 

[jim hardy]

""Big suckers - wonder how many foot-pounds?? ""

looks like the reactor head is pretty thick, too...
as a non - MechE i confuse the terms bolt and stud. I guess a stud is just a bolt without a head, may be other differences.

Mechanical engineers (i'm not one but used to drink beer with some) want a certain amount of tension in a bolt. Tension tells them how tightly the bolt is pulling the pieces together .


We non-mechanical folks think of a bolt as solid, but actually it's a real stout spring that you stretch ever so slightly by torquing the nut.
For big ones they measure the stretch instead of torque because it's a more precise indicator of tension.
Torque can fool you, for if there's a lot of friction in the threads from rust or dirt then the torque is being wasted in twisting the bolt instead of stretching it.

Those big fellas probably have a small hole down the center for a measuring rod to measure how much they're stretched.

Here's a table of strengths of various steels for various grades of bolts
http://www.americanfastener.com/technical/grade_markings_steel.asp
There's about a 3 fold range of strength.
i'd bet these are an exotic alloy like ASTM A490, about halfway down.

PS thanks guys for your comments on the dearth of good unit 3 photos that appeared while i was typing.
I will fix my explanation of the "optical illusion" so it's readable. Sure would like your critique , but i respect the high level of discourse here and won't put up gibberish.

old jim

 

[Bodge]

How come Greenpeace are detecting upto 120,000 bq of I-131 in 1kg of seaweed found 52km south of Fukushima Daiichi? [collected 5th May]

Even if gigantic releases of I-131 were made during the 1st week after the quake, would large amounts still be detectable 60 days after fission supposedly ceased?

Is this certain proof that fission is ongoing at Daiichi?

Does anyone know how many terabecquerels of I-131 could have been released if all fission stopped 11th March, but 90% of all 3 cores melted?

If the release was as high as 1 petabecquerel then that would still leave close to 4 terabecquerels after 8 half lives. That's then got to be distributed over 100km of coastline and make its way into seaweed...

I am still confused!

http://www.greenpeace.org/internati...ublications/nuclear/2011/RAP110522-GPJ-01.pdf

http://www.greenpeace.org/internati.../publications/nuclear/2011/Report SCK CEN.pdf

 

[clancy688]

Does anyone know how many terabecquerels of I-131 could have been released if all fission stopped 11th March, but 90% of all 3 cores melted?

In https://www.physicsforums.com/showthread.php?t=493058" thread I calculated with NUCENGs help the I131 and C137 core inventories of Fukushima Daiichi 1-3 at March 11th. Allover, it's ~6000 PBq I131. But TEPCO claimed that there were 81000 PBq I131 available for release.

http://www.nisa.meti.go.jp/english/files/en20110412-4.pdf"

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110421e2.pdf" But there are probably more leaks.

 

[jim hardy]

That'd be the place to look for iodine. Seaweed concentrates it.

""Seaweed is particularly rich in iodine: that is, concentrations are 100-1000 times higher than in fish. For example, kombu, a typical and commonly consumed seaweed, contains approximately 130 000 µg of iodine/100 g, while values in sardine and horse mackerel, taken as examples of the highest iodine concentrations in fish, are approximately 250 µg of iodine/100 g (Science and Technology Agency, Japan, 2001).""

http://www.nature.com/ejcn/journal/v56/n5/full/1601380a.html

 

[Bodge]

wow

Between 6 and 81 exa-becquerels of I-131 released.

After 10 half lives there could be upto 80 peta-becquerels of I-131 remaining in the environment (including on site).

 

[clancy688]

wow

Between 6 and 81 exa-becquerels of I-131 released.

Er, no... that's what was initially in the cores. Just that there were three meltdowns doesn't indicate how much got released.
Most of the stuff is probably still inside the leaking containments.

 

[Most Curious]

""Big suckers - wonder how many foot-pounds?? ""

looks like the reactor head is pretty thick, too...
as a non - MechE i confuse the terms bolt and stud. I guess a stud is just a bolt without a head, may be other differences.

Yea, there are a gazillion varieties of bolts and studs! Sizes, materials, thread types, qualities and on and on.

Mechanical engineers (i'm not one but used to drink beer with some) want a certain amount of tension in a bolt. Tension tells them how tightly the bolt is pulling the pieces together .


We non-mechanical folks think of a bolt as solid, but actually it's a real stout spring that you stretch ever so slightly by torquing the nut.
For big ones they measure the stretch instead of torque because it's a more precise indicator of tension.
Torque can fool you, for if there's a lot of friction in the threads from rust or dirt then the torque is being wasted in twisting the bolt instead of stretching it.

Those big fellas probably have a small hole down the center for a measuring rod to measure how much they're stretched.

Here's a table of strengths of various steels for various grades of bolts
http://www.americanfastener.com/technical/grade_markings_steel.asp
There's about a 3 fold range of strength.
i'd bet these are an exotic alloy like ASTM A490, about halfway down.


old jim

I am an aircraft mechanic - A&P - and old racecar mechanic. We use stretch to tension small bolts too! A "range" of torque is specified and a range of "stretch". Threads are to be clean and either dry or lubed depending on the manufacturer's instructions. Ya better not get too much stretch before you reach specified torque or the bolt is likely entering into the plastic range rather than the elastic where you want it! Those get removed, threads mashed and put in the round file.

Sorry about the off topic post - just fascinating how LARGE those studs are and the incredible loads on them with 1000 PSI ++ against that reactor head!

The containment head picture seems to show it uses bolts. I have heard two theories - one that it bolts into the concrete surrounding the steel of the DW (which I doubt) and the other that the bolts go into the steel flange on the DW.

Either way, it looks like #3 leaked!

 

[clancy688]

I hope that's not counting as "offtopic":

There's a lot of talk about recriticality at Unit 3. By chance, I just discovered that there was indeed a criticality. But not during the course of this accident. 23 years ago:

http://search.japantimes.co.jp/cgi-bin/nn20070323a3.html

http://www.thefreelibrary.com/2ND+L...e+happened+at+TEPCO+reactor+in...-a0161020955

Apparently, japanese reactors have a habit of "losing" their control rods. Is that of any concern for the current accident? Just wondering...

 

[Astronuc]

Apparently, japanese reactors have a habit of "losing" their control rods. Is that of any concern for the current accident? Just wondering...

Having inadvertent withdraw of a control rod, or rod drop accident, is a design basis accident, and it is a concern. Having a lot of control rods dropping out at the same time would be a really big deal.

Rod drop accidents are a concern because they insert positive reactivity into the core which if uncontrolled can result in a burst of power to the point were the fuel and core are damaged, which is both a safety and economic concern.

Rod drop scenarios typically involve a stuck rod in the core which is critical, such that when the rod drops, the core goes supercritical and power surges.

When all control rods are in the core, the drop of one or a few would not cause a criticality.

If they all fell out, then the reactor would spike in power and one could have a severely damaged core.

In the Fukushima event, if the core melted, then the stainless steel control rods melted with the fuel. I'm not yet convinced that any of the cores 'melted'. I do expect that there is a significant amount of cladding breached and probably broken, and perhaps pellets have disintegrated.

I would like to see the analyses (which predict melting) that have been performed to understand what assumption were made with respect to heat transfer in the core.

 

[westfield]

snip >
you can see the concrete cap not there but i can't tell for sure about the yellow thing on right. In the hi-res it's a maybe.

< snip

Is this the yellow curved looking debris in the smashed NW corner of RB #3 you are looking at? It may be the large yellow tank as seen in the not so smashed RB #4

http://i1185.photobucket.com/albums/z360/fukuwest/misc/Unit3nwcornerdisplacedlargeyellowtankatlowerfloorcopy.jpg"

 

[jim hardy]

""I would like to see the analyses (which predict melting) that have been performed to understand what assumption were made with respect to heat transfer in the core. ""

here's a hypothetical analysis done some years back of a Brown's Ferry (TVA) BWR , section nine is the analysis of severe core damage they thought would happen if one of these things ever got a long term loss of all AC power. section 8 is the lead-in, around page seventy.

http://www.ornl.gov/info/reports/1981/3445600211884.pdf
i think it's been linked here before. surely there's newer ones.

the others i know of, SARA, GENFLO, and ORNL's Severe Accident Mitigation have been already linked here by other folks.

Here's an interesting one on bottom head failure , it sort of meshes with reports from Japan...
http://www.osti.gov/bridge/servlets/purl/6124656-R8y05j/6124656.pdf

and this one is too math intense for me but you'll do fine with it
http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/25/044/25044840.pdf
it's by swinkendorf, and it's referenced by some ANS guys in their correspondence.
i have his doctors thesis also on similar subject and am looking for the link i downloaded it from because it's 220 pages.. will put link up when find it.

hope this helps. jim

 

[Godzilla1985]

Y'all should take ten minutes of your time and have a good look at Jim's photo analysis of the "Snaggleteeth", found here: http://www.scribd.com/doc/55934120/A-couple-of-Fukushima-Photos

Don't recall seeing any attention brought to that particular spot before in this thread.

 

[jim hardy]

Astro - here's another European study of criticality on reflood... a lot like SARA . they also mention computational instability so maybe their computer codes don't do so well on these.. perhaps a job for analog computers ?? (just kidding, I'm real old school)
http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/28/059/28059598.pdf

It mentions possibility of periodic power excursions which sounds a lot like phrases in early news reports about a reactor that 'spat steam'.

 

[jim hardy]

thank you Zilla.

It is a work in progress. i hope to get it cleaned up enough to make it readable.

The shadowy "snaggletooth apparition" shows up a lot of places. It might be worth the trouble to train your eye to see it. but i apologize for the tedious instructions - will clean them up. Takes ten minutes now, more if you upload the hi-res pics linked.

the other one is much shorter , http://www.scribd.com/doc/55960157/MyLastFukushimaPhoto

They're both accessible at http://www.scribd.com/jim_hardy_9

jim

 

[jim hardy]

@ Westfield:

Your photos have incredibly good quality. I'm not that good yet.

I believe the yellow "tank" you pictured in your unit 4 photo IS the reactor containment cap..that's just where it sits in the drone photo, if I'm not turned around, in NW corner.

i believe what i circled is further back and below that object you highlighted - i think i am seeing the round thing at lower left corner of your yellow rectangle , now covered with mud from rain and helicopter water drops..my unit 3photo shows only a little bit of its top.
Here it is in a March 16 picture of rubble pile before it got all covered with mud.
Two things are circled in red. Upper right is i think vessel cap, other is vessel head. Cap is obscured by a tree, that's why it looks broken.

i think the object you highlighted is the yellow-ish rectangle to right of my upper red circle .

I apologize for low quality. to get hi res see my longwinded writeup "A Couple Fukkushima Photos" at scribd < http://www.scribd.com/jim_hardy_9 > but just skip to last page where i give links to hi-res zip file.

the pictures are so blurry it's not possible to strongly assert anything.
Only reason i mention it is two photos from different angles generally agree.

and if the pressure readings from plant are true, it's not a possibility.
Still if you look at he radiation surveys of the plant there's a "hot" piece of rubble right where i have head. If it were something light surely they'd have moved it by now.

here's what a head looks like from underneath

and you see how perfectly round the lower object is.

compare this picture to survey maps...

sorry guys i didnt mean to hog the board here. Will be quiet now.

old jim

 

[~kujala~]

Somebody asked earlier what is the importance of this new leak from the waste disposal facility.

As far as I see it we must see the whole picture. There has probably been high-level leak from units #1 - #3 to groundwater for 2 months and medium-level leak from unit #4 to groundwater for 2 months also. At the current moment the leaks from #3 and #4 seem to have a significant decline:

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110526e4.pdf

The leaks from #1 and #2 are decreasing also.

Nevertheless, even if there was a new leak from the waste disposal facility and even if this leak would end up in groundwater (which at the current moment seems not to be happening) this leak would not mean a lot compared to what already has happened. The same applies to the leaks into the sea. They had mega-leak from unit #2 pit into the sea and now this leak has been plugged. It's probably impossible to have a leak having such enormous contamination anymore.

The much bigger problem, as I see it, is TEPCO's calculations about the water they have to move from the reactor/turbine buildings outside.

TEPCO has perhaps calculated their estimates based on the water that has accumulated in the turbine/reactor buildings. They have also calculated the amount that is going to accumulate because they are feeding new water all the time.

But has TEPCO taken into account the possibility that tsunami waters have increased the surface level of groundwater? Even if they were able to transfer all water in the turbine/reactor buildings today, tomorrow there could be more water in the reactor/turbine buildings because groundwater could leak in.

I think what they should do is to hire a couple of groundwater specialists who would try to calculate the following things:
- How much water did tsunami left in the plant area?
- How much did the surface level of groundwater increase after tsunami (if any)?
- How much water are we going to expect in the plant area from the rains? Rain water infiltrates into the ground and eventually reaches groundwater and because groundwater is polluted rain water will also be polluted.
- How much time is it going to take for this elevated groundwater to reach again its normal level?
- What is the maximum amount of groundwater that could leak into the reactor/turbine buildings and that could accumulate in the sub-drain pits?

Then they should increase their evaluation of needed storage capacity by the maximum amount of groundwater that could still leak into the turbine/reactor buildings and by the maximum amount of water that could accumulate in the sub-drain pits and has to be emptied. They should assume worst-case scenario and so from there everything that turns out not to be so bad would be a good thing indeed.

Anybody wants to try to calculate the total amount of water that should perhaps be taken into account?

Edit: The good thing is that after a while (perhaps 1 or 2 months from now on) all groundwater will be low-level contaminated. And after that one possibility is that this low-level contaminated water will be directly pumped to the sea as far it accumulates in the reactor/turbine buildings and sub-drain pits. Time is on TEPCO's side!

 

[NUCENG]

On Mamoru's layout plan for Fukushima Daiichi unit 3 at http://3.bp.blogspot.com/-JaxFid8Qo...AAko/t5TVRl5sb-4/s1600/R3++completa+small.jpg there is a white rectangle a few steps south of Diesel engine 3A called (in Italian) "boccaporto cisterna carburante" (Fuel tank hatch). So, my understanding is that the fuel tanks used by the diesel generators are located there, underground. If they can withstand the pressure from the water during the flooding and if the air intakes are located high enough, these tanks are probably OK.

Fuel tanks are vented and have transfer pumps. Seawater contamination of fuel would render the fuel unusable until it can be separated. That requires power. Fuel transfer pumps could also have been damaged and not visible in the images.

But I agree underground fuel storage tanks are probably intact.The generators all died about the same time (1545 or so). They were probably running on fuel in their local day tanks.

We know that two employees were killed inside the turbine building during the tsunami. Water entered the buildings. If the air cooled diesels were located above the water damage, that points to the switchgear, breakers, and electrical distribution centers that connect the generator output to the safety equipment. Flooding those electrical panels would trip the diesels, including air cooled generators. The electrical damage would also have prevented using intact diesels after the tsunami was gone.

 

[tonio]

@ Westfield:
I believe the yellow "tank" you pictured in your unit 4 photo IS the reactor containment cap..that's just where it sits in the drone photo, if I'm not turned around, in NW corner.
old jim

I looked for your "yellow tank" on an aerial photo of R3 and I believe I have found it. I compared its dimensions with the yellow reactor cap visible in R4. It seems to have about half to two-thirds of the size of the R4 cap, thus it seems to be something else.

 

[ascot317]

...Rod drop accidents are a concern because they insert positive reactivity into the core which if uncontrolled can result in a burst of power to the point were the fuel and core are damaged, which is both a safety and economic concern...

Astronuc, I've always wondered why these BWR's use bottom feeding rods in the first place.

From a safety point of view this is the most challenging. I know how they have designed the system to be "fail safe", but why make it harder and riskier than it has to be?


If this suggestion would have gone over my desk without really good arguments, I'd probably start questioning the mental state of my planners.

The only reason I can see is making loading from the top easier.

 

[NUCENG]

Astronuc, I've always wondered why these BWR's use bottom feeding rods in the first place.

From a safety point of view this is the most challenging. I know how they have designed the system to be "fail safe", but why make it harder and riskier than it has to be?


If this suggestion would have gone over my desk without really good arguments, I'd probably start questioning the mental state of my planners.

The only reason I can see is making loading from the top easier.

The whole idea in a BWR is to boil water in the core. That steam is very "wet" and would damage a turbine if used directly. At the top of the RPV there are steam dryers and separators to improve steam quality. That prevents using top inserted rods. The hydraulic control rod drive mechanisms CRDMs are therefore at the bottom of the RPV. If unlatched, rods drift into the core under the driving force of reactor pressure. In a SCRAM high pressure water forces them into the core in a few seconds.

 

[clrcdd]

this document might be of interest in regard to recriticality in BWRs
http://bit.ly/mpxlJB

source:
http://www.sciencedirect.com/science/article/pii/S0029549301003922

 

[tsutsuji]

Does this fall into the good or the bad news category? No leak into groundwater is surely good, but there wasn't supposed to be any kind of leak, I assume? What, if anything, does it tell that also the wastewater facility leaks somehow?

They said : "Cracks in floors and other surfaces were subject to on-site examination, and every visually-identified crack was confirmed to have been repaired with polymer cement waterproof coating" : http://www.nisa.meti.go.jp/english/files/en20110520-2.pdf

http://www.yomiuri.co.jp/science/news/20110527-OYT1T00712.htm says that the interstices at the door between the Miscellaneous solid waste volume reduction treatment building (incinerator building) basement and the corridor had been filled with resin as part of the "making more watertight" job, but that was obviously "not sufficient"...

The corridor dimensions are 70~80 x 4.5 x 4.5 m.
The water level there was 2.2 m on May 26th
Radiation at the surface of the water was 70 mSv
A detailed map is available at http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110527_01-e.pdf

The water level at the Miscellaneous solid waste volume reduction treatment building (incinerator building) decreased by
20 mm between May 25 7:00 AM and May 26 7:00 AM : http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110526_02-e.pdf
58 mm between May 26 7:00 AM and May 27 7:00 AM : http://www.tepco.co.jp/nu/fukushima-np/images/handouts_110527_02-j.pdf

 

[jlduh]

Somebody asked earlier what is the importance of this new leak from the waste disposal facility.

As far as I see it we must see the whole picture. There has probably been high-level leak from units #1 - #3 to groundwater for 2 months and medium-level leak from unit #4 to groundwater for 2 months also. At the current moment the leaks from #3 and #4 seem to have a significant decline:

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110526e4.pdf

The leaks from #1 and #2 are decreasing also.

Nevertheless, even if there was a new leak from the waste disposal facility and even if this leak would end up in groundwater (which at the current moment seems not to be happening) this leak would not mean a lot compared to what already has happened. The same applies to the leaks into the sea. They had mega-leak from unit #2 pit into the sea and now this leak has been plugged. It's probably impossible to have a leak having such enormous contamination anymore.

The much bigger problem, as I see it, is TEPCO's calculations about the water they have to move from the reactor/turbine buildings outside.

TEPCO has perhaps calculated their estimates based on the water that has accumulated in the turbine/reactor buildings. They have also calculated the amount that is going to accumulate because they are feeding new water all the time.

But has TEPCO taken into account the possibility that tsunami waters have increased the surface level of groundwater? Even if they were able to transfer all water in the turbine/reactor buildings today, tomorrow there could be more water in the reactor/turbine buildings because groundwater could leak in.

I think what they should do is to hire a couple of groundwater specialists who would try to calculate the following things:
- How much water did tsunami left in the plant area?
- How much did the surface level of groundwater increase after tsunami (if any)?
- How much water are we going to expect in the plant area from the rains? Rain water infiltrates into the ground and eventually reaches groundwater and because groundwater is polluted rain water will also be polluted.
- How much time is it going to take for this elevated groundwater to reach again its normal level?
- What is the maximum amount of groundwater that could leak into the reactor/turbine buildings and that could accumulate in the sub-drain pits?

Then they should increase their evaluation of needed storage capacity by the maximum amount of groundwater that could still leak into the turbine/reactor buildings and by the maximum amount of water that could accumulate in the sub-drain pits and has to be emptied. They should assume worst-case scenario and so from there everything that turns out not to be so bad would be a good thing indeed.

Anybody wants to try to calculate the total amount of water that should perhaps be taken into account?

Edit: The good thing it that after a while (perhaps 1 or 2 months from now on) all groundwater will be low-level contaminated. And after that one possibility is that this low-level contaminated water will be directly pumped to the sea as far it accumulates in the reactor/turbine buildings and sub-drain pits. Time is on TEPCO's side!

Without having a detailed mapping of the underground area and water table, including data from piezometers (small wells to measure underground water level) with possible seasonal variations, i think it will be very difficult to answer your questions. Still, i already partially answered one concerning the rain water, i got very few comments on the number i gave but you can still read the post... if i find it again (don't find it, hope it has not been deleted...)

I was calculating that with an annual rain height of 1250mm, based on the seasonal curve and with the rainy season coming, over an area of 400m x1000m which is an estimate of the main area that is scattered with debris (and so is contaminated), it will sum up a total of aroud 250 000 tons of rainwater in the next few months (and 500 000 tons for the complete year) that will wash this mess and will finish in the ocean for the main part (don't forget that there is a rainwater collection system for the plant, we don't know how this system is designed and how many outputs towards the sea there are, but I'm pretty sure this goes to the sea anyway because it is not supposed to be radioactive in normal conditions).

For the water in the basements, you have to understand that any flow comes from a differential of local hydrostatic pressure, even minimal. So as the basements are below ground water level (by how much, that is THE question), the direction and amount of the flow (inward or outward, from the basement standpoint) is depending of the relative height of water inside the basement and water outside of it (water table). Of course if the basement is fully waterproof, then no flow, but this is not the case (N°5 and N°6 have flows from the watertable it seems, which may have moved up as you said with tsunami). So what I foresee is the possibility that when the basements where almost empty (with regular pumps ejecting out the inflows from the watertable, which was probably routine operation to keep these basements dry), then of course the direction of flow was from outside to inside (because of hydrostatic differential). When the basements are filling in with water, the differential is reducing and eventually, this differential can be inverted if water level inside basement becomes higher than water table level outside. Then the flow will invert also, and so leakage from basement towards watertable can happen (with contamination).

Things may be a little bit more complex than this but this is the general idea.

For detailed calculations again, this is not possible without reliable data, mapping and computer program.

 

[Borek]

i already partially answered one concerning the rain water, i got very few comments on the number i gave but you can still read the post... if i find it again (don't find it, hope it has not been deleted...)

https://www.physicsforums.com/showpost.php?p=3321203&postcount=8171

 

[jlduh]

Thanks BOREK! You are far better than me to find my posts

By the way i never got one post deleted here without explanation and a mail, so I appreciate this from the moderators and especially you Borek. Let's say it to be clear

 

[NUCENG]

here's a generic refueling photo, shows top of vessel open with head bolts installed. Note circled walkway - vessel protrudes above refueling cavity floor and walkway presumably crosses vessel to containment flange. I think the outer green ring is the bolt circle for containment cap, perhaps NucEng or somebody with BWR experience can correct me.

never mind deck loop it's just a hose..
four white spots must be reflections of ceiling lights.

pls excuse if a repeat.

This appears to be a photo taken during cavity floodup prior to refueling. As indicated by others the cattle chute is visible leading off to the spent fuel pool. The bio-shield blocks have been removed from the cattle chute. The number of people on the refueling machine makes me think it is during floodup. They are probably doing checks to prepare for refueling. The white spots are likely the underwater lamps installed on the drywell walls. The bolting studs you see are for the drywell cap. Inside the cavity there is the reactor vessel head and its bolting ring but they are not visible in the picture.

edit: on second guess those white spots may be reflections of lights. The perspective of the lights appears wrong for them to be mounted on the drywell wall, especially the one closest to the camera.

 

[tsutsuji]

One can catch a glimpse of a diagram detailing the water treatment facility on the following video of an interview of Areva Japan's president : http://news.tv-asahi.co.jp/news/web/html/210527034.html . The schedule for the launch of the facility has been postponed to mid-June. The delay is caused by some other manufacturers involved in the project.

The projection of dust fixating coating on the reactor and turbine buildings is starting today. It is important to have this done before the heavy "tsuyu" rains start pouring. http://www.tokyo-np.co.jp/article/national/news/CK2011052702000195.html?ref=rank

 

[jlduh]

The projection of dust fixating coating on the reactor and turbine buildings is starting today : http://www.tokyo-np.co.jp/article/national/news/CK2011052702000195.html?ref=rank

According to http://www.nikkei.com/news/category...39F9FE2E2E2E2;at=DGXZZO0195165008122009000000 it is important to have this done before the heavy "tsuyu" rains start pouring.

Yep, if you meditate a bit on the numbers i gave in the post above for rainwater volumes that this area will receive in the next months, we understand why they are so concerned to do this before.

But the question is how good is this product to resist heavy rainwater falls?

Read also here:

http://www3.nhk.or.jp/daily/english/27_02.html

Antiscattering chemical to be sprayed on buildings
The operator of the damaged Fukushima Daiichi nuclear power plant will spray an anti-scattering agent onto its buildings to prevent radioactive dust from spreading.

[...]

The chemical hardening agent selected for the task is usually used to contain asbestos.

[...]

Tokyo Electric Power Company says it will use two fire engines to spray the chemical onto building walls. However, TEPCO says it cannot spray all the walls because debris still blocks access to some area.

[...]

However, the chemical won't be applied to all areas because if it gets inside the pool that contains spent fuel rods it might interfere with the circulation of cooling water.

The forecast for the coming 5 days in fukushima area is a total of around 110mm of rain, which translates to 44 000 tons of water in my reference area of 1000m x 400m. Not a bird pee...

http://www.weather-forecast.com/locations/Fukushima/forecasts/latest

 

[zapperzero]

Yep, if you meditate a bit on the numbers i gave in the post above for rainwater volumes that this area will receive in the next months, we understand why they are so concerned to do this before.

But the question is how good is this product to resist heavy rainwater falls?

It's polymer glue. It will hold. Maybe some will be blown or scraped off in high winds, but that's all.

 

[Rive]

It's polymer glue. It will hold. Maybe some will be blown or scraped off in high winds, but that's all.

It'll hold only while there is something ~solid beneath, and it can do nothing with any water coming from outside the sprayed area.

I'm worried and expecting problems.

 

[tsutsuji]

The last sentence of http://www.tokyo-np.co.jp/article/national/news/CK2011052702000195.html?ref=rank says that they've already spread this dust-fixating coating on the ground in a number of places since the last decade of April, but they subsequently discovered that new dust originating from the walls of the buildings was depositing again on the coating.

 

[MadderDoc]

<..> If you have fifteen minutes to kill, and promise to not accuse me here of fearmongering , i welcome your comment at this link, or about it here:
http://www.scribd.com/jim_hardy_9<..>

The first 'leg' of your contention, that it is possible to 'see' that unit 3 reactor/containment caps are missing is exceedingly likely due to an illusion.

Because, it is exceedingly likely that what you _do_ see when looking at that area of the top of the building is largely the imprint of the overhead crane waggon, sitting on top of the two huge overhead crane traversal beams.

Here is a markup side by side, of the unit 3 rooftop, and a photo detail from unit 3 before the disaster showing the overhead crane parked close to the south wall of the building:

During the explosive events the overhead crane fell to the floor, ending up with its beams spanning across the reactor area, with the crane waggon crashing close to its center. These huge objects now very effectively block the view to the area underneath them, exactly there where the reactor shield and caps were situated in the intact reactor building. So, from mere inspection of this area in photos very little can be said about the current position and intactness of the shield plugs, and the RV and CV caps.