Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[jlduh]

Did you see any recent footage of the plant/reactors on TV?

I only have pictures from Tepco webcam (i cannot have the livefeed from TBS/JNN here in France, and anyway we hardly see N°1 reactor from this camera...).

Just want to mention this video which comes back at the end around this N°4 leaning building. It may be related to the way this camera operates so an other footage from helicopter for example, or even satellite view, could clarify this hypothesis...



Something else, could someone tell me what is the title of this parameter (Unit 1)

https://spreadsheets.google.com/spr...ZDbX39YK-iFb0Iw&hl=ja&authkey=CP6ewJkO#gid=41

 

[mrcurious]

http://www3.nhk.or.jp/daily/english/13_02.html"


Radioactive water leaked while being transferred

Interesting comments;

"Tokyo Electric Power Company says an operation to transfer highly radioactive water pooled in the turbine building of the Fukushima Daiichi nuclear power plant's No.3 reactor caused contamination of the sea nearby."

"The company transferred radioactive water from the turbine building of the No.3 reactor earlier this month. It says during that process radioactive water leaked out from an underground pipe connected to the pit."

Huh?

"The company admitted in a news conference on Thursday that prior inspections to prevent leaks were inadequate."

Methinks their inspections are just fine, they have a problem with disclosing critical information on a timely basis.

Friday, May 13, 2011 05:21 +0900 (JST)

 

[mrcurious]

Why would there be a need to relocate Tokyo?
I see nothing remotely threatening that city.

Tokyo is seldom downwind from Fukushima.

I think "seldom" is the functional word in your sentence. With the monsoon season upon them Japan's luck at having most of their atomospheric radiation ending up in Alaska, Canada and the West Coast may be at an end. All it will take for a major league size panic in Tokyo is two blows...one from a reactor and one from Zeus casting a wary eye south-southwest instead of east.

 

[bytepirate]

I have a question for the forum physicists.

There has been allusions to a view that the material in a SFP cannot go critical.

Why would anybody make this claim?

The fuel which was in the #3 SFP was powering a reactor just before the time it was taken out of the core; on top of that, there were new rods in the inventory in the pool at the time of the explosion on March 14th.

The fuel rods could have been broken up and squished into about any configuration imaginable by the shockwave from the hydrogen explosion hitting the wall of the fuel pond.

Is there an actual physicist posting here who will come to the support of those who claim that a criticality in SFP 3 was an impossibility?

If so, will you show us the math which gives this proof?

i wonder, if anyone said 'impossible'. there is an undisputed chance for re-criticality in SFPs, but it's a small chance.
currently, evidence (at least that, that is available to the public) neither proofs nor disproofs a criticality in one of the pools.
for the maths and more information, use this (pre-accident) google search: http://www.google.com/search?q=criticality+"spent+fuel+pool"+daterange:0-2455632

 

[unlurk]

there is an undisputed chance for re-criticality in SFPs

Are you a Physicist?
Can I use this as a citation in this forum?

 

[mrcurious]

http://www.youtube.com/watch?feature=player_embedded&v=FptmoVcgpqg"

2, 3 and 4 puffing away like locomotives...

Anyone want to comment on why #3 appears to be smoking from the north end of the building? It's hard to tell with the wind blowing but at this time of day the prevailing winds change from offshore to onshore and they swirl back and forth. If you watch for a few minutes you can catch them at a null point.

 

[bytepirate]

Are you a Physicist?
Can I use this as a citation in this forum?

you can cite, whatever you want ;-)
but citing 'bytepirate' (not a physicist, but an 'universal dilettante') will not give you more credibility :D

rather cite this: 'The committee could probably design configurations in which fuel might be deformed or relocated to enable its re-criticality, but the committee judges such an event to be unlikely. Also, the committee notes that while re-criticality would certainly be an undesirable outcome, criticality accidents have happened several times at locations around the world and have not been catastrophic offsite. An accompanying breach of the fuel cladding would still be the chief concern.' (http://www.nap.edu/openbook.php?record_id=11263&page=38)

 

[Giordano]

http://www.youtube.com/watch?feature=player_embedded&v=FptmoVcgpqg"

2, 3 and 4 puffing away like locomotives...

The camera died for me... is the periodicity of the camera functioning correlated with locomotive effect you are mentioning?

Actually, a locomotice is a great analogy since it can pruduce both smoke and steam, exactly like Fukushima Daiichi.

 

[clancy688]

The camera died for me... is the periodicity of the camera functioning correlated with locomotive effect you are mentioning?

Actually, a locomotice is a great analogy since it can pruduce both smoke and steam, exactly like Fukushima Daiichi.

The camera never worked for me... maybe only people in the US and Japan can access it.

A locomotive doesn't only produce smoke and steam, it can also explode if the pressure inside the boiler gets to high!

 

[mrcurious]

The camera died for me... is the periodicity of the camera functioning correlated with locomotive effect you are mentioning?

Actually, a locomotice is a great analogy since it can pruduce both smoke and steam, exactly like Fukushima Daiichi.

When I tried to bring up the JNN YouTube feed it says "Live Feed Over". However, this is a Newsslice page on wordpress that is still up, don't know exactly where they are getting the feed from JNN...I'm guessing it's live. I haven't noticed any correlation between reactor action and functioning of the camera.

UPDATE - YouTube feed back up...here's the url for tha newsslice page; I don't know it it's a different feed, thought it was funny I could pull it up while the direct YouTube was down, might have been a coincidence.

http://newsslice.wordpress.com/fukushima-nuclear-plant-updates/

 

[Astronuc]

i wonder, if anyone said 'impossible'. there is an undisputed chance for re-criticality in SFPs, but it's a small chance.
currently, evidence (at least that, that is available to the public) neither proofs nor disproofs a criticality in one of the pools.
for the maths and more information, use this (pre-accident) google search: http://www.google.com/search?q=criticality+"spent+fuel+pool"+daterange:0-2455632

Spent fuel assemblies have reactivities of k<1.

Degradation of boraflex is well known in the industry, and it is monitored.

Only a criticality analysis can determine if a given SFP is at risk of criticality, and that depends on the presence of fresh fuel in the SFP, and it's geometry.

Utilities are required by law to maintain a certain margin to criticality in a SFP. I seriously doubt that anyone outside of TEPCO has the capability to perform the appropriat analysis. One would need the burnups (from depletion calculations) and initial enrichments of all the fuel assemblies, as well as the lattices designs (enrichment and distributions) of any fresh fuel assemblies in the SFP, and the actual state of the boron absorber in the FK SFPs.

Otherwise, one is simply making unsubstantiatd claims or wild speculation, which is a violation of PF guidelines.

 

[unlurk]

Otherwise, one is simply making unsubstantiatd claims or wild speculation, which is a violation of PF guidelines.

So it's prohibited to discuss the criticality of SFP #3 in this forum?

 

[Astronuc]

So it's prohibited to discuss the criticality of SFP #3 in this forum?

Overly Speculative Posts:
One of the main goals of PF is to help students learn the current status of physics as practiced by the scientific community; accordingly, Physicsforums.com strives to maintain high standards of academic integrity. There are many open questions in physics, and we welcome discussion on those subjects provided the discussion remains intellectually sound. It is against our Posting Guidelines to discuss, in most of the PF forums or in blogs, new or non-mainstream theories or ideas that have not been published in professional peer-reviewed journals or are not part of current professional mainstream scientific discussion. Personal theories/Independent Research may be submitted to our Independent Research Forum, provided they meet our Independent Research Guidelines; Personal theories posted elsewhere will be deleted. Poorly formulated personal theories, unfounded challenges of mainstream science, and overt crackpottery will not be tolerated anywhere on the site. Linking to obviously "crank" or "crackpot" sites is prohibited.

https://www.physicsforums.com/showthread.php?t=414380

Discussing criticality of an SFP is fine as long as one avoids overly speculation or making unsubstantiated or false claims. Misinformation and misrepresentation is prohibited.

 

[jlduh]

The camera died for me... is the periodicity of the camera functioning correlated with locomotive effect you are mentioning?

Actually, a locomotice is a great analogy since it can pruduce both smoke and steam, exactly like Fukushima Daiichi.

It seems it depends from which country you are. Several europeans here can't get the livefeed (including me) because of legal rights apparently.

So again, if some can snapshot some images of interest, or even record some videos and post them, that would be greatly appreciated by those people

 

[unlurk]

Overly Speculative Posts:

So it's prohibited to discuss the criticality of SFP #3 in this forum?

 

[Astronuc]

So it's prohibited to discuss the criticality of SFP #3 in this forum?

Not as along as one adheres to the guidelines - to which each member agrees as a condition of participation.

 

[mrcurious]

It seems it depends from which country you are. Several europeans here can't get the livefeed (including me) because of legal rights apparently.

So again, if some can snapshot some images of interest, or even record some videos and post them, that would be greatly appreciated by those people

It's quiet again now. Strange how all 3 could be actively chugging then go mum at the same time. But I'll mention again it's the first time I saw so much smoke coming out of the north or northwest area of #3. If you use the tower a ref point, it was obscured but clearly emanating from somewhere behind the left half of the tower at or below what's left of the service floor.

 

[ascot317]

It's quiet again now. Strange how all 3 could be actively chugging then go mum at the same time.

It's 8:50 AM in Japan now.

That's either due to local weather at night (as discussed before), or because they fill the SFP's at night and this is creating a lot of fog. Or even both.
It would make sense to fill up the SFP's at night in the latter case; makes for a safer working environment during daytime, doesn't it.

 

[LD5060]

With regard to the path for hydrogen. Remember water reading 10s of R/hr to hundreds of R/hr with alrge amounts of I-131 has been showing up in the Turbine Buildngs and trenches. It has obviously been contaminated by damaged fuel from the reactors, not the spent fuel pools. Also remember that the reactor extends through every pipe going into that vessel to the inborad isolation vallve in the drywell. High pressure, packing leak and gases from the reactor are now in the Drywell. High pressure inborad isolation valve seat leak and the gass are now in the Reactor Building and into the Turbine Building through pretty darn big feedwater an main steam lines. It seems to me this is the only way you get water like that into a Turbine Building basement and hydrogen explosions in the Raector Buildings. I am not sure about the electrical penetrations that may also be a pathway. Just a thought. Sorry if treading on ground already plowed. Based upon the April 8th DW CAM reading it also looks like Unit 1 vessel integrity reported by TEPCO today was lost then.

 

[Townes]

It's quiet again now. Strange how all 3 could be actively chugging then go mum at the same time.

Could be that the wind picked up. Lots of wind sounds on the live feed now.

 

[Dmytry]

It's quiet again now. Strange how all 3 could be actively chugging then go mum at the same time. But I'll mention again it's the first time I saw so much smoke coming out of the north or northwest area of #3. If you use the tower a ref point, it was obscured but clearly emanating from somewhere behind the left half of the tower at or below what's left of the service floor.

if they all do it at same time then it is weather conditions changing (humidity, wind speed).

 

[Giordano]

Would it be possible to make a decent estimation of how much heat that is generated from unit 2-4 from videovisuals of how much steam that is generated?

Is the idea too wild? Old stupid idea probably...

(I have no live feed now, but I had earlier)

 

[Astronuc]

One can see steam from the hot water tap from one's kitchen sink. The not water is probably about 130-135°F (55-57°C). Water at FK maybe hotter @ 60°C or slightly more in the SFP, but perhaps not 100°C. In the reactor vessels, the temperatures are expected to be hotter than the SFPs, unless they get the appropriate cooling.

 

[StrangeBeauty]

(I have no live feed now, but I had earlier)

FYI they sometimes change the URL of the live feed. What has worked for me is to go to their channel page and hit the "LIVE" button above the display, which takes you to the current feed. Yes, at times the feed is blank, or clouded over (much of yesterday), etc.

Strange how all 3 could be actively chugging then go mum at the same time. But I'll mention again it's the first time I saw so much smoke coming out of the north or northwest area of #3. If you use the tower a ref point, it was obscured but clearly emanating from somewhere behind the left half of the tower at or below what's left of the service floor.

Like Dymtry, my first thought for the apparent synchrony was changing atmospheric conditions. No smoke/steam atm. A lot of camera jitter today for some reason.

I also previously had noticed smoke/steam apparently coming from the NE side of #3 which seemed wrong (smoke/steam appears to becoming from the middle of #2, where it should be), but I am not convinced I wasn't being fooled by the camera angle + very long telephoto shot -- I think it's very hard to conclude something definitive from the quality of this data.

 

[mrcurious]

They got the water crane on the south side of #3 right now, you can see it moving around, pretty cool.

 

[bytepirate]

Spent fuel assemblies have reactivities of k<1.

Degradation of boraflex is well known in the industry, and it is monitored.

Only a criticality analysis can determine if a given SFP is at risk of criticality, and that depends on the presence of fresh fuel in the SFP, and it's geometry.

Utilities are required by law to maintain a certain margin to criticality in a SFP. I seriously doubt that anyone outside of TEPCO has the capability to perform the appropriat analysis. One would need the burnups (from depletion calculations) and initial enrichments of all the fuel assemblies, as well as the lattices designs (enrichment and distributions) of any fresh fuel assemblies in the SFP, and the actual state of the boron absorber in the FK SFPs.

Otherwise, one is simply making unsubstantiatd claims or wild speculation, which is a violation of PF guidelines.

if tepco would not have considered the possibility of criticality, why would they have added boron to the cooling water?

PF quidelines: 'Personal theories posted elsewhere will be deleted'
if this guideline would be applied consequently, this thread would be dead as a dodo^^

just a personal statement: i love wild speculations. but i hate it, when they are not based on evidence and/or they are defended beyond a reasonable point.

EDIT: i was not sure if 'defended beyond a reasonable point' is correct english, so i googled it - the only hit was my post *3 minutes after posting*. google must have a high opinion of this forum^^

 

[mscharisma]

It seems it depends from which country you are. Several europeans here can't get the livefeed (including me) because of legal rights apparently.

If indeed your and others' inability to receive the feed is that it is blocked because of your location, I recommend signing up with a private VPN service. You connect to their private server in whatever country you choose (US or Japan, if you like) and get the feed essentially through them. One service I have been using without trouble is Super VPN, but there are many others out there. Hope this helps.

 

[Giordano]

One can see steam from the hot water tap from one's kitchen sink. The not water is probably about 130-135°F (55-57°C). Water at FK maybe hotter @ 60°C or slightly more in the SFP, but perhaps not 100°C. In the reactor vessels, the temperatures are expected to be hotter than the SFPs, unless they get the appropriate cooling.

I was thinking that the amount of steam generated was proportional to how much heat that is generated, no matter what the temperatures are in the pools of water.

I guess I am assuming steady state, which I can't assume since the temperatures are rising and falling as well as water levels due to evaporaion and external refuelling.

(and to try to estimate the steam generation from a camera I suppose is very speculative)

 

[Most Curious]

Overpressure in the drywell would first be vented to the torus, which is one reason why I can't accept (yet) that the cap would unseat and release gas before other primary containment failure. Proceeding further, even if the cap did unseat and release gas, as soon as enough was released the internal pressure would drop below the threshold needed and the seal would be re-established. Not sure about the time for that to happen, though, and how much gas would need to be released to reduce the pressure far enough.

What if the weakest part of the cavity above the cap was the path to the equipment pool? There would be no hydrostatic pressure at all on the other side of that barrier if the pool was empty.

Will respond more after digesting the rest (and dinner!).

M&M here are a couple links you might find interesting:

http://drinkthekoolaid.org/post/3948078791/possible-cause-of-reactor-building-explosions

http://www.nrc.gov/reading-rm/doc-collections/gen-comm/bulletins/1978/bl78009.html

The first is from a site I might question EXCEPT it was discussed on another forum amongst some folks that work in similar plants and they believed it was accurate. The second is from the NRC.

Those documents would suggest to me that DW head leakage would have been possible if not downright likely from the pressures at Fukushima. Leakage at the DW head seal would go into the refueling well and easily escape between the removable concrete blocks at the refuel channel and concrete segments or “plug” at the top of the refueling well. Leakage of very hot steam past the o-ring could have damaged / destroyed it, just as hot gas did in the Challenger disaster.

I have no doubt that the DW itself contained a lot of hydrogen from zirconium oxidation. The nitrogen used to inert the DW had probably leaked and been flushed away by repeated venting. Whether that hydrogen entered the DW from leaks of reactor piping and pump seals or from repeated steam venting via the relief valves, I have no idea.

I believe DW head seal leakage MAY have been part of the hydrogen leak path, although I doubt it was the ONLY one. In the case of Unit #3, it appears to still be leaking.


There is another link I am searching for that had a list of the known / estimated failure pressures of various components of the DW & SC. If someone finds it, please post it!

IIRC, the bellows between DW & SC was likely to fail first. Be interesting to find the source of that information and compare to the 2 links above.

 

[MiceAndMen]

Currently catching up on posts, only on page 428 so far, but I found something that may be of interest...

New Refueling Floor Diagram

I found an interesting refueling floor plan diagram in a GE BWR manual. The diagram is labeled "Typical Dual Unit Refueling Floor Arrangement", but the left half, viewed alone, seems to be somewhat like the Fukushima ones. I haven't bothered to convert feet and inches to metric. The attached image is the dual-unit arrangement and the link goes to the single-unit photoshop job I cropped out (1550 x 1300).

http://min.us/mvnWv8N

The general shape and location of the pools (with North to the left), the drywell head laydown area, the elevator, the main equipment hatch, and the stairwells in the NW and NE corners all seem to be in pretty good agreement with how I envision the "typical" Fukushima floorplan to be. It seems like a good additional point of reference.

 

[NUCENG]

Overpressure in the drywell would first be vented to the torus, which is one reason why I can't accept (yet) that the cap would unseat and release gas before other primary containment failure. Proceeding further, even if the cap did unseat and release gas, as soon as enough was released the internal pressure would drop below the threshold needed and the seal would be re-established. Not sure about the time for that to happen, though, and how much gas would need to be released to reduce the pressure far enough.

What if the weakest part of the cavity above the cap was the path to the equipment pool? There would be no hydrostatic pressure at all on the other side of that barrier if the pool was empty.

Will respond more after digesting the rest (and dinner!).

Yes the drywell pressure vents to the torus. Steam is condensed in the suppression pool to help reduce the pressure increase. However, the torus is heating up and some of the released material are non-condensibles like hydrogen gas. As time goes on both drywell and torus pressure increase. The unit 1 containment pressure was more that twice the design pressure, That was more than enough to fail the drywell cap seal ring and stretch the holddown bolts. It is likely this process was repeated at unit 2 and unit 3.

 

[jim hardy]

"So it's prohibited to discuss the criticality of SFP #3 in this forum? "

i'm not a reactor physicist but did take a course in it a little over forty years ago.
Here's a link to a short course :
http://www.if.uidaho.edu/~gunner/ME443-543/LectureNotes/ReactorPhysics.pdf

it's pretty decent explanation of the basics.

i'll refer to one just page in my attempted explanation below.

I too looked into pool criticality and mentor is right - you need to know basically how many atoms per cubic centimeter you have of fuel, water and poisons to predict criticality with accuracy. We don't have that.

There are people who earn their living doing that calculation and they could give you a convincing answer yea or nay if they had the info Mentor mentioned.. I will tell you why i did not pursue it any further.

The basic premise of a spent fuel pit is you build it so criticality is impossible. You do that by two different means:
1. Put so much space between fuel assemblies that a flying neutron stands a really good chance of missing a fuel atom on its way out of the neighborhood. If the chance of a neutron missing a fuel atom is more than 0.55 (page 12) then criticality is impossible. It doesn't take much distance.

2. Put poison in the pool so that a flying neutron stands a decent chance of hitting a poison atom instead of a fuel atom. That adds to the probability it'll miss a fuel atom. You can use closer geometry if you have poison.

Some places do both. In PWR's there's loads of boron in the pool water, and they've taken to adding boron to the construction materials for the racks to further assure safety in case the pool somehow gets diluted with unborated water.

BWR's don't use borated water like PWR's do so if they use poison it's either those Boraflex plastic inserts or boron bearing steel racks.

I emailed Arnie Gundersen over a month ago and asked him - since he said his company made the Fukushima racks how about telling us something about them - did he use boraflex or boron steel or simple geometry to assure legal requirement on subcriticality (Keff < 0.95 which is the requirement stateside) .
He never answered but just went on a mild rant in next video about prompt criticality which to me sounds like he's BS'ing. I now think he has alarmist leanings but that's just my opinion.

so my OPINION as an old guy who has drunk beer with real reactor engineers is this:
If you took all the stuff in the 3 spent fuel pool and ran it through your blender it would not go critical.
There should be old control rods and probably Boraflex in there too. The steel racks themselves are a mild poison and a great one if they're boron steel.
And there's not a lot of fuel in 3 either, the Japanese are ahead of USA on that note. To get the pool critical you'd have to get the boron out and still have water. And the seawater they added has the property chlorine(NaCl) is another mild poison.

That sort of cross checks with impression i took away from that underwater video. The rubble looked to me blown into pool from higher up and laying on top of fuel. Criticality should have emptied the pool and steam cleaned it.

That's my opinion. I hope a genuine reactor engineer chimes in for you."""if tepco would not have considered the possibility of criticality, why would they have added boron to the cooling water?""
If i were in their shoes I'd do it just to make sure.
If they have Boraflex plastic in the racks, when fuel got uncovered did it melt out the Boraflex? Borating would prevent criticality when you cover fuel with water again.

 

[TCups]

ROOF DAMAGE FLOOR PLAN OVERLAY, UNIT 3

Find attached my assessment of the state of the roof structure of unit 3, after the explosion.

Based on visual inspection of photos, each field in a 16x24 matrix covering the entire roof structure was assessed to one of five categories of damage, see legend. The method used gives the assessment a resolution of about 1.5 meter.

Fragments found on the roof of unit 3 were assessed, as were fragments of the roof structure locatable to the south and the east side of the building. Due to poor photo coverage and their inter-mixture with other debris fragments which ended to the north of the building could not be inspected. Those parts of the structure from the N end and from the SE corner which could not be inspected were assessed based on plausibility, judging from visually inspected close-by or bordering fields.

This, of course is MadderDoc's work combined with MiceAndMen's recent post attachment showing a pretty accurate floor plan. Interesting.

 

[rowmag]

Something else, could someone tell me what is the title of this parameter (Unit 1)

https://spreadsheets.google.com/spr...ZDbX39YK-iFb0Iw&hl=ja&authkey=CP6ewJkO#gid=41

FPC skimmer surge tank level (mm)

 

[etudiant]

ROOF DAMAGE FLOOR PLAN OVERLAY, UNIT 3



This, of course is MadderDoc's work combined with MiceAndMen's recent post attachment showing a pretty accurate floor plan. Interesting.

Thank you very much for this. It is by far the best visual summary yet of the current situation.

It would help if someone would reverse the image. The descriptions show as mirror writing currently.